scholarly journals Could SARS-CoV-2 be transmitted via speech droplets?

2020 ◽  
Author(s):  
Philip Anfinrud ◽  
Christina E. Bax ◽  
Valentyn Stadnytskyi ◽  
Adriaan Bax
Keyword(s):  
Laser Light ◽  
Face Mask ◽  
Primary Mode ◽  
Viral Loads ◽  
Naked Eye ◽  
Light Passing ◽  
Spoken Words ◽  
Mode Of Transmission ◽  
Patient Presentation

Speaking may be a primary mode of transmission of SARS-CoV-2. Considering that reports of asymptomatic transmission account for 50-80% of COVID-19 cases and that saliva has peak viral loads at time of patient presentation, droplet emission while speaking could be a significant factor driving transmission and warrants further study. We used a planar beam of laser light passing through a dust-free enclosure to detect saliva droplets emitted while speaking. We found that saying the words ‘Stay Healthy’ generates thousands of droplets that are otherwise invisible to the naked eye. A damp homemade cloth face mask dramatically reduced droplet excretion, with none of the spoken words causing a droplet rise above the background. Our preliminary findings have important implications for pandemic mitigation efforts.

IS Corona virus (COVID-19) droplets or airborne? Perspectives (Preprint)

2020 ◽  
Author(s):  
Tilahun Beyene Sr
Keyword(s):  
Scientific Community ◽  
Face Mask ◽  
Physical Distance ◽  
Prevention Strategy ◽  
Confined Space ◽  
Effective Prevention ◽  
Body Of Knowledge ◽  
Corona Virus ◽  
Public Areas ◽  
Mode Of Transmission

UNSTRUCTURED Abstract This scientific perspective of mode of transmission of COVID-19 is to aid scientific community in generating hypothesis. The inadequate evidence on SARS-COV-2 transmission has hindered development of effective prevention strategy and resulted in continues pandemic of the COVID-19. Therefore, in this perspective existing evidences are discussed, hypothesis are generated regarding COVID-19 mode of transmission and recommendations are forwarded based on existing body of knowledge. Two meter (2m) physical distance is not completely safe even for large droplets and wearing face mask is a key in prevention of SARS-COV-2 in public areas and confined space.

Transient interference gratings and holograms in dyed plastic

1984 ◽  
Vol 62 (7) ◽  
pp. 669-673
Author(s):  
Sergio Calixto ◽  
R. A. Lessard
Keyword(s):  
Real Time ◽  
Diffraction Efficiency ◽  
Laser Light ◽  
Thick Layer ◽  
Double Exposure ◽  
Naked Eye ◽  
Sufficient Intensity ◽  
Exposure Holography ◽  
Reading Beam ◽  
Made In

Transient diffraction gratings were holographically made in dyed plastic by absorbing laser light. Mean energy values of 40 mJ/cm2 absorbed in a 3-mm thick layer were needed to make gratings that lasted about 10 s. The writing beams and a reading one of different wavelength were simultaneously made to fall on the plastic: the reading beam was diffracted by the grating, which produced transient diffracted beams of sufficient intensity to be seen by the naked eye or to be stored permanently by conventional photographic methods. Curves showing diffraction efficiency versus exposure with grating frequency as a parameter are presented. Applications to real-time single and double exposure holography are also discussed.

scholarly journals The SARS-CoV-2 viral load in COVID-19 patients is lower on face mask filters than on nasopharyngeal swabs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Smolinska ◽  
David S. Jessop ◽  
Kirk L. Pappan ◽  
Alexandra De Saedeleer ◽  
Amerjit Kang ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Face Mask ◽  
Protective Equipment ◽  
Viral Loads ◽  
Non Invasive ◽  
Home Testing ◽  
Viral Particles ◽  
Mean Diameter ◽  
The Face ◽  
Respiratory Droplets

AbstractFace masks and personal respirators are used to curb the transmission of SARS-CoV-2 in respiratory droplets; filters embedded in some personal protective equipment could be used as a non-invasive sample source for applications, including at-home testing, but information is needed about whether filters are suited to capture viral particles for SARS-CoV-2 detection. In this study, we generated inactivated virus-laden aerosols of 0.3–2 microns in diameter (0.9 µm mean diameter by mass) and dispersed the aerosolized viral particles onto electrostatic face mask filters. The limit of detection for inactivated coronaviruses SARS-CoV-2 and HCoV-NL63 extracted from filters was between 10 to 100 copies/filter for both viruses. Testing for SARS-CoV-2, using face mask filters and nasopharyngeal swabs collected from hospitalized COVID-19-patients, showed that filter samples offered reduced sensitivity (8.5% compared to nasopharyngeal swabs). The low concordance of SARS-CoV-2 detection between filters and nasopharyngeal swabs indicated that number of viral particles collected on the face mask filter was below the limit of detection for all patients but those with the highest viral loads. This indicated face masks are unsuitable to replace diagnostic nasopharyngeal swabs in COVID-19 diagnosis. The ability to detect nucleic acids on face mask filters may, however, find other uses worth future investigation.

