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Heo SJ, Thakur S, Chen X, Loebel C, Xia B, McBeath R, Burdick JA, Shenoy VB, Mauck RL, Lakadamyali M. Aberrant chromatin reorganization in cells from diseased fibrous connective tissue in response to altered chemomechanical cues. Nat Biomed Eng 2023; 7:177-191. [PMID: 35996026 PMCID: PMC10053755 DOI: 10.1038/s41551-022-00910-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 06/14/2022] [Indexed: 11/09/2022]
Abstract
Changes in the micro-environment of fibrous connective tissue can lead to alterations in the phenotypes of tissue-resident cells, yet the underlying mechanisms are poorly understood. Here, by visualizing the dynamics of histone spatial reorganization in tenocytes and mesenchymal stromal cells from fibrous tissue of human donors via super-resolution microscopy, we show that physiological and pathological chemomechanical cues can directly regulate the spatial nanoscale organization and density of chromatin in these tissue-resident cell populations. Specifically, changes in substrate stiffness, altered oxygen tension and the presence of inflammatory signals drive chromatin relocalization and compaction into the nuclear boundary, mediated by the activity of the histone methyltransferase EZH2 and an intact cytoskeleton. In healthy cells, chemomechanically triggered changes in the spatial organization and density of chromatin are reversible and can be attenuated by dynamically stiffening the substrate. In diseased human cells, however, the link between mechanical or chemical inputs and chromatin remodelling is abrogated. Our findings suggest that aberrant chromatin organization in fibrous connective tissue may be a hallmark of disease progression that could be leveraged for therapeutic intervention.
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Affiliation(s)
- Su-Jin Heo
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Shreyasi Thakur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xingyu Chen
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Materials Science Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Claudia Loebel
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Boao Xia
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Rowena McBeath
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jason A Burdick
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
- BioFrontiers Institute and Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Vivek B Shenoy
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Materials Science Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert L Mauck
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA.
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA.
| | - Melike Lakadamyali
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Zwicker D. The intertwined physics of active chemical reactions and phase separation. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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3
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Seguini G, Zanenga F, Cannetti G, Perego M. Thermodynamics and ordering kinetics in asymmetric PS-b-PMMA block copolymer thin films. SOFT MATTER 2020; 16:5525-5533. [PMID: 32500912 DOI: 10.1039/d0sm00441c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The ordering kinetics of standing cylinder-forming polystyrene-block-poly(methyl methacrylate) block copolymers (molecular weight: 39 kg mol-1) close to the order-disorder transition is experimentally investigated following the temporal evolution of the correlation length at different annealing temperatures. The growth exponent of the grain-coarsening process is determined to be 1/2, signature of a curvature-driven ordering mechanism. The measured activation enthalpy and the resulting Meyer-Neldel temperature for this specific copolymer along with the data already known for PS-b-PMMA block copolymers in strong segregation limit allow investigation of the interplay between the ordering kinetics and the thermodynamic driving force during the grain coarsening. These findings unveil various phenomena concomitantly occurring during the thermally activated ordering kinetics at segmental, single chain, and collective levels.
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Affiliation(s)
- Gabriele Seguini
- IMM-CNR, Unit of Agrate Brianza, Via C. Olivetti 2, I-20864 Agrate Brianza, Italy.
| | - Fabio Zanenga
- IMM-CNR, Unit of Agrate Brianza, Via C. Olivetti 2, I-20864 Agrate Brianza, Italy.
| | - Gianluca Cannetti
- IMM-CNR, Unit of Agrate Brianza, Via C. Olivetti 2, I-20864 Agrate Brianza, Italy.
| | - Michele Perego
- IMM-CNR, Unit of Agrate Brianza, Via C. Olivetti 2, I-20864 Agrate Brianza, Italy.
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Weber CA, Zwicker D, Jülicher F, Lee CF. Physics of active emulsions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:064601. [PMID: 30731446 DOI: 10.1088/1361-6633/ab052b] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phase separating systems that are maintained away from thermodynamic equilibrium via molecular processes represent a class of active systems, which we call active emulsions. These systems are driven by external energy input, for example provided by an external fuel reservoir. The external energy input gives rise to novel phenomena that are not present in passive systems. For instance, concentration gradients can spatially organise emulsions and cause novel droplet size distributions. Another example are active droplets that are subject to chemical reactions such that their nucleation and size can be controlled, and they can divide spontaneously. In this review, we discuss the physics of phase separation and emulsions and show how the concepts that govern such phenomena can be extended to capture the physics of active emulsions. This physics is relevant to the spatial organisation of the biochemistry in living cells, for the development of novel applications in chemical engineering and models for the origin of life.
