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Blackburn E. Characterizing self-assembled structures made with magnetic Janus nanoparticles. IUCrJ 2024; 11:131-132. [PMID: 38427456 PMCID: PMC10916292 DOI: 10.1107/s2052252524001532] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Small-angle X-ray scattering has revealed how magnetic Janus particles pair up in solutions in small and large magnetic fields.
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Affiliation(s)
- Elizabeth Blackburn
- Division of Synchrotron Radiation Research, Department of Physics, Lund University, SE-22100 Lund, Sweden
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2
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Manna G, Zinn T, Sharpnack L, Narayanan T. Orientational ordering and assembly of silica-nickel Janus particles in a magnetic field. IUCrJ 2024; 11:109-119. [PMID: 38099813 PMCID: PMC10833383 DOI: 10.1107/s205225252301000x] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024]
Abstract
The orientation ordering and assembly behavior of silica-nickel Janus particles in a static external magnetic field were probed by ultra small-angle X-ray scattering (USAXS). Even in a weak applied field, the net magnetic moments of the individual particles aligned in the direction of the field, as indicated by the anisotropy in the recorded USAXS patterns. X-ray photon correlation spectroscopy (XPCS) measurements on these suspensions revealed that the corresponding particle dynamics are primarily Brownian diffusion [Zinn, Sharpnack & Narayanan (2023). Soft Matter, 19, 2311-2318]. At higher fields, the magnetic forces led to chain-like configurations of particles, as indicated by an additional feature in the USAXS pattern. A theoretical framework is provided for the quantitative interpretation of the observed anisotropic scattering diagrams and the corresponding degree of orientation. No anisotropy was detected when the magnetic field was applied along the beam direction, which is also replicated by the model. The method presented here could be useful for the interpretation of oriented scattering patterns from a wide variety of particulate systems. The combination of USAXS and XPCS is a powerful approach for investigating asymmetric colloidal particles in external fields.
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Affiliation(s)
| | - Thomas Zinn
- ESRF – The European Synchrotron, 38043 Grenoble, France
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3
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Miali ME, Chien W, Moore TL, Felici A, Palange AL, Oneto M, Fedosov D, Decuzzi P. Assessing Differential Particle Deformability under Microfluidic Flow Conditions. ACS Biomater Sci Eng 2023; 9:3690-3698. [PMID: 37194468 PMCID: PMC10265569 DOI: 10.1021/acsbiomaterials.3c00120] [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: 01/28/2023] [Accepted: 04/24/2023] [Indexed: 05/18/2023]
Abstract
Assessing the mechanical behavior of nano- and micron-scale particles with complex shapes is fundamental in drug delivery. Although different techniques are available to quantify the bulk stiffness in static conditions, there is still uncertainty in assessing particle deformability in dynamic conditions. Here, a microfluidic chip is designed, engineered, and validated as a platform to assess the mechanical behavior of fluid-borne particles. Specifically, potassium hydroxide (KOH) wet etching was used to realize a channel incorporating a series of micropillars (filtering modules) with different geometries and openings, acting as microfilters in the direction of the flow. These filtering modules were designed with progressively decreasing openings, ranging in size from about 5 down to 1 μm. Discoidal polymeric nanoconstructs (DPNs), with a diameter of 5.5 μm and a height of 400 nm, were realized with different poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) ratios (PLGA/PEG), namely, 5:1 and 1:0, resulting in soft and rigid particles, respectively. Given the peculiar geometry of DPNs, the channel height was kept to 5 μm to limit particle tumbling or flipping along the flow. After thorough physicochemical and morphological characterization, DPNs were tested within the microfluidic chip to investigate their behavior under flow. As expected, most rigid DPNs were trapped in the first series of pillars, whereas soft DPNs were observed to cross multiple filtering modules and reach the micropillars with the smallest opening (1 μm). This experimental evidence was also supported by computational tools, where DPNs were modeled as a network of springs and beads immersed in a Newtonian fluid using the smoothed particle hydrodynamics (SPH) method. This preliminary study presents a combined experimental-computational framework to quantify, compare, and analyze the characteristics of particles having complex geometrical and mechanical attributes under flow conditions.
