cord-005112-9mxqwqty	2009	Nanopore-based methods are used for single DNA molecule analysis and the capacitance counter is useful in liquids of low electrical conductivity and in sensing the changes of cell contents. In this paper, we review the major advancement of microfluidic particle counting techniques: microfluidic resistive repulse sensors, nanopore sensors, capacitance counters, light-scattering and light-blocking detectors, fluorescent detectors, and micro particle image velocimetry (PIV) counters. The microfluidic resistive pulse technique applies the basic working principle of the Coulter counter to microchannels for counting micro-and sub-micron particles. The key advantages of the microfluidic RPS include label-free particle detection and simplicity without other peripheral complex instruments other than a simple electric circuit and a micro-or nano-scale sized channel. They coupled the RPS with laser fiber-optic fluorescence technique to demonstrate a flow cytometer LOC that is able to detect fluorescent and non-fluorescent particles simultaneously, and the RPS signal-to-noise ratio is improved significantly.
cord-006892-n2ncamqh	2018	For example, chemical conjugation of mannoside-based saccharides on the surface of Rabbit hemorrhagic disease virus (RHDV) VLP selectively targets the mannose receptor expressed on the surface of APCs, inducing increased uptake and alteration of antigen cross-presentation in murine dendritic cells [57] . While the induction of a potent humoral immune response and the subsequent production of anti-VLP antibodies is the primary desired outcome of most commercial VLP vaccines, these is increasing appreciation for the role of vaccine-induced cell-mediated immunity [123] [124] [125] . Novel Epstein-Barr virus-like particles incorporating gH/gL-EBNA1 or gB-LMP2 induce high neutralizing antibody titers and EBV-specific T-cell responses in immunized mice Induction of immune memory following administration of a prophylactic quadrivalent human papillomavirus (HPV) types 6/11/16/18 L1 virus-like particle (VLP) vaccine. Antigen incorporated in virus-like particles is delivered to specific dendritic cell subsets that induce an effective antitumor immune response in vivo
cord-006947-nrzjedhi	2017	Keywords: membranes, nanoparticles, capillary interactions, lipid bilayers, emulsions, viruses, interfaces (Some figures may appear in colour only in the online journal) For micrometer-sized particles, the contrib ution of the line tension is negligible; the trapping energy is proportional to the liquid-vapor interface tension γ v and decreases with decreasing contact angle, see figure 6 . Reprinted with permission from [78] copyright of The Royal Society of Chemistry (f) Deformation profiles of an interface around a particle with Hauser''s cube shape at contact angle θ = 56.28 Whether a particle stabilizes or destabilizes a film furthermore depends on the orientation that the particle assumes at the interface [102] , see section 2.4. Because the energy for an orientation where only one spherical particle is in contact with an interface does not depend on the tilt angle, an arrest in such a state could be caused by surface roughness.
cord-007131-q0cy9dej	2006	It is important to predict the environment around the breathing human because inhalation of virus (avian influenza, SARS) is recently severe worldwide problem, and air pollution caused by diesel emission particle (DEP) and asbestos attract a great deal of attention. In the present study, three‐dimensional numerical simulation was carried out to predict unsteady flows around a breathing human and how suspended particulate matter (SPM, diameter∼1 μm) reaches the human nose in inhalation and exhalation. In the calculation, we find out smaller breathing angle and the closer distance between the human nose and pollutant region are effective in the inhalation of SPM. (3) The particle captured efficiency tends to become higher and particles tend to reach the human nose faster as the breathing angle becomes smaller. (3) The particle captured efficiency tends to become higher and particles tend to reach the human nose faster as the breathing angle becomes smaller.
cord-007363-h8xa83nw	2019	On the other hand, the Eulerian approach, which treats the dispersed particles as a continuous phase, has gained relatively higher reputation in saving computational cost and simulating pollutant concentration, whilst it cannot predict particle motions or provide particle transport tracks. Rim and Novoselac (2009) once investigated experimentally the airflow field and human thermal plume in a displacement ventilated room containing a seated manikin, which had a very similar setup with the model of this study. In terms of the PSI-C method, the computational domain needs firstly to be divided into a number of small control volumes (or cells, which are for post-processing purpose only and are different to the computational meshes), then a number of particle trajectories are selected for concentration calculation from the numerical results yielded from the E-L model. Both the Eulerian-Eulerian model and the Eulerian-Lagrangian model were employed in this study to simulate particulate contaminant transport in a displacement ventilated room containing a thermal manikin.
cord-008454-8brxpotx	2008	The morphology of negatively stained virus particles is sufficient for grouping purposes but it is necessary to use immune electron microscopy (IEM) to differentiate morphologically identical but antigenically distinct viruses. Virus particles are sometimes present in such large numbers in clinical specimens that they can be detected directly by electron microscopy and negative staining methods in particular can be used to provide a rapid diagnosis. Immune electron microscopy on sectioned material presents considerable technical difficulties and viral content of tissue homogenates may be too low for negative stain IEM so a virus seen in the tissue cannot always be sufficiently well identified for diagnostic purposes. Similarly, thin section studies on livers of marmosets infected with hepatitis A virus showed cytoplasmic picornavirus-like particles which could be extracted for use as antigen to detect antibodies by negative stain IEM (Provost et al., 197513) and by complement fixation (Provost et al., 1975a) .
cord-008917-ek8rp4kh	1980	971) report that they have seen pleomorphic coronavirus-like particles in a specimen of human faeces and postulate that these may have derived from an intestinal yeast-like organism and suggest Blastocystis (now believed to be a protozoon 1). Moreover, in general, there exists a large species variation in therapeutic or toxic effects of chemical substances, and additionally an interspecies difference exists in drug metabolism and pharmacological response, especially to liposoluble drugs 2-all of which points should be considered when extrapolating our findings in rats to man. Nevertheless, we feel very strongly that those drugs which evoke a positive response in our rat model are potentially harmful in the hereditary porphyrias and should be avoided. In our experience, 25% of patients with premyxoedema have a normal basal TSH but exaggerated response to thyrotrophin-releasing hormone (TRH). Coronavirus particles in faeces from patients with gastroenteritis
cord-009769-cql7go58	2011	In order to characterize alveolar flow patterns and inhaled particle transport during synchronous ventilation, we have conducted measurements for a range of dimensionless parameters physiologically relevant to the upper acini. The current work focuses on the effect of geometric and dynamic parameters on fluid flow and particle transport in the upper acini (respiratory bronchioles). Since the alveolar geometry, Reynolds and Womersley numbers, and the resulting flow patterns vary along the acinar tree, fluid mixing and dispersion, and particle transport may exhibit differences across acinar generations. Despite an overall similarity between the flow patterns, the alveolar fluid exhibits smaller velocities for smaller DV/V at each time step during a complete breathing cycle: the inward/outward velocities during peak inhalation/exhalation are smaller and show that particle deposition is highest for DV/V 5 0.5 after 5 and 10 cycles. This paper presents alveolar flow patterns and particle transport results for a range of geometric and dynamic parameters within the acinar region of the human lung.
cord-009825-6cargkwy	2014	The review summarizes knowledge about size‐dependent particle deposition in different regions of the respiratory tract, techniques for measuring indoor bioaerosols, and evidence for diseases caused by airborne exposure to bioaerosols. Then, the article proceeds to discuss several additional processes that can affect indoor bioaerosol levels: deposition onto room surfaces, bioaerosol intrusion from outdoor air, indoor emission sources, and other factors, including bioaerosol control, airborne growth and decay, and indoor transport and mixing. In the summaries to follow, I highlight several field-sampling studies whose results provide important clues about bioaerosol concentrations, associated particle-size distributions, and potential influencing factors. The importance of deposition as a removal mechanism for airborne bioaerosol particles can be explored by comparing b to the air exchange rate. For these larger particles, deposition is an important mechanism influencing the fate of bioaerosols even for buildings with relatively high air exchange rates.
