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Li D, Wang L, Liao W, Sun T, Katul G, Bou-Zeid E, Maronga B. Persistent urban heat. Sci Adv 2024; 10:eadj7398. [PMID: 38598635 PMCID: PMC11006209 DOI: 10.1126/sciadv.adj7398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 03/07/2024] [Indexed: 04/12/2024]
Abstract
Urban surface and near-surface air temperatures are known to be often higher than their rural counterparts, a phenomenon now labeled as the urban heat island effect. However, whether the elevated urban temperatures are more persistent than rural temperatures at timescales commensurate to heat waves has not been addressed despite its importance for human health. Combining numerical simulations by a global climate model with a surface energy balance theory, it is demonstrated here that urban surface and near-surface air temperatures are significantly more persistent than their rural counterparts in cities dominated by impervious materials with large thermal inertia. Further use of these materials will result in even stronger urban temperature persistence, especially for tropical cities. The present findings help pinpoint mitigation strategies that can simultaneously ameliorate the larger magnitude and stronger persistence of urban temperatures.
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Affiliation(s)
- Dan Li
- Department of Earth and Environment, Boston University, Boston, MA, USA
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
| | - Linying Wang
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Weilin Liao
- Guangdong Key Laboratory for Urbanization and Geo-simulation, School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
| | - Ting Sun
- Institute for Risk and Disaster Reduction, University College London, London, UK
| | - Gabriel Katul
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, USA
| | - Elie Bou-Zeid
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, USA
| | - Björn Maronga
- Institute of Meteorology and Climatology, Leibniz University Hannover, Hannover, Germany
- Geophysical Institute, University of Bergen, Bergen, Norway
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2
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Eldeeb MH, Camacho Lopez LJ, Fontanesi F. Mitochondrial respiratory supercomplexes of the yeast Saccharomyces cerevisiae. IUBMB Life 2024. [PMID: 38529880 DOI: 10.1002/iub.2817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/28/2024] [Indexed: 03/27/2024]
Abstract
The functional and structural relationship among the individual components of the mitochondrial respiratory chain constitutes a central aspect of our understanding of aerobic catabolism. This interplay has been a subject of intense debate for over 50 years. It is well established that individual respiratory enzymes associate into higher-order structures known as respiratory supercomplexes, which represent the evolutionarily conserved organizing principle of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, supercomplexes are formed by a complex III homodimer flanked by one or two complex IV monomers, and their high-resolution structures have been recently elucidated. Despite the wealth of structural information, several proposed supercomplex functions remain speculative and our understanding of their physiological relevance is still limited. Recent advances in the field were made possible by the construction of yeast strains where the association of complex III and IV into supercomplexes is impeded, leading to diminished respiratory capacity and compromised cellular competitive fitness. Here, we discuss the experimental evidence and hypotheses relative to the functional roles of yeast respiratory supercomplexes. Moreover, we review the current models of yeast complex III and IV assembly in the context of supercomplex formation and highlight the data scattered throughout the literature suggesting the existence of cross talk between their biogenetic processes.
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Affiliation(s)
- Mazzen H Eldeeb
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Lizeth J Camacho Lopez
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
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3
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Chen R, Glauninger H, Kahan DN, Shangguan J, Sachleben JR, Riback JA, Drummond DA, Sosnick TR. HDX-MS finds that partial unfolding with sequential domain activation controls condensation of a cellular stress marker. Proc Natl Acad Sci U S A 2024; 121:e2321606121. [PMID: 38513106 PMCID: PMC10990091 DOI: 10.1073/pnas.2321606121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/29/2024] [Indexed: 03/23/2024] Open
Abstract
Eukaryotic cells form condensates to sense and adapt to their environment [S. F. Banani, H. O. Lee, A. A. Hyman, M. K. Rosen, Nat. Rev. Mol. Cell Biol. 18, 285-298 (2017), H. Yoo, C. Triandafillou, D. A. Drummond, J. Biol. Chem. 294, 7151-7159 (2019)]. Poly(A)-binding protein (Pab1), a canonical stress granule marker, condenses upon heat shock or starvation, promoting adaptation [J. A. Riback et al., Cell 168, 1028-1040.e19 (2017)]. The molecular basis of condensation has remained elusive due to a dearth of techniques to probe structure directly in condensates. We apply hydrogen-deuterium exchange/mass spectrometry to investigate the mechanism of Pab1's condensation. Pab1's four RNA recognition motifs (RRMs) undergo different levels of partial unfolding upon condensation, and the changes are similar for thermal and pH stresses. Although structural heterogeneity is observed, the ability of MS to describe populations allows us to identify which regions contribute to the condensate's interaction network. Our data yield a picture of Pab1's stress-triggered condensation, which we term sequential activation (Fig. 1A), wherein each RRM becomes activated at a temperature where it partially unfolds and associates with other likewise activated RRMs to form the condensate. Subsequent association is dictated more by the underlying free energy surface than specific interactions, an effect we refer to as thermodynamic specificity. Our study represents an advance for elucidating the interactions that drive condensation. Furthermore, our findings demonstrate how condensation can use thermodynamic specificity to perform an acute response to multiple stresses, a potentially general mechanism for stress-responsive proteins.
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Affiliation(s)
- Ruofan Chen
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
| | - Hendrik Glauninger
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
- Graduate Program in Biophysical Sciences, Division of Physical Sciences, University of Chicago, Chicago, IL60637
| | - Darren N. Kahan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
| | - Julia Shangguan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
| | | | - Joshua A. Riback
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
- Graduate Program in Biophysical Sciences, Division of Physical Sciences, University of Chicago, Chicago, IL60637
| | - D. Allan Drummond
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL60637
| | - Tobin R. Sosnick
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL60637
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL60637
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4
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Handa T, Holbrook M, Olsen N, Holtzman LN, Huber L, Wang HI, Bonn M, Barmak K, Hone JC, Pasupathy AN, Zhu X. Spontaneous exciton dissociation in transition metal dichalcogenide monolayers. Sci Adv 2024; 10:eadj4060. [PMID: 38295176 PMCID: PMC10830119 DOI: 10.1126/sciadv.adj4060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
Since the seminal work on MoS2, photoexcitation in atomically thin transition metal dichalcogenides (TMDCs) has been assumed to result in excitons, with binding energies order of magnitude larger than thermal energy at room temperature. Here, we reexamine this foundational assumption and show that photoexcitation of TMDC monolayers can result in a substantial population of free charges. Performing ultrafast terahertz spectroscopy on large-area, single-crystal TMDC monolayers, we find that up to ~10% of excitons spontaneously dissociate into charge carriers with lifetimes exceeding 0.2 ns. Scanning tunneling microscopy reveals that photocarrier generation is intimately related to mid-gap defects, likely via trap-mediated Auger scattering. Only in state-of-the-art quality monolayers, with mid-gap trap densities as low as 109 cm-2, does intrinsic exciton physics start to dominate the terahertz response. Our findings reveal the necessity of knowing the defect density in understanding photophysics of TMDCs.