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Affiliation(s)
- Christoph A Weber
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany. Center for Systems Biology Dresden, CSBD, Dresden, Germany. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
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Zwicker D, Hyman AA, Jülicher F. Suppression of Ostwald ripening in active emulsions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:012317. [PMID: 26274171 DOI: 10.1103/physreve.92.012317] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 05/06/2023]
Abstract
Emulsions consisting of droplets immersed in a fluid are typically unstable since they coarsen over time. One important coarsening process is Ostwald ripening, which is driven by the surface tension of the droplets. Stability of emulsions is relevant not only in complex fluids but also in biological cells, which contain liquidlike compartments, e.g., germ granules, Cajal bodies, and centrosomes. Such cellular systems are driven away from equilibrium, e.g., by chemical reactions, and thus can be called active emulsions. In this paper, we study such active emulsions by developing a coarse-grained description of the droplet dynamics, which we analyze for two different chemical reaction schemes. We first consider the simple case of first-order reactions, which leads to stable, monodisperse emulsions in which Ostwald ripening is suppressed within a range of chemical reaction rates. We then consider autocatalytic droplets, which catalyze the production of their own droplet material. Spontaneous nucleation of autocatalytic droplets is strongly suppressed and their emulsions are typically unstable. We show that autocatalytic droplets can be nucleated reliably and their emulsions stabilized by the help of chemically active cores, which catalyze the production of droplet material. In summary, different reaction schemes and catalytic cores can be used to stabilize emulsions and to control their properties.
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Affiliation(s)
- David Zwicker
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
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6
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Abstract
Cellular membranes are a heterogeneous mix of lipids, proteins and small molecules. Special groupings enriched in saturated lipids and cholesterol form liquid-ordered domains, known as "lipid rafts," thought to serve as platforms for signaling, trafficking and material transport throughout the secretory pathway. Questions remain as to how the cell maintains small fluid lipid domains, through time, on a length scale consistent with the fact that no large-scale phase separation is observed. Motivated by these examples, we have utilized a combination of mechanical modeling and in vitro experiments to show that membrane morphology plays a key role in maintaining small domain sizes and organizing domains in a model membrane. We demonstrate that lipid domains can adopt a flat or dimpled morphology, where the latter facilitates a repulsive interaction that slows coalescence and helps regulate domain size and tends to laterally organize domains in the membrane.
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Mitchell SJ, Landau DP. Phase separation in a compressible 2D Ising model. PHYSICAL REVIEW LETTERS 2006; 97:025701. [PMID: 16907460 DOI: 10.1103/physrevlett.97.025701] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Indexed: 05/11/2023]
Abstract
We perform a high precision Monte Carlo study of asymptotic domain growth in a compressible two-dimensional spin-exchange Ising model with continuous particle positions and zero total magnetization, and we investigate the effects of compressibility and lattice mismatch on the late-time domain growth law, R(t) = A + Bt(n). For mismatched systems, we measure significant deviations from the theoretically expected n = 1/3 late-time growth (n = 0.224 +/- 0.004), and for a compressible model with no mismatch, we measure only a slight deviation from n = 1/3. These results strongly suggest that the current understanding of the classes of domain growth is incomplete.
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Affiliation(s)
- S J Mitchell
- Department of Physics, The Center for Simulational Physics, University of Georgia, Athens, 30602-2451, USA.
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Hu Y, Meleson K, Israelachvili J. Thermodynamic equilibrium of domains in a two-component Langmuir monolayer. Biophys J 2006; 91:444-53. [PMID: 16632506 PMCID: PMC1483102 DOI: 10.1529/biophysj.106.081000] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This [corrected] article outlines the results from a combined experimental and theoretical study on the properties of circular domains in a mixed Langmuir monolayer at thermodynamic equilibrium. The mixed monolayer consisted of a binary mixture of dimyristoyl-phosphatidyl-choline and dihydrocholesterol. A long-term fluorescence microscopy study of these domains was carried out over the course of approximately 60 h. Image analysis of the domains over time revealed that the domains ripened slowly with an [corrected] increase in mean domain radius and a [corrected] decrease in domain number density. At the end of the measurement, the domains remained polydisperse, and true thermodynamic equilibrium was not reached. Theoretically, collective thermodynamic equilibrium properties such as mean domain size and size distribution were calculated by combining micelle self-assembly theory and the "equivalent dipole" model for the self-energy of two-dimensional domains. The calculations predicted existence of finite-sized circular domains at equilibrium. This suggests that equilibrium circular monolayer domains of single- or multicomponent lipids with a finite size distribution should form only at very limited experimental conditions. Both the predicted mean domain size and size distribution are strongly affected by line tension and dipole moment density difference. A comparison between the theoretical and experimental results is made.