cord-010022-e19vm7vp	2006	This technique was termed immune electron microscopy and the virus-like particles were called Norwalk agent.* It is estimated that these two agents account for 50% of hitherto undiagnosed gastroenteritis around the world. Even more recently electron microscopy and immune electron microscopy have been shown to be critical techniques for detecting new virus-like particles associated with gastroenteritis in humans. Caliciviruses, also approximately 28 to 30 nm in size, have been associated with diarrhea in human infants according to several Additional small round viruses (27 to 40 nm) have been distinguished by electron microscopy in fecal specimens from infants with nonbacterial gastroenteritis. Visualization by immune electron microscopy of a 27-nm particle associated with acute infectious nonbacterial gastroenteritis Small round virus-like particles associated with acute gastroenteritis in Japanese children Detection by immune electron microscopy of 26-27 nm virus-like particles associated with two family outbreaks of gastroenteritis
cord-010910-hz2vyw6c	2020	title: Macrophage-like THP-1 cells show effective uptake of silica nanoparticles carrying inactivated diphtheria toxoid for vaccination Porous silica has been identified as an effective adjuvant for more than a decade, and we have therefore investigated the take up rate by an immortalized macrophage-like cell line of a number of mesoporous silica nanoparticles (MSNPs) with differing diameter and pore size. Our previous work compared the antigen loading and unloading capacity of mesoporous silica nanoparticles (MSNPs), with a variety of different pore sizes, and external diameters (Huang et al. To assess the uptake of the different silica nanoparticles, and to determine whether this was affected by size, porosity or loading, we tested the ability of the particles to be taken up into macrophage-like cells. We investigated a range of sizes of silica nanoparticles to determine the effect on uptake by THP-1 macrophage-like cells.
cord-022504-tk7v4hoj	2012	During the process, large volumes of ultrapure water are consumed to clean the surface of the wafer, which generates large quantity of CMP wastewater typically having high solid content resulting from slurry abrasive particles of SiO 2 , Al 2 O 3 , or CeO 2 , depending on the nature of the CMP application. 7.2.6.2 Industrial processes with cleanrooms Cleanrooms and associated controlled environments (e.g., in the case of an ISO Class 3 cleanroom, the maximum permissible airborne particle concentration is less than 10 3 particles/m 3 for particles with the size of 0.1 m or larger, while the airborne particle concentration in ordinary indoor environments is on the order of 10 9 particles/m 3 or higher) are usually adopted to avoid particle contamination in industrial processes where precision products such as engineered nanoparticles, semiconductors, and other electronic or optical devices are fabricated because the deposition of particles onto product surfaces causes their yield reduction and quality deterioration.
cord-022538-1g9kmpdi	2008	During the process, large volumes of ultrapure water are consumed to clean the surface of the wafer, which generates large quantity of CMP wastewater typically having high solid content resulting from slurry abrasive particles of SiO 2 , Al 2 O 3 , or CeO 2 , depending on the nature of the CMP application. Cleanrooms and associated controlled environments (e.g., in the case of an ISO Class 3 cleanroom, the maximum permissible airborne particle concentration is less than 10 3 particles/m 3 for particles with the size of 0.1 m or larger, while the airborne particle concentration in ordinary indoor environments is on the order of 10 9 particles/m 3 or higher) are usually adopted to avoid particle contamination in industrial processes where precision products such as engineered nanoparticles, semiconductors, and other electronic or optical devices are fabricated because the deposition of particles onto product surfaces causes their yield reduction and quality deterioration.
cord-031037-up0z1yaf	2020	In an open-labeled randomized controlled human study of 68 subjects with common cold infections including rhinoviruses and coronaviruses, as well as enterovirus and influenza A virus, nasal delivery of 2-3% hypertonic saline 2-8 times a day (median thricea-day) significantly lowered duration of illness, as well as use of over-the-counter medications, household transmissions, and viral shedding (Ramalingam et al., 2019) . Suppression of bioaerosol by delivery of the FEND aerosol relative to placebo control occurred particularly at the high dose (see Supplemental Material for lower doses), as shown in Fig. 5a , with six of the eight subjects breathing out over the duration of 12 h post treatment, a significantly lower mean particle count per liter relative to placebo (p < 0.05). Our finding that nasal inspiration of FEND in a group of 10 healthy human subjects reduces exhaled particles between 45 and 99% by way of an aerosol too large to penetrate the lower airways (Figs 8 and 9) , suggests that the upper airways are a primary source of expired bioaerosol.
cord-032161-sbtu48c2	2013	• The summit point can be obtained from the lognormal distribution curve of light scattering probably depends on the particle area or volume; when the problem is related to the light refraction property, arithmetic average diameter D 1 should be used, because this property depends on the dimension of particle length. If particle diameters follow normal distribution, a straight line will be obtained when the abscissa represents the particle size and the ordinate means the cumulative distribution frequency. If particle size distribution is quite different from normal distribution, such as an extreme case shown in Fig. 1 .23 which represents the sampled particle size distribution curve in the cleanroom air, large deviation could be found when the lognormal probability graph paper is plotted.
cord-032165-nyj72o21	2013	So the total deposition amount of particles on the surface with area 1 cm 2 per hour can be obtained in the cleanroom, where the airborne particle concentration is 1,000 pc/L and the air velocity is 0.3 m/s. Table 6 .11 shows the comparison of measured data and calculated data about the deposition amount of particles on the surface with unit area in the room with air supply. In the flowing air, small particles will follow the movement of airflow with the same velocity [10] . From the above analysis, when there is air supply with a certain speed in the room where the indoor area is very small, the buoyant flow generated will cause very large influence, when the fluorescent lamp was installed at a relative high position of the vertical wall (such as above 1.5 m).
cord-032174-qu5mm9r1	2013	The reading value of the flowmeter 20 L/min is the indication value in the calibration condition, so the actual flow rate q 1 through the flowmeter should be According to the actual collected particle concentration 18.31 L/min after correction, the calculated indoor particle concentration is 371.4#/L, so the indoor air cleanliness level does not reach Class 7. The example of the application of Fig. 16 .10 is shown as follows: When the particle counter with small sampling volume 2.83 L/min is used to detect particles with diameter 5 μm (only for this particle size) from airflow with velocity 0.5 m/s, should any correction be made? For the common particle counters with large, medium, and small sampling flow rates at home and abroad, Reynolds numbers Re in the sampling tube are shown in Table 16 .3. So the following requirement must be satisfied: For particle counter with medium and low sampling flow rates, calculation results are shown in Table 16 .4.
cord-032188-y02b92pe	2013	When the air filter is operated under lower flow rate, the efficiency increases and the pressure drop decreases. This is because the dust deposited is comparatively large for air filters with low efficiency and the filter medium is sparse, which will cause particles to penetrate when pressure drop increases and cause deposited particles to rebound and resuspend. Particle counting efficiency of glass fibrous medium-efficiency air filter (d f ¼ 16 μm, H ¼ 20 mm, α ¼ 0.037, v ¼ 0.28 m/s) with atmospheric dust was performed at Institute of HVAC of China Academy of Building Research, which is shown in Table 4 .13. The pressure drop of nuclear microporous membrane is large, so it is not suitable for common air filter, but it is very useful for special filtration (for the application field where particles with diameter larger than certain value are not allowed to penetrate).
cord-102908-sr7j8z9c	2020	We used differential binary labelling and statistical modelling to extract estimates of stoichiometry, our strategy is outlined in Figure 1 ; note that this approach can be generalised to apply to many other multi-component systems (i.e. how many protein x are found in assembly y?). As described above, our experimental design utilizes antibody labelled with spectrally distinct dyes allowing binary scoring of individual virus particles as positive if they interact with at least one Ab B molecule ( Figure 1 ). We have demonstrated quantitative analysis of 9C12 interaction with individual Adv particles ( Figure 3) ; we have confirmed that differential labelling of antibody does not bias binding ( Figure 4A & B) ; and that we could detect single molecules of 9C12 Biotin allowing discrimination of positive and negative AdV-9C12 complexes ( Figure 4C & D). However, using stoichiometric estimates to calibrate fluorescent data revealed population heterogeneity with a small proportion of virus particles binding ∼200 antibody molecules.