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Affiliation(s)
- Taketo Handa
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Madisen Holbrook
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - Nicholas Olsen
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Luke N. Holtzman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Lucas Huber
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Hai I. Wang
- Max Planck Institute for Polymer Research, Mainz 55128, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Mainz 55128, Germany
| | - Katayun Barmak
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - James C. Hone
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | | | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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5
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Moutanabbir O, Assali S, Attiaoui A, Daligou G, Daoust P, Vecchio PD, Koelling S, Luo L, Rotaru N. Nuclear Spin-Depleted, Isotopically Enriched 70 Ge/ 28 Si 70 Ge Quantum Wells. Adv Mater 2024; 36:e2305703. [PMID: 38009242 DOI: 10.1002/adma.202305703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/15/2023] [Indexed: 11/28/2023]
Abstract
The p-symmetry of the hole wavefunction is associated with a weaker hyperfine interaction, which makes hole spin qubits attractive candidates to implement quantum processors. However, recent studies demonstrate that hole qubits are still very sensitive to nuclear spin bath, thus highlighting the need for nuclear spin-free germanium (Ge) qubits to suppress this decoherence channel. Herein, this work demonstrates the epitaxial growth of 73 Ge- and 29 Si-depleted, isotopically enriched 70 Ge/silicon-germanium (SiGe) quantum wells. The growth is achieved by reduced pressure chemical vapor deposition using isotopically purified monogermane 70 GeH4 and monosilane 28 SiH4 with an isotopic purity higher than 99.9% and 99.99%, respectively. The quantum wells consist of a series of 70 Ge/SiGe heterostructures grown on Si wafers. The isotopic purity is investigated using atom probe tomography (APT) following an analytical procedure addressing the discrepancies caused by the overlap of isotope peaks in mass spectra. The nuclear spin background is found to be sensitive to the growth conditions with the lowest concentration of 73 Ge and 29 Si is below 0.01% in the Ge well and SiGe barriers. The measured average distance between nuclear spins reaches 3-4 nm in 70 Ge/28 Si70 Ge, which is an order of magnitude larger than in natural Ge/SiGe heterostructures. The spread of the hole wavefunction and the residual nuclear spin background in APT voluminals comparable to the size of realistic quantum dots are also discussed.
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Affiliation(s)
- Oussama Moutanabbir
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Simone Assali
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Anis Attiaoui
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Gérard Daligou
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Patrick Daoust
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Patrick Del Vecchio
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Sebastian Koelling
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Lu Luo
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Nicolas Rotaru
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
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6
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Erik Maris JJ, Parker LA, Stanciakova K, Nikolopoulos N, Berendsen KMH, van Blaaderen A, Meirer F, Rabouw FT, Weckhuysen BM. Molecular Accessibility and Diffusion of Resorufin in Zeolite Crystals. Chemistry 2024; 30:e202302553. [PMID: 37815001 DOI: 10.1002/chem.202302553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/07/2023] [Accepted: 10/09/2023] [Indexed: 10/11/2023]
Abstract
We have used confocal laser scanning microscopy on the small, fluorescent resorufin dye molecule to visualize molecular accessibility and diffusion in the hierarchical, anisotropic pore structure of large (~10 μm-sized) zeolite-β crystals. The resorufin dye is widely used in life and materials science, but only in its deprotonated form because the protonated molecule is barely fluorescent in aqueous solution. In this work, we show that protonated resorufin is in fact strongly fluorescent when confined within zeolite micropores, thus enabling fluorescence microimaging experiments. We find that J-aggregation guest-guest interactions lead to a decrease in the measured fluorescence intensity that can be prevented by using non-fluorescent spacer molecules. We characterized the pore space by introducing resorufin from the outside solution and following its diffusion into zeolite-β crystals. The eventual homogeneous distribution of resorufin molecules throughout the zeolite indicates a fully accessible pore network. This enables the quantification of the diffusion coefficient in the straight pores of zeolite-β without the need for complex analysis, and we found a value of 3×10-15 m2 s-1 . Furthermore, we saw that diffusion through the straight pores of zeolite-β is impeded when crossing the boundaries between zeolite subunits.
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Affiliation(s)
- J J Erik Maris
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
- Optical Materials Engineering Laboratory, ETH Zürich, Leonhardstrasse 21, 8092, Zürich, Switzerland
| | - Luke A Parker
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
- TNO, Princetonlaan 6, 3584 CB, Utrecht (The, Netherlands
| | - Katarina Stanciakova
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
| | - Nikolaos Nikolopoulos
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
| | - Koen M H Berendsen
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
| | - Alfons van Blaaderen
- Soft Condensed Matter Group, Utrecht University, Debye Institute for Nanomaterials Science, Princetonplein 1, 3584 CC, Utrecht (The, Netherlands
| | - Florian Meirer
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
| | - Freddy T Rabouw
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
- Soft Condensed Matter Group, Utrecht University, Debye Institute for Nanomaterials Science, Princetonplein 1, 3584 CC, Utrecht (The, Netherlands
| | - Bert M Weckhuysen
- Inorganic Chemistry and Catalysis Group, Utrecht University, Debye Institute for Nanomaterials Science and, Institute for Sustainable and Circular Chemistry, Universiteitsweg 99, 3584 CG, Utrecht (The, Netherlands
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7
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Plá V, Bitsika S, Giannetto MJ, Ladron-de-Guevara A, Gahn-Martinez D, Mori Y, Nedergaard M, Møllgård K. Structural characterization of SLYM-a 4th meningeal membrane. Fluids Barriers CNS 2023; 20:93. [PMID: 38098084 PMCID: PMC10722698 DOI: 10.1186/s12987-023-00500-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1-3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.
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Affiliation(s)
- Virginia Plá
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Styliani Bitsika
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Michael J Giannetto
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladron-de-Guevara
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Daniel Gahn-Martinez
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yuki Mori
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark.
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark.
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Nguyen G, King K, Stirling L. Telerehabilitation use and experiences in occupational and physical therapy through the early stages of the COVID-19 pandemic. PLoS One 2023; 18:e0291605. [PMID: 37939089 PMCID: PMC10631673 DOI: 10.1371/journal.pone.0291605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/31/2023] [Indexed: 11/10/2023] Open
Abstract
Telehealth has helped to increase access to rehabilitative services such as occupational and physical therapy. The early COVID-19 pandemic amplified the need for remote access to care, and the rapid implementation of telehealth systems provided a unique opportunity to learn from clinicians' experiences adopting telehealth for telerehabilitation applications. To understand these experiences, a self-administered online survey was conducted to capture perspectives on ease of telerehabilitation use and adoption from occupational and physical therapists. The survey captured retrospective views on telerehabilitation use pre-pandemic as well as real-time perspectives on telerehabilitation during the early stages of the pandemic (July to August 2020). The survey gathered information on clinician demographics (N = 109), clinicians' experiences with adopting or utilizing telerehabilitation systems, and their perceptions on remotely performing cognitive, emotional, and physical assessments via video-conferencing (a common mode of telehealth). Responses demonstrated a modest increase in telerehabilitation as a care setting (rate increase from 3.4% to 19.3%), and telerehabilitation was more generally tried during the early stages of the pandemic (41 clinicians explicitly reported telerehabilitation use). However, technology access and acceptance remained low, with 38 clinicians (35%) expressing concerns that technology was ineffective or impractical, unavailable, not covered by insurance, or not desired by their patients. Video-conferencing technology was perceived as generally ill-equipped to support clinicians in performing remote assessment tasks. Physical assessment tasks were considered particularly difficult, with 55% of clinicians rating their ability to perform these tasks in the range of moderately difficult to unable to perform. To address these difficulties and better augment clinical care, clinicians require more robust assessment methods that may combine video, mobile, and wearable technologies that would be accessible to a patient at home. When designing future telerehabilitation tools, information captured through these modes must be task-relevant, standardized, and understandable to a remote clinician.
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Affiliation(s)
- Golda Nguyen
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Katelyn King
- Department of Biomedical Engineering, Department of Robotics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Leia Stirling
- Department of Industrial and Operations Engineering, Department of Robotics, University of Michigan, Ann Arbor, Michigan, United States of America
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9
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Hoyer D, Bennett JS, Reddish J, Holder S, Howard R, Benam M, Levine J, Ludlow F, Feinman G, Turchin P. Navigating polycrisis: long-run socio-cultural factors shape response to changing climate. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220402. [PMID: 37718603 PMCID: PMC10505849 DOI: 10.1098/rstb.2022.0402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/26/2023] [Indexed: 09/19/2023] Open
Abstract
Climate variability and natural hazards like floods and earthquakes can act as environmental shocks or socioecological stressors leading to instability and suffering throughout human history. Yet, societies experience a wide range of outcomes when facing such challenges: some suffer from social unrest, civil violence or complete collapse; others prove more resilient and maintain key social functions. We currently lack a clear, generally agreed-upon conceptual framework and evidentiary base to explore what causes these divergent outcomes. Here, we discuss efforts to develop such a framework through the Crisis Database (CrisisDB) programme. We illustrate that the impact of environmental stressors is mediated through extant cultural, political and economic structures that evolve over extended timescales (decades to centuries). These structures can generate high resilience to major shocks, facilitate positive adaptation, or, alternatively, undermine collective action and lead to unrest, violence and even societal collapse. By exposing the ways that different societies have reacted to crises over their lifetime, this framework can help identify the factors and complex social-ecological interactions that either bolster or undermine resilience to contemporary climate shocks. This article is part of the theme issue 'Climate change adaptation needs a science of culture'.
