LitCovid-sentences  

PMC:7299399 / 72024-79228 JSONTXT 11 Projects

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Id Subject Object Predicate Lexical cue
T274 0-90 Sentence denotes Nanotechnology-Based Solutions to Increase the Efficiency and Safety of Protective Devices
T275 91-337 Sentence denotes Cryoelectron microscopy (cryo-EM) studies show that SARS-CoV-2 virions are particles near the larger end of the NP size range (70–90 nm).21,201 However, when dispersed into the air, the infectious particles exist as functionally larger particles.
T276 338-617 Sentence denotes Initially, liquid droplets containing coronavirus virions originating from the respiratory tract of infected patients are emitted during normal breathing, forced expiration (e.g., coughing and sneezing), or aerosol-generating medical procedures (e.g., intubation and suctioning).
T277 618-879 Sentence denotes Liquid droplets emitted into the air through these mechanisms originate from points throughout the respiratory tract and carry within them virions as well as other materials associated with the airways, including bacterial cells and epithelial cells (Figure 5).
T278 880-1010 Sentence denotes Droplets are emitted over a wide size range, and their potential viral burden is a cubic function of particle diameter (Figure 6).
T279 1011-1183 Sentence denotes Thus, larger droplets have the potential to carry a significantly larger burden of virions according to their size and are substantially more hazardous than small droplets.
T280 1184-1263 Sentence denotes Once emitted into the air, water from droplets immediately begins to evaporate.
T281 1264-1426 Sentence denotes Water loss is associated with a rapid decrease in both particle diameter and terminal settling velocity (the equilibrium rate of fall of a particle in still air).
T282 1427-1578 Sentence denotes The rate of evaporation of the largest droplets (>150 μm) is often insufficient to slow their swift descent in air, and they impact on nearby surfaces.
T283 1579-1705 Sentence denotes However, the rapid water loss and sharp slowing of settling velocity of smaller droplets enables them to avoid a similar fate.
T284 1706-1873 Sentence denotes Their constituent solid residues are instead drawn together during evaporation and cemented with dried respiratory secretions, and they remain aloft as droplet nuclei.
T285 1874-2017 Sentence denotes Several epidemiological studies have supported the potential for droplet nuclei to be an important means of transmission for SARS-CoV-2.202,203
T286 2018-2109 Sentence denotes Figure 5 Droplets and droplet nuclei as important mechanism for transmission of infection.
T287 2110-2314 Sentence denotes Liquid droplets containing SARS-CoV-2 virions originating from the respiratory tract of infected patients are emitted into the air and carry other materials including bacterial cells and epithelial cells.
T288 2315-2407 Sentence denotes They are reduced in size by evaporation to small, dry particles resulting in droplet nuclei.
T289 2408-2484 Sentence denotes Figure 6 Maximum theoretical viral burden versus droplet nucleus size (nm).
T290 2485-2615 Sentence denotes Assuming a median virion size of about 100 nm, a droplet nucleus of 1 μm diameter could contain up to 370 randomly packed virions.
T291 2616-2685 Sentence denotes A similar 10 μm diameter droplet nucleus could contain up to 360,000.
T292 2686-2877 Sentence denotes In practical terms, however, the size-defining element of a droplet nucleus is determined by the component item with the largest volume, which is often a bacterial cell or an epithelial cell.
T293 2878-2991 Sentence denotes Thus, droplet nuclei in the 1–10 μm size range and above contain far fewer virions than this theoretical maximum.
T294 2992-3140 Sentence denotes Filter media, such as those used in N95 masks and in mechanical ventilation systems, consist of myriad interwoven fibers through which air is moved.
T295 3141-3210 Sentence denotes Their purpose is to arrest particles as they move through the matrix.
T296 3211-3305 Sentence denotes Filters capture particles chiefly by three mechanisms: impaction, interception, and diffusion.
T297 3306-3528 Sentence denotes Impaction occurs when the momentum of a particle propelled toward a filter fiber prevents the particle from diverging around the fiber along the flow lines of the air stream, causing the particle to collide with the fiber.