cord-222700-yof5x4ct	2020	We reveal an efficient separation strategy via the counterintuitive effect of negative mobility when particles of a given size are transported in a direction opposite to the applied constant force. Motivated by the large size range encountered in biochemical applications, a crucial result of this work is a demonstration of a tunable separation strategy, in which the size of the particle undergoing separation may be effectively controlled by variation of the parameters characterizing the external force applied to the particle, e.g. the magnitude of the static bias. Therefore, in contrast, in this work we harvest the negative mobility effect to develop the particle separation strategy in which the particle size intended for isolation will be controlled by changing only the parameters characterizing the externally applied force, namely, the static bias f or the amplitude a or the frequency ω of the harmonic driving.
cord-233294-jnic4o2j	2020	We studied the effects of air purification (on/off), door condition (open/close), and particle sizes on the temporal concentration distribution of particles. Furthermore, research on the effects of air purifiers is needed to develop guidelines and protocols to reduce waiting time between patients and ensure the safe operation of dental offices. Figure 4a shows the lowest particle concentrations in the room when the high-speed air purifier is running from the beginning of the operation. The particle removal time varies with particle size although the air purifier and open door help reduce the concentration of all-size particles in the generation zone. • In the worst-scenario scenario with no protection system in the closed-door office and continuous high-speed drilling, it takes 95 min for 0.5 m particles to return to background level and that it takes a shorter time for particles larger than 0.5 m to be removed from the air. Running high-speed air purifier at the beginning of the operation is the most effective scenario in reducing airborne particle concentrations.
cord-252147-bvtchcbt	2011	Modular protein engineering, virus-like particles (VLPs), and other self-assembling entities are envisioned as modulatable novel protein nanoparticles able to include many desirable properties in the correct delivery of drugs and nucleic acids. 120 Modular fusion proteins that combine distinct functions required for cell type-specific uptake and intracellular delivery of DNA or drugs present an attractive approach for the development of self-assembling vectors for targeted gene or drug delivery. 215, 216 Although VLP-based vaccines have been primarily developed for their use against the corresponding virus, in the last decades genetic engineering or chemical modifications have been applied in order to generate chimeric VLPs. Thus, on the one hand, commonly short heterologous peptide epitopes or full proteins that are unable to form VLPs or that are unsafe for vaccination have been presented on surface-exposed loops or fused to N-or C-exposed termini of structural viral capsid proteins on VLPs. 154, 161, 210 Different HPV, 217-219 HBV, 220,221 parvovirus, 222, 223 and chimeric polyoma VLPs have been engineered 170, 175 and tested for different applications including vaccination against viral or bacterial diseases, against virus-induced tumors, and more recently, for immunotherapy of nonviral cancer.
cord-253092-igic5pxc	2016	The objective of this study is to analyze outdoor particle penetration and transport, and their impact on indoor air, in a multi-zone and multi-story building using a CONTAMW simulation. The results of the particle simulation also indicated that the airflow characteristics, combined with deposition rates, cause the lower floors of a multi-story building to be exposed to higher fine particle concentrations compared with the upper floors of the building. A careful computer simulation study with reliable inputs for key simulation parameters, such as the particle penetration coefficient and deposition rate, may be capable of providing comprehensive insights for understanding particle transport in multi-story buildings. In this study, a field test on the reference building was conducted using the natural decay method to identify the particle size-resolved penetration coefficient and deposition rate; the obtained values were used as simulation parameters.
cord-253922-qjsd3whg	1995	title: Shedding of "virus-like" particles in canine faeces Abstract Diarrhoeic faeces from about 500 dogs were examined by negative stain electron microscopy. As well as parvovirus, and some of the other recognised viral causes of gastroenteritis, unusual "virus-like" particles were observed in about 8% of the samples. An additional 74 samples of normal faeces yielded no "virus-like" particles. During this work we observed unusual "virus-like" particles similar to those recorded by Hamilton et al. The "virus-like" particles were usually spherical and had a thick wall which was penetrated by numerous pores (Fig. I ) . Parvovirus particles were observed in some samples containing the viruslike particles ( Fig. 8) We have observed these "virus-like" particles in diarrhoeic canine faeces from 198 1 to 1994. Perhaps the "virus-like" particles are some structures associated with bacteria or parasites in the gut of dogs. Viruses and virus-like particles in the faeces of dogs with and without diarrhoea
cord-255314-mqexsqzj	2008	title: Impact of Health on Particle Size of Exhaled Respiratory Aerosols: Case‐control Study A setup composed of a modified hood connected to an electrical low pressure impactor, which allows for the study of a wide range of particle sizes (from 7 nm to 10 μm), has been developed in order to collect exhaled breaths. As a consequence, further research on the exhaled breath should be undertaken with symptomatic volunteers and would require the analysis of this wide range of particle sizes. In particular, it is not possible at present to determine the impact of volunteer health on the particle size of exhaled respiratory aerosols. The experimental approach consisted of firstly developing a system that allows measurement of fine particles exhaled from a greater numbers of volunteers (78 individuals), with and without, symptoms. Following this, the size differences between aerosols emitted by symptomatic volunteers and controls were determined.
cord-258118-j26v354r	2020	Apart from the numerous chemicals, surgical smoke had been shown to harbour intact bacterial and virus particles especially COVID-19 in the current time. OBJECTIVE: To identify the inhalational, infectious, chemical, and mutagenic risks of surgical smoke and suggest evidence-based hazard reduction strategies. Heating of tissues causes vaporisation of protein and fat which results surgical smoke(2) which contain particles from combustion and numerous chemicals like hydrocarbons, acrylonitrile, phenols and fatty acids and biological particles, viruses, and bacteria which are known to be potentially hazardous. In COVID-19 outbreak scenario, the use of surgical diathermy has to be minimised or avoided due to the very high risk of viral spread among operating room personals. Multiple precautions like use of a standard surgical mask, laser or high filtration mask, masks coated with nanoparticles, operating room ventilation guidelines, and use of wall suction have been using to reduce the health hazards, but each one has its own limitations.
cord-258762-vabyyx01	2020	To address the clinical implication over a long period of time, the systems approach is built upon previous work on multi-scale modeling of surgical flow in a large operating room suite and takes into account human behavior factors. Clinical environments are too complex to model with the traditional modeling method of airflow and particle transportation because both the source intensity of surgical smoke [19] as well as the mechanism of propagation via door openings [20] are largely dominated by human factors. The indoor air quality is a linear set of differential equations that will be slightly more complex than a standard compartment model since the coefficient will be stochastic, the sources and output/leaks of the particles term will have a time delay built in, and the hallway will require a transport equation.
cord-261908-olcuq6tm	2011	The fate of the droplet nuclei on inhalation also depends on their size; particles greater than five microns are likely to remain in the upper airways but smaller particles are more likely to deposit in the alveoli and so may transmit infections of the lower respiratory tract such as tuberculosis [22, 23] . The large number of aerosols emitted by the vuvuzela raises the possibility that, if used by persons with an infection of the respiratory tract, they could act a conduit for the spread of infectious particles. To obtain the desired trumpet sound when blowing the vuvuzela air is forced through the lips into the opening of the instrument which may serve to create further aerosols, or alter the size of droplets produced elsewhere in the respiratory tract. Exhale duration, peak air velocity, particle concentration and mean particle diameter recorded during playing the vuvuzela and shouting by four male and four female volunteers.
cord-265164-ybh5yljw	2004	The drift flux model, which considers the settling of particles or droplets under the effect of gravitational sedimentation, is adopted to simulate the droplets transport and distribution indoors during respiration and sneezing or coughing process, while the simplified model for solving the continuous fluid flow is combined. The results show that droplets or particles generated by normal breathing process transport a relatively short distance, while droplets or particles generated during coughing or sneezing may travel much longer distances, which may pose adverse effect on human bodies for defending the SARS or other infectious diseases. To calculate the three-dimensional and non-isothermal airflow inside ventilated rooms, a well validated simplified methodology combined with N-point air supply opening model [4] , a zero equation turbulence model [5] is applied. Numerical studies on the transport and distribution of particles or droplets generated by normal respiration and sneezing or coughing indoors result in the following conclusions:
cord-265642-7mu530yp	2019	Using protein expression systems it is possible to produce virus-like particles (VLPs), which are made up of monomers, which are able to multimerize into VLPs, and display the antigenic determinants of target pathogens on their surface. For example, in different laboratories different eukaryotic systems for viral protein expression, including plant cells, are used to produce VLPs which are used for vaccination against the hepatitis C virus (HCV) [36] . Antigen of the duck hepatitis A virus produced in the baculovirus expression system assembles into VLPs immediately in the cultured Spodoptera frugiperda (sf9) cells, while immunization of ducklings with the obtained VLPs induces a high level humoral immune response and protects them from developing the disease [46] . Expression vectors for foreign protein production in plants have been developed based on plant viruses, which allows obtaining plant-producing recombinant viruses or VLPs displaying the target antigen on their surface [101, 102] .