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Affiliation(s)
- Daniel Hoyer
- Complexity Science Hub, 1080 Vienna, Austria
- Evolution Institute, San Antonio, FL 33576, USA
| | - James S. Bennett
- Complexity Science Hub, 1080 Vienna, Austria
- University of Washington, Seattle, WA 98195, USA
| | | | | | | | - Majid Benam
- Complexity Science Hub, 1080 Vienna, Austria
| | - Jill Levine
- Evolution Institute, San Antonio, FL 33576, USA
| | | | - Gary Feinman
- Field Museum of Natural History, Chicago, IL 60605, USA
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10
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Li C, Schramma N, Wang Z, Qari NF, Jalaal M, Latz MI, Cai S. Ultrasensitive and robust mechanoluminescent living composites. Sci Adv 2023; 9:eadi8643. [PMID: 37862415 PMCID: PMC10588950 DOI: 10.1126/sciadv.adi8643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023]
Abstract
Mechanosensing, the transduction of extracellular mechanical stimuli into intracellular biochemical signals, is a fundamental property of living cells. However, endowing synthetic materials with mechanosensing capabilities comparable to biological levels is challenging. Here, we developed ultrasensitive and robust mechanoluminescent living composites using hydrogels embedded with dinoflagellates, unicellular microalgae with a near-instantaneous and ultrasensitive bioluminescent response to mechanical stress. Not only did embedded dinoflagellates retain their intrinsic mechanoluminescence, but with hydrophobic coatings, living composites had a lifetime of ~5 months under harsh conditions with minimal maintenance. We 3D-printed living composites into large-scale mechanoluminescent structures with high spatial resolution, and we also enhanced their mechanical properties with double-network hydrogels. We propose a counterpart mathematical model that captured experimental mechanoluminescent observations to predict mechanoluminescence based on deformation and applied stress. We also demonstrated the use of the mechanosensing composites for biomimetic soft actuators that emitted colored light upon magnetic actuation. These mechanosensing composites have substantial potential in biohybrid sensors and robotics.
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Affiliation(s)
- Chenghai Li
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nico Schramma
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, Amsterdam 1098XH, Netherlands
| | - Zijun Wang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nada F. Qari
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Maziyar Jalaal
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, Amsterdam 1098XH, Netherlands
| | - Michael I. Latz
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
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11
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Chen S, Liu P, Pei Q, Yu ZG, Aitken ZH, Li W, Wu Z, Banerjee R, Srolovitz DJ, Liaw PK, Zhang YW. Ideal plasticity and shape memory of nanolamellar high-entropy alloys. Sci Adv 2023; 9:eadi5817. [PMID: 37831772 PMCID: PMC10575575 DOI: 10.1126/sciadv.adi5817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 09/11/2023] [Indexed: 10/15/2023]
Abstract
Understanding the relationship among elemental compositions, nanolamellar microstructures, and mechanical properties enables the rational design of high-entropy alloys (HEAs). Here, we construct nanolamellar AlxCoCuFeNi HEAs with alternating high- and low-Al concentration layers and explore their mechanical properties using a combination of molecular dynamic simulation and density functional theory calculation. Our results show that the HEAs with nanolamellar structures exhibit ideal plastic behavior during uniaxial tensile loading, a feature not observed in homogeneous HEAs. This remarkable ideal plasticity is attributed to the unique deformation mechanisms of phase transformation coupled with dislocation nucleation and propagation in the high-Al concentration layers and the confinement and slip-blocking effect of the low-Al concentration layers. Unexpectedly, this ideal plasticity is fully reversible upon unloading, leading to a remarkable shape memory effect. Our work highlights the importance of nanolamellar structures in controlling the mechanical and functional properties of HEAs and presents a fascinating route for the design of HEAs for both functional and structural applications.
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Affiliation(s)
- Shuai Chen
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Ping Liu
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Qingxiang Pei
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Zhi Gen Yu
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Zachary H. Aitken
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Wanghui Li
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Zhaoxuan Wu
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Rajarshi Banerjee
- Department of Materials Science and Engineering, University of North Texas, Denton, TX 76207, USA
| | - David J. Srolovitz
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Peter K. Liaw
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA
| | - Yong-Wei Zhang
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
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12
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Sutton GP, Szczecinski NS, Quinn RD, Chiel HJ. Phase shift between joint rotation and actuation reflects dominant forces and predicts muscle activation patterns. PNAS Nexus 2023; 2:pgad298. [PMID: 37822766 PMCID: PMC10563792 DOI: 10.1093/pnasnexus/pgad298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023]
Abstract
During behavior, the work done by actuators on the body can be resisted by the body's inertia, elastic forces, gravity, or viscosity. The dominant forces that resist actuation have major consequences on the control of that behavior. In the literature, features and actuation of locomotion, for example, have been successfully predicted by nondimensional numbers (e.g. Froude number and Reynolds number) that generally express the ratio between two of these forces (gravitational, inertial, elastic, and viscous). However, animals of different sizes or motions at different speeds may not share the same dominant forces within a behavior, making ratios of just two of these forces less useful. Thus, for a broad comparison of behavior across many orders of magnitude of limb length and cycle period, a dimensionless number that includes gravitational, inertial, elastic, and viscous forces is needed. This study proposes a nondimensional number that relates these four forces: the phase shift (ϕ) between the displacement of the limb and the actuator force that moves it. Using allometric scaling laws, ϕ for terrestrial walking is expressed as a function of the limb length and the cycle period at which the limb steps. Scale-dependent values of ϕ are used to explain and predict the electromyographic (EMG) patterns employed by different animals as they walk.
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Affiliation(s)
- G P Sutton
- School of Life Sciences, University of Lincoln, Lincoln LN6 7TS, UK
| | - N S Szczecinski
- Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, USA
| | - R D Quinn
- Department of Mechanical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - H J Chiel
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Neuroscience, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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13
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Devi A, Speyer G, Lynch M. The divergence of mean phenotypes under persistent directional selection. Genetics 2023; 224:iyad091. [PMID: 37200616 PMCID: PMC10552002 DOI: 10.1093/genetics/iyad091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 02/26/2023] [Accepted: 05/04/2023] [Indexed: 05/20/2023] Open
Abstract
Numerous organismal traits, particularly at the cellular level, are likely to be under persistent directional selection across phylogenetic lineages. Unless all mutations affecting such traits have large enough effects to be efficiently selected in all species, gradients in mean phenotypes are expected to arise as a consequence of differences in the power of random genetic drift, which varies by approximately five orders of magnitude across the Tree of Life. Prior theoretical work examining the conditions under which such gradients can arise focused on the simple situation in which all genomic sites affecting the trait have identical and constant mutational effects. Here, we extend this theory to incorporate the more biologically realistic situation in which mutational effects on a trait differ among nucleotide sites. Pursuit of such modifications leads to the development of semi-analytic expressions for the ways in which selective interference arises via linkage effects in single-effects models, which then extend to more complex scenarios. The theory developed clarifies the conditions under which mutations of different selective effects mutually interfere with each others' fixation and shows how variance in effects among sites can substantially modify and extend the expected scaling relationships between mean phenotypes and effective population sizes.