scholarly journals Colorimetric RT-LAMP SARS-CoV-2 diagnostic sensitivity relies on color interpretation and viral load

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mateus Nóbrega Aoki ◽  
Bruna de Oliveira Coelho ◽  
Luiz Gustavo Bentim Góes ◽  
Paola Minoprio ◽  
Edison Luiz Durigon ◽  
...  
Keyword(s):  
Viral Load ◽  
Reaction Time ◽  
Color Change ◽  
Rna Virus ◽  
Point Of Care ◽  
Respiratory Viruses ◽  
Lamp Reaction ◽  
Clinical Samples ◽  
Viral Loads ◽  
Naked Eye

AbstractThe use of RT-LAMP (reverse transcriptase—loop mediated isothermal amplification) has been considered as a promising point-of-care method to diagnose COVID-19. In this manuscript we show that the RT-LAMP reaction has a sensitivity of only 200 RNA virus copies, with a color change from pink to yellow occurring in 100% of the 62 clinical samples tested positive by RT-qPCR. We also demonstrated that this reaction is 100% specific for SARS-CoV-2 after testing 57 clinical samples infected with dozens of different respiratory viruses and 74 individuals without any viral infection. Although the majority of manuscripts recently published using this technique describe only the presence of two-color states (pink = negative and yellow = positive), we verified by naked-eye and absorbance measurements that there is an evident third color cluster (orange), in general related to positive samples with low viral loads, but which cannot be defined as positive or negative by the naked eye. Orange colors should be repeated or tested by RT-qPCR to avoid a false diagnostic. RT-LAMP is therefore very reliable for samples with a RT-qPCR Ct < 30 being as sensitive and specific as a RT-qPCR test. All reactions were performed in 30 min at 65 °C. The use of reaction time longer than 30 min is also not recommended since nonspecific amplifications may cause false positives.

Connecting with the Public on ‘Nano’ – Lessons from a Demo Using Ouzo and Laser Pointers

2013 ◽  
Vol 1532 ◽  
Author(s):  
Robert Pinschmidt ◽  
Marc Kai
Keyword(s):  
Laser Light ◽  
Lessons Learned ◽  
Particle Sizes ◽  
Small Particles ◽  
The Public ◽  
Naked Eye ◽  
Micron Size ◽  
Written Descriptions ◽  
Wave Properties ◽  
Water Alcohol

ABSTRACTThe general public is typically positive towards ‘Nano’, but often have limited and anecdotal information from which to draw informed conclusions. We present lessons learned from a new demonstration for 1-on-1 and small group science expo table use that appears to captivate and lead to active learning for ages seven to adult. ‘Making Nanoparticles with Ouzo’ covers: 1. issues in measuring and seeing small particles; 2. light as having wave properties with wavelengths in the nm range; 3. using green (510 nm) and red (650 nm) laser pointers as ‘rulers’; 4. using the liqueur Ouzo (a blend of water, alcohol and water insoluble anethole oil) to illustrate and ‘illuminate’ nanoparticles invisible to the naked eye; 5. demonstrating that the anethole particles do not initially scatter laser light, but do as water is added and particle sizes increase; 6. allowing a visitor to ‘make nanoparticles’ by warming up a cold dispersion of cloudy anethole particles (micron size) in warm water until they vanish.Although a lot of information is presented, a surprising amount of it seems to stick, if it is presented and built in story form from widely appreciated concepts, with samples and props people can see and hold, and with a few diagrams and written descriptions.

scholarly journals COVID 19 Pandemic; A Review on Understanding the Mode of Transmission and Application of Strategies to Delay/Stop Transmission with Special Reference to India

2021 ◽  
Vol 14 (1) ◽  
pp. 140-144
Author(s):  
Sameer Singhal ◽  
Prachi Singhal ◽  
Amit Mittal ◽  
B K Agarwal ◽  
MahalaquaNazli Khatib ◽  
...  
Keyword(s):  
Close Contact ◽  
Face Mask ◽  
Viral Disease ◽  
Definitive Treatment ◽  
Metallic Surfaces ◽  
Early Screening ◽  
Indian Government ◽  
Management Board ◽  
Modes Of Transmission ◽  
Mode Of Transmission

Background: SARS CoV-2 has globally affected more than 31 hundred thousand population with more than 2 hundred thousand deaths till date, since its inception from Wuhan, China in December 2019. World is still clueless regarding definitive treatment for this highly contagious disease. Till then we have to rely on time tested methods to delay/stop transmission of this viral disease by observing social isolation, hand hygiene and wearing face mask. Objective: The main objective of this review paper is to focus on different modes of transmission of this virus, comparison of this virus with previous similar analogy viral diseases like SARS and MERS and different strategies that can be planned or are ongoing to reduce/delay transmission of this virus in community contacts, especially in context to India. Methods: PUBMED, Google Scholar and BioRxiv search was performed with keywords; COVID- 19, mode of transmission, infection, India, BCG. Around 538 eligible papers were evaluated from time period of January 1 to 29 April 2020 and results were summarized Results: On analysis of different papers on mode of transmission it was found that this virus is highly contagious and spreads through air droplet, close contact, through fomites and different metallic surfaces and through aerosol in surroundings with high aerosol generating procedures only. Also, it can spread both in asymptomatic and symptomatic phase equally so early testing is essential. Also, it is mutating in different host environments so it is imperative to include different strains in vaccine preparation. Conclusion: Results demonstrate the fact that early screening, social distancing, isolation of symptomatic patients, respiratory etiquette are the main armaments presently to deal with this virus till effective treatment or vaccine becomes available in the near future. Furthermore, we would like to suggest the Indian government to create a National Viral Disease Management Board on lines of National Tuberculosis Elimination program to prevent and control such viral outbreaks in future.

