37,038 results match your criteria Astronomy And Astrophysics Review[Journal]


A Lamin-Associated Chromatin Model for Chromosome Organization.

Biophys J 2020 May 20. Epub 2020 May 20.

Department of Physics, Indian Institute of Technology Bombay, Mumbai, India. Electronic address:

We propose a simple model for chromatin organization based on the interaction of the chromatin fibers with lamin proteins along the nuclear membrane. Lamin proteins are known to be a major factor that influences chromatin organization and hence gene expression in the cells. We provide a quantitative understanding of lamin-associated chromatin organization in a crowded macromolecular environment by systematically varying the heteropolymer segment distribution and the strength of the lamin-chromatin attractive interaction. Read More

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http://dx.doi.org/10.1016/j.bpj.2020.05.014DOI Listing

Whole-heart, ungated, free-breathing, cardiac-phase-resolved myocardial perfusion MRI by using Continuous Radial Interleaved simultaneous Multi-slice acquisitions at sPoiled steady-state (CRIMP).

Magn Reson Med 2020 Jun 3. Epub 2020 Jun 3.

Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA.

Purpose: To develop a whole-heart, free-breathing, non-electrocardiograph (ECG)-gated, cardiac-phase-resolved myocardial perfusion MRI framework (CRIMP; Continuous Radial Interleaved simultaneous Multi-slice acquisitions at sPoiled steady-state) and test its quantification feasibility.

Methods: CRIMP used interleaved radial simultaneous multi-slice (SMS) slice groups to cover the whole heart in 9 or 12 short-axis slices. The sequence continuously acquired data without magnetization preparation, ECG gating or breath-holding, and captured multiple cardiac phases. Read More

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http://dx.doi.org/10.1002/mrm.28337DOI Listing

Efficient growth and characterization of one-dimensional transition metal tellurides inside carbon nanotubes.

Nanoscale 2020 Jun 3. Epub 2020 Jun 3.

Department of Chemistry, Nagoya University, Nagoya 464-8602, Japan.

Atomically thin one-dimensional (1D) van der Waals wires of transition metal monochalocogenides (TMMs) have been anticipated as promising building blocks for integrated nanoelectronics. While reliable production of TMM nanowires has eluded scientists over the past few decades, we finally demonstrated a bottom-up fabrication of MoTe nanowires inside carbon nanotubes (CNTs). Still, the current synthesis method is based on vacuum annealing of reactive MoTe2, and limits access to a variety of TMMs. Read More

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http://dx.doi.org/10.1039/d0nr03129aDOI Listing

Hysteresis and criticality in hybrid percolation transitions.

Chaos 2020 May;30(5):051102

CCSS, CTP, and Department of Physics and Astronomy, Seoul National University, Seoul 08826, South Korea.

Phase transitions (PTs) are generally classified into second-order and first-order transitions, each exhibiting different intrinsic properties. For instance, a first-order transition exhibits latent heat and hysteresis when a control parameter is increased and then decreased across a transition point, whereas a second-order transition does not. Recently, hybrid percolation transitions (HPTs) are issued in diverse complex systems, in which the features of first-order and second-order PTs occur at the same transition point. Read More

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http://dx.doi.org/10.1063/5.0008189DOI Listing

Solitary phase waves in a chain of autonomous oscillators.

Chaos 2020 May;30(5):053119

Institute for Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam-Golm, Germany.

In the present paper, we study phase waves of self-sustained oscillators with a nearest-neighbor dispersive coupling on an infinite lattice. To analyze the underlying dynamics, we approximate the lattice with a quasi-continuum (QC). The resulting partial differential model is then further reduced to the Gardner equation, which predicts many properties of the underlying solitary structures. Read More

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http://dx.doi.org/10.1063/1.5144939DOI Listing

Entropy production and fluctuation theorems on complex networks.

Chaos 2020 May;30(5):053125

CCSS, CTP and Department of Physics and Astronomy, Seoul National University, Seoul 08826, South Korea.

Entropy production (EP) is a fundamental quantity useful for understanding irreversible process. In stochastic thermodynamics, EP is more evident in probability density functions of trajectories of a particle in the state space. Here, inspired by a previous result that complex networks can serve as state spaces, we consider a data packet transport problem on complex networks. Read More

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http://dx.doi.org/10.1063/1.5143031DOI Listing

Cut-off values to evaluate exercise-induced asthma in eucapnic voluntary hyperventilation test for children.