cord-271616-h6iauddk	2013	We hypothesize that the surface charge distribution of the clay and virus envelope dictates how the components react and affect aggregation, viral stability, and infectivity. Edge-attached viral envelopes distort to increase contact area with the positively charged platelet edges indicating that the virion surface is negatively charged. The MMT-mediated sequestration and disassembly result in reduced infectivity, suggesting that clays may reduce infectivity of enveloped pathogenic viruses in soils and sediments. Figure 4 shows an aggregate of clay platelets and partially disassembled virions (dashed arrows) and MMT-NCs (solid arrows). As the detergent-isolated NC particles in the aggregates retain their original morphology, the interaction with the clay is likely weaker than that between the MMT and the partially disassembled virions. Interactions between colloidal clay and suspended viral particles result in the stripping of the viral envelope and a consequent loss of infectivity of the phage φ6.
cord-272248-d0ybu9o3	2020	In consideration of these occasions, the present study aims to simulate airborne pathogen projection through breathing, coughing, and sneezing during the ophthalmic examination and suggest preventive measures for diminishing transmission. In order to understand the social distancing phenomenon and airborne pathogen spread during the ophthalmic examination, two scenarios with two different conditions based on exit flow velocities were considered: The configurations for these cases are depicted in Fig. 2 . For instance, in case of an exit flow of~12,000 mm/s without any preventive action, Fig. 4 Airborne particle projection during the ophthalmic examination with the protective breath shield: a exhalation (the maximum flow velocity at the exit from the patient''s mouth is~1000 mm/s), b coughing/sneezing (the maximum flow velocity at the exit from the patient''s mouth is~12,000 mm/s) the average horizontal distance of the flow front was obtained to be~1300 mm.
cord-273382-7w8fli6w	2020	title: In vitro comparison of surgical techniques in times of the SARS-CoV-2 pandemic: electrocautery generates more droplets and aerosol than laser surgery or drilling Five typical surgical intervention techniques (mechanical stress with a passive instrument with and without suction, CO(2) laser treatment, drilling and bipolar electrocoagulation) were examined and compared regarding resulting particle release. The aim of the presented study was therefore to develop an experimental setup for the simultaneous assessment of aerosol and particle formation in various typical ENT interventions. Similarly, no particle or aerosol formation was detected during mechanical impact by use of a passive instrument in direct tissue contact with additional suction (cf. The laser treatment of the tissue did not lead to a detectable particle formation at any of the three points in time of the analysis (see Fig. 3 , third line).
cord-274305-mnyy41po	2020	The purpose of this review, therefore, is to examine (1) what is currently known regarding the physics of aerosol creation, (2) the types of environmental contaminants generated by dental procedures, (3) the nature, quantity, and sources of microbiota in these contaminants and (4) the risk of disease transmission from patients to dental healthcare workers. Well‐controlled, large‐scale, multi center studies using atraumatic air harvesters, open‐ended methods for microbial characterization and integrated data modeling are urgently needed to characterize the microbial constituents of aerosols created during dental procedures and to estimate time and extent of spread of these infectious agents. The purpose of this review, therefore, is to examine what is currently known regarding the physics of aerosol creation, the types of aerosols generated by dental procedures, the nature, quantity, and sources of microbiota in these aerosols and the probability of disease transmission from patients to dental healthcare workers.
cord-274355-6hiutrct	2020	This study investigates the transport mechanism and deposition patterns of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) within a typical six bedded general inpatient ward cubicle through numerical simulation. Although it is widely assumed that increasing the air change rate (ACH) can reduce infection risks, it was shown that the risk of exposure to pathogens could increase with an increased ventilation rate under certain circumstances BUILD SIMUL https://doi.org/10.1007/s12273-020-0623-4 Satheesan et al. As the number of research studies on ventilation systems for general inpatient wards with respect to air change rate and exhaust airflow rate is limited, this study evaluates the combined impacts of these two parameters on the airflow as well as infection risk distributions of droplet nuclei of size 0.167 μm (i.e. MERS-CoV) within an air-conditioned general inpatient ward cubicle. Furthermore, the randomness associated with particle deposition rates (r w , r c , and r f ) under different air change rate conditions can be attributed to the asymmetric airflow distribution patterns and locations of the infected patients.
cord-274780-fmnro0kw	1981	Astroviruses were detected by electron microscopy in the feces from a 4 month old kitten with diarrhea. Astroviruses were detected by electron microscopy in the feces from a 4 month old kitten with diarrhea. The clinical disease manifested by the cat and the observed morphology of the viral particles are consistent with previous reports on astroviruses of other species. The clinical disease manifested by the cat and the observed morphology of the viral particles are consistent with previous reports on astroviruses of other species. Viral antigen was detected by indirect immunofluorescent staining within the cytoplasm of cultured cells infected with fecal material of human (10, 11) and bovine (23) astroviruses. Studies on the pathogenesis of astrovirus infection in lambs have shown the site of virus multiplication to be the mature villous epithelial cells of the small intestine (21, 22) .
cord-276323-0n4aws2q	1980	Examination of the differentially centrifuged ultracentrifugation pellet of the patient''s stool by electrorimicroscopy with negative staining revealed large numbers of "coronavirus-1ike particles" type 34 ( fig. Those vesicles that were separate from the rest showed projections from their surface that were similar to the projections seen in the coronavirus-like particles visualised by negative staining, (fig. SiR,&mdash;An endogenous opioid neurotransmitter system whose activation mimics exogenous opiate action had been postulated for many years but has only recently been describe.1,2 There is now compelling evidence that corticotrophin (ACTH) and (3-lipotropin/ (3-endorphin are formed from a larger recursor protein which has been called pro-ACTH/endorphin..5 ACTH and &bgr;-LHP/&bgr;endorphin are located and stored in the same cells and secretory granules within the pituitary, and under all stimulatory and inhibitory conditions all fragments are released together.3-5 In animals the major source of plasma &bgr;-LPH/&bgr;-endorphin is the pituitary so that a reduced concentration in the pituitary causes reductions in circulating blood levels of P-LPH, (3-endorphin, ACTH, and cortisol.
cord-279716-kxfc4npg	2007	Background Influenza virus was used to characterize the efficacy of a cyclone‐based, two‐stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles. Results Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two‐stage bioaerosol sampler. In order to quantify the relative amount of viral particles or fungal spores collected at each stage of the bioaerosol sampler, qPCR was performed in parallel using either serial 10-fold dilutions of cDNA generated from a single dose of non-aerosolized FluMist Ò containing approximately 10 7 TCID 50 per influenza strain or genomic DNA isolated from 10 7 spores. In this study, by aerosolizing FluMist Ò , we demonstrate the recovery of aerosolized viral particles using the bioaerosol sampler and detection of influenza by qPCR.
cord-280272-mn596x1p	2020	We have tested the ability of magnetic Nanotrap® (NT) particles to improve stability and detection of Venezuelan equine encephalitis virus (VEEV), viral capsid protein, and viral genomic RNA in whole human blood at elevated temperature and prolonged storage conditions. We have tested the ability of magnetic Nanotrap ® (NT) particles to improve stability and detection of Venezuelan equine encephalitis virus (VEEV), viral capsid protein, and viral genomic RNA in whole human blood at elevated temperature and prolonged storage conditions. In this study, we sought to apply new magnetic NT particles that consist of NIPAm copolymers functionalized with reactive red 120 to evaluate the efficacy of preservation of infectious VEEV, viral RNA, and VEEV capsid protein in whole blood samples at ambient and elevated temperature as well as at low and high humidity conditions.