scholarly journals Design of Currency Sanitizer using UV-C Light

2021 ◽  
Vol 9 (VI) ◽  
pp. 1209-1210
Author(s):  
Ajinkya Pund
Keyword(s):  
Microbial Load ◽  
Primary Mode ◽  
Ultraviolet C ◽  
Mode Of Transmission ◽  
Uv C

Currency is the primary mode of transmission of microbes and infection. Currency sanitization is a simple and least expensive means of preventing infection. Various sanitizing products are on the market in the form of antimicrobial and alcohol-based sanitizers which are meant to reduce/remove microbial load of the skin. The UV-C currency sanitizer is one of the best sanitizer for currency sanitization. This paper provides information about the Design of Currency Sanitizer Using UV-C Light. It is simple a currency sanitizing device which use ultraviolet–C type light of wavelength (254nm) to sanitize the currency surface. In which 254nm wavelength two 4w of light has used for sanitization the highest disinfectant capacity. Keywords: Currency Sanitization, UV-C light

Element 87—Francium

2013 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Time Lag ◽  
Polarized Light ◽  
Cold Fusion ◽  
Liquid Solution ◽  
Journal Articles ◽  
Time Magazine ◽  
Natural Sources ◽  
Naked Eye ◽  
Light Passing ◽  
Pathological Science

One of the most remarkable things about element 87 is the number of times that people claimed to have discovered it after it was predicted by Mendeleev in 1871 and given the provisional name of eka-caesium . It was recognized early on that the periodic table more or less fizzles out after element 83, or bismuth. All subsequent elements are radioactive and therefore unstable, with a few exceptions like uranium and thorium. But this fact did not deter a number of scientists from searching for element 87 among natural sources and in many cases from claiming to have isolated it. For example, Druce and Loring in England thought they had identified the element by using the classic method developed by Moseley for measuring the K α and K β lines of any element’s X-ray spectrum. But it was not to be. In the 1930s, it was the turn of Professor Fred Allison from the Alabama Polytechnic Institute (now Auburn University). Allison developed what he called a magneto-optical method for detecting elements and compounds based on a supposed time lag in the development of the Faraday effect, whereby the application of a magnetic field causes a beam of polarized light passing through a liquid solution to be rotated. Allison mistakenly thought that every element gave a particular time lag, which he claimed was observed with the naked eye, and that this effect could be used to identify each substance. He boldly claimed in a number of journal articles, and even a special feature in Time Magazine, that he had observed elements 87 and also 85, both of which were still missing at the time. Literally hundreds of papers were published on this effect, including a number of studies arguing that it was spurious. But these days the Allison effect is often featured in accounts of pathological science, alongside the claims for N-rays and cold fusion.

scholarly journals Field and Molecular Epidemiology: How Viral Sequencing Changed Transmission Inferences in the First Portuguese SARS-CoV-2 Infection Cluster

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1116
Author(s):  
Nicole Pedro ◽  
Veronica Fernandes ◽  
Bruno Cavadas ◽  
João Tiago Guimarães ◽  
Henrique Barros ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Work Environment ◽  
Extended Family ◽  
Work Environments ◽  
Primary Mode ◽  
Related Individuals ◽  
Mode Of Transmission ◽  
Viral Sequencing ◽  
Comprehensive Characterization

Field epidemiology and viral sequencing provide a comprehensive characterization of transmission chains and allow a better identification of superspreading events. However, very few examples have been presented to date during the COVID-19 pandemic. We studied the first COVID-19 cluster detected in Portugal (59 individuals involved amongst extended family and work environments), following the return of four related individuals from work trips to Italy. The first patient to introduce the virus would be misidentified following the traditional field inquiry alone, as shown by the viral sequencing in isolates from 23 individuals. The results also pointed out family, and not work environment, as the primary mode of transmission.

Chronic Laser Exposure Effects on Rabbit Retina

1972 ◽  
Vol 30 ◽  
pp. 54-55
Author(s):  
Burton B. Silver ◽  
Theodore Lawwill
Keyword(s):  
Laser Irradiation ◽  
Laser Light ◽  
Broad Band ◽  
Argon Laser ◽  
Atropine Sulfate ◽  
Ultrastructural Changes ◽  
Laser Exposure ◽  
Rabbit Retina ◽  
Histological Changes ◽  
Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

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