Clin Physiol Funct Imaging 2020 Jun 3. Epub 2020 Jun 3.

Department of Pediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland.

Backround And Aim: The eucapnic voluntary hyperventilation (EVH) testing is a diagnostic tool for diagnostics of exercise-induced bronchoconstriction; while the testing has become more common among children, data on the test's feasibility among children remains limited. Our aim was to investigate EVH testing feasibility among children, diagnostic testing cutoff values, and which factors affect testing outcomes.

Methods: We recruited 134 patients aged 10-16 years with a history of exercise-induced dyspnea and 100 healthy control children to undergo 6-minute EVH testing. Read More

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http://dx.doi.org/10.1111/cpf.12647DOI Listing

Elevated amyloidoses of human IAPP and amyloid beta by lipopolysaccharide and their mitigation by carbon quantum dots.

Nanoscale 2020 Jun 3. Epub 2020 Jun 3.

ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia. and Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, 200032, China.

Type 2 diabetes (T2D) and Alzheimer's disease (AD) represent two most prevalent amyloid diseases with a significant global burden. Pathologically, T2D and AD are characterized by the presence of amyloid plaques consisting primarily of toxic human islet amyloid polypeptide (IAPP) and amyloid beta (Aβ). It has been recently revealed that the gut microbiome plays key functions in the pathological progression of neurological disorders through the production of bacterial endotoxins, such as lipopolysaccharide (LPS). Read More

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http://dx.doi.org/10.1039/d0nr02710cDOI Listing

Application of Mitochondrially Targeted Nanoconstructs to Neoadjuvant X-ray-Induced Photodynamic Therapy for Rectal Cancer.

ACS Cent Sci 2020 May 24;6(5):715-726. Epub 2020 Apr 24.

ARC Centre of Excellence for Nanoscale Biophotonics, Graduate School of Biomedical Engineering, University of New South Wales, Kensington, New South Wales 2052, Australia.

In this work, we brought together two existing clinical techniques used in cancer treatment-X-ray radiation and photodynamic therapy (PDT), whose combination termed X-PDT uniquely allows PDT to be therapeutically effective in deep tissue. To this end, we developed mitochondrially targeted biodegradable polymer poly(lactic--glycolic acid) nanocarriers incorporating a photosensitizer verteporfin, ultrasmall (2-5 nm) gold nanoparticles as radiation enhancers, and triphenylphosphonium acting as the mitochondrial targeting moiety. The average size of the nanocarriers was about 160 nm. Read More

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http://dx.doi.org/10.1021/acscentsci.9b01121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7256935PMC

Quantifying Biophoton Emissions From Human Cells Directly Exposed to Low-Dose Gamma Radiation.

Dose Response 2020 Apr-Jun;18(2):1559325820926763. Epub 2020 May 19.

Department of Biology, McMaster University, Hamilton, Ontario, Canada.

Biophoton emission leading to bystander effects (BEs) was shown in beta-irradiated cells; however, technical challenges precluded the analysis of the biophoton role in gamma-induced BEs. The present work was to design an experimental approach to determine if, what type, and how many biophotons could be produced in gamma-irradiated cells. Photon emission was measured in HCT116 p53 cells irradiated with a total dose of 22 mGy from a cesium-137 source at a dose rate of 45 mGy/min. Read More

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http://dx.doi.org/10.1177/1559325820926763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238447PMC

Low-dose phase retrieval of biological specimens using cryo-electron ptychography.

Nat Commun 2020 Jun 2;11(1):2773. Epub 2020 Jun 2.

National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.

Cryo-electron microscopy is an essential tool for high-resolution structural studies of biological systems. This method relies on the use of phase contrast imaging at high defocus to improve information transfer at low spatial frequencies at the expense of higher spatial frequencies. Here we demonstrate that electron ptychography can recover the phase of the specimen with continuous information transfer across a wide range of the spatial frequency spectrum, with improved transfer at lower spatial frequencies, and as such is more efficient for phase recovery than conventional phase contrast imaging. Read More

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http://dx.doi.org/10.1038/s41467-020-16391-6DOI Listing

Characterizing distinct components of tactical aircraft noise sources.

J Acoust Soc Am 2020 May;147(5):3550

Blue Ridge Research and Consulting, LLC, Asheville, North Carolina 28801, USA.