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Affiliation(s)
- Archana Devi
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287, USA
| | - Gil Speyer
- Knowledge Enterprise, Arizona State University, Tempe, AZ 85287, USA
| | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287, USA
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14
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Hanson SE, Ray WJ, Santhanakrishnan A, Patek SN. Mantis Shrimp Locomotion: Coordination and Variation of Hybrid Metachronal Swimming. Integr Org Biol 2023; 5:obad019. [PMID: 37388570 PMCID: PMC10303694 DOI: 10.1093/iob/obad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 05/03/2023] [Accepted: 05/24/2023] [Indexed: 07/01/2023] Open
Abstract
Across countless marine invertebrates, coordination of closely spaced swimming appendages is key to producing diverse locomotory behaviors. Using a widespread mechanism termed hybrid metachronal propulsion, mantis shrimp swim by moving five paddle-like pleopods along their abdomen in a posterior to anterior sequence during the power stroke and a near-synchronous motion during the recovery stroke. Despite the ubiquity of this mechanism, it is not clear how hybrid metachronal swimmers coordinate and modify individual appendage movements to achieve a range of swimming capabilities. Using high-speed imaging, we measured pleopod kinematics of mantis shrimp (Neogonodactylus bredini), while they performed two swimming behaviors: burst swimming and taking off from the substrate. By tracking each of the five pleopods, we tested how stroke kinematics vary across swimming speeds and the two swimming behaviors. We found that mantis shrimp achieve faster swimming speeds through a combination of higher beat frequencies, smaller stroke durations, and partially via larger stroke angles. The five pleopods exhibit non-uniform kinematics that contribute to the coordination and forward propulsion of the whole system. Micro-hook structures (retinacula) connect each of the five pleopod pairs and differ in their attachment across pleopods-possibly contributing to passive kinematic control. We compare our findings in N. bredini to previous studies to identify commonalities across hybrid metachronal swimmers at high Reynolds numbers and centimeter scales. Through our large experimental dataset and by tracking each pleopod's movements, our study reveals key parameters by which mantis shrimp adjust and control their swimming, yielding diverse locomotor abilities.
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Affiliation(s)
- S E Hanson
- Department of Biology, Duke University, Durham, NC 27708, USA
| | | | - A Santhanakrishnan
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK 74078, USA
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15
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Lee KL, Kowach G, Li F, Voiculescu I. Liquid Viscosity Sensor Using a Surface Acoustic Wave Device for Medical Applications Including Blood and Plasma. Sensors (Basel) 2023; 23:5911. [PMID: 37447761 DOI: 10.3390/s23135911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/07/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023]
Abstract
Blood viscosity is the defining health indicator for hyperviscosity syndrome patients. This paper introduces an alternative approach for the real-time monitoring of blood viscosity by employing a surface-horizontal surface acoustic wave (SH-SAW) device at room temperature. A novel bi-layer waveguide is constructed on top of the SAW device. This device enables the SAW sensing of liquid droplets utilizing a bi-layer waveguide, consisting of a zinc oxide (ZnO) enhancement layer and Parlyene C, that facilitates the promotion of the surface horizontal mode. The ZnO piezoelectric thin-film layer enhanced the local particle displacement and dielectric coupling while the Parylene C layer constrained the wave mode at the interface of the piezoelectric material and polymer material. The device was tested with a liquid drop on the SAW delay-line path. Both experimental and finite element analysis results demonstrated the benefits of the bi-layer waveguide. The simulation results confirmed that the displacement field of local particles increased 9 times from 1.261 nm to 11.353 nm with the Parylene C/ZnO bi-layer waveguide structure. The device demonstrated a sensitivity of 3.57 ± 0.3125 kHz shift per centipoise enabling the potential for high precision blood viscosity monitoring.
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Affiliation(s)
- Kun-Lin Lee
- Department of Mechanical Engineering, The City College of the City University of New York, New York, NY 10031, USA
| | - Glen Kowach
- Department of Chemistry and Biochemistry, The City College of the City University of New York, New York, NY 10031, USA
| | - Fang Li
- Department of Mechanical Engineering, New York Institute of Technology, Old Westbury, NY 11568, USA
| | - Ioana Voiculescu
- Department of Mechanical Engineering, The City College of the City University of New York, New York, NY 10031, USA
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16
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Attiaoui A, Daligou G, Assali S, Skibitzki O, Schroeder T, Moutanabbir O. Polarization-Tuned Fano Resonances in All-Dielectric Short-Wave Infrared Metasurface. Adv Mater 2023:e2300595. [PMID: 37015255 DOI: 10.1002/adma.202300595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/14/2023] [Indexed: 05/28/2023]
Abstract
The short-wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface-based nanophotonics despite its strategic importance in sensing and imaging applications. This is mainly attributed to the lack of material systems to tailor light-matter interactions in this range. Herein, this limitation is addressed and an all-dielectric silicon-integrated metasurface enabling polarization-induced Fano resonance control at SWIR frequencies is demonstrated. The platform consists of a 2D Si/Ge0.9 Sn0.1 core/shell nanowire array on a silicon wafer. By tuning the light polarization, it is shown that the metasurface reflectance can be efficiently engineered due to Fano resonances emerging from the electric and magnetic dipoles competition. The interference of optically induced dipoles in high-index nanowire arrays offers additional degrees of freedom to tailor the directional scattering and the flow of light while enabling sharp polarization-modulated resonances. This tunablity is harnessed in nanosensors yielding an efficient detection of 10-2 changes in the refractive index of the surrounding medium.
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Affiliation(s)
- Anis Attiaoui
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Gérard Daligou
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Simone Assali
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
| | - Oliver Skibitzki
- IHP-Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236, Frankfurt (Oder), Germany
| | - Thomas Schroeder
- Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, 12489, Berlin, Germany
| | - Oussama Moutanabbir
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada
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17
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Sivak VV, Eickbusch A, Royer B, Singh S, Tsioutsios I, Ganjam S, Miano A, Brock BL, Ding AZ, Frunzio L, Girvin SM, Schoelkopf RJ, Devoret MH. Real-time quantum error correction beyond break-even. Nature 2023; 616:50-55. [PMID: 36949196 DOI: 10.1038/s41586-023-05782-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/02/2023] [Indexed: 03/24/2023]
Abstract
The ambition of harnessing the quantum for computation is at odds with the fundamental phenomenon of decoherence. The purpose of quantum error correction (QEC) is to counteract the natural tendency of a complex system to decohere. This cooperative process, which requires participation of multiple quantum and classical components, creates a special type of dissipation that removes the entropy caused by the errors faster than the rate at which these errors corrupt the stored quantum information. Previous experimental attempts to engineer such a process1-7 faced the generation of an excessive number of errors that overwhelmed the error-correcting capability of the process itself. Whether it is practically possible to utilize QEC for extending quantum coherence thus remains an open question. Here we answer it by demonstrating a fully stabilized and error-corrected logical qubit whose quantum coherence is substantially longer than that of all the imperfect quantum components involved in the QEC process, beating the best of them with a coherence gain of G = 2.27 ± 0.07. We achieve this performance by combining innovations in several domains including the fabrication of superconducting quantum circuits and model-free reinforcement learning.
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Affiliation(s)
- V V Sivak
- Department of Physics, Yale University, New Haven, CT, USA.
- Department of Applied Physics, Yale University, New Haven, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, CT, USA.
- Google AI Quantum, Santa Barbara, CA, USA.
| | - A Eickbusch
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - B Royer
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Département de Physique, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - S Singh
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - I Tsioutsios
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - S Ganjam
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - A Miano
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - B L Brock
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - A Z Ding
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - L Frunzio
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - S M Girvin
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - R J Schoelkopf
- Department of Physics, Yale University, New Haven, CT, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
- Yale Quantum Institute, Yale University, New Haven, CT, USA
| | - M H Devoret
- Department of Physics, Yale University, New Haven, CT, USA.
- Department of Applied Physics, Yale University, New Haven, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, CT, USA.