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Affiliation(s)
- Marco E. Miali
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Wei Chien
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
- Institute
of Biological Information Processing, Forschungszentrum
Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Thomas Lee Moore
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Alessia Felici
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Anna Lisa Palange
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Michele Oneto
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Dmitry Fedosov
- Institute
of Biological Information Processing, Forschungszentrum
Jülich GmbH, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Paolo Decuzzi
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
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4
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Yamakov VI, Rains AA, Kang JH, Das L, Rashid R, Su J, Viggiano RP, Connell JW, Lin Y. Pressure Dependence of Solid Electrolyte Ionic Conductivity: A Particle Dynamics Study. ACS Appl Mater Interfaces 2023. [PMID: 37218678 DOI: 10.1021/acsami.3c01279] [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] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The search for safe, reliable, and compact high-capacity energy storage devices has led to increased interest in all-solid-state battery research. The use of solid electrolytes provides enhanced safety and durability due to their reduced flammability and increased mechanical strength compared to organic liquid electrolytes. Still, the use of solid electrolytes remains challenging. A significant issue is their generally low Li-ion conductivity, which depends on the lattice diffusion of Li ions through the solid phase, as well as on the limited contact area between the electrolyte particles. While the lattice diffusion can be addressed through the chemistry of the solid electrolyte material, the contact area is a mechanical and structural problem of packing and compression of the electrolyte particles depending on their size and shape. This work studies the effect of pressurization on the electrolyte conductivity exploring cases of low as well as high grain boundary (GB) conductivity, compared to the bulk conductivity. Scaling dependence, σ ∼ Pη, of the conductivity σ with pressure P is revealed. For an idealized electrolyte represented as spheres in hexagonal closely packed configuration, η = 2/3 and η = 1/3 have been theoretically calculated for the two cases of low and high GB conductivity, respectively. For randomly packed spheres, the equivalent exponent values were numerically estimated to be approximately 3/4 and 1/2, respectively, which are higher than the closed packed values due to the additional decrease of porosity with the increase in pressure. As demonstrated in the study, experimental measurement of η can indicate which type of bulk or GB conductivity is dominant in a particular electrolyte powder and could be used in addition to electrochemical impedance spectroscopy measurements.
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Affiliation(s)
| | - April A Rains
- NASA Interns, Fellows, and Scholars (NIFS) Program, NASA Langley Research Center, Hampton, Virginia 23681, United States
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Jin Ho Kang
- Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, Virginia 23681, United States
| | - Lopamudra Das
- National Institute of Aerospace, Hampton, Virginia 23666, United States
| | - Rehan Rashid
- NASA Interns, Fellows, and Scholars (NIFS) Program, NASA Langley Research Center, Hampton, Virginia 23681, United States
| | - Ji Su
- Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, Virginia 23681, United States
| | - Rocco P Viggiano
- Materials Chemistry and Physics Branch, NASA Glenn Research Center, Cleveland, Ohio 44135, United States
| | - John W Connell
- Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, Virginia 23681, United States
| | - Yi Lin
- Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, Virginia 23681, United States
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5
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Stiasny K, Medits I, Roßbacher L, Heinz FX. Impact of structural dynamics on biological functions of flaviviruses. FEBS J 2023; 290:1973-1985. [PMID: 35246954 PMCID: PMC10952610 DOI: 10.1111/febs.16419] [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: 01/11/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 11/30/2022]
Abstract
Flaviviruses comprise a number of mosquito- or tick-transmitted human pathogens of global public health importance. Advances in structural biology techniques have contributed substantially to our current understanding of the life cycle of these small enveloped RNA viruses and led to deep insights into details of virus assembly, maturation and cell entry. In addition to large-scale conformational changes and oligomeric rearrangements of envelope proteins during these processes, there is increasing evidence that smaller-scale protein dynamics (referred to as virus "breathing") can confer extra flexibility to these viruses for the fine-tuning of their interactions with the immune system and possibly with cellular factors they encounter in their complex ecological cycles in arthropod and vertebrate hosts. In this review, we discuss how work with tick-borne encephalitis virus has extended our view on flavivirus breathing, leading to the identification of a novel mechanism of antibody-mediated infection enhancement and demonstrating breathing intermediates of the envelope protein in the process of membrane fusion. These data are discussed in the context of other flaviviruses and the perspective of a potential role of virus breathing to cope with the requirements of adaptation and replication in evolutionarily very different hosts.