Noise from a tactical aircraft can impact operations due to concerns regarding military personnel noise exposure and community annoyance and disturbance. The efficacy of mission planning can increase when the distinct, complex acoustic source mechanisms creating the noise are better understood. For each type of noise, equivalent acoustic source distributions are obtained from a tied-down F-35B operating at various engine conditions using the hybrid method for acoustic source imaging of Padois, Gauthier, and Berry [J. Read More

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http://dx.doi.org/10.1121/10.0001260DOI Listing

Seabed and range estimation of impulsive time series using a convolutional neural network.

J Acoust Soc Am 2020 May;147(5):EL403

University of Washington, Seattle, Washington 98195,

In ocean acoustics, many types of optimizations have been employed to locate acoustic sources and estimate the properties of the seabed. How these tasks can take advantage of recent advances in deep learning remains as open questions, especially due to the lack of labeled field data. In this work, a Convolutional Neural Network (CNN) is used to find seabed type and source range simultaneously from 1 s pressure time series from impulsive sounds. Read More

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http://dx.doi.org/10.1121/10.0001216DOI Listing

Characterizing plasma with emission tomography-Feasibility study on synthetic and experimental data.

Rev Sci Instrum 2020 May;91(5):053102

Department of Physics, Center for Accelerator Science, Old Dominion University, Norfolk, Virginia 23529, USA.

We present a feasibility study on different tomographic algorithms to overcome the issues of finite sets of projection data, limited viewing angles, and noisy data, which cause the tomographic reconstruction to be an ill-posed inversion problem. We investigated three approaches: single angle Abel inversion, two angle approach, and multiple angle 2D plasma tomography. These methods were tested on symmetric and asymmetric sample functions and on experimental results from a supersonic flowing argon microwave plasma sustained in a cylindrical quartz cavity. Read More

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http://dx.doi.org/10.1063/1.5138921DOI Listing

A cryogenic ice setup to simulate carbon atom reactions in interstellar ices.

Rev Sci Instrum 2020 May;91(5):054501

Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden, The Netherlands.

The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an existing ultrahigh vacuum setup, SURFace REaction SImulation DEvice (SURFRESIDE), which extends this double atom (H/D, O, and N) beamline apparatus with a third atom (C) beamline to a unique system that is fully suited to explore complex organic molecule solid-state formation under representative interstellar cloud conditions. The parameter space for this system is discussed, which includes the flux of the carbon atoms hitting the ice sample, their temperature, and the potential impact of temperature on ice reactions. Read More

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http://dx.doi.org/10.1063/5.0003692DOI Listing

Strong permanent magnet gradient deflector for Stern-Gerlach-type experiments on molecular beams.

Rev Sci Instrum 2020 May;91(5):053202

Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA.

We describe the design, assembly, and testing of a magnet intended to deflect beams of paramagnetic nanoclusters, molecules, and atoms. It is energized by high-grade permanent neodymium magnets. This offers a convenient option in terms of cost, portability, and scalability of the construction while providing field and gradient values (1. Read More

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http://dx.doi.org/10.1063/5.0007602DOI Listing

Design of microresonators to minimize thermal noise below the standard quantum limit.

Rev Sci Instrum 2020 May;91(5):054504

Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.

Microfabricated resonators play a crucial role in the development of quantum measurement, including future gravitational wave detectors. We use a micro-genetic algorithm and a finite element method to design a microresonator whose geometry is optimized to maximize the sub-Standard Quantum Limit (SQL) performance including lower thermal noise (TN) below the SQL, a broader sub-SQL region, and a sub-SQL region at lower frequencies. For the proposed design, we study the effects of different geometries of the mirror pad and cantilever microresonator on sub-SQL performance. Read More

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http://dx.doi.org/10.1063/1.5143484DOI Listing

Object surveillance with radio-frequency atomic magnetometers.

Rev Sci Instrum 2020 May;91(5):055002

National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom.

The capabilities of a radio-frequency atomic magnetometer for object detection based on magnetic induction tomography are explored. The determination of object orientation is demonstrated by utilizing the measurement geometry. The self-compensation configuration of the atomic magnetometer is implemented to address the issue of saturation of the sensor response by the radio-frequency primary field that generates the object signature. Read More

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http://dx.doi.org/10.1063/1.5145251DOI Listing

Nematic ordering of worm-like polymers near an interface.