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18
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Kucukyildirim S, Ozdemirel HO, Lynch M. Similar mutation rates but different mutation spectra in moderate and extremely halophilic archaea. G3 (Bethesda) 2023; 13:jkac303. [PMID: 36519377 PMCID: PMC9997560 DOI: 10.1093/g3journal/jkac303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/02/2021] [Accepted: 11/03/2022] [Indexed: 12/23/2022]
Abstract
Archaea are a major part of Earth's microbiota and extremely diverse. Yet, we know very little about the process of mutation that drives such diversification. To expand beyond previous work with the moderate halophilic archaeal species Haloferax volcanii, we performed a mutation-accumulation experiment followed by whole-genome sequencing in the extremely halophilic archaeon Halobacterium salinarum. Although Hfx. volcanii and Hbt. salinarum have different salt requirements, both species have highly polyploid genomes and similar GC content. We accumulated mutations for an average of 1250 generations in 67 mutation accumulation lines of Hbt. salinarum, and revealed 84 single-base substitutions and 10 insertion-deletion mutations. The estimated base-substitution mutation rate of 3.99 × 10-10 per site per generation or 1.0 × 10-3 per genome per generation in Hbt. salinarum is similar to that reported for Hfx. volcanii (1.2 × 10-3 per genome per generation), but the genome-wide insertion-deletion rate and spectrum of mutations are somewhat dissimilar in these archaeal species. The spectra of spontaneous mutations were AT biased in both archaea, but they differed in significant ways that may be related to differences in the fidelity of DNA replication/repair mechanisms or a simple result of the different salt concentrations.
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Affiliation(s)
| | | | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287, USA
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19
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Savytskyy R, Botzem T, Fernandez de Fuentes I, Joecker B, Pla JJ, Hudson FE, Itoh KM, Jakob AM, Johnson BC, Jamieson DN, Dzurak AS, Morello A. An electrically driven single-atom "flip-flop" qubit. Sci Adv 2023; 9:eadd9408. [PMID: 36763660 PMCID: PMC9916988 DOI: 10.1126/sciadv.add9408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
The spins of atoms and atom-like systems are among the most coherent objects in which to store quantum information. However, the need to address them using oscillating magnetic fields hinders their integration with quantum electronic devices. Here, we circumvent this hurdle by operating a single-atom "flip-flop" qubit in silicon, where quantum information is encoded in the electron-nuclear states of a phosphorus donor. The qubit is controlled using local electric fields at microwave frequencies, produced within a metal-oxide-semiconductor device. The electrical drive is mediated by the modulation of the electron-nuclear hyperfine coupling, a method that can be extended to many other atomic and molecular systems and to the hyperpolarization of nuclear spin ensembles. These results pave the way to the construction of solid-state quantum processors where dense arrays of atoms can be controlled using only local electric fields.
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Affiliation(s)
- Rostyslav Savytskyy
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Tim Botzem
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | | | - Benjamin Joecker
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Jarryd J. Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Fay E. Hudson
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Kohei M. Itoh
- School of Fundamental Science and Technology, Keio University, Kohoku-ku, Yokohama, Japan
| | - Alexander M. Jakob
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Brett C. Johnson
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - David N. Jamieson
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Andrew S. Dzurak
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
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20
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Chang I, Hartline DK, Lenz PH, Takagi D. Larval fish counteract ram and suction to capture evasive prey. R Soc Open Sci 2022; 9:220714. [PMID: 36340513 PMCID: PMC9626256 DOI: 10.1098/rsos.220714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
A simple hydrodynamic model of predator-prey interactions between larval clownfish and copepod prey is used to elucidate how larval fish capture highly evasive copepods. Fish larvae are considered to be suction feeders; however, video observations revealed that successful captures by clownfish larvae were preceded by rapidly accelerating lunges (ram), while the role of suction to draw prey into the fish's mouth was less clear. Simulations were made of the fish's strike, varying strengths of ram and suction to characterize optimal strategies for copepod capture given known evasive capabilities. Our results suggest that, contrary to expectations, suction feeding is dominant only in older larvae, whereas ram feeding is the dominant mode for early larvae. Despite the relatively weak suction produced by smaller larvae, it still plays a crucial role in prey capture through hydrodynamic stealth. Escape-triggering water deformations from the strike can be cancelled through controlled suction. Experimental data obtained from larval clownfish agree with model results, suggesting that the primary role of suction in early larvae is providing hydrodynamic stealth rather than capture.
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Affiliation(s)
- Irvin Chang
- Department of Mathematics, University of Hawai'i at Mānoa, 2565 McCarthy Mall, Honolulu, HI 96822, USA
| | - Daniel K. Hartline
- Pacific Biosciences Research Center, University of Hawai‘i at Mānoa, 1993 East-West Road, Honolulu, HI 96822, USA
| | - Petra H. Lenz
- Pacific Biosciences Research Center, University of Hawai‘i at Mānoa, 1993 East-West Road, Honolulu, HI 96822, USA
| | - Daisuke Takagi
- Department of Mathematics, University of Hawai'i at Mānoa, 2565 McCarthy Mall, Honolulu, HI 96822, USA
- Pacific Biosciences Research Center, University of Hawai‘i at Mānoa, 1993 East-West Road, Honolulu, HI 96822, USA
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21
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Turchin P, Whitehouse H, Gavrilets S, Hoyer D, François P, Bennett JS, Feeney KC, Peregrine P, Feinman G, Korotayev A, Kradin N, Levine J, Reddish J, Cioni E, Wacziarg R, Mendel-Gleason G, Benam M. Disentangling the evolutionary drivers of social complexity: A comprehensive test of hypotheses. Sci Adv 2022; 8:eabn3517. [PMID: 35749491 PMCID: PMC9232109 DOI: 10.1126/sciadv.abn3517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
During the Holocene, the scale and complexity of human societies increased markedly. Generations of scholars have proposed different theories explaining this expansion, which range from broadly functionalist explanations, focusing on the provision of public goods, to conflict theories, emphasizing the role of class struggle or warfare. To quantitatively test these theories, we develop a general dynamical model based on the theoretical framework of cultural macroevolution. Using this model and Seshat: Global History Databank, we test 17 potential predictor variables proxying mechanisms suggested by major theories of sociopolitical complexity (and >100,000 combinations of these predictors). The best-supported model indicates a strong causal role played by a combination of increasing agricultural productivity and invention/adoption of military technologies (most notably, iron weapons and cavalry in the first millennium BCE).
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Affiliation(s)
- Peter Turchin
- Complexity Science Hub Vienna, Vienna, Austria
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
- Centre for the Study of Social Cohesion, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | - Harvey Whitehouse
- Centre for the Study of Social Cohesion, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | - Sergey Gavrilets
- Department of Ecology and Evolutionary Biology, Department of Mathematics, Center for the Dynamics of Social Complexity, University of Tennessee, Knoxville, TN, USA
| | - Daniel Hoyer
- Seshat: Global History Databank, Evolution Institute, San Antonio, FL, USA
- George Brown College, Toronto, Canada
- Evolution Institute, San Antonio, FL, USA
| | - Pieter François
- Centre for the Study of Social Cohesion, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | | | | | | | - Gary Feinman
- Field Museum of Natural History, Chicago, IL, USA
| | - Andrey Korotayev
- National Research University Higher School of Economics, Moscow, Russia
| | - Nikolay Kradin
- Institute of History, Archaeology and Ethnology, Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia
| | | | | | - Enrico Cioni
- Seshat: Global History Databank, Evolution Institute, San Antonio, FL, USA
| | - Romain Wacziarg
- University of California Los Angeles, Anderson School of Management, Los Angeles, CA, USA
| | | | - Majid Benam
- Complexity Science Hub Vienna, Vienna, Austria
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22
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Li C, Soleyman R, Kohandel M, Cappellaro P. SARS-CoV-2 Quantum Sensor Based on Nitrogen-Vacancy Centers in Diamond. Nano Lett 2022; 22:43-49. [PMID: 34913700 PMCID: PMC8691455 DOI: 10.1021/acs.nanolett.1c02868] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/04/2021] [Indexed: 05/05/2023]
Abstract
The development of highly sensitive and rapid biosensing tools targeted to the highly contagious virus SARS-CoV-2 is critical to tackling the COVID-19 pandemic. Quantum sensors can play an important role because of their superior sensitivity and fast improvements in recent years. Here we propose a molecular transducer designed for nitrogen-vacancy (NV) centers in nanodiamonds, translating the presence of SARS-CoV-2 RNA into an unambiguous magnetic noise signal that can be optically read out. We evaluate the performance of the hybrid sensor, including its sensitivity and false negative rate, and compare it to widespread diagnostic methods. The proposed method is fast and promises to reach a sensitivity down to a few hundreds of RNA copies with false negative rate less than 1%. The proposed hybrid sensor can be further implemented with different solid-state defects and substrates, generalized to diagnose other RNA viruses, and integrated with CRISPR technology.
