5,287 results match your criteria demonstrate narrow

Optimal Reopening Pathways With COVID-19 Vaccine Rollout and Emerging Variants of Concern.

Front Public Health 2021 7;9:729141. Epub 2021 Sep 7.

Department of Mathematics and Statistics, York University, Toronto, ON, Canada.

We developed a stochastic optimization technology based on a COVID-19 transmission dynamics model to determine optimal pathways from lockdown toward reopening with different scales and speeds of mass vaccine rollout in order to maximize social economical activities while not overwhelming the health system capacity in general, hospitalization beds, and intensive care units in particular. We used the Province of Ontario, Canada as a case study to demonstrate the methodology and the optimal decision trees; but our method and algorithm are generic and can be adapted to other settings. Our model framework and optimization strategies take into account the likely range of social contacts during different phases of a gradual reopening process and consider the uncertainties of these contact rates due to variations of individual behaviors and compliance. Read More

View Article and Full-Text PDF
September 2021

Sleep trajectories from early adolescence to emerging adulthood: Evidence from a nine-year population-based study.

J Adolesc 2021 Sep 20;92:177-188. Epub 2021 Sep 20.

National Sun Yat-sen University, Taiwan.

Introduction: Adolescence to emerging adulthood is a developmental period when individuals experience substantial biological changes and social transitions. In East Asian societies, this period is also marked by high pressure around college entrance exams. However, little is known about how young people's sleep changes over time, or how it is impacted by social institutions in the cultural context. Read More

View Article and Full-Text PDF
September 2021

Electron phase-space control in photonic chip-based particle acceleration.

Nature 2021 Sep 22;597(7877):498-502. Epub 2021 Sep 22.

Physics Department, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.

Particle accelerators are essential tools in science, hospitals and industry. Yet their costs and large footprint, ranging in length from metres to several kilometres, limit their use. The recently demonstrated nanophotonics-based acceleration of charged particles can reduce the cost and size of these accelerators by orders of magnitude. Read More

View Article and Full-Text PDF
September 2021

A Snake-Inspired Layer-Driven Continuum Robot.

Soft Robot 2021 Sep 21. Epub 2021 Sep 21.

Institute of Plasma Physics, Chinese Academy of Science, Hefei, China.

Continuum robots with redundant degrees of freedom and postactuated devices are suitable for application in aerospace, nuclear facilities, and other narrow and multiobstacle special environments. The development of a snake-inspired continuum robot is presented in this study. The morphological skeleton structure of the snake body is simulated using underactuated continuum joints, which include several rigid-body joints in series. Read More

View Article and Full-Text PDF
September 2021

Aqueous vaginal contrast and scheduled hematocolpos with magnetic resonance imaging to delineate complex müllerian anomalies.

Fertil Steril 2021 Sep 18. Epub 2021 Sep 18.

The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, New York-Presbyterian Hospital/Weill Cornell Medical Center, New York, New York.

Objective: To demonstrate the advantage of using aqueous vaginal contrast and scheduled hematocolpos with magnetic resonance imaging (MRI) to improve the delineation of gynecologic anatomy and to recommend that this modality be considered in patients with complex müllerian anomalies.

Design: Video demonstration of MRI adjuncts to improve visualization of gynecologic anatomy.

Setting: Academic Hospital. Read More

View Article and Full-Text PDF
September 2021

Electrochemical control of [FeFe]-hydrogenase single crystals reveals complex redox populations at the catalytic site.

Dalton Trans 2021 Sep 21;50(36):12655-12663. Epub 2021 Sep 21.

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

Elucidating the distribution of intermediates at the active site of redox metalloenzymes is vital to understanding their highly efficient catalysis. Here we demonstrate that it is possible to generate, and detect, the key catalytic redox states of an [FeFe]-hydrogenase in a protein crystal. Individual crystals of the prototypical [FeFe]-hydrogenase I from (CpI) are maintained under electrochemical control, allowing for precise tuning of the redox potential, while the crystal is simultaneously probed Fourier Transform Infrared (FTIR) microspectroscopy. Read More

View Article and Full-Text PDF
September 2021

Coherent-scatterer enhancement and Klein-tunneling suppression by potential barriers in gapped graphene with chirality-time-reversal symmetry.