J Chem Phys 2020 May;152(20):204907

Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

The phase behavior of semi-flexible polymers is integral to various contexts, from materials science to biophysics, many of which utilize or require specific confinement geometries as well as the orientational behavior of the polymers. Inspired by collagen assembly, we study the orientational ordering of semi-flexible polymers, modeled as Maier-Saupe worm-like chains, using self-consistent field theory. We first examine the bulk behavior of these polymers, locating the isotropic-nematic transition and delineating the limit of stability of the isotropic and nematic phases. Read More

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http://dx.doi.org/10.1063/1.5132928DOI Listing

The DIRAC code for relativistic molecular calculations.

J Chem Phys 2020 May;152(20):204104

Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, NL-1081HV Amsterdam, The Netherlands.

DIRAC is a freely distributed general-purpose program system for one-, two-, and four-component relativistic molecular calculations at the level of Hartree-Fock, Kohn-Sham (including range-separated theory), multiconfigurational self-consistent-field, multireference configuration interaction, electron propagator, and various flavors of coupled cluster theory. At the self-consistent-field level, a highly original scheme, based on quaternion algebra, is implemented for the treatment of both spatial and time reversal symmetry. DIRAC features a very general module for the calculation of molecular properties that to a large extent may be defined by the user and further analyzed through a powerful visualization module. Read More

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http://dx.doi.org/10.1063/5.0004844DOI Listing

Hierarchical machine learning of potential energy surfaces.

J Chem Phys 2020 May;152(20):204110

Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom.

We present hierarchical machine learning (hML) of highly accurate potential energy surfaces (PESs). Our scheme is based on adding predictions of multiple Δ-machine learning models trained on energies and energy corrections calculated with a hierarchy of quantum chemical methods. Our (semi-)automatic procedure determines the optimal training set size and composition of each constituent machine learning model, simultaneously minimizing the computational effort necessary to achieve the required accuracy of the hML PES. Read More

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http://dx.doi.org/10.1063/5.0006498DOI Listing

Effect of Ar Gas Pressure on LSPR Property of Au Nanoparticles: Comparison of Experimental and Theoretical Studies.

Nanomaterials (Basel) 2020 May 31;10(6). Epub 2020 May 31.

University of Angers, MOLTECH Anjou, CNRS UMR 6200, 2 Bd Lavoisier, F-49045 Angers, France.

In this study, the thin films were produced by using pulsed laser deposition (PLD) technique from gold (Au) nanoparticles deposited on two kinds of substrates under different argon (Ar) gas pressure. Microscope glass slides and silicon (100) wafers were used as amorphous and crystal substrates. The films were deposited under 2 × 10 mbar, 1 × 10 mbar, 2 × 10 mbar argon (Ar) ambient gas pressure. Read More

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http://dx.doi.org/10.3390/nano10061071DOI Listing

Series of Near-IR-Absorbing Transition Metal Complexes with Redox Active Ligands.

Molecules 2020 May 29;25(11). Epub 2020 May 29.

Inorganic Materials Chemistry research group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.

New soluble and intensely near-IR-absorbing transition metal (Ti, Zr, V, Ni) complexes were synthesized using a redox non-innocent ,'-bis(3,5-di-tertbutyl-2-hydroxy-phenyl) -1,2-phenylenediamine (HL) as a ligand precursor. In all the complexes, ([Ti(L), [Zr(L)], [V(L)(HL)] and [Ni(HL)], two organic molecules coordinate to the metal center as tri- or tetradentate ligands. The solid-state structures of the complexes were determined using single crystal XRD, and the compounds were further characterized with Electrospray Ionisation Mass Spectrometry (ESI-MS). Read More

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http://dx.doi.org/10.3390/molecules25112531DOI Listing

How to Get the Best from Low-Cost Particulate Matter Sensors: Guidelines and Practical Recommendations.

Sensors (Basel) 2020 May 29;20(11). Epub 2020 May 29.

Department of Chemistry "G. Ciamician", Alma Mater Studiorum University of Bologna, 40126 Bologna, Italy.

Low-cost sensors based on the optical particle counter (OPC) are increasingly being used to collect particulate matter (PM) data at high space and time resolution. In spite of their huge explorative potential, practical guidelines and recommendations for their use are still limited. In this work, we outline a few best practices for the optimal use of PM low-cost sensors based on the results of an intensive field campaign performed in Bologna (44°30' N, 11°21' E; Italy) under different weather conditions. Read More

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http://dx.doi.org/10.3390/s20113073DOI Listing

Imprint and transfer fabrication of freestanding plasmonic membranes.