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Affiliation(s)
- Karin Stiasny
- Center for VirologyMedical University of ViennaAustria
| | - Iris Medits
- Center for VirologyMedical University of ViennaAustria
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6
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Barrios EA, Rains AA, Lin Y, Su J, Connell JW, Viggiano RP, Dornbusch DA, Wu JJ, Yamakov V. Li-Ion Permeability of Holey Graphene in Solid State Batteries: A Particle Dynamics Study. ACS Appl Mater Interfaces 2022; 14:21363-21370. [PMID: 35500131 DOI: 10.1021/acsami.2c03012] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lithium (Li)-ion permeability of holey graphene (hG) for use as an electrically conducting scaffold in solid-state battery electrodes is explored through the means of a particle dynamics simulation model. While carbon materials do not typically exhibit Li-ion conductivity, the unique structural motif of hG, which consists of two-dimensional nanosheets with arrays of through-thickness holes, may present an opportunity for Li-ion conductors (i.e., solid electrolyte (SE) particles) to make contacts through the holes. In our model, the SE is presented as a system of hard elastic spheres conductive to Li-ions. The SE spheres are in contact with each other through compression between two plane current collectors. One hG layer is inserted between the current collectors and parallel to them. Randomly distributed circular holes in the hG allow for contact between the SE particles on both sides of the hG layer. By solving the Li-ion conducting network formed between the electrodes through the contact points of all the particles, the overall conductivity of the system was calculated as a function of SE particle size and the size and number of the hG holes (i.e., hG porosity). A critical ratio of around 4 between the SE particle size and the pore size was found. Below this critical value, the hG layer becomes practically transparent for Li-ions. This study helps to guide the design of highly efficient solid-state electrode composition and architectures using hG as a unique electrically conducting scaffold.
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Affiliation(s)
- Elizabeth A Barrios
- National Institute of Aerospace, Hampton, Virginia 23666, United States
- NASA Marshall Space Flight Center, Huntsville, Alabama 35808, United States
| | - April A Rains
- University of Georgia, Department of Chemistry, Athens, Georgia 30602, United States
| | | | | | | | | | | | | | - Vesselin Yamakov
- National Institute of Aerospace, Hampton, Virginia 23666, United States
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7
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Chaugule V, Wong CY, Inthavong K, Fletcher DF, Young PM, Soria J, Traini D. Combining experimental and computational techniques to understand and improve dry powder inhalers. Expert Opin Drug Deliv 2022; 19:59-73. [PMID: 34989629 DOI: 10.1080/17425247.2022.2026922] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
INTRODUCTION : Dry Powder Inhalers (DPIs) continue to be developed to deliver an expanding range of drugs to treat an ever-increasing range of medical conditions; with each drug and device combination needing a specifically designed inhaler. Fast regulatory approval is essential to be first to market, ensuring commercial profitability. AREAS COVERED : In vitro deposition, particle image velocimetry, and computational modelling using the physiological geometry and representative anatomy can be combined to give complementary information to determine the suitability of a proposed inhaler design and to optimise its formulation performance. In combination they allow the entire range of questions to be addressed cost-effectively and rapidly. EXPERT OPINION : Experimental techniques and computational methods are improving rapidly, but each needs a skilled user to maximize results obtained from these techniques. Multidisciplinary teams are therefore key to making optimal use of these methods and such qualified teams can provide enormous benefits to pharmaceutical companies to improve device efficacy and thus time to market. There is already a move to integrate the benefits of Industry 4.0 into inhaler design and usage, a trend that will accelerate.