J Phys Condens Matter 2021 Sep 20. Epub 2021 Sep 20.

Space Vehicles Directorate, Air Force Research Laboratory, Air Force Research Laboratory, Kirtland Air Force Base, NM 87117, USA, SE Kirtland AFB, 87117, UNITED STATES.

We have utilized the finite-difference approach to explore electron-tunneling properties in gapped graphene through various electrostatic-potential barriers changing from Gaussian to a triangular envelope function in comparison with a square potential barrier. Transmission coefficient is calculated numerically for each case and applied to corresponding tunneling conductance. It is well known that Klein tunneling in graphene will be greatly reduced in a gapped graphene. Read More

View Article and Full-Text PDF
September 2021

Localization of Na channel clusters in narrowed perinexi of gap junctions enhances cardiac impulse transmission via ephaptic coupling: a model study.

J Physiol 2021 Sep 17. Epub 2021 Sep 17.

Department of Physiology, University of Bern, Bern, Switzerland.

Key Points: Ephaptic coupling is a cardiac conduction mechanism involving nanoscale-level interactions between the sodium (Na ) current and the extracellular potential in narrow intercalated disc clefts. When gap junctional coupling is reduced, ephaptic coupling acts in conjunction with the classical cardiac conduction mechanism based on gap junctional current flow. In intercalated discs, Na channels form clusters that are preferentially located in the periphery of gap junction plaques, in nanodomains known as perinexi, but the electrophysiological role of these perinexi was never examined. Read More

View Article and Full-Text PDF
September 2021

Sublattice Dependence and Gate Tunability of Midgap and Resonant States Induced by Native Dopants in Bernal-Stacked Bilayer Graphene.

Phys Rev Lett 2021 Sep;127(10):106401

Department of Physics, University of California, Santa Cruz, California 95064, USA.

The properties of semiconductors can be crucially impacted by midgap states induced by dopants, which can be native or intentionally incorporated in the crystal lattice. For Bernal-stacked bilayer graphene (BLG), which has a tunable band gap, the existence of midgap states induced by dopants or adatoms has been investigated theoretically and observed indirectly in electron transport experiments. Here, we characterize BLG midgap states in real space, with atomic-scale resolution with scanning tunneling microscopy and spectroscopy. Read More

View Article and Full-Text PDF
September 2021

Perovskite light-emitting/detecting bifunctional fibres for wearable LiFi communication.

Light Sci Appl 2020 Sep 16;9(1):163. Epub 2020 Sep 16.

MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.

Light fidelity (LiFi), which is emerging as a compelling technology paradigm shifting the common means of high-capacity wireless communication technologies, requires wearable and full-duplex compact design because of its great significance in smart wearables as well as the 'Internet of Things'. However, the construction of the key component of wearable full-duplex LiFi, light-emitting/detecting bifunctional fibres, is still challenging because of the conflicting process between carrier separation and recombination, as well as the highly dynamic film-forming process. Here, we demonstrate light-emitting/detecting bifunctional fibres enabled by perovskite QDs with hybrid components. Read More

View Article and Full-Text PDF
September 2020

Lepidoptera demonstrate the relevance of Murray's Law to circulatory systems with tidal flow.

BMC Biol 2021 Sep 15;19(1):204. Epub 2021 Sep 15.

Department of Mechanical Engineering, Stanford University, Stanford, USA.

Background: Murray's Law, which describes the branching architecture of bifurcating tubes, predicts the morphology of vessels in many amniotes and plants. Here, we use insects to explore the universality of Murray's Law and to evaluate its predictive power for the wing venation of Lepidoptera, one of the most diverse insect orders. Lepidoptera are particularly relevant to the universality of Murray's Law because their wing veins have tidal, or oscillatory, flow of air and hemolymph. Read More

View Article and Full-Text PDF
September 2021

Delay-and-sum-to-delay-standard-deviation factor: a promising adaptive beamformer.

Opt Lett 2021 Sep;46(18):4662-4665

A new adaptive weighting method [delay-and-sum-to-delay-standard-deviation factor (DASDSF)] combined with minimum variance (MV) beamforming is introduced in photoacoustic imaging (PAI). Existing MV-based beamformers improve photoacoustic image quality in terms of achieving narrow main lobes and, thus, improving spatial resolution. But, the beamformers give a strong side-lobe signal strength that greatly degrades the reconstructed image contrast. Read More

View Article and Full-Text PDF
September 2021

kW-level monolithic single-mode narrow-linewidth all-solid photonic bandgap fiber amplifier.