Nanotechnology 2020 Jun 2. Epub 2020 Jun 2.

Electrical and Computer Engineering, Iowa State University, Ames, Iowa, UNITED STATES.

This paper reports an imprint and transfer approach for the rapid and inexpensive fabrication of the ultra-thin freestanding plasmonic membrane (FPM) that supports surface plasmon resonances. The imprint and transfer fabrication method involves the soft imprint lithography on an ultrathin polymer film, transfer of the perforated polymer film to a supporting frame, subsequent deposition of gold, and final removal of the polymer film. Without using any sophisticated lithography and etching processes, the imprint and transfer method can produce freestanding gold membranes with 2D arrays of submicrometer-sized holes that support plasmonic modes in the mid-wavelength infrared (mid-IR) range. Read More

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http://dx.doi.org/10.1088/1361-6528/ab98bfDOI Listing

γ9δ2T cell diversity and the receptor interface with tumor cells.

J Clin Invest 2020 Jun 2. Epub 2020 Jun 2.

Center for Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.

γ9δ2T cells play a major role in cancer immune surveillance, yet the clinical translation of their in vitro promise remains challenging. To address limitations of previous clinical attempts utilizing expanded γ9δ2T cells, we explored the clonal diversity of γ9δ2T cell repertoires and characterized their target. We demonstrated that only a fraction of expanded γ9δ2T cells is active against cancer cells, and that activity of the parental clone, or functional avidity of selected γ9δ2TCRs does not associate with clonal frequency. Read More

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http://dx.doi.org/10.1172/JCI132489DOI Listing

Performance of Human and Server Prediction in CAPRI rounds 38-45.

Proteins 2020 Jun 1. Epub 2020 Jun 1.

Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, 65211.

CAPRI challenges offer a variety of blind tests for protein-protein interaction prediction. In CAPRI Rounds 38-45, we generated a set of putative binding modes for each target with an FFT-based docking algorithm, and then scored and ranked these binding modes with a proprietary scoring function, ITScorePP. We have also developed a novel web server, Rebipp. Read More

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http://dx.doi.org/10.1002/prot.25956DOI Listing

Publisher Correction: Interlayer excitons: Moiré or not.

Nat Mater 2020 Jun 1. Epub 2020 Jun 1.

Department of Physics and Astronomy, University of Sheffield, Sheffield, UK.

An amendment to this paper has been published and can be accessed via a link at the top of the paper. Read More

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http://dx.doi.org/10.1038/s41563-020-0718-4DOI Listing

Counterintuitive effects of isotopic doping on the phase diagram of H-HD-D molecular alloy.

Proc Natl Acad Sci U S A 2020 Jun 1. Epub 2020 Jun 1.

Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China;

Molecular hydrogen forms the archetypical quantum solid. Its quantum nature is revealed by behavior which is classically impossible and by very strong isotope effects. Isotope effects between [Formula: see text], [Formula: see text], and HD molecules come from mass difference and the different quantum exchange effects: fermionic [Formula: see text] molecules have antisymmetric wavefunctions, while bosonic [Formula: see text] molecules have symmetric wavefunctions, and HD molecules have no exchange symmetry. Read More

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http://dx.doi.org/10.1073/pnas.2001128117DOI Listing

The Interaction of Hydrogen with the van der Waals Crystal -InSe.

Molecules 2020 May 28;25(11). Epub 2020 May 28.

School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.

The emergence of the hydrogen economy requires development in the storage, generation and sensing of hydrogen. The indium selenide ( γ -InSe) van der Waals (vdW) crystal shows promise for technologies in all three of these areas. For these applications to be realised, the fundamental interactions of InSe with hydrogen must be understood. Read More

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http://dx.doi.org/10.3390/molecules25112526DOI Listing

Recent Progress on Extended Wavelength and Split-Off Band Heterostructure Infrared Detectors.

Micromachines (Basel) 2020 May 28;11(6). Epub 2020 May 28.

Center for Nano-Optics (CeNo), Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30033, USA.

