60,027 results match your criteria physics large

Enhanced singlet oxygen production over a photocatalytic stable metal organic framework composed of porphyrin and Ag.

J Colloid Interface Sci 2021 May 18;602:300-306. Epub 2021 May 18.

State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, PR China. Electronic address:

Porphyrin is an important photosensitizer for singlet oxygen (O) formation. However, porphyrin derivatives still display low efficiency and difficult recovery. In this work, an Ag-based MOFs (AgTPyP; TPyP, 5,10,15,20-tetra(4-pyridyl) porphyrin) is synthesized. Read More

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A CLK1-KKT2 Signaling Pathway Regulating Kinetochore Assembly in Trypanosoma brucei.

mBio 2021 Jun 15:e0068721. Epub 2021 Jun 15.

York Biomedical Research Institute, Department of Biology, University of York, Heslington, United Kingdom.

During mitosis, eukaryotic cells must duplicate and separate their chromosomes in a precise and timely manner. The apparatus responsible for this is the kinetochore, which is a large protein structure that links chromosomal DNA and spindle microtubules to facilitate chromosome alignment and segregation. The proteins that comprise the kinetochore in the protozoan parasite Trypanosoma brucei are divergent from yeast and mammals and comprise an inner kinetochore complex composed of 24 distinct proteins (KKT1 to KKT23, KKT25) that include four protein kinases, CLK1 (KKT10), CLK2 (KKT19), KKT2, and KKT3. Read More

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Negative Magnetoresistance in the GeSn Strip.

ACS Appl Mater Interfaces 2021 Jun 15. Epub 2021 Jun 15.

State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China.

Discovery of topological materials associated with an exotic phenomenon has attracted increasing attention in modern condensed matter physics. A typical example is the chiral anomaly proposed in the Dirac or Weyl semimetals. In addition to the well-known topological semimetals, such as TaAs and NaBi, recently, group IV GeSn alloys were also proposed to be Dirac semimetals in theory, demonstrating potential applications compatible with current Si-based technology. Read More

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Climate variability of the East Asian winter monsoon and associated extratropical-tropical interaction: a review.

Ann N Y Acad Sci 2021 Jun 14. Epub 2021 Jun 14.

Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.

The East Asian winter monsoon (EAWM) is one of the most important climate systems during boreal winter. It has a large meridional extent and provides a vital bridge between the mid-to-high latitudes and the tropics. This paper reviews the latest research on the climate variability of the EAWM, with particular emphasis on the associated processes of extratropical-tropical interaction. Read More

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Parametric excitation of wrinkles in elastic sheets on elastic and viscoelastic substrates.

Haim Diamant

Eur Phys J E Soft Matter 2021 Jun 14;44(6):78. Epub 2021 Jun 14.

School of Chemistry, Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, 6997801, Israel.

Thin elastic sheets supported on compliant media form wrinkles under lateral compression. Since the lateral pressure is coupled to the sheet's deformation, varying it periodically in time creates a parametric excitation. We study the resulting parametric resonance of wrinkling modes in sheets supported on semi-infinite elastic or viscoelastic media, at pressures smaller than the critical pressure of static wrinkling. Read More

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Pressure-induced changes on the morphology and gene expression in mammalian cells.

Biol Open 2021 Jun 15. Epub 2021 Jun 15.

RIKEN Center for Biosystems Dynamics Research, Laboratory for Comprehensive Bioimaging, Kobe, Hyogo 650-0047, Japan.

We evaluated the effect of high hydrostatic pressure on mouse embryonic fibroblasts (MEFs) and mouse embryonic stem (ES) cells. Hydrostatic pressures of 15, 30, 60, and 90 MPa were applied for 10 minutes, and changes in gene expression were evaluated. Among genes related to mechanical stimuli, death-associated protein 3 was upregulated in MEF subjected to 90 MPa pressure, however, other genes known to be upregulated by mechanical stimuli did not change significantly. Read More

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Insights from modeling into structure, entanglements, and dynamics in attractive polymer nanocomposites.

Soft Matter 2021 Jun 15. Epub 2021 Jun 15.

Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.

Conformations, entanglements and dynamics in attractive polymer nanocomposites are investigated in this work by means of coarse-grained molecular dynamics simulation, for both weak and strong confinements, in the presence of nanoparticles (NPs) at NP volume fractions φ up to 60%. We show that the behavior of the apparent tube diameter dapp in such nanocomposites can be greatly different from nanocomposites with nonattractive interactions. We find that this effect originates, based on a mean field argument, from the geometric confinement length dgeo at strong confinement (large φ) and not from the bound polymer layer on NPs (interparticle distance ID <2Rg) as proposed recently based on experimental measurements. Read More

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Metastable states in plateaus and multi-wave epidemic dynamics of Covid-19 spreading in Italy.

Sci Rep 2021 06 14;11(1):12412. Epub 2021 Jun 14.

Institute of Crystallography, Consiglio Nazionale delle Ricerche CNR, via Salaria Km 29.300, Monterotondo, 00015, Rome, Italy.

The control of Covid 19 epidemics by public health policy in Italy during the first and the second epidemic waves has been driven by using reproductive number R(t) to identify the supercritical (percolative), the subcritical (arrested), separated by the critical regime. Here we show that to quantify the Covid-19 spreading rate with containment measures there is a need of a 3D expanded parameter space phase diagram built by the combination of R(t) and doubling time T(t). In this space we identify the Covid-19 dynamics in Italy and its administrative Regions. Read More

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Light from a firefly at temperatures considerably higher and lower than normal.

Sci Rep 2021 Jun 14;11(1):12498. Epub 2021 Jun 14.

Department of Physics, Gauhati University, Guwahati, 781014, India.

Bioluminescence emissions from a few species of fireflies have been studied at different temperatures. Variations in the flash-duration have been observed and interesting conclusions drawn in those studies. Here we investigate steady-state and pulsed emissions from male specimens of the Indian species Sclerotia substriata at temperatures considerably higher and lower than the ones at which they normally flash. Read More

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Lattice quantum electrodynamics in (3+1)-dimensions at finite density with tensor networks.

Nat Commun 2021 Jun 14;12(1):3600. Epub 2021 Jun 14.

Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Padova, Italy.

Gauge theories are of paramount importance in our understanding of fundamental constituents of matter and their interactions. However, the complete characterization of their phase diagrams and the full understanding of non-perturbative effects are still debated, especially at finite charge density, mostly due to the sign-problem affecting Monte Carlo numerical simulations. Here, we report the Tensor Network simulation of a three dimensional lattice gauge theory in the Hamiltonian formulation including dynamical matter: Using this sign-problem-free method, we simulate the ground states of a compact Quantum Electrodynamics at zero and finite charge densities, and address fundamental questions such as the characterization of collective phases of the model, the presence of a confining phase at large gauge coupling, and the study of charge-screening effects. Read More

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Source sector and fuel contributions to ambient PM and attributable mortality across multiple spatial scales.

Nat Commun 2021 06 14;12(1):3594. Epub 2021 Jun 14.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

Ambient fine particulate matter (PM) is the world's leading environmental health risk factor. Reducing the PM disease burden requires specific strategies that target dominant sources across multiple spatial scales. We provide a contemporary and comprehensive evaluation of sector- and fuel-specific contributions to this disease burden across 21 regions, 204 countries, and 200 sub-national areas by integrating 24 global atmospheric chemistry-transport model sensitivity simulations, high-resolution satellite-derived PM exposure estimates, and disease-specific concentration response relationships. Read More

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Zirconium metal-organic frameworks incorporating tetrathiafulvalene linkers: robust and redox-active matrices for confinement of metal nanoparticles.

Chem Sci 2020 Jan 9;11(7):1918-1925. Epub 2020 Jan 9.