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Affiliation(s)
- V Chaugule
- Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC), Department of Mechanical and Aerospace Engineering, Monash University, Clayton Campus, Melbourne, VIC 3800, Australia
| | - C Y Wong
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW 2037, Australia
| | - K Inthavong
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, VIC 3083, Australia
| | - D F Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - P M Young
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW 2037, Australia.,Department of Marketing, Macquarie Business School, Macquarie University, NSW 2109, Australia
| | - J Soria
- Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC), Department of Mechanical and Aerospace Engineering, Monash University, Clayton Campus, Melbourne, VIC 3800, Australia
| | - D Traini
- Respiratory Technology, Woolcock Institute of Medical Research, Sydney, NSW 2037, Australia.,Macquarie Medical School, Department of Biological Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, NSW 2109, Australia
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8
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Wu Y, Zhang H, Li MS, Sheng S, Wang J, Wu FA. A double-population chaotic self-adaptive evolutionary dynamics model for the prediction of supercritical carbon dioxide solubility in polymers. R Soc Open Sci 2022; 9:211419. [PMID: 35116155 PMCID: PMC8767190 DOI: 10.1098/rsos.211419] [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: 09/19/2021] [Accepted: 11/25/2021] [Indexed: 05/03/2023]
Abstract
Solubility of gas in polymers is an important physico-chemical property of foam materials and widely used in the preparation and modification of new materials. Under the conditions of high temperature and high pressure, the dissolution process is a nonlinear, non-equilibrium and dynamic process, so it is difficult to establish an accurate solubility calculation model. Inspired by particle dynamics and evolutionary algorithm, this paper proposes a hybrid model based on chaotic self-adaptive particle dynamics evolutionary algorithm (CSA-PD-EA), which can use the iterative process of particles in evolutionary algorithms at the dynamic level to simulate the mutual diffusion process of molecules during dissolution. The predicted solubility of supercritical CO2 in poly(d,l-lactide-co-glycolide), poly(l-lactide) and poly(vinyl acetate) indicated that the comprehensive prediction performance of the CSA-PD-EA model was high. The calculation error and correlation coefficient were, respectively, 0.3842 and 0.9187. The CSA-PD-EA model showed prominent advantages in accuracy, efficiency and correlation over other computational models, and its calculation time was 4.144-15.012% of that of other dynamic models. The CSA-PD-EA model has wide application prospects in the computation of physical and chemical properties and can provide the basis for the theoretical calculation of multi-scale complex systems in chemistry, materials, biology and physics.
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Affiliation(s)
- Yan Wu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, People's Republic of China
- School of Mathematics and Computer Science, Gannan Normal University, Ganzhou Jiangxi 341000, People's Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212018, People's Republic of China
| | - Hang Zhang
- College of Physics and Electronic Information, Gannan Normal University, Ganzhou Jiangxi 341000, People's Republic of China
| | - Meng-shan Li
- College of Physics and Electronic Information, Gannan Normal University, Ganzhou Jiangxi 341000, People's Republic of China
| | - Sheng Sheng
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, People's Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212018, People's Republic of China
| | - Jun Wang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, People's Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212018, People's Republic of China
| | - Fu-an Wu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, People's Republic of China
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212018, People's Republic of China
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9
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Tiribocchi A, Montessori A, Lauricella M, Bonaccorso F, Brown KA, Succi S. Microscale modelling of dielectrophoresis assembly processes. Philos Trans A Math Phys Eng Sci 2021; 379:20200407. [PMID: 34455845 DOI: 10.1098/rsta.2020.0407] [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] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/04/2021] [Indexed: 06/13/2023]
Abstract
This work presents a microscale approach for simulating the dielectrophoresis assembly of polarizable particles under an external electric field. The model is shown to capture interesting dynamical and topological features, such as the formation of chains of particles and their incipient aggregation into hierarchical structures. A quantitative characterization in terms of the number and size of these structures is also discussed. This computational model could represent a viable numerical tool to study the mechanical properties of particle-based hierarchical materials and suggest new strategies for enhancing their design and manufacture. This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'.