The use of multilayer semiconductor heterojunction structures has shown promise in infrared detector applications. Several heterostructures with innovative compositional and architectural designs have been displayed on emerging infrared technologies. In this review, we aim to illustrate the principles of heterostructure detectors for infrared detection and explore the recent progress on the development of detectors with the split-off band and threshold wavelength extension mechanism. Read More

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http://dx.doi.org/10.3390/mi11060547DOI Listing

Ferromagnetic CoSe Broadband Photodetector at Room Temperature.

Nanotechnology 2020 Jun 1. Epub 2020 Jun 1.

Department of Electrical Engineering, Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, CHINA.

Broadband infrared photodetectors based on two-dimensional (2D) materials which are the research focus in the infrared field, have wide applications in remote sensing, thermal imaging, and astronomy observation. In this article, the photodetector based on 2D ferromagnetic material CoSe is studied at room temperature, demonstrating the air-stable, broadband, and up to long wavelength properties. The CoSe material is applied to infrared photodetectors for the first time. Read More

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http://dx.doi.org/10.1088/1361-6528/ab9867DOI Listing

Purification and Structural Characterization of Aggregation-Prone Human TDP-43 Involved in Neurodegenerative Diseases.

iScience 2020 May 15;23(6):101159. Epub 2020 May 15.

Molecular Biophysics Group, Department of Biochemistry & Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, Liverpool L69 7ZB, UK. Electronic address:

Mislocalization, cleavage, and aggregation of the human protein TDP-43 is found in many neurodegenerative diseases. As is the case with many other proteins that are completely or partially structurally disordered, production of full-length recombinant TDP-43 in the quantities necessary for structural characterization has proved difficult. We show that the full-length TDP-43 protein and two truncated N-terminal constructs 1-270 and 1-263 can be heterologously expressed in E. Read More

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http://dx.doi.org/10.1016/j.isci.2020.101159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7262455PMC

Multi-Channel Whole-Head OPM-MEG: Helmet Design and a Comparison with a Conventional System.

Neuroimage 2020 May 29:116995. Epub 2020 May 29.

Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.

Magnetoencephalography (MEG) is a powerful technique for functional neuroimaging, offering a non-invasive window on brain electrophysiology. MEG systems have traditionally been based on cryogenic sensors which detect the small extracranial magnetic fields generated by synchronised current in neuronal assemblies, however, such systems have fundamental limitations. In recent years, non-cryogenic quantum-enabled sensors, called optically-pumped magnetometers (OPMs), in combination with novel techniques for accurate background magnetic field control, have promised to lift those restrictions offering an adaptable, motion-robust MEG system, with improved data quality, at reduced cost. Read More

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http://dx.doi.org/10.1016/j.neuroimage.2020.116995DOI Listing

Phase Diagram and Structure Map of Binary Nanoparticle Superlattices from a Lennard-Jones Model.

ACS Nano 2020 Jun 3. Epub 2020 Jun 3.

Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States.

A first-principles prediction of the binary nanoparticle phase diagram assembled by solvent evaporation has eluded theoretical approaches. In this paper, we show that a binary system interacting through the Lennard-Jones (LJ) potential contains all experimental phases in which nanoparticles are effectively described as quasi hard spheres. We report a phase diagram consisting of 53 equilibrium phases, whose stability is quite insensitive to the microscopic details of the potentials, thus giving rise to some type of universality. Read More

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http://dx.doi.org/10.1021/acsnano.0c00250DOI Listing

Introductory lecture: origins and applications of efficient visible photoluminescence from silicon-based nanostructures.

Authors:
Leigh Canham

Faraday Discuss 2020 Jun 1. Epub 2020 Jun 1.

School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

A variety of silicon-based nanostructures with dimensions in the 1-5 nm range now emit tunable photoluminescence (PL) spanning the visible range. Achievement of high photoluminescence quantum efficiency (PLQY) relies critically on their surface chemistry passivation and an impressive "tool box" of options have been developed. Two distinct PL bands are dominant. Read More

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http://dx.doi.org/10.1039/d0fd00018cDOI Listing

Immune Response After Cochlear Implantation.

Front Neurol 2020 14;11:341. Epub 2020 May 14.

Bioacoustics Research Laboratory, Department of Neurosciences, University of Padua, Padua, Italy.