Opt Lett 2021 Sep;46(18):4458-4461

Further power scaling of narrow-linewidth fiber lasers is critical for beam combining. Using all-solid photonic bandgap fibers with large effective mode areas and strong higher-order-mode suppression is an interesting approach. Previously, we demonstrated ∼400 single-frequency single-mode power at 1064 nm from a 50/400 photonic bandgap fiber amplifier, limited only by transverse mode instability (TMI). Read More

View Article and Full-Text PDF
September 2021

Electrokinetics of polymeric fluids in narrow rectangular confinements.

Soft Matter 2021 Sep 15. Epub 2021 Sep 15.

Discipline of Mechanical Engineering, Indian Institute of Technology Gandhinagar, Gujarat-382355, India.

The flow of polymeric liquids in narrow confinements with a rectangular cross section, in the presence of electrical double layers is analyzed here. Our analysis is motivated by the fact that many of the previous studies on the flow of complex fluids tend to focus on highly idealized parallel plate channels, which are markedly different from the rectangular ducts, used in many experiments and devices. We consider the combined electroosmotic and pressure driven flows as well as the streaming potential resulting from a mechanically driven flow. Read More

View Article and Full-Text PDF
September 2021

Visual quantitation of silver contamination in fresh water via accumulative length of microparticles in capillary-driven microfluidic devices.

Talanta 2021 Dec 12;235:122707. Epub 2021 Jul 12.

Department of Biomedical Engineering, City University of Hong Kong, Hong Kong. Electronic address:

Silver is a heavy metal commonly used as bacteriostatic agents or disinfectants. However, excess amount of silver ion (Ag) could lead to adverse biological effects on human health. To monitor silver ions in environmental samples, we report a visual quantitative method for analyzing the trace amount of Ag. Read More

View Article and Full-Text PDF
December 2021

Delivery of Healthcare Resources Using Autonomous Ground Vehicle Convoy Systems: An Overview.

Front Robot AI 2021 26;8:611978. Epub 2021 Aug 26.

Academy Center for UAS Research, Department of Electrical and Computer Engineering, United States Air Force Academy (USAF Academy), Colorado Springs, CO, United States.

Utilizing military convoys in humanitarian missions allows for increased overall performance of healthcare logistical operations. To properly gauge performance of autonomous ground convoy systems in military humanitarian operations, a proper framework for comparative performance metrics needs to be established. Past efforts in this domain have had heavy focus on narrow and specialized areas of convoy performance such as human factors, trust metrics, or string stability analysis. Read More

View Article and Full-Text PDF

Asymmetric Reproductive Barriers and Gene Flow Promote the Rise of a Stable Hybrid Zone in the Mediterranean High Mountain.

Front Plant Sci 2021 25;12:687094. Epub 2021 Aug 25.

Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain.

Hybrid zones have the potential to shed light on evolutionary processes driving adaptation and speciation. Secondary contact hybrid zones are particularly powerful natural systems for studying the interaction between divergent genomes to understand the mode and rate at which reproductive isolation accumulates during speciation. We have studied a total of 720 plants belonging to five populations from two (Brassicaceae) species presenting a contact zone in the Sierra Nevada mountains (SE Spain). Read More

View Article and Full-Text PDF

Tuning of the Interconnecting Layer for Monolithic Perovskite/Organic Tandem Solar Cells with Record Efficiency Exceeding 21.

Nano Lett 2021 Sep 10;21(18):7845-7854. Epub 2021 Sep 10.

School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China.

The photovoltaic performance of inorganic perovskite solar cells (PSCs) still lags behind the organic-inorganic hybrid PSCs due to limited light absorption of wide bandgap CsPbIBr under solar illumination. Constructing tandem devices with organic solar cells can effectively extend light absorption toward the long-wavelength region and reduce radiative photovoltage loss. Herein, we utilize wide-bandgap CsPbIBr semiconductor and narrow-bandgap PM6:Y6-BO blend to fabricate perovskite/organic tandem solar cells with an efficiency of 21. Read More

View Article and Full-Text PDF
September 2021

A versatile photodetector assisted by photovoltaic and bolometric effects.