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Affiliation(s)
- A Tiribocchi
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini, 19, 00185 Rome, Italy
| | - A Montessori
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini, 19, 00185 Rome, Italy
| | - M Lauricella
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini, 19, 00185 Rome, Italy
| | - F Bonaccorso
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini, 19, 00185 Rome, Italy
- Department of Physics and INFN, University of Rome 'Tor Vergata', Via della Ricerca Scientifica, 1 00133 Rome, Italy
| | - K A Brown
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA
| | - S Succi
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini, 19, 00185 Rome, Italy
- Institute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
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10
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Hesham O, Wainer G. Advanced models for centroidal particle dynamics: short-range collision avoidance in dense crowds. Simulation 2021; 97:529-543. [PMID: 34366490 PMCID: PMC8293761 DOI: 10.1177/00375497211003126] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Computer simulation of dense crowds is finding increased use in event planning, congestion prediction, and threat assessment. State-of-the-art particle-based crowd methods assume and aim for collision-free trajectories. That is an idealistic yet not overly realistic expectation, as near-collisions increase in dense and rushed settings compared with typically sparse pedestrian scenarios. Centroidal particle dynamics (CPD) is a method we defined that explicitly models the compressible personal space area surrounding each entity to inform its local pathing and collision-avoidance decisions. We illustrate how our proposed agent-based method for local dynamics can reproduce several key emergent dense crowd phenomena at the microscopic level with higher congruence to real trajectory data and with more visually convincing collision-avoidance paths than the existing state of the art. We present advanced models in which we consider distraction of the pedestrians in the crowd, flocking behavior, interaction with vehicles (ambulances, police) and other advanced models that show that emergent behavior in the simulated crowds is similar to the behavior observed in reality. We discuss how to increase confidence in CPD, potentially making it also suitable for use in safety-critical applications, including urban design, evacuation analysis, and crowd-safety planning.
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Affiliation(s)
| | - Gabriel Wainer
- Gabriel Wainer, Department of Systems and Computer Engineering, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S5B6, Canada.
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11
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Palazzolo DL. Editorial: Characteristics and Composition of Aerosol Generated by Electronic Cigarettes: What Is the Impact on Human Health? Front Physiol 2021; 12:719605. [PMID: 34366903 PMCID: PMC8340017 DOI: 10.3389/fphys.2021.719605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/29/2021] [Indexed: 11/15/2022] Open
Affiliation(s)
- Dominic L Palazzolo
- Department of Physiology, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, TN, United States
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12
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Cembranos JAR, Valcarcel JG, Torralba FJM. Non-Geodesic Incompleteness in Poincaré Gauge Gravity. Entropy (Basel) 2019; 21:E280. [PMID: 33266995 DOI: 10.3390/e21030280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 11/17/2022]
Abstract
In this work, we review the study of singularities in Poincaré gauge theories of gravity. Since one of the most recent studies used the appearance of black hole regions of arbitrary dimension as an indicator of singular behavior, we also give some explicit examples of these structures and study how particles behave around them.