A cochlear implant (CI) is an electronic device that enables hearing recovery in patients with severe to profound hearing loss. Although CIs are a successful treatment for profound hearing impairment, their effectivity may be improved by reducing damages associated with insertion of electrodes in the cochlea, thus preserving residual hearing ability. Inner ear trauma leads to inflammatory reactions altering cochlear homeostasis and reducing post-operative audiological performances and electroacoustic stimulation. Read More

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http://dx.doi.org/10.3389/fneur.2020.00341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240074PMC

X-ray nano-tomography of complete scales from the ultra-white beetles Lepidiota stigma and Cyphochilus.

Sci Data 2020 May 29;7(1):163. Epub 2020 May 29.

Department of Mechanical Engineering, The University of Sheffield, Sheffield, S3 7HQ, UK.

High resolution X-ray nano-tomography experiments are often limited to a few tens of micrometer size volumes due to detector size. It is possible, through the use of multiple overlapping tomography scans, to produce a large area scan which can encompass a sample in its entirety. Mounting and positioning regions to be scanned is highly challenging and normally requires focused ion beam approaches. Read More

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http://dx.doi.org/10.1038/s41597-020-0502-yDOI Listing

First-passage times and normal tissue complication probabilities in the limit of large populations.

Sci Rep 2020 May 29;10(1):8786. Epub 2020 May 29.

Theoretical Physics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, United Kingdom.

The time of a stochastic process first passing through a boundary is important to many diverse applications. However, we can rarely compute the analytical distribution of these first-passage times. We develop an approximation to the first and second moments of a general first-passage time problem in the limit of large, but finite, populations using Kramers-Moyal expansion techniques. Read More

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http://dx.doi.org/10.1038/s41598-020-64618-9DOI Listing

MR-guided proton therapy: a review and a preview.

Radiat Oncol 2020 May 29;15(1):129. Epub 2020 May 29.

Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching, Germany.

Background: The targeting accuracy of proton therapy (PT) for moving soft-tissue tumours is expected to greatly improve by real-time magnetic resonance imaging (MRI) guidance. The integration of MRI and PT at the treatment isocenter would offer the opportunity of combining the unparalleled soft-tissue contrast and real-time imaging capabilities of MRI with the most conformal dose distribution and best dose steering capability provided by modern PT. However, hybrid systems for MR-integrated PT (MRiPT) have not been realized so far due to a number of hitherto open technological challenges. Read More

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http://dx.doi.org/10.1186/s13014-020-01571-xDOI Listing

Phenotypic delay in the evolution of bacterial antibiotic resistance: Mechanistic models and their implications.

PLoS Comput Biol 2020 May 29;16(5):e1007930. Epub 2020 May 29.

School of Physics and Astronomy, The University of Edinburgh, Edinburgh, United Kingdom.

Phenotypic delay-the time delay between genetic mutation and expression of the corresponding phenotype-is generally neglected in evolutionary models, yet recent work suggests that it may be more common than previously assumed. Here, we use computer simulations and theory to investigate the significance of phenotypic delay for the evolution of bacterial resistance to antibiotics. We consider three mechanisms which could potentially cause phenotypic delay: effective polyploidy, dilution of antibiotic-sensitive molecules and accumulation of resistance-enhancing molecules. Read More

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http://dx.doi.org/10.1371/journal.pcbi.1007930DOI Listing

Sediment metal enrichment and ecological risk assessment of ten ports and estuaries in the World Harbours Project.

Mar Pollut Bull 2020 Jun 12;155:111129. Epub 2020 May 12.

Sydney Institute of Marine Science, Mosman, NSW, Australia.

Ten global harbours were assessed for sediment quality by quantifying the magnitude of anthropogenic change and ecological risk. Anthropogenic change (enrichment) was high for Derwent River and Sydney estuary, moderate for Santander Harbour, Rio de Janeiro and Dublin Port, slight for Hong Kong, minimal for Darwin. All 10 enrichment indices used showed similar results. Read More

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http://dx.doi.org/10.1016/j.marpolbul.2020.111129DOI Listing

Double-Scaling Limit in the Principal Chiral Model: A New Noncritical String?

Phys Rev Lett 2020 May;124(19):191602

Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden, Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, 2100 Copenhagen, Denmark, and Hamilton Mathematics Institute, Trinity College Dublin, Dublin 2, Ireland.