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Affiliation(s)
- Yufang Hu
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California, USA.
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Asciutto E, Roland C, Sagui C. Self-assembled patterns and strain-induced instabilities for modulated systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:021504. [PMID: 16196570 DOI: 10.1103/physreve.72.021504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Indexed: 05/04/2023]
Abstract
The self-assembled domain patterns of modulated systems are characteristic of a wide variety of chemical and physical systems, and are the result of competing interactions. From a technological point of view, there is considerable interest in these domain patterns, as they form suitable templates for the fabrication of nanostructures. We have analyzed the domains and instabilities that form in modulated systems, and show that a large variety of patterns--based on long-lived metastable or glassy states--may be formed as a compromise between the required equilibrium modulation period and the strain present in the system. The strain results from topologically constrained trajectories in phase space, that effectively preclude the equilibrium configuration.
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Affiliation(s)
- Eliana Asciutto
- Center for High Performance Simulations and Department of Physics, The North Carolina State University, Raleigh, North Carolina 27695-8202 USA
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Sagui C, Asciutto E, Roland C. New and exotic self-organized patterns for modulated nanoscale systems. NANO LETTERS 2005; 5:389-395. [PMID: 15794631 DOI: 10.1021/nl048224t] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The self-assembled domain patterns of modulated systems are the result of competing short-range attractive and long-range repulsive interactions found in diverse physical and chemical systems. From an application point of view, there is considerable interest in these domain patterns, as they form templates suitable for the fabrication of nanostructures. In this work we have generated a variety of new and exotic patterns, which represent either metastable or glassy states. These patterns arise as a compromise between the required equilibrium modulation period and the strain resulting from topologically constrained trajectories in phase space that effectively preclude the equilibrium configuration.
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Affiliation(s)
- Celeste Sagui
- Center for High Performance Simulation and Department of Physics, The North Carolina State University, Raleigh, NC 27695-8202, USA.
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11
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Wickham RA, Shi AC, Wang ZG. Nucleation of stable cylinders from a metastable lamellar phase in a diblock copolymer melt. J Chem Phys 2003. [DOI: 10.1063/1.1572461] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Pays K, Mabille C, Schmitt V, Leal-Calderon F, Bibette J. Understanding the Stability and Lifetime of Emulsions. J DISPER SCI TECHNOL 2002. [DOI: 10.1080/01932690208984198] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Balázsi G, Cornell-Bell A, Neiman AB, Moss F. Synchronization of hyperexcitable systems with phase-repulsive coupling. PHYSICAL REVIEW E 2001; 64:041912. [PMID: 11690057 DOI: 10.1103/physreve.64.041912] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2001] [Indexed: 11/07/2022]
Abstract
We study two-dimensional arrays of FitzHugh-Nagumo elements with nearest-neighbor coupling from the viewpoint of synchronization. The elements are diffusively coupled. By varying the diffusion coefficient from positive to negative values, interesting synchronization patterns are observed. The results of the simulations resemble the intracellular oscillation patterns observed in cultured human epileptic astrocytes. Three measures are proposed to determine the degree of synchronization (or coupling) in both the simulated and the experimental system.
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Affiliation(s)
- G Balázsi
- Center for Neurodynamics, University of Missouri-St Louis, 8001 Natural Bridge Road, St Louis, Missouri 63121-4499, USA
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14
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Mattsson TR, Mills G, Metiu H. A new method for simulating the late stages of island coarsening in thin film growth: The role of island diffusion and evaporation. J Chem Phys 1999. [DOI: 10.1063/1.479152] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Teixeira PI, Mulder BM. Cell dynamics model of droplet formation in polymer-dispersed liquid crystals. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1996; 53:1805-1815. [PMID: 9964442 DOI: 10.1103/physreve.53.1805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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16
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Rutenberg AD. Comment on "Theory of spinodal decomposition". PHYSICAL REVIEW LETTERS 1996; 76:158. [PMID: 10060458 DOI: 10.1103/physrevlett.76.158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Sagui C, Desai RC. Effects of long-range repulsive interactions on Ostwald ripening. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:2822-2840. [PMID: 9963729 DOI: 10.1103/physreve.52.2822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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18
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Sagui C, Desai RC. Late-stage kinetics of systems with competing interactions quenched into the hexagonal phase. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:2807-2821. [PMID: 9963728 DOI: 10.1103/physreve.52.2807] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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