cord-282858-zikoui4h	2020	Its predecessor, SARS-CoviD-1, the agent that caused Severe Acute Respiratory Syndrome (SARS) in Hong Kong in 2003, showed strong evidence of opportunistic airborne transmission in different environments, such as collective housing environments (8) , indoor environments such as airplanes (9), and health service institutions (10) . (12) that suggested transmission of SARS-CoV-2 through infected surfaces and contaminated individual protection equipment as well as long distance environment contamination. In health care settings, the Center for Disease Control''s recommendations for prevention of airborne transmission include maintaining a negative pressure environment, fine filtering of exhaust air from infected patients'' rooms, maintaining high air exchange rates (12 air exchanges per hour), shutting recirculation ducts, and establishing pressure cascades (2) in these settings until further evidence of long distance transmission is obtained Unfortunately, these precautionary measures have not yet been applied in most health care facilities in Brazil. Evidence of Airborne Transmission of the Severe Acute Respiratory Syndrome Virus
cord-285077-okwck5sv	2020	CONCLUSION: Coblation and electrocautery procedures generate >100-fold increases in aerosol concentrations over background; only coblation and drilling produce aerosolized viral DNA. Coblation and electrocautery procedures generate .100-fold increases in aerosol concentrations over background; only coblation and drilling produce aerosolized viral DNA. 10, 11 We proposed to build on these studies by measuring particle size and concentration and by trying to detect aerosolized viral DNA and viable virus during common otolaryngology procedures, using a murine model for cytomegalovirus (CMV) infection. The results also indicated that drilling and microdebrider did not cause statistically significant increases in aerosol concentrations and total counts when compared with background (.870 \ Tukey-adjusted P value \ .930; Figures 2 and 3 , Table 3 ). The results from our study demonstrate that a number of these procedures can generate relatively large concentrations of aerosolized particles and that a significant percentage are small enough to pass unimpeded through conventional surgical and even N95 masks.
cord-286878-5nv3ec5l	2020	Using an in‐situ simulation model, we evaluated laryngoscopist exposure of airborne particles sized 0.3 ‐ 5.0 microns using five aerosol containment devices (aerosol box; sealed box with and without suction; vertical drape; and horizontal drape) compared with no aerosol containment device. Compared with no device use, the aerosol box showed an increase in 1.0, 2.5 and 5.0 micron airborne particle exposure at 300 seconds (p = 0.002, 0.008, 0.002, respectively). To guide our institutional protocols for the airway management of patients with suspected or confirmed COVID-19, we sought to test whether different aerosol containment devices confer any protective advantage to the laryngoscopist specifically with respect to airborne particle dispersal. Our primary research question was how aerosol containment devices (aerosol boxes and plastic drapes) placed over a patient during tracheal intubation compare to no intervention with respect to exposure of the laryngoscopist to airborne particles?
cord-287708-0qvwjejv	2020	We studied the application of pulsed laser ablation (PLA) for particle size reduction in non-steroidal anti-inflammatory drugs (NSAIDs). In this work, three NSAIDs (ibuprofen, meloxicam and niflumic acid) with different chemical structures but similar solubility, dissociation constant, particle size and crystallinity were selected as targets to study the effect of a high-energy pulsed laser beam on the chemical degradation and particle size distribution of the ablated drug particles. We studied the chemical composition and particle size distribution of the ablated particles, the optical absorption of the target drugs and made fast photography measurements too. Size distribution (measured by SMPS) of ibuprofen particles produced by laser ablation at 532 nm and 1064 nm wavelengths can be seen in Fig. 6 . conclusion PLA can be applied for the size reduction of poorly water-soluble NSAIDs. In the case of meloxicam, ibuprofen and niflumic acid, submicron to nanometer size particles can be produced by careful selection of the laser parameters, reducing the initial mean average sizes by orders of magnitude.
cord-287751-52e0tlcu	2020	To reduce the influence of dilution on quantitative source estimates, a methodology for improving the accuracy of source apportionment results by incorporating a measure of dispersion, the ventilation coefficient, into the PMF analysis (called dispersion normalized PMF, DN-PMF) was applied to a PNC dataset measured from a field campaign that includes the Spring Festival event and the start of the COVID-19 lockdown in Tianjin, China. In addition to measured PNC data, auxiliary variables include gaseous pollutants (SO 2 , NO 2 , CO and O 3 ), PM 1 , PM 1-2.5 (PM 2.5 -PM 1 ), radiation and selected potential source tracer species (OC, EC, NO 3 -analyses to support factor interpretation. The best solution with the optimal number of factors was evaluated with selection criteria of appropriately narrow distributions of scaled residuals of PNCs and the physical interpretability of factors in terms of (a) examination of size factor profiles and its association with external variables, (b) source directionality from CBPF plots, and (c) diel patterns.
cord-289521-zun6tp2o	2020	title: Reducing aerosol dispersion by High Flow Therapy in COVID‐19: High Resolution Computational Fluid Dynamics Simulations of Particle Behavior during High Velocity Nasal Insufflation with a Simple Surgical Mask Here, we present a subsequent high‐resolution simulation (higher complexity/reliability) to provide a more accurate and precise particle characterization on the effect of surgical masks on patients during HVNI, Low‐Flow Oxygen therapy (LFO2), and tidal breathing. METHODS: This in‐silico modeling study of HVNI, LFO2, and tidal breathing presents ANSYS Fluent Computational Fluid Dynamics simulations that evaluate the effect of Type I surgical mask use over patient face on particle/droplet behavior. The in-silico model included a room simulation to evaluate the fluid dynamic behavior of the effect of a surgical mask on particles which may be generated in the airway while receiving HVNI therapy. Simulations were performed on control cases modeling a patient on HVNI (40L•min -1 ), Low Flow Oxygen (LFO2) therapy (6L•min -1 via Nasal Cannula), and simulated breathing (tidal breathing, no therapy) without a surgical mask.
cord-292928-a4bn30ul	2015	This review also provides the information on the concentration levels of various airborne microorganisms in different indoor environments, their associated health effects as well as various bioaerosol control mechanisms worked upon till now. A recently developed electrostatic precipitator had no charging unit in the inlet while the physical collection efficiency strongly depended on the precipitation voltage which eventually depended on the charge present on the airborne microbes naturally due to aerosolization (Kunkel, 1950; Flagan, 2001 ) thereby making collection possible by differentiating between the positively and negatively charged microorganisms by adding a signature to the bioaerosol particle sampled (Lee et al., 2004a; ; Lee et al., 2004b) . Whole genome sequencing has also been applied to study the airborne microbial community in various indoor and outdoor environments of NYC after collecting air samples using a Wet Cyclone Portable Air Sampler at the flow rate of 450 L/min (Yooseph et al., 2013) .
cord-297377-yy1dq81q	2020	Breath shields have long been a standard feature of slit lamps and act as a physical barrier between the examiner and subject but there is an absence of evidence on their effectiveness in reducing droplet transmission and respiratory infections. We then tested the effect of placing a fluid resistant surgical facemask (BARRIER 4313, Mölnlycke Healthcare, Sweden) over the nebuliser mouthpiece alone and in combination with the large shield. The surgical facemask and large shield offered the best protection, while the small standard shield seemed to be effective for larger particles (Fig. 2) . Evidence from a large-clusterbased randomised control trial showed no benefit from using N95 masks compared to surgical facemasks to reduce influenza and other respiratory viral illnesses [8] . Despite the close proximity of slit lamp examinations, the effectiveness of shielding together with the short contact time and lack of aerosol generation, leads us to expect the risk of transmission from this route to be low.