T298 3529-3631 Sentence denotes Impaction is the primary mechanism responsible for removing particles greater than 500 nm in diameter.
T299 3632-3892 Sentence denotes Interception occurs when a particle diverges around a fiber along the flow lines of the airstream, the distance between the vector of the airstream and the centroid of the particle is smaller than the radius of the particle, and the particle touches the fiber.
T300 3893-3972 Sentence denotes Interception operates efficiently on particles greater than 200 nm in diameter.
T301 3973-4141 Sentence denotes Diffusion is the final important mechanism of particle removal, and it is most effective at removing very fine particles less than 200 nm, especially at low flow rates.
T302 4142-4322 Sentence denotes Particles around 300 nm in diameter are least subject to these three removal mechanisms, and they are considered the “most penetrating” particles for a majority of filter types.204
T303 4323-4654 Sentence denotes When virus-laden droplet nuclei are deposited on filter media, they penetrate the filter matrix to different depths depending on their size characteristics: larger particles tend to become impacted or intercepted nearer the surface of the intake-facing side, whereas smaller particles penetrate more deeply into the fibrous matrix.
T304 4655-4810 Sentence denotes In the case of filtering facepiece masks, cyclical breathing can cause changes in the physical characteristics of particles after they have been deposited.
T305 4811-4938 Sentence denotes Humid exhaled air causes hygroscopic droplet nuclei to swell, becoming larger than they were when captured on filtration media.
T306 4939-5096 Sentence denotes This size change can affect the ability of the filter fibers to retain particles and can lead to redistribution, shedding, or even breakthrough of particles.
T307 5097-5263 Sentence denotes From the standpoint of COVID-19, there are many opportunities for nanotechnology-based solutions to increase the efficiency and safety of air filter and mask devices.
T308 5264-5749 Sentence denotes Some specific opportunities include (i) improving particle capture and retention characteristics, particularly, in the 300 nm diameter size range; (ii) reducing the effects of exhaled humid air on particle redistribution; (iii) rapid inactivation of membrane-bound microbes including enveloped viruses upon capture; and (iv) thin, high-efficiency filtration media for personal masks that are able to be reused repeatedly without loss of efficiency (e.g., novel electrospun nanofibers).
T309 5750-6089 Sentence denotes In this context, recent findings exploring the performance of several fabrics commonly used in cloth masks, alone or in combination, suggest that the combined mechanical and electrostatic effect observed in hybrids enabled enhanced performance with a filtration efficiency >80 and >90% for particle sizes <300 and >300 nm, respectively.205
T310 6090-6225 Sentence denotes Electrospinning is a technique that is widely used to produce nanofibers with diameters smaller than a micrometer (typically, ∼100 nm).
T311 6226-6380 Sentence denotes Even a micron-thin layer of nanofibers can capture the smallest droplets containing viruses and bacteria and prevent them from traveling through the mask.
T312 6381-6568 Sentence denotes TiO2-coated nanofibers deposited on a filter surface by the electrospinning process can capture submicrometer droplets and destroy the virus upon UV irradiation or under natural sunlight.
T313 6569-6859 Sentence denotes After a micrometer-thick film of polyamide 11 nanofibers was deposited on polypropylene filter fabric, TiO2 NPs were directly electrosprayed onto the nanofibers.206 Scanning electron microscopy (Figure 7) demonstrated that nanofibers were uniformly coated by TiO2 NPs without agglomeration.
T314 6860-6970 Sentence denotes TiO2-coated filters showed excellent photocatalytic and bactericidal activity and photoinduced hydrophilicity.
T315 6971-7130 Sentence denotes Figure 7 Scanning electron microscope images of electrospun nanofibers on polypropylene filter fabric (a) and titania-coated electrospun nylon nanofibers (b).
T316 7131-7172 Sentence denotes Reprinted with permission from ref (206).
T317 7173-7204 Sentence denotes Copyright 2010 Springer Nature.