Department of Chemistry College Station TX 77843 USA

Redox-active metal-organic frameworks (MOFs), with highly ordered porous structures and redox tunability, have attracted research interest in the fields of catalysis, energy storage, and electrochemical sensing. However, the chemical lability has limited the application scope of many redox-active MOFs. Herein, we selected stable Zr inorganic nodes and redox-active tetrathiafulvalene (TTF)-based linkers to construct two robust, redox-active MOFs, namely compounds ([Zr(TTFTB)O(OH)]) and ([Zr(Me-TTFTB)O(OH)(CHCOO)]) (TTFTB = tetrathiafulvalene tetrabenzoate; Me-TTFTB = tetrathiafulvalene tetramethylbenzoate). Read More

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January 2020

IrInS, a polar, metal-rich semiconducting subchalcogenide.

Chem Sci 2019 Dec 10;11(3):870-878. Epub 2019 Dec 10.

Department of Chemistry, Northwestern University Evanston Illinois 60208 USA

Subchalcogenides are uncommon, and their chemical bonding results from an interplay between metal-metal and metal-chalcogenide interactions. Herein, we present IrInS, a novel semiconducting subchalcogenide compound that crystallizes in a new structure type in the polar 31 space group, with unit cell parameters = 13.9378(12) Å, = 8. Read More

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December 2019

CsAlBOF: a beryllium-free deep-ultraviolet nonlinear optical material with enhanced thermal stability.

Chem Sci 2019 Nov 5;11(3):694-698. Epub 2019 Nov 5.

CAS Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics & Chemistry, CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices 40-1 South Beijing Road Urumqi 830011 China

The design of new beryllium-free deep-ultraviolet nonlinear optical materials is important but challenging. Here, we describe a new strategy to search for such materials based on rational selection of fundamental structural units. By combining asymmetric AlOF tetrahedra and π-conjugated BO rings, a new aluminum borate fluoride, CsAlBOF was obtained. Read More

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November 2019

An unsupervised multi-scale framework with attention-based network (MANet) for lung 4D-CT registration.

Phys Med Biol 2021 Jun 14. Epub 2021 Jun 14.

Shandong Provincial Third Hospital, Jinan, Shandong, CHINA.

Deformable image registration (DIR) of 4D-CT is very important in many radiotherapeutic applications including tumor target definition, image fusion, dose accumulation and response evaluation. It is a challenging task to performing accurate and fast DIR of lung 4D-CT images due to its large and complicated deformations. In this study, we propose an unsupervised multi-scale DIR framework with attention-based network (MANet). Read More

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A numerical study of the statistics of roughness parameters for fluctuating interfaces.

J Phys Condens Matter 2021 Jun 14. Epub 2021 Jun 14.

Physics of complex systems (PCSL), Ecole Polytechnique Federale de Lausanne, Route Cantonale, Lausanne, VD, 1015, SWITZERLAND.

Self-affine rough interfaces are ubiquitous in experimental systems, and display characteristic scaling properties as a signature of the nature of disorder in their supporting medium, i.e. of the statistical features of its heterogeneities. Read More

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Effect of matrix heterogeneity on cell mechanosensing.

Soft Matter 2021 Jun 14. Epub 2021 Jun 14.

Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, USA. and University of Wisconsin Carbone Cancer Center, Madison, WI, USA.

Cells sense mechanical signals within the extracellular matrix, the most familiar being stiffness, but matrix stiffness cannot be simply described by a single value. Randomness in matrix structure causes stiffness at the scale of a cell to vary by more than an order of magnitude. Additionally, the extracellular matrix contains ducts, blood vessels, and, in cancer or fibrosis, regions with abnormally high stiffness. Read More

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Classifying ABCA4 mutation severity using age-dependent ultra-widefield fundus autofluorescence-derived total lesion size.

Retina 2021 Jun 4. Epub 2021 Jun 4.

Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia.

Purpose: To establish a mutation-specific age-dependent ultra-widefield fundus autofluorescence (UWF-FAF) trajectory in a large Stargardt disease (STGD1) cohort using total lesion size (TLS) and to develop a clinical method for variant classification.

Methods: A retrospective study of patients with biallelic ABCA4 mutations were evaluated with UWF-FAF. Boundaries of TLS, defined by stippled hyper/hypoautofluorescence, were outlined manually. Read More

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Sensation and Perception of a Bioinspired Flexible Smart Sensor System.