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13
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Mondal S, Majumdar A, Griffiths IM. Nematohydrodynamics for colloidal self-assembly and transport phenomena. J Colloid Interface Sci 2018; 528:431-442. [PMID: 30168421 DOI: 10.1016/j.jcis.2018.05.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 05/21/2018] [Accepted: 05/21/2018] [Indexed: 11/27/2022]
Abstract
HYPOTHESIS Colloidal particles in a nematic liquid crystal (NLC) exhibit very different behaviour to that observed in an isotropic medium. Such differences arise principally due to the nematic-induced elastic stresses exerted due to the interaction of NLC molecules with interfaces, which compete with traditional fluid viscous stresses on the particle. THEORY A systematic mathematical analysis of particles in an NLC microfluidic channel is performed using the continuum Beris-Edwards framework coupled to the Navier-Stokes equations. We impose strong homeotropic anchoring on the channel walls and weak homeotropic anchoring on the particle surfaces. FINDINGS The viscous and NLC forces act on an individual particle in opposing directions, resulting in a critical location in the channel where the particle experiences zero net force in the direction perpendicular to the flow. For multi-particle aggregation we show that the final arrangement is independent of the initial configuration, but the path towards achieving equilibrium is very different. These results uncover new mechanisms for particle separation and routes towards self-assembly.
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Affiliation(s)
- Sourav Mondal
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK
| | - Apala Majumdar
- Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, UK
| | - Ian M Griffiths
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK.
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14
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Lindesmith LC, Mallory ML, Debbink K, Donaldson EF, Brewer-Jensen PD, Swann EW, Sheahan TP, Graham RL, Beltramello M, Corti D, Lanzavecchia A, Baric RS. Conformational Occlusion of Blockade Antibody Epitopes, a Novel Mechanism of GII.4 Human Norovirus Immune Evasion. mSphere 2018; 3. [PMID: 29435493 DOI: 10.1128/mSphere.00518-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/05/2018] [Indexed: 12/29/2022] Open
Abstract
Extensive antigenic diversity within the GII.4 genotype of human norovirus is a major driver of pandemic emergence and a significant obstacle to development of cross-protective immunity after natural infection and vaccination. However, human and mouse monoclonal antibody studies indicate that, although rare, antibodies to conserved GII.4 blockade epitopes are generated. The mechanisms by which these epitopes evade immune surveillance are uncertain. Here, we developed a new approach for identifying conserved GII.4 norovirus epitopes. Utilizing a unique set of virus-like particles (VLPs) representing the in vivo-evolved sequence diversity within an immunocompromised person, we identify key residues within epitope F, a conserved GII.4 blockade antibody epitope. The residues critical for antibody binding are proximal to evolving blockade epitope E. Like epitope F, antibody blockade of epitope E was temperature sensitive, indicating that particle conformation regulates antibody access not only to the conserved GII.4 blockade epitope F but also to the evolving epitope E. These data highlight novel GII.4 mechanisms to protect blockade antibody epitopes, map essential residues of a GII.4 conserved epitope, and expand our understanding of how viral particle dynamics may drive antigenicity and antibody-mediated protection by effectively shielding blockade epitopes. Our data support the notion that GII.4 particle breathing may well represent a major mechanism of humoral immune evasion supporting cyclic pandemic virus persistence and spread in human populations. IMPORTANCE In this study, we use norovirus virus-like particles to identify key residues of a conserved GII.4 blockade antibody epitope. Further, we identify an additional GII.4 blockade antibody epitope to be occluded, with antibody access governed by temperature and particle dynamics. These findings provide additional support for particle conformation-based presentation of binding residues mediated by a particle "breathing core." Together, these data suggest that limiting antibody access to blockade antibody epitopes may be a frequent mechanism of immune evasion for GII.4 human noroviruses. Mapping blockade antibody epitopes, the interaction between adjacent epitopes on the particle, and the breathing core that mediates antibody access to epitopes provides greater mechanistic understanding of epitope camouflage strategies utilized by human viral pathogens to evade immunity.
