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1
Delikhoon, Mahdieh, Marcelo I. Guzman, Ramin Nabizadeh, and Abbas Norouzian Baghani. "Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review." International Journal of Environmental Research and Public Health 18, no. 2 (January 6, 2021): 395. http://dx.doi.org/10.3390/ijerph18020395.
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The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact, and fecal–oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Herein, different databases are reviewed to evaluate modes of transmission of SARS-CoV-2 and study the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. Droplet transmission was commonly reported to occur in particles with diameter >5 µm that can quickly settle gravitationally on surfaces (1–2 m). Instead, fine and ultrafine particles (airborne transmission) can stay suspended for an extended period of time (≥2 h) and be transported further, e.g., up to 8 m through simple diffusion and convection mechanisms. Droplet and airborne transmission of SARS-CoV-2 can be limited indoors with adequate ventilation of rooms, by routine disinfection of toilets, using negative pressure rooms, using face masks, and maintaining social distancing. Other preventive measures recommended include increasing the number of screening tests of suspected carriers of SARS-CoV-2, reducing the number of persons in a room to minimize sharing indoor air, and monitoring people’s temperature before accessing a building. The work reviews a body of literature supporting the transmission of SARS-CoV-2 through air, causing COVID-19 disease, which requires coordinated worldwide strategies.
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Fernstrom, Aaron, and Michael Goldblatt. "Aerobiology and Its Role in the Transmission of Infectious Diseases." Journal of Pathogens 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/493960.
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Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease), the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors), as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes), while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases.
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Harrichandra, Amelia, A. Michael Ierardi, and Brian Pavilonis. "An estimation of airborne SARS-CoV-2 infection transmission risk in New York City nail salons." Toxicology and Industrial Health 36, no. 9 (September 2020): 634–43. http://dx.doi.org/10.1177/0748233720964650.
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Although airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from person-to-person over long distances is currently thought to be unlikely, the current epidemiological evidence suggests that airborne SARS-CoV-2 infection transmission in confined, indoor spaces is plausible, particularly when outdoor airflow rates are low and when face masks are not utilized. We sought to model airborne infection transmission risk assuming five realistic exposure scenarios using previously estimated outdoor airflow rates for 12 New York City nail salons, a published quanta generation rate specific to SARS-CoV-2, as well as the Wells–Riley equation to assess risk under both steady-state and non-steady-state conditions. Additionally, the impact of face mask-wearing by occupants on airborne infection transmission risk was also evaluated. The risk of airborne infection transmission across all salons and all exposure scenarios when not wearing face masks ranged from <0.015% to 99.25%, with an average airborne infection transmission risk of 24.77%. Wearing face masks reduced airborne infection transmission risk to between <0.01% and 51.96%, depending on the salon, with an average airborne infection transmission risk of 7.30% across all salons. Increased outdoor airflow rates in nail salons were generally strongly correlated with decreased average airborne infection transmission risk. The results of this study indicate that increased outdoor airflow rates and the use of face masks by both employees and customers could substantially reduce SARS-CoV-2 transmission in New York City nail salons. Businesses should utilize multiple layers of infection control measures (e.g. social distancing, face masks, and outdoor airflow) to reduce airborne infection transmission risk for both employees and customers.
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ZHANG, Jiangong, Zheyuan GAN, Jun ZHAO, and ying Lu. "Analysis of active interference on radio station from AC UHV power." E3S Web of Conferences 64 (2018): 05003. http://dx.doi.org/10.1051/e3sconf/20186405003.
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The problems of Electromagnetic Interference in Airborne Intelligence Radar Stations near the AC UHV Transmission Lines are researched in this paper, which is mainly active interference. The calculation method for the interferences is analysed, and then the proper protection distances of the AC UHV transmission line to the radar station are given. The paper analyzed the active interference of AC UHV transmission lines, and focuses on the active interference caused by the line corona on the active radar of nearby airborne intelligence when the transmission line is under normal operation. In the end, this paper proposes the recommended values of active interference protection distance for 1000kV AC UHV transmission lines and airborne intelligence radar stations.
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Hassan, Najmul, and Noor M. Khan. "Cost-effective reliable transmission service for Internet of Flying Things." International Journal of Distributed Sensor Networks 17, no. 6 (June 2021): 155014772110178. http://dx.doi.org/10.1177/15501477211017820.
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High-speed quality Internet provision for aircraft passengers is thought to be one of the major unresolved challenges for ubiquitous Internet provision. This article aims to resolve the problem of airborne Internet access with high quality of service for modern Internet of things devices. Large remote regions in the ocean along the busy air routes (e.g. Atlantic Ocean) require high-speed, reliable, and low-cost airborne Internet (i.e. Internet provision to the aircraft) to manage various delay- and throughput-sensitive applications. Conventional satellite-based solutions can be an alternate for Internet provision in such far-flung areas; but, such solutions are lacking quality of service (with longer delays and low bandwidth) and are significantly costly. Fortunately, the underwater optical fiber cables deployed across the oceans pass along the same busy air routes. This infrastructure of underwater optical fiber cables can be exploited for Internet backbone providing high quality of service for wireless Internet provision to the commercial aircraft. Dedicated stationary ships deployed along these underwater optical fiber cables can be utilized for Internet provision, navigation, and security to ships and aircraft. This article not only proposes the networking infrastructure of the submarine cable-based airborne Internet access architecture but also presents a novel routing scheme for airborne ad hoc networks. Also, we analyze quality of service provision as compared to other existing techniques. Our simulation results show that our proposed solution outperforms other existing schemes for airborne Internet service provision, in the presence of high mobility and dynamic topology changes.
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Hashimoto, Kaho, Zhengtao Ai, and Arsen Melikov. "Airborne transmission during short-term events under stratum ventilation." E3S Web of Conferences 111 (2019): 01098. http://dx.doi.org/10.1051/e3sconf/201911101098.
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Past studies on airborne spread of expiratory droplet nuclei between occupants were focused on long-term exposure under steady-state conditions. However, exposure during short-term events can be widely found in practice, e.g. medical examination or short meeting. Airborne transmission during short-term events under stratum ventilation was examined experimentally in this study. Two breathing thermal manikins were employed to simulate a standing infected person and a standing exposed person. The manikins were placed face-to-face and face-to-back to reproduce the exposure conditions with the highest and the