ACS Nano 2021 Jun 14. Epub 2021 Jun 14.

Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics and Center for Carbon-Based Electronics, Peking University, Beijing 100871, China.

The somatosensory system helps the human body to become aware of various stimuli and to interact with its surroundings. Humans are able to identify and to process abundant sensory information quickly due to their unique perception characteristics. As the largest sensory organ, skin has a large number of discrete receptors to sense and to transform stimuli of touch, pressure, pain, temperature, . Read More

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Revealing the signaling regulation of hydrogen peroxide to cell pyroptosis using a ratiometric fluorescent probe in living cells.

Chem Commun (Camb) 2021 Jun 14. Epub 2021 Jun 14.

Information Materials and Intelligent Sensing Laboratory of Anhui Province, School of Chemistry and Chemical Engineering and Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China. and Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei, Anhui 230601, China.

A ratiometric fluorescent probe with a large emission shift was developed for the accurate measurement of hydrogen peroxide (H2O2) in sophisticated pyroptosis signaling pathways. The results reported here demonstrate that H2O2, as a principal member of ROS, is a critical upstream signaling molecule in regulating pyroptosis. Read More

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Systemic inequalities in indoor air pollution exposure in London, UK.

Build Cities 2021 7;2(1):425-448. Epub 2021 May 7.

Environmental Hazards and Emergencies Department, Public Health England, UK.

Deprived communities in many cities are exposed to higher levels of outdoor air pollution, and there is increasing evidence of similar disparities for indoor air pollution exposure. There is a need to understand the drivers for this exposure disparity in order to develop effective interventions aimed at improving population health and reducing health inequities. With a focus on London, UK, this paper assembles evidence to examine why indoor exposure to PM, NO and CO may disproportionately impact low-income groups. Read More

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Prediction and Classification of Formation Energies of Binary Compounds by Machine Learning: An Approach without Crystal Structure Information.

ACS Omega 2021 Jun 26;6(22):14533-14541. Epub 2021 May 26.

Department of Physics & Guangdong Provincial Key Laboratory of Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, China.

It is well believed that machine learning models could help to predict the formation energies of materials if all elemental and crystal structural details are known. In this paper, it is shown that even without detailed crystal structure information, the formation energies of binary compounds in various prototypes at the ground states can be reasonably evaluated using machine-learning feature abstraction to screen out the important features. By combining with the "white-box" sure independence screening and sparsifying operator (SISSO) approach, an interpretable and accurate formation energy model is constructed. Read More

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Filtrates with Hydroxyl Radicals Prepared using Al + Acid + HO for Removing Organic Pollutants.

ACS Omega 2021 Jun 26;6(22):14182-14190. Epub 2021 May 26.

Energy Materials & Physics Group, Department of Physics, Shanghai University, Shanghai 200444, China.

In this work, for the first time, high-activity filtrates were prepared by the reaction of aluminum (Al) powder with hydrogen peroxide (HO) in acidic solution and then filtration, which were used to degrade various organic pollutants such as phenol, methyl orange, and bisphenol A. It was found that the filtrates can effectively degrade and mineralize various organic pollutants and have a high efficiency comparable to their parent Al + acid + HO suspensions. The filtrates can keep their high activity for several weeks under ambient conditions, and the activity depends on their initial pH value. Read More

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Conquering the Tyranny of Number With Digital Microfluidics.

Front Chem 2021 26;9:676365. Epub 2021 May 26.

Department of Computer Science, National Tsing Hua University, Hsinchu, Taiwan.

The development of large-scale integration based on soft lithography has ushered a new revolution in microfluidics. This technology, however, relies inherently on pneumatic control of micromechanical valves that require air pressure to operate, while digital microfluidics uses a purely electrical signal on an electrode for droplet manipulation. In this article, we discuss the prospect and current challenges of digital microfluidics to solve the problem of the tyranny of numbers in arbitrary fluidic manipulation. Read More

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Attenuation coefficient estimation in Fourier-domain OCT of multi-layered phantoms.

Biomed Opt Express 2021 May 15;12(5):2744-2758. Epub 2021 Apr 15.