cord-300435-vs0ntcsb	2018	Four sediments in the colloidal size range: goethite, montmorillonite, illite, and kaolinite, were suspended with the bacteriophage φ6, a model enveloped virus, to determine relative rates of heteroaggregation and the effect of aggregation on virus viability. A study of heteroaggregation of the non-enveloped cowpea mosaic virus with colloidal hematite revealed that at pH 6, at which hematite carries a positive surface charge and the virus a negative charge, the aggregates accumulated four times as many viruses as hematite particles Vilker et al. In this work, we employ turbidity measurements to investigate the heteroaggregation of a model envelope virus, the bacteriophage φ6, with colloidal goethite and three clay minerals: illite, kaolinite and montmorillonite. Although imprecise knowledge of doublet shape complicates calculations of heteroaggregation rates, analysis of the turbidity slope coupled with particle concentrations allows one to determine relative aggregation rates between φ6 and the four sediment types, elucidating the nature of the interaction.
cord-304048-wncau6zm	2011	This paper investigated the microparticle deposition and distribution due to the presence of duct bends by employing the Eulerian approach with Reynolds stress turbulent model and a Lagrangian trajectory method. Furthermore, models of fast power and exponential decay trend are demonstrated to uncover the relationship among enhancement factor of deposition velocity behind bend, dimensionless distance behind bends and particle Stokes number. Where N d and N f are the particle number deposited in a bend and those in the straight duct of fully developed flow section with a length D, respectively. Particle deposition distribution and deposition velocity in 90 ventilation bends with different surface materials were analyzed numerically, and the simulation results were also validated with experimental data.
cord-306371-jmaqkovs	2010	The present study evaluated parameters of importance for spray drying of siRNA-loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) into nanocomposite microparticles intended for inhalation. The identified optimum conditions were applied for spray drying of siRNA-loaded nanocomposite microparticles, resulting in a product with a low water content (0.78% w/w) and an aerodynamic particle diameter considered suitable for inhalation. In conclusion, the present results show that spray drying is a suitable technique for producing nanocomposite microparticles comprising siRNA-containing PLGA NPs for potential use in inhalation therapy. To overcome the macrophage clearance and still benefit from a particle size suitable for deep lung deposition and sustained release, the present study employs nanocomposite microparticles consisting of co-spray-dried PLGA NPs and a carbohydrate excipient. The optimum formulation found to provide a low water content, a sufficient yield and a small particle size was with mannitol as the carbohydrate excipient, a total dry substance concentration of 30 mg/ mL and a ratio of NPs to excipient of 0.2.
cord-310948-nt378esz	2020	Objective: To determine the effectiveness of non-medical grade washable masks or face coverings in controlling airborne dispersion from exhalation (both droplet and aerosol), and to aid in establishing public health strategies on the wearing of masks to reduce COVID-19 transmission. If the SARS-CoV-2 aerosol is considered with an ability to infect for more than 3 hours with TCID50 of greater than 10 2 as noted in a recent laboratory study [1] then the understanding the effectiveness of non-medical masks and face coverings to control human exhalation aerosol dispersion has significant importance for broad public health infectious disease strategy, especially with asymptomatic or pre-symptomatic populations. The goal of this research is to determine the statistically significant factors and effectiveness of non-medical grade washable masks or face coverings in the control of aerosol dispersion of human exhalation, and to aid in establishing public health strategies or policies on the wearing of masks.
cord-311311-rmv5rfst	2020	Three advances to be discussed in detail are (1) recognition and inclusion of sampler wall deposits; (2) development of a new sampling and analytical procedure for respirable crystalline silica that allows non-destructive field analysis at the end of the sampling period; and (3) development of a new sampler to collect the portion of sub-300 nm aerodynamic diameter particles that would deposit in human airways. Three advances to be discussed in detail are (1) recognition and inclusion of sampler wall deposits; (2) development of a new sampling and analytical procedure for respirable crystalline silica that allows non-destructive field analysis at the end of the sampling period; and (3) development of a new sampler to collect the portion of sub-300 nm aerodynamic diameter particles that would deposit in human airways. RCS is collected on a direct-on-filter (DoF) sampler (EoS™ Silica Cassette, Zefon International, Inc.) attached to any one of several different cyclones to select the respirable dust fraction.
cord-311486-auuyjct6	2020	For clarity, I neither stated that particles above 5 µm were large nor referred at all to whether these are visible or not and I am unclear why these are referred to in Professor Murphy''s letter. However, the behaviour of particles is highly complex, not dependent only on size and much debated: as I stated in my article "the dichotomy into> 5 and < 5 µm particles leading to droplet or airborne spread, respectively, is likely to be simplistic, with aerosols being maintained over a wider range of particle size". I infer that Professor Murphy''s concerns are that larger particles than described contribute to aerosols and therefore that airborne transmission is a significant risk, and that the 2 m ''droplet zone'' is insufficient. Personal protective equipment during the coronavirus disease (COVID) 2019 pandemic -a narrative review Personal protective equipment during the coronavirus disease (COVID) 2019 pandemic -a narrative review The role of particle size in aerosolised pathogen transmission: a review
cord-312223-qgwzgazd	2013	RESULTS: Screening of NanoTrap particles indicated that one particle, NT53, was the most efficient at RVFV capture as demonstrated by both qRT-PCR and plaque assays. RVFV that was inactivated through either detergent or heat treatment was still found bound to NT53, indicating the ability to use NanoTrap particles for viral capture prior to transport to a BSL-2 environment. Our study demonstrates that NanoTrap particles are capable of capturing whole virus, and can be assayed with both qRT-PCR and plaque assays. A) Seven different types of NanoTrap particles were incubated with viral supernatants containing RVFV (1E+7 pfu/ml) for 30 minutes at room temperature and washed 4 times with water. In order to determine if the amplification observed in the qRT-PCR assay was due to the NanoTrap particle capturing intact viral particles or association of viral RNA (presumably due to lysed virus) with the particles, plaque assays were performed.
cord-312236-8eaqn8eu	2007	Aerosol droplet dispersion and transport in a ventilated enclosure depend on the ventilation scheme, particle size, density, concentration, source location, etc. The key objectives of the present work are (i) to apply the new Eulerian approach to study droplet dispersion and transport in a ventilated room, and (ii) to highlight the influence of droplet sizes and ventilation scheme on mixing characteristics. To investigate droplet nuclei dispersion and transport using the new drift-flux approach, an enclosure with two identical model occupants with heat energy dissipated is selected (Fig. 1 ). Fig. 4 shows the combined results modeled by the drift-flux and Lagrangian approaches at the breathing plane and the mid-plane for 0.75 and 2 s elapsing from the commencing of the droplet emitting process. Inferring from the results presented, it can be observed that for the well-mixed ventilation scheme, the dispersion pattern is dominated by the high velocity airflow, and the different between droplet sizes is not obvious.
cord-313825-bbjxd86y	2016	The lung is the first target organ for air pollution and PM exposure is associated with reduced lung function, increased lung inflammation, asthma, respiratory infections, lung cancer and exacerbation of COPD, which lead to systemic inflammation and oxidative stress affecting blood, vasculature, heart and brain, ultimately contribute to the premature mortality ( Fig. 2) [3, 8, 14, 16] . These specific features of UFPs can significantly contribute to the adverse effects through ROS over-production by the redox-active organic chemicals and metals on particle surface, resulting in cellular oxidative stress [18, 19, 21, 44, 48] . These include: (i) carbon core of PM and UFPs could induce ROS generation and oxidative stress; (ii) catalytic conversion of PAHs to quinones by cytochrome P450 in the endoplasmic reticulum; (iii) quinone redox cycling by NADPH-dependent P450 reductase in microsomes; (iv) mitochondrial perturbation leading to electron leakage in the inner membrane; and (v) NADPH oxidase activity in the macrophage surface membrane and associated phagosomes.
cord-313971-czcs1y9w	2014	Specifically, in section 2, we identify the sources, species, size distributions, and concentrations of Identifying the source of microorganisms and dust in livestock production systems helps to elucidate how airborne transmission is generated, and ultimately can help to develop and implement strategies that prevent such transmission from beginning (Bull et al., 2006; Cambra-Lopez, 2010) . Investigations of the size distribution of microorganisms and dust in livestock production systems may provide a useful overview of their quantitative importance, indicate the health risk for human and animals, and facilitate the establishment and evaluation of control techniques. Previous studies showed that the biological decay of airborne microorganisms was species-dependent and was determined by many external factors, such as humidity, oxygen concentration, temperature, ozone concentration, radiation (UV, γ -ray, X-ray), air ions, and air pollutants (CO, SO 2 , and NO x ; Benbough, 1971; Lighthart, 1973) .