We initiate a systematic, non-perturbative study of the large-N expansion in the two-dimensional SU(N)×SU(N) principal Chiral model (PCM). Starting with the known infinite-N solution for the ground state at fixed chemical potential, we devise an iterative procedure to solve the Bethe ansatz equations order by order in 1/N. The first few orders, which we explicitly compute, reveal a systematic enhancement pattern at strong coupling calling for the near-threshold resummation of the large-N expansion. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.191602DOI Listing

Coupling Rydberg Atoms to Microwave Fields in a Superconducting Coplanar Waveguide Resonator.

Phys Rev Lett 2020 May;124(19):193604

Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.

Rydberg helium atoms traveling in pulsed supersonic beams have been coupled to microwave fields in a superconducting coplanar waveguide (CPW) resonator. The atoms were initially prepared in the 1s55s ^{3}S_{1} Rydberg level by two-color two-photon laser excitation from the metastable 1s2s ^{3}S_{1} level. Two-photon microwave transitions between the 1s55s ^{3}S_{1} and 1s56s ^{3}S_{1} levels were then driven by the 19. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.193604DOI Listing

Doing Spin Physics with Unpolarized Particles.

Phys Rev Lett 2020 May;124(19):192001

School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082, China.

Twisted, or vortex, particles refer to freely propagating non-plane-wave states with helicoidal wave fronts. In this state, the particle possesses a nonzero orbital angular momentum with respect to its average propagation direction. Twisted photons and electrons have been experimentally demonstrated, and creation of other particles in twisted states can be anticipated. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.192001DOI Listing

Nonequilibrium Strategy for Fast Target Search on the Genome.

Phys Rev Lett 2020 May;124(19):198101

SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.

Vital biological processes such as genome repair require fast and efficient binding of selected proteins to specific target sites on DNA. Here we propose an active target search mechanism based on "chromophoresis," the dynamics of DNA-binding proteins up or down gradients in the density of epigenetic marks, or colors (biochemical tags on the genome). We focus on a set of proteins that deposit marks from which they are repelled-a case which is only encountered away from thermodynamic equilibrium. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.198101DOI Listing

Multipath Optical Recombination of Intervalley Dark Excitons and Trions in Monolayer WSe_{2}.

Phys Rev Lett 2020 May;124(19):196802

Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.

Excitons and trions (or exciton polarons) in transition metal dichalcogenides (TMDs) are known to decay predominantly through intravalley transitions. Electron-hole recombination across different valleys can also play a significant role in the excitonic dynamics, but intervalley transitions are rarely observed in monolayer TMDs, because they violate the conservation of momentum. Here we reveal the intervalley recombination of dark excitons and trions through more than one path in monolayer WSe_{2}. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.196802DOI Listing

Geometric Induction in Chiral Superconductors.

Phys Rev Lett 2020 May;124(19):197001

Department of Physics, Stockholm University, Stockholm SE-106 91, Sweden.

We consider a number of effects due to the interplay of superconductivity, electromagnetism, and elasticity, which are unique for thin membranes of layered chiral superconductors. Some of them should be within the reach of present technology, and could be useful for characterizing materials. More speculatively, the enriched control of Josephson junctions they afford might find useful applications. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.197001DOI Listing

Raman Response in the Nematic Phase of FeSe.

Phys Rev Lett 2020 May;124(19):197602

School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.

Raman experiments on bulk FeSe revealed that the low-frequency part of the B_{1g} Raman response R_{B1g}(Ω), which probes nematic fluctuations, rapidly decreases below the nematic transition at T_{n}∼85  K. Such behavior is expected when a gap opens up and at a first glance is inconsistent with the fact that FeSe remains a metal below T_{n}. We argue that the drop of R_{B1g}(Ω) can be ascribed to the fact that the nematic order drastically changes the orbital content of low-energy excitations near hole and electron pockets, making them nearly mono-orbital. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.197602DOI Listing

Twin-Airy Point-Spread Function for Extended-Volume Particle Localization.

Phys Rev Lett 2020 May;124(19):198104

School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom.

The localization of point sources in optical microscopy enables nm-precision imaging of single-molecules and biological dynamics. We report a new method of localization microscopy using twin Airy beams that yields precise 3D localization with the key advantages of extended depth range, higher optical throughput, and potential for imaging higher emitter densities than are possible using other techniques. A precision of better than 30 nm was achieved over a depth range in excess of 7  μm using a 60×, 1. Read More

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http://dx.doi.org/10.1103/PhysRevLett.124.198104DOI Listing