Department of Imaging Physics, Delft University of Technology, 2628 CJ, Delft, The Netherlands.

Optical properties, such as the attenuation coefficients of multi-layer tissue samples, could be used as a biomarker for diagnosis and disease progression in clinical practice. In this paper, we present a method to estimate the attenuation coefficients in a multi-layer sample by fitting a single scattering model for the OCT signal to the recorded OCT signal. In addition, we employ numerical simulations to obtain the theoretically achievable precision and accuracy of the estimated parameters under various experimental conditions. Read More

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Single-ion magnetism in the extended solid-state: insights from X-ray absorption and emission spectroscopy.

Chem Sci 2020 Oct 7;11(43):11801-11810. Epub 2020 Oct 7.

The University of Manchester at Harwell, Diamond Light Source Harwell Campus OX11 0DE UK

Large single-ion magnetic anisotropy is observed in lithium nitride doped with iron. The iron sites are two-coordinate, putting iron doped lithium nitride amongst a growing number of two coordinate transition metal single-ion magnets (SIMs). Uniquely, the relaxation times to magnetisation reversal are over two orders of magnitude longer in iron doped lithium nitride than other 3d-metal SIMs, and comparable with high-performance lanthanide-based SIMs. Read More

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October 2020

A neutron scattering perspective on the structure, softness and dynamics of the ligand shell of PbS nanocrystals in solution.

Chem Sci 2020 Aug 3;11(33):8875-8884. Epub 2020 Aug 3.

Institute of Physical and Theoretical Chemistry, University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany

Small-angle neutron and X-ray scattering, neutron backscattering and neutron time-of-flight spectroscopy are applied to reveal the structure of the ligand shell, the temperature-dependent diffusion properties and the phonon spectrum of PbS nanocrystals functionalized with oleic acid in deuterated hexane. The nanocrystals decorated with oleic acid as well as the desorbed ligand molecules exhibit simple Brownian diffusion with a Stokes-Einstein temperature-dependence and inhibited freezing. Ligand molecules desorbed from the surface show strong spatial confinement. Read More

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K-edge X-ray absorption spectroscopy of the ligand environment of single-site Au/C catalysts during acetylene hydrochlorination.

Chem Sci 2020 Jun 24;11(27):7040-7052. Epub 2020 Jun 24.

Cardiff Catalysis Institute, School of Chemistry, Cardiff University Main Building, Park Place Cardiff CF10 3AT UK

The replacement of HgCl/C with Au/C as a catalyst for acetylene hydrochlorination represents a significant reduction in the environmental impact of this industrial process. Under reaction conditions atomically dispersed cationic Au species are the catalytic active site, representing a large-scale application of heterogeneous single-site catalysts. While the metal nuclearity and oxidation state under operating conditions has been investigated in catalysts prepared from and thiosulphate, limited studies have focused on the ligand environment surrounding the metal centre. Read More

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UV/Vis photochemistry database: Structure, content and applications.

J Quant Spectrosc Radiat Transf 2020 Sep;253

Chemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom.

The "science-softCon UV/Vis Photochemistry Database" (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV-Vis-NIR spectral data and other photochemical information assembled from published peer-reviewed papers. Read More

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September 2020

Third-Order Nonlinear Optical Behavior of an Amide-Tricarboxylate Zinc(II) Metal-Organic Framework with Two-Fold 3D+3D Interpenetration.

Inorg Chem 2021 Jun 13. Epub 2021 Jun 13.

EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, U.K.

A new metal-organic framework (MOF), [Zn(μ-O)(μ-L)(HO)]·DMF (ZSTU-10), was assembled from zinc(II) nitrate and ,',″-bis(4-carboxylate)trimesicamide linkers and fully characterized. Its crystal structure discloses an intricate two-fold 3D+3D interpenetrated MOF driven by the [Zn(μ-O)]-based tetragonal secondary building units and the C3-symmetric tris-amide-tricarboxylate linkers (μ-L). Topological analysis of ZSTU-10 reveals two interpenetrated 3,6-connected nets with an (rutile) topology. Read More

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