cord-314009-7t1bzc7f	2016	The modern definition of an adjuvant includes not only classical immune stimulators but also any aspects of particle size, shape, and surface chemistry that enhance vaccine immunogenicity. 71 A self-assembling nanofibrous hydrogel induced an antibody response when tested as a vaccine delivery platform, either alone or formulated with CpG adjuvant (TLR9 agonist) as a delivery system for recombinant hepatitis B surface antigen (HBsAg). 73, 74 For example, 165 nm-diameter liposomes assembled from cationic lipid, cationic polymer, and plasmid DNA were shown to target antigen to draining lymph nodes, resulting in enhanced DC activation and immunity. These particles were specifically designed to electrostatically interact with commercial hemagglutinin antigens to generate an influenza vaccine with enhanced immune responses compared with the hemagglutinin alone. Advax, a polysaccharide adjuvant derived from delta inulin, provides improved influenza vaccine protection through broad-based enhancement of adaptive immune responses
cord-318495-1w74wf02	2019	The demonstration of hotspots for the generation of copyback DVGs from respiratory syncytial virus (RSV) and the identification of specific nucleotides that determine where copy-back DVGs rejoin further demonstrate that the generation of copy-back DVGs is not completely random, but instead that specific sequences encoded in the viral genome direct or facilitate their formation 50 in some infections, DVG generation is not a completely stochastic process and, instead, virus-encoded sequences favour the production and/or amplification of predominant DVGs. It remains to be determined whether conservation is a property of certain DVG types and which specific sequences and/or RNA structures lead to DVG generation in these conditions. Persistent infection with infectious pancreatic necrosis virus mediated by defective-interfering (DI) virus particles in a cell line showing strong interference but little DI replication I Interferon-inducing defective-interfering particles as mediators of cell sparing: possible role in persistent infection by vesicular stomatitis virus
cord-319221-x834qscq	2020	The present study investigates aerosol transport and surface deposition in a realistic classroom environment using computational fluid-particle dynamics simulations. Other strategies for COVID-19 mitigation may include the use of glass screens as barriers to reduce aerosol transport between people in the room, opening windows, and redistributing students in classrooms, but the ability of these measures to reduce aerosol transmission from one person to another needs to be carefully evaluated. The objective of the present work is to investigate aerosol transport and surface deposition in a model classroom environment using computational fluid-particle dynamics (CFPD) simulations. Figure 4 shows the effect of particle size on the fraction of aerosol particles released from student 5''s mouth that deposit on different surfaces in the room, such as ground, ceiling and walls, desks, and students, or escape from the outlet of the air conditioning system.
cord-322880-zfc9w5y6	2020	title: Respiratory droplets get suspended longer and spread wider in temperate environments compared to tropics and implications for SARS-CoV-2 transmission The combined effect of change in size of the droplet as well as the density amplifies the influence that environmental relative humidity would have on the particle settling velocity. It is possible that droplets discharged from infected individuals in places like New York City could shrink in size quickly and remain airborne for considerable period of time. A simple understanding of the mechanics of droplet size, dispersion and displacement could help infection control and public health measures to minimize spread and mitigate the risk of people getting infected especially in hotspots like hospital environments or other closed spaces. A simple understanding of the mechanics of droplet size, dispersion and displacement could help infection control and public health measures to minimize spread and mitigate the risk of people getting infected especially in hotspots like hospital environments or other closed spaces.
cord-324585-2rx84imv	2020	13 −16 In this paper, we report the results of experiments where we measure the filtration efficiencies of a number of common fabrics, as well as selective combinations for use as hybrid cloth masks, as a function of aerosol sizes ranging from ∼10 nm to 6 μm. 25 There have been a few studies reported on the use of cloth face masks mainly during or after the Influenza Pandemic in 2009; [8] [9] [10] [11] [12] 26 However, there is still a lack of information that includes (i) the performance of various fabrics as a function of particle size from the nanoscale to the micron sized (particularly important because this covers the ∼10 nm to ∼5 μm size scale for aerosols) and (ii) the effect of hybrid multilayer approaches for masks that can combine the benefits of different filtering mechanisms across different aerosol size ranges.
cord-325915-dw989txm	2014	The number of publications [24, [38] [39] [40] [41] [42] [43] [44] [45] [46] and patents [301] [302] [303] describing the purification or concentration of virus particles by centrifugation methods demonstrates that these procedures are extensively used at industrial-and small-scale levels for viral vectors and vaccine production processes. In summary, the main advantages of ultrafiltration compared with other methods are their high-throughput and (for the concentration of active virus particles) the gentle processing at optimal operating conditions [43, 47] that results in improved efficacies for purification of viral vectors for gene therapy. Considering a complete purification train for the production of vaccines or gene therapy vectors (Figure 1) , current improvements of the dynamic binding capacities in chromatography media might facilitate the removal of the initial concentration step within the downstream process.
cord-326409-m3rgspxc	2007	authors: Lai, Alvin C.K.; Chen, F.Z. title: Comparison of a new Eulerian model with a modified Lagrangian approach for particle distribution and deposition indoors Results reveal that the standard k–ε Lagrangian model over-predicts particle deposition compared to the present turbulence-corrected Lagrangian approach. In the present work, we compared particle distribution and deposition rates for a small model chamber by the two approaches. (1), while within the concentration boundary layer, the particle wall flux is determined with a one-dimensional semi-empirical particle deposition model (Lai and Nazaroff, 2000) and the results are substituted into Eq. Overall speaking, the results modeled by the two approaches agree well with each other; as the particle size increases, the deposition fraction increases. For submicron particles, the deposition fractions predicted by Lagrangian (without near-wall turbulent correction) is higher than those predicted with correction and Eulerian drift flux prediction follows. Modeling indoor particle deposition from turbulent flow onto smooth surfaces
cord-327507-ic3tdx59	2020	The present prospective study investigated the quantitative and qualitative particle load in the operating room (OR) depending on location, time of surgery and use of laminar air flow (LAF) system. However, recommendations of existing reviews or meta-analyses examining the use of LAF systems in reduction of surgical site infection (SSI) are usually based on inhomogeneous studies with different types and sizes of LAF systems [13, 14, 17, 18] , where there may also be a lack of standardization of possible cofounders (antibiotic prophylaxis, patient related risk factors). The aim of the present study is therefore to evaluate the quantitative and qualitative particle load in the operating room depending on the measurement location (inside LAF area, margin of LAF area and outside LAF panel), the time of surgery and the use of a LAF system.
cord-329135-g8fuax6p	2016	Numerous successful studies are described that point to best practice in bioaerosol sampling, from the use of small personal samplers to monitor workers'' pathogen exposure through to large static samplers collecting airborne microbes in various healthcare settings. 11, 53 If the target microbe is unknown and a general assessment of bioaerosol particles present in an environment is sought, then the use of different types of sampling devices will mitigate the limitations of individual samplers, making a comprehensive study more likely. Correlation between active and passive sampling was also described during a study comparing different ventilation regimes in OTs. 12 Using a Surface Air System sampler (SAS, International Pbi, Milan, Italy) operating at 180 L/min and settle plates, both with tryptic soy agar, the study showed that unidirectional airflows within OTs did not guarantee low counts of airborne bacteria. Effect of sampling time and air humidity on the bioefficiency of filter samplers for bioaerosol collection
cord-329137-5pw07qje	2012	In addition, immature HAstV bears a striking resemblance to the structure of hepatitis E virus (HEV)-like particles, as previously predicted from structural similarity of the crystal structure of the astrovirus spike domain with the HEV P-domain [Dong, J., Dong, L., Méndez, E. Similarities between their capsid shells and dimeric spikes and between the sequences of their capsid proteins suggest that these viral families are phylogenetically related and may share common assembly and activation mechanisms. Immature, uncleaved particles, which are strikingly similar in appearance to HEV-like particles (HEV-lp), 14 Trypsin cleavage of the coat protein between the conserved (white boxes) and variable (shaded boxes) domains is required for viral maturation. If the cleaved proteins remain noncovalently associated with the capsid shell, then one would still expect to see surface density in the images of individual particles, even if the polypeptides do not conform to icosahedral symmetry.