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Affiliation(s)
- Changhao Li
- Research Laboratory of Electronics and Department of
Nuclear Science and Engineering, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United
States
| | - Rouhollah Soleyman
- Department of Applied Mathematics,
University of Waterloo, Waterloo, Ontario N2L 3G1,
Canada
| | - Mohammad Kohandel
- Department of Applied Mathematics,
University of Waterloo, Waterloo, Ontario N2L 3G1,
Canada
| | - Paola Cappellaro
- Research Laboratory of Electronics and Department of
Nuclear Science and Engineering, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United
States
- Department of Physics, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United
States
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23
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Osborne MG, Geiger CJ, Corzett CH, Kram KE, Finkel SE. Removal of Toxic Volatile Compounds in Batch Culture Prolongs Stationary Phase and Delays Death of Escherichia coli. Appl Environ Microbiol 2021; 87:e0186021. [PMID: 34613759 PMCID: PMC8612265 DOI: 10.1128/aem.01860-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 09/26/2021] [Indexed: 12/28/2022] Open
Abstract
The mechanisms controlling entry into and exit from the death phase in the bacterial life cycle remain unclear. Although bacterial growth studies in batch cultures traditionally focus on the first three phases during incubation, two additional phases, the death phase and the long-term stationary phase, are less understood. Although there are a number of stressors that arise during long-term batch culture, including nutrient depletion and the accumulation of metabolic toxins such as reactive oxidative species, their roles in cell death are not well-defined. By manipulating the environmental conditions of Escherichia coli incubated in long-term batch culture through chemical and mechanical means, we investigated the role of volatile metabolic toxins in modulating the onset of the death phase. Here, we demonstrate that with the introduction of substrates with high binding affinities for volatile compounds, toxic by-products of normal cell metabolism, into the headspace of batch cultures, cells display a prolonged stationary phase and delayed entry into the death phase. The addition of these substrates allows cultures to maintain a high cell density for hours to days longer than cultures incubated under standard growth conditions. A similar effect is observed when the gaseous headspace in culture flasks is continuously replaced with sterile air, mechanically preventing the accumulation of metabolic by-products in batch cultures. We establish that toxic compound(s) are produced during the exponential phase, demonstrate that buildup of toxic by-products influence entry into the death phase, and present a novel tool for improving high-density growth in batch culture that may be used in future research or industrial or biotechnology applications. IMPORTANCE Bacteria, such as Escherichia coli, are routinely used in the production of biomaterials because of their efficient and sustainable capacity for synthesis of bioproducts. Industrial applications of microbial synthesis typically utilize cells in the stationary phase, when cultures have the greatest density of viable cells. By manipulating culture conditions to delay the transition from the stationary phase to the death phase, we can prolong the stationary phase on a scale of hours to days, thereby maintaining the maximum density of cells that would otherwise quickly decline. Characterization of the mechanisms that control entry into the death phase for the model organism E. coli not only deepens our understanding of the bacterial life cycle but also presents an opportunity to enhance current protocols for batch culture growth and explore similar effects in a variety of widely used bacterial strains.
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Affiliation(s)
- Melisa G. Osborne
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Christopher J. Geiger
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Christopher H. Corzett
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Karin E. Kram
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Steven E. Finkel
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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24
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Vahapoglu E, Slack-Smith JP, Leon RCC, Lim WH, Hudson FE, Day T, Tanttu T, Yang CH, Laucht A, Dzurak AS, Pla JJ. Single-electron spin resonance in a nanoelectronic device using a global field. Sci Adv 2021; 7:7/33/eabg9158. [PMID: 34389538 PMCID: PMC8363148 DOI: 10.1126/sciadv.abg9158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Spin-based silicon quantum electronic circuits offer a scalable platform for quantum computation, combining the manufacturability of semiconductor devices with the long coherence times afforded by spins in silicon. Advancing from current few-qubit devices to silicon quantum processors with upward of a million qubits, as required for fault-tolerant operation, presents several unique challenges, one of the most demanding being the ability to deliver microwave signals for large-scale qubit control. Here, we demonstrate a potential solution to this problem by using a three-dimensional dielectric resonator to broadcast a global microwave signal across a quantum nanoelectronic circuit. Critically, this technique uses only a single microwave source and is capable of delivering control signals to millions of qubits simultaneously. We show that the global field can be used to perform spin resonance of single electrons confined in a silicon double quantum dot device, establishing the feasibility of this approach for scalable spin qubit control.
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Affiliation(s)
- Ensar Vahapoglu
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia.
| | - James P Slack-Smith
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia.
| | - Ross C C Leon
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Tom Day
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Tuomo Tanttu
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Chih Hwan Yang
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia.
| | - Jarryd J Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia.
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25
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Scarpa JR, Jiang P, Gao VD, Vitaterna MH, Turek FW, Kasarskis A. NREM delta power and AD-relevant tauopathy are associated with shared cortical gene networks. Sci Rep 2021; 11:7797. [PMID: 33833255 PMCID: PMC8032807 DOI: 10.1038/s41598-021-86255-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/27/2020] [Indexed: 02/01/2023] Open
Abstract
Reduced NREM sleep in humans is associated with AD neuropathology. Recent work has demonstrated a reduction in NREM sleep in preclinical AD, pointing to its potential utility as an early marker of dementia. We test the hypothesis that reduced NREM delta power and increased tauopathy are associated with shared underlying cortical molecular networks in preclinical AD. We integrate multi-omics data from two extensive public resources, a human Alzheimer's disease cohort from the Mount Sinai Brain Bank (N = 125) reflecting AD progression and a (C57BL/6J × 129S1/SvImJ) F2 mouse population in which NREM delta power was measured (N = 98). Two cortical gene networks, including a CLOCK-dependent circadian network, are associated with NREM delta power and AD tauopathy progression. These networks were validated in independent mouse and human cohorts. Identifying gene networks related to preclinical AD elucidate possible mechanisms associated with the early disease phase and potential targets to alter the disease course.
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Affiliation(s)
- Joseph R Scarpa
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Peng Jiang
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA
| | - Vance D Gao
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA
| | - Martha H Vitaterna
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA
| | - Fred W Turek
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA
| | - Andrew Kasarskis
- Icahn Institute for Genomics and Multiscale Biology, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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26
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Pérez-Ruiz ER, Vivoni ER, Templeton NP. Urban land cover type determines the sensitivity of carbon dioxide fluxes to precipitation in Phoenix, Arizona. PLoS One 2020; 15:e0228537. [PMID: 32049986 PMCID: PMC7015425 DOI: 10.1371/journal.pone.0228537] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 01/17/2020] [Indexed: 11/18/2022] Open
Abstract
Urbanization modifies land surface characteristics with consequent impacts on local energy, water, and carbon dioxide (CO2) fluxes. Despite the disproportionate impact of cities on CO2 emissions, few studies have directly quantified CO2 conditions for different urban land cover patches, in particular for arid and semiarid regions. Here, we present a comparison of eddy covariance measurements of CO2 fluxes (FC) and CO2 concentrations ([CO2]) in four distinct urban patches in Phoenix, Arizona: a xeric landscaping, a parking lot, a mesic landscaping, and a suburban neighborhood. Analyses of diurnal, daily, and seasonal variations of FC and [CO2] were related to vegetation activity, vehicular traffic counts, and precipitation events to quantify differences among sites in relation to their urban land cover characteristics. We found that the mesic landscaping with irrigated turf grass was primarily controlled by plant photosynthetic activity, while the parking lot in close proximity to roads mainly exhibited the signature of vehicular emissions. The other two sites that had mixtures of irrigated vegetation and urban surfaces displayed an intermediate behavior in terms of CO2 fluxes. Precipitation events only impacted FC in urban patches without outdoor water use, indicating that urban irrigation decouples CO2 fluxes from the effects of infrequent storms in an arid climate. These findings suggest that the proportion of irrigated vegetation and urban surfaces fractions within urban patches could be used to scale up CO2 fluxes to a broader city footprint.