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Bhattacharyya S, Kim K, Teizer W. Remodeling Tau and Prion Proteins Using Nanochaperons. ACTA ACUST UNITED AC 2017; 1:e1700108. [PMID: 32646192 DOI: 10.1002/adbi.201700108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/16/2017] [Indexed: 11/08/2022]
Abstract
There is increasing evidence that tau protein behaves in a prion-like manner in tauopathy. The stabilization of tau protein using a small molecular compound can limit tauopathy associated morbidity that advances with ageing. Here, a lab-on-a-chip experiment is reported, where gold citrate nanoparticles (5 nm, AuNPs) can remodel mutant tau protein (P301L) and prion, thus resolving the mutant tau- and prion-mediated impairment of kinesin cargo transport on microtubules. It is found that tau protein is overexpressed in Alzheimer's disease (AD) patient serum samples and the tau conformational change can also be affected in human serum samples of AD when treated with AuNPs ex vivo. Similarly, AuNPs reorganizing the prion protein and inducing conformational changes of prions in AD serum have been observed, while having no effect on alpha-synuclein in Parkinson patient serum. The mapping of AD serum mediated traffic jams, using particle tracking and mean square displacement analysis, and the observed recovery of uninterrupted processive motor functions by AuNP treatment show that kinesin cargo assays might be a useful method for future ex vivo validation of a targeted therapy against tauopathy before administration, a viable option to combat various neurodegenerative disorders arising from the susceptibility of amyloidogenic proteins toward aggregation.
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Affiliation(s)
- Sanjib Bhattacharyya
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Kyongwan Kim
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Winfried Teizer
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.,Department of Physics and Astronomy, Texas A&M University, College Station, TX, 77843, USA.,Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843, USA
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Urbani R, Westermeier F, Banusch B, Sprung M, Pfohl T. Brownian and advective dynamics in microflow studied by coherent X-ray scattering experiments. J Synchrotron Radiat 2016; 23:1401-1408. [PMID: 27787246 DOI: 10.1107/s1600577516012613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 08/04/2016] [Indexed: 06/06/2023]
Abstract
Combining microfluidics with coherent X-ray illumination offers the possibility to not only measure the structure but also the dynamics of flowing samples in a single-scattering experiment. Here, the power of this combination is demonstrated by studying the advective and Brownian dynamics of colloidal suspensions in microflow of different geometries. Using an experimental setup with a fast two-dimensional detector and performing X-ray correlation spectroscopy by calculating two-dimensional maps of the intensity auto-correlation functions, it was possible to evaluate the sample structure and furthermore to characterize the detailed flow behavior, including flow geometry, main flow directions, advective flow velocities and diffusive dynamics. By scanning a microfocused X-ray beam over a microfluidic device, the anisotropic auto-correlation functions of driven colloidal suspensions in straight, curved and constricted microchannels were mapped with the spatial resolution of the X-ray beam. This method has not only a huge potential for studying flow patterns in complex fluids but also to generally characterize anisotropic dynamics in materials.
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Affiliation(s)
- Raphael Urbani
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland
| | - Fabian Westermeier
- Max Planck Institute for the Structure and Dynamics of Matter, CFEL, 22761 Hamburg, Germany
| | - Benjamin Banusch
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland
| | - Michael Sprung
- Photon Science, Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Thomas Pfohl
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland
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Kurzak J, Mirkovic D, Pettitt BM, Johnsson SL. AUTOMATIC GENERATION OF FFT FOR TRANSLATIONS OF MULTIPOLE EXPANSIONS IN SPHERICAL HARMONICS. Int J High Perform Comput Appl 2008; 22:219-230. [PMID: 19763233 PMCID: PMC2744990 DOI: 10.1177/1094342008090915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The fast multipole method (FMM) is an efficient algorithm for calculating electrostatic interactions in molecular simulations and a promising alternative to Ewald summation methods. Translation of multipole expansion in spherical harmonics is the most important operation of the fast multipole method and the fast Fourier transform (FFT) acceleration of this operation is among the fastest methods of improving its performance. The technique relies on highly optimized implementation of fast Fourier transform routines for the desired expansion sizes, which need to incorporate the knowledge of symmetries and zero elements in the input arrays. Here a method is presented for automatic generation of such, highly optimized, routines.
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Affiliation(s)
- Jakub Kurzak
- DEPARTMENT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE, UNIVERSITY OF TENNESSEE, KNOXVILLE, TENNESSEE 37996 ( )
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