cord-332255-7sxioviw	1982	The pathogenesis of porcine rotavirus in gnotobiotic piglets was studied by light microscopy (LM) , fl uorescent antibody technique (FA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and it was demonstrated that clinical signs were correlated with viral replication and with induced virus lesions in the small intestine (McAdaragh, Bergeland, Meyer, Johnshoy, Stotz, Benfield and Hammer, 1980; Narita, Fukusho, Konno and Shimizu, 1982; Pearson and McNulty, 1979; Theil, Bohl, Cross, Kohler and Agnes, 1978; Torres-Medina and Underdahl, 1980) . The present paper describes the morphological changes in infected intestinal cells of 2-day-old piglets inoculated orally with porcine rotavirus and discusses the penetration of virus into the absorptive cells. These infected cells had lost most of their staining density and contained many virus particles within the distended RER. In the cytoplasm of the infected cells, non-membrane bound, granular matrices containing an electron-dense virus core were present (Fig. 8) .
cord-336901-q6kgzuob	2015	To apply this method to real-time detection of airborne microorganisms, airborne Escherichia coli, Bacillus subtilis, and Staphylococcus epidermidis cells were introduced into the micro-optofluidic platform via bioaerosol generation, and a liquid-type particle collection setup was used. In comparison with traditional microscopy cell counting and colony culture methods, this micro-optofluidic platform is not only more accurate in terms of the detection efficiency for airborne microorganisms but it also provides additional information on the total particle number concentration. Our optofluidic system involves the following steps: (1) sampling of airborne microorganisms; (2) mixing and reacting in a microchannel for staining; and (3) real-time detection and analysis of the particle by means of light scattering (SC) and bacterial fluorescence (FL). To evaluate the particle detection efficiency for airborne microorganisms, the total concentration of bacteria obtained from the FL signal of the micro-optofluidic platform was compared with the conventional fluorescence microscopy cell counting and colony counting methods.
cord-336948-8yqdhcnz	2020	If, for the sake of argument, we consider Stoke''s law for the drag of spherical particles, valid below Reynolds numbers of Re = 1, the terminal sink velocity (also known as the settling velocity) of particles will be given by [26] : where ρ p , ρ g , g, μ, d denote the density of the particles (essentially water in the present case), density of the gas (air), gravity, dynamic viscosity of the gas and diameter of the particle respectively. -Spatial discretization using unstructured grids (in order to allow for arbitrary geometries and adaptive refinement); -Spatial approximation of unknowns with simple linear finite elements (in order to have a simple input/output and code structure); -Edge-based data structures (for reduced access to memory and indirect addressing); -Temporal approximation using implicit integration of viscous terms and pressure (the interesting scales are the ones associated with advection); -Temporal approximation using explicit, high-order integration of advective terms; -Low-storage, iterative solvers for the resulting systems of equations (in order to solve large 3-D problems); and -Steady results that are independent from the timestep chosen (in order to have confidence in convergence studies).
cord-337957-z9ssp0rs	2009	In this work, a well-resolved Large Eddy Simulation (LES) was performed to compute the concentration profiles of monodisperse aerosols in non-isothermal low-Reynolds turbulent flow taking place in an enclosed environment. In the present work, measurements and numerical simulations of contaminant particle concentration evolution in a mechanically ventilated room with heated sources have been carried out. However, the aim of this work is twofold: (i) to test the capabilities of the in-house code Code_Saturne to investigate aerosol transport under displacement ventilation with two heated human models using LES, (ii) to compare the aerosol concentration fields computed by both the Lagrangian and the drift-flux Eulerian approaches in the framework of LES, and (iii) to compare the experimental results with model predictions. Both measurements and numerical simulations of airflow field and particle concentration were carried out in a downscaled chamber with two identical model occupants as depicted in Fig. 1 .
cord-339475-okw6la2b	2005	As an indication of their effectiveness, about one half of all 3-~tm particles inhaled through the mouth deposit in the alveolar region. As an indication of their effectiveness, about one half of all 3-~tm particles inhaled through the mouth deposit in the alveolar region. The diseases resulting from exposure to ambient aerosols include pulmonary emphysema, bronchitis, and, perhaps, lung cancer. However, none of the harmful components mentioned above exists in ambient particles at sufficiently high concentration levels to cause a specific disease. Complexity in chemical characteristics of ambient particles has led to considerable difficulty in identifying the components responsible for adverse health effects. Aerosol particles can serve as an effective carrier for ambient peroxides and reactive oxygen species to reach the alveolar region. When these reactive species are adsorbed on particle surfaces, they can easily reach the alveolar region and thereby lead to an adverse effect greater than in tracheobronchial airways. Pulmonary effects of inhaled ultrafine particles
cord-340639-hdn85mik	2004	The use of an improperly ÿt-tested tight-ÿtting respirator may further decrease the respiratory protection level because of the additional particle penetration that occurs through the face-seal leaks (Chen et al., 1990; Chen & Willeke, 1992; Oestenstad, Dillion, & Perkins, 1990a; Oestenstad, Perkins, & Rose, 1990b) . A breathing manikin with a face-sealed respiratory mask was exposed to the airborne polydisperse surrogate aerosols that simulated viral and bacterial particles with respect to their aerodynamic size. The natural aerosol concentration in the indoor test chamber was not su cient, particularly for the measurement inside the mask, because the ÿlter removed considerable number of ambient airborne particles. The drastic decrease of the particle penetration through the respirator ÿlter due to continuous unipolar ion emission may be critical in providing additional respiratory protection by existing masks against viral and bacterial particles.
cord-352743-goier9an	2015	In this work, a transient mathematical multi-region zonal transport model of particle behavior resulting from high momentum respiratory activities (HMRA) is developed focusing on the transient inter-personal exposure (IPE) in indoor spaces ventilated by displacement ventilation (DV) systems. Furthermore, many efforts have been made to reveal the effect of ventilation types, relative orientation between the occupants, sneezing and coughing velocities, in addition to droplet size distribution on the transient spread of exhaled droplets in variable types of indoor environments using CFD and experimental simulations. In order to assess the risk of HMRA, the effect of different variables such DV flow rate, coughing velocity, particle diameter, and distance between the occupants on cross-infection is studied. The coughing velocity largely affected the exposure during the first Fig. 8a and b illustrate respectively the effect of the particle diameter on the variation with time of the normalized concentration at the breathing level of the exposed person and the infection index.
cord-355883-uyrn281a	2020	title: Observations of new particle formation, modal growth rates, and direct emissions of sub-10 nm particles in an urban environment Ambient measurements were carried out at North Carolina State University in Raleigh, NC between April to June 2019 and November 2019 to May 2020 to investigate the temporal variability of size distribution and number concentration of ultrafine particles. Finally, if 227 there were nucleation mode particles present, resulting in an increase in the ultrafine particle 228 number concentration, but growth was not continuous or sustained, this event was classified as 229 Class C. Due to the 5 nm lower limit in the size distribution data, the growth rates calculated 259 between 5-10 nm were used to estimate the approximate start time of each Class A event. The general start time of all Class A events was 367 also pronounced in the diurnal variation of particle number concentration plots shown in Figure 368 5a.
cord-356116-c40e3zp7	2014	FINDINGS: A novel experimental cough chamber facility – the FLUGIE – has been developed to study the far-field aerodynamics and aerosol transport of droplets produced by the coughs from humans naturally-infected with influenza. The novelty of the current collaborative research projectthe Western Cold and Flu (WeCoF) aerosol studylies in the fact that the fluid dynamics of the jet aerosols produced by a minimally-confined cough is being examined concurrently with the biological processes associated with virus droplet formation and transmission, using human subjects when they are naturally infected by influenza virus and, again, when they return to health. A novel experimental facilitythe FLUGIEhas been designed to study the far-field aerodynamics of human coughs produced by subjects naturally-infected with respiratory viruses, together with measurement of the viral content of the droplets produced by those coughs, in order to quantify the factors relating to person-toperson airborne transmission of virus.