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Affiliation(s)
- Elí R. Pérez-Ruiz
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States of America
- Departamento de Ingeniería Civil y Ambiental, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, México
| | - Enrique R. Vivoni
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States of America
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States of America
| | - Nicole P. Templeton
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States of America
- Holistic Engineering and Land Management, Phoenix, AZ, United States of America
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27
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Wang Z, Wang YB, Yin J, Tóvári E, Yang Y, Lin L, Holwill M, Birkbeck J, Perello DJ, Xu S, Zultak J, Gorbachev RV, Kretinin AV, Taniguchi T, Watanabe K, Morozov SV, Anđelković M, Milovanović SP, Covaci L, Peeters FM, Mishchenko A, Geim AK, Novoselov KS, Fal’ko VI, Knothe A, Woods CR. Composite super-moiré lattices in double-aligned graphene heterostructures. Sci Adv 2019; 5:eaay8897. [PMID: 32064323 PMCID: PMC6989342 DOI: 10.1126/sciadv.aay8897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/22/2019] [Indexed: 05/30/2023]
Abstract
When two-dimensional (2D) atomic crystals are brought into close proximity to form a van der Waals heterostructure, neighbouring crystals may influence each other's properties. Of particular interest is when the two crystals closely match and a moiré pattern forms, resulting in modified electronic and excitonic spectra, crystal reconstruction, and more. Thus, moiré patterns are a viable tool for controlling the properties of 2D materials. However, the difference in periodicity of the two crystals limits the reconstruction and, thus, is a barrier to the low-energy regime. Here, we present a route to spectrum reconstruction at all energies. By using graphene which is aligned to two hexagonal boron nitride layers, one can make electrons scatter in the differential moiré pattern which results in spectral changes at arbitrarily low energies. Further, we demonstrate that the strength of this potential relies crucially on the atomic reconstruction of graphene within the differential moiré super cell.
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Affiliation(s)
- Zihao Wang
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Yi Bo Wang
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - J. Yin
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - E. Tóvári
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Y. Yang
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - L. Lin
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - M. Holwill
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - J. Birkbeck
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - D. J. Perello
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Shuigang Xu
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - J. Zultak
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - R. V. Gorbachev
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Henry Royce Institute for Advanced Materials, Oxford Road, Manchester M13 9PL, UK
| | - A. V. Kretinin
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Department of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - T. Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - K. Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - S. V. Morozov
- Institute of Microelectronics Technology RAS, Chernogolovka 142432, Russia
| | - M. Anđelković
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium
| | - S. P. Milovanović
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium
| | - L. Covaci
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium
| | - F. M. Peeters
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium
| | - A. Mishchenko
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - A. K. Geim
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - K. S. Novoselov
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Centre for Advanced 2D Materials, National University of Singapore, Singapore 117546, Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing 400714, China
| | - Vladimir I. Fal’ko
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Henry Royce Institute for Advanced Materials, Oxford Road, Manchester M13 9PL, UK
| | - Angelika Knothe
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - C. R. Woods
- Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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28
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Li D, Liao W, Rigden AJ, Liu X, Wang D, Malyshev S, Shevliakova E. Urban heat island: Aerodynamics or imperviousness? Sci Adv 2019; 5:eaau4299. [PMID: 30949572 PMCID: PMC6447381 DOI: 10.1126/sciadv.aau4299] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 02/12/2019] [Indexed: 05/07/2023]
Abstract
More than half of the world's population now live in cities, which are known to be heat islands. While daytime urban heat islands (UHIs) are traditionally thought to be the consequence of less evaporative cooling in cities, recent work sparks new debate, showing that geographic variations of daytime UHI intensity were largely explained by variations in the efficiency with which urban and rural areas convect heat from the land surface to the lower atmosphere. Here, we reconcile this debate by demonstrating that the difference between the recent finding and the traditional paradigm can be explained by the difference in the attribution methods. Using a new attribution method, we find that spatial variations of daytime UHI intensity are more controlled by variations in the capacity of urban and rural areas to evaporate water, suggesting that strategies enhancing the evaporation capability such as green infrastructure are effective ways to mitigate urban heat.
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Affiliation(s)
- Dan Li
- Department of Earth and Environment, Boston University, Boston, MA, USA
- Corresponding author.
| | - Weilin Liao
- School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
| | - Angela J. Rigden
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - Xiaoping Liu
- School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
| | - Dagang Wang
- School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
| | - Sergey Malyshev
- NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
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29
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Tang X, Chen Y, Li X, Liu J, Ying Z. A reinforcement learning approach to personalized learning recommendation systems. Br J Math Stat Psychol 2019; 72:108-135. [PMID: 30277574 DOI: 10.1111/bmsp.12144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 07/05/2018] [Indexed: 06/08/2023]
Abstract
Personalized learning refers to instruction in which the pace of learning and the instructional approach are optimized for the needs of each learner. With the latest advances in information technology and data science, personalized learning is becoming possible for anyone with a personal computer, supported by a data-driven recommendation system that automatically schedules the learning sequence. The engine of such a recommendation system is a recommendation strategy that, based on data from other learners and the performance of the current learner, recommends suitable learning materials to optimize certain learning outcomes. A powerful engine achieves a balance between making the best possible recommendations based on the current knowledge and exploring new learning trajectories that may potentially pay off. Building such an engine is a challenging task. We formulate this problem within the Markov decision framework and propose a reinforcement learning approach to solving the problem.
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Affiliation(s)
- Xueying Tang
- Department of Statistics, Columbia University, New York, New York, USA
| | - Yunxiao Chen
- Department of Psychology, Institute for Quantitative Theory and Methods, Emory University, Atlanta, Georgia, USA
| | - Xiaoou Li
- School of Statistics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jingchen Liu
- Department of Statistics, Columbia University, New York, New York, USA
| | - Zhiliang Ying
- Department of Statistics, Columbia University, New York, New York, USA
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30
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Fu Z, Jiang L, Wardini JL, MacDonald BE, Wen H, Xiong W, Zhang D, Zhou Y, Rupert TJ, Chen W, Lavernia EJ. A high-entropy alloy with hierarchical nanoprecipitates and ultrahigh strength. Sci Adv 2018; 4:eaat8712. [PMID: 30333993 PMCID: PMC6184785 DOI: 10.1126/sciadv.aat8712] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/07/2018] [Indexed: 05/23/2023]
Abstract
High-entropy alloys (HEAs) are a class of metallic materials that have revolutionized alloy design. They are known for their high compressive strengths, often greater than 1 GPa; however, the tensile strengths of most reported HEAs are limited. Here, we report a strategy for the design and fabrication of HEAs that can achieve ultrahigh tensile strengths. The proposed strategy involves the introduction of a high density of hierarchical intragranular nanoprecipitates. To establish the validity of this strategy, we designed and fabricated a bulk Fe25Co25Ni25Al10Ti15 HEA to consist of a principal face-centered cubic (fcc) phase containing hierarchical intragranular nanoprecipitates. Our results show that precipitation strengthening, as one of the main strengthening mechanisms, contributes to a tensile yield strength (σ0.2) of ~1.86 GPa and an ultimate tensile strength of ~2.52 GPa at room temperature, which heretofore represents the highest strength reported for an HEA with an appreciable failure strain of ~5.2%.