Light Sci Appl 2020 Sep 10;9(1):160. Epub 2020 Sep 10.

State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yutian Road, Shanghai, 200083, China.

The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors. However, the limited exploitation of basic properties makes it difficult for devices to stand out. Here, we demonstrate a hybrid heterostructure with ultrathin vanadium dioxide film and molybdenum ditelluride nanoflake. Read More

View Article and Full-Text PDF
September 2020

Genetic Regulation of Vessel Morphology in .

Front Plant Sci 2021 23;12:705596. Epub 2021 Aug 23.

US Forest Service, Pacific Southwest Research Station, Davis, CA, United States.

During secondary growth, forest trees can modify the anatomy of the wood produced by the vascular cambium in response to environmental conditions. Notably, the trees of the model angiosperm genus, , reduce the risk of cavitation and hydraulic failure under water stress by producing water-conducting vessel elements with narrow lumens, which are more numerous and more interconnected with each other. Here, we determined the genetic architecture of vessel traits affecting hydraulic physiology and resilience to water stress. Read More

View Article and Full-Text PDF

Training Spiking Neural Networks in the Strong Coupling Regime.

Neural Comput 2021 04;33(5):1199-1233

Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases/National Institutes of Health, Bethesda, MD 20814, U.S.A.

Recurrent neural networks trained to perform complex tasks can provide insight into the dynamic mechanism that underlies computations performed by cortical circuits. However, due to a large number of unconstrained synaptic connections, the recurrent connectivity that emerges from network training may not be biologically plausible. Therefore, it remains unknown if and how biological neural circuits implement dynamic mechanisms proposed by the models. Read More

View Article and Full-Text PDF

Split-enzyme immunoassay to monitor EGFR-HER2 heterodimerization on cell surfaces.

Acta Biomater 2021 Sep 5. Epub 2021 Sep 5.

Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, United States; Department of Biomedical Engineering, Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112, United States. Electronic address:

Over 30,000 protein-protein interactions with pathological implications have been identified; yet, discovering and investigating drugs that target these specific interactions is greatly limited by the inability to monitor native protein-protein interactions (PPIs) efficiently. The two most frequently used tools to monitor PPIs, resonance-energy transfer (RET) assays and protein complementation assays (PCA), face significant limitations. RET assays have a narrow working range of 10 to 50 Å, while PCA require permanent attachment of a reporter probe to a protein of interest by chemical conjugation or genetic engineering. Read More

View Article and Full-Text PDF
September 2021

Melanoma cells adopt features of both mesenchymal and amoeboid migration within confining channels.

Sci Rep 2021 Sep 7;11(1):17804. Epub 2021 Sep 7.

Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Ave, Albany, NY, 12208, USA.

For metastasis to occur, cancer cells must traverse a range of tissue environments. In part, this is accomplished by cells adjusting their migration mode to one that is best suited to the environment. Melanoma cells have been shown to be particularly plastic, frequently using both mesenchymal and amoeboid (bleb-based) modes of migration. Read More

View Article and Full-Text PDF
September 2021

Ultrasensitive detection of endocrine disruptors via superfine plasmonic spectral combs.

Light Sci Appl 2021 Sep 7;10(1):181. Epub 2021 Sep 7.

Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.

The apparent increase in hormone-induced cancers and disorders of the reproductive tract has led to a growing demand for new technologies capable of detecting endocrine disruptors. However, a long-lasting challenge unaddressed is how to achieve ultrahigh sensitive, continuous, and in situ measurement with a portable device for in-field and remote environmental monitoring. Here we demonstrate a simple-to-implement plasmonic optical fiber biosensing platform to achieve an improved light-matter interaction and advanced surface chemistry for ultrasensitive detection of endocrine disruptors. Read More

View Article and Full-Text PDF
September 2021

Optimal frequency band selection using blind and targeted features for spectral coherence-based bearing diagnostics: A comparative study.

ISA Trans 2021 Aug 24. Epub 2021 Aug 24.