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Affiliation(s)
- Zhiqiang Fu
- Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640, China
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Lin Jiang
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
- Materials and Structural Analysis, Thermo Fisher Scientific, Hillsboro, OR 97124, USA
| | - Jenna L. Wardini
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Benjamin E. MacDonald
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Haiming Wen
- Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Wei Xiong
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Dalong Zhang
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Yizhang Zhou
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Timothy J. Rupert
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
| | - Weiping Chen
- Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640, China
| | - Enrique J. Lavernia
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA
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31
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Hile SJ, Fricke L, House MG, Peretz E, Chen CY, Wang Y, Broome M, Gorman SK, Keizer JG, Rahman R, Simmons MY. Addressable electron spin resonance using donors and donor molecules in silicon. Sci Adv 2018; 4:eaaq1459. [PMID: 30027114 PMCID: PMC6044739 DOI: 10.1126/sciadv.aaq1459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 06/01/2018] [Indexed: 05/27/2023]
Abstract
Phosphorus donor impurities in silicon are a promising candidate for solid-state quantum computing due to their exceptionally long coherence times and high fidelities. However, individual addressability of exchange coupled donors with separations ~15 nm is challenging. We show that by using atomic precision lithography, we can place a single P donor next to a 2P molecule 16 ± 1 nm apart and use their distinctive hyperfine coupling strengths to address qubits at vastly different resonance frequencies. In particular, the single donor yields two hyperfine peaks separated by 97 ± 2.5 MHz, in contrast to the donor molecule that exhibits three peaks separated by 262 ± 10 MHz. Atomistic tight-binding simulations confirm the large hyperfine interaction strength in the 2P molecule with an interdonor separation of ~0.7 nm, consistent with lithographic scanning tunneling microscopy images of the 2P site during device fabrication. We discuss the viability of using donor molecules for built-in addressability of electron spin qubits in silicon.
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Affiliation(s)
- Samuel J. Hile
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Lukas Fricke
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Matthew G. House
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Eldad Peretz
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Chin Yi Chen
- Network for Computational Nanotechnology, Purdue University, West Lafayette, IN 47907, USA
| | - Yu Wang
- Network for Computational Nanotechnology, Purdue University, West Lafayette, IN 47907, USA
| | - Matthew Broome
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Samuel K. Gorman
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Joris G. Keizer
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Rajib Rahman
- Network for Computational Nanotechnology, Purdue University, West Lafayette, IN 47907, USA
| | - Michelle Y. Simmons
- Centre for Quantum Computation and Communication Technology (CQCT), School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
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Lipatov A, Lu H, Alhabeb M, Anasori B, Gruverman A, Gogotsi Y, Sinitskii A. Elastic properties of 2D Ti 3C 2T x MXene monolayers and bilayers. Sci Adv 2018; 4:eaat0491. [PMID: 29922719 PMCID: PMC6003751 DOI: 10.1126/sciadv.aat0491] [Citation(s) in RCA: 259] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/27/2018] [Indexed: 05/17/2023]
Abstract
Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a large class of materials that are finding numerous applications ranging from energy storage and electromagnetic interference shielding to water purification and antibacterial coatings. Yet, despite the fact that more than 20 different MXenes have been synthesized, the mechanical properties of a MXene monolayer have not been experimentally studied. We measured the elastic properties of monolayers and bilayers of the most important MXene material to date, Ti3C2T x (T x stands for surface termination). We developed a method for preparing well-strained membranes of Ti3C2T x monolayers and bilayers, and performed their nanoindentation with the tip of an atomic force microscope to record the force-displacement curves. The effective Young's modulus of a single layer of Ti3C2T x was found to be 0.33 ± 0.03 TPa, which is the highest among the mean values reported in nanoindentation experiments for other solution-processed 2D materials, including graphene oxide. This work opens a pathway for investigating the mechanical properties of monolayers and bilayers of other MXenes and extends the already broad range of MXenes' applications to structural composites, protective coatings, nanoresonators, and membranes that require materials with exceptional mechanical properties.
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Affiliation(s)
- Alexey Lipatov
- Department of Chemistry, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
| | - Haidong Lu
- Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
| | - Mohamed Alhabeb
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - Babak Anasori
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - Alexei Gruverman
- Department of Physics and Astronomy, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
| | - Yury Gogotsi
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - Alexander Sinitskii
- Department of Chemistry, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska–Lincoln, Lincoln, NE 68588, USA
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Khurgin JB. Replacing noble metals with alternative materials in plasmonics and metamaterials: how good an idea? Philos Trans A Math Phys Eng Sci 2017; 375:rsta.2016.0068. [PMID: 28219999 PMCID: PMC5321829 DOI: 10.1098/rsta.2016.0068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/11/2016] [Indexed: 05/23/2023]
Abstract
Noble metals that currently dominate the fields of plasmonics and metamaterials suffer from large ohmic losses. Some of the new plasmonic materials, such as doped oxides and nitrides, have smaller material loss, and using them in place of metals carries the promise of reduced-loss plasmonic and metamaterial structures, with sharper resonances and higher field concentrations. This promise is put to a rigorous analytical test in this work, which reveals that having low material loss is not sufficient to have reduced modal loss in plasmonic structures. To reduce the modal loss, it is absolutely necessary for the plasma frequency to be significantly higher than the operational frequency. Using examples of nanoparticle plasmons and gap plasmons one comes to the conclusion that, even in the mid-infrared spectrum, metals continue to hold an advantage over alternative media when it comes to propagation distances and field enhancements. Of course, the new materials still have an application niche where high absorption loss is beneficial, e.g. in medicine and thermal photovoltaics.This article is part of the themed issue 'New horizons for nanophotonics'.
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Affiliation(s)
- Jacob B Khurgin
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
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Jung J, Do BC, Yang QD. Augmented finite-element method for arbitrary cracking and crack interaction in solids under thermo-mechanical loadings. Philos Trans A Math Phys Eng Sci 2016; 374:20150282. [PMID: 27242303 PMCID: PMC4901250 DOI: 10.1098/rsta.2015.0282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/07/2016] [Indexed: 06/05/2023]
Abstract
In this paper, a thermal-mechanical augmented finite-element method (TM-AFEM) has been proposed, implemented and validated for steady-state and transient, coupled thermal-mechanical analyses of complex materials with explicit consideration of arbitrary evolving cracks. The method permits the derivation of explicit, fully condensed thermal-mechanical equilibrium equations which are of mathematical exactness in the piece-wise linear sense. The method has been implemented with a 4-node quadrilateral two-dimensional (2D) element and a 4-node tetrahedron three-dimensional (3D) element. It has been demonstrated, through several numerical examples that the new TM-AFEM can provide significantly improved numerical accuracy and efficiency when dealing with crack propagation problems in 2D and 3D solids under coupled thermal-mechanical loading conditions. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.
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Affiliation(s)
- J Jung
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL 33124, USA
| | - B C Do
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL 33124, USA
| | - Q D Yang
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL 33124, USA
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Abstract
The pinning of interfaces and free discontinuities by defects and heterogeneities plays an important role in a variety of phenomena, including grain growth, martensitic phase transitions, ferroelectricity, dislocations and fracture. We explore the role of length scale on the pinning of interfaces and show that the width of the interface relative to the length scale of the heterogeneity can have a profound effect on the pinning behaviour, and ultimately on hysteresis. When the heterogeneity is large, the pinning is strong and can lead to stick-slip behaviour as predicted by various models in the literature. However, when the heterogeneity is small, we find that the interface may not be pinned in a significant manner. This shows that a potential route to making materials with low hysteresis is to introduce heterogeneities at a length scale that is small compared with the width of the phase boundary. Finally, the intermediate setting where the length scale of the heterogeneity is comparable to that of the interface width is characterized by complex interactions, thereby giving rise to a non-monotone relationship between the relative heterogeneity size and the critical depinning stress.
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Affiliation(s)
- Likun Tan
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Kaushik Bhattacharya
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
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