State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China. Electronic address:

Identifying a spectral frequency band with abundant fault information from spectral coherence is essential for improved envelope spectrum-based bearing diagnosis. Both blind features and targeted features have been employed to distinguish informative spectral frequency band of spectral coherence. However, how to select appropriate feature to correctly discriminate the optimal frequency band of spectral coherence in different scenarios is problematic. Read More

View Article and Full-Text PDF

Plastic debris increases circadian temperature extremes in beach sediments.

J Hazard Mater 2021 08 17;416:126140. Epub 2021 May 17.

Bird Group, Department of Life Sciences, The Natural History Museum, Tring, Hertfordshire HP23 6AP, United Kingdom.

Plastic pollution is the focus of substantial scientific and public interest, leading many to believe the issue is well documented and managed, with effective mitigation in place. However, many aspects are poorly understood, including fundamental questions relating to the scope and severity of impacts (e.g. Read More

View Article and Full-Text PDF

Antibiotic prophylaxis for traumatic facial fractures.

J Clin Pharm Ther 2021 Sep 6. Epub 2021 Sep 6.

Department of Surgery, Banner - University Medical Center, Tucson, AZ, USA.

What Is Known And Objective: The purpose of this paper is to discuss the limitations of the evidence supporting the SIS recommendations for antibiotic prescribing in patients with traumatic facial fractures and to provide suggestions for clinical decision-making and further research in this area given the wide variation in prescribing practices.

Comment: The Surgical Infection Society (SIS) recently published guidelines on antibiotic use in patients with traumatic facial fractures. The guidelines recommend against the use of prophylactic antibiotics for all adult patients with mandibular or non-mandibular facial fractures undergoing non-operative or operative procedures. Read More

View Article and Full-Text PDF
September 2021

Inkjet-Printing-Based Density Profile Engineering of Single-Walled Carbon Nanotube Networks for Conformable High-On/Off-Performance Thin-Film Transistors.

ACS Appl Mater Interfaces 2021 Sep 6;13(36):43163-43173. Epub 2021 Sep 6.

Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, Korea.

Random networks of single-walled carbon nanotubes (SWCNTs) offer new-form-factor electronics such as transparent, flexible, and intrinsically stretchable devices. However, the long-standing trade-off between carrier mobility and on/off ratio due to the coexistence of metallic and semiconducting nanotubes has limited the performance of SWCNT-random-network-based thin-film transistors (SWCNT TFTs), hindering their practical circuit-level applications. Methods for high-purity separation between metallic and semiconducting nanotubes have been proposed, but they require high cost and energy and are vulnerable to contamination and nanotube shortening, leading to performance degradation. Read More

View Article and Full-Text PDF
September 2021

Phospholipid/zein hybrid nanoparticles as promising carriers for the protection and delivery of all-trans retinoic acid.

Mater Sci Eng C Mater Biol Appl 2021 Sep 21;128:112331. Epub 2021 Jul 21.

Department of Health Sciences, University "Magna Græcia" of Catanzaro, Campus Universitario "S Venuta", I-88100 Catanzaro, Italy. Electronic address:

A totally biodegradable mixed system made up of phospholipids and zein was developed in order to effectively improve the photostability of all-trans retinoic acid (ATRA) preserving its pharmacological properties. Photon correlation spectroscopy showed that the formulation obtained using phospholipon 85G and zein at a ratio of 7:3 w/w was characterized by an average diameter of less than 200 nm, a narrow size distribution and a significant time- and temperature-dependent stability. The use of specific cryoprotectants such as mannose and glucose favoured the long-term storage of the nanocarriers after the freeze-drying procedure. Read More

View Article and Full-Text PDF
September 2021

Leaf form diversification in an ornamental heirloom tomato results from alterations in two different HOMEOBOX genes.

Curr Biol 2021 Aug 27. Epub 2021 Aug 27.

Department of Plant Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA. Electronic address:

Domesticated plants display diverse phenotypic traits. However, the influence of breeding effort on this phenotypic diversity remains unknown. Here, we demonstrate that a single nucleotide deletion in the homeobox motif of BIPINNATA, a BEL-LIKE HOMEODOMAIN gene, led to a highly complex leaf phenotype in an heirloom tomato (Solanum lycopersicum), Silvery Fir Tree (SiFT), which is used as a landscaping and ornamental plant. Read More

View Article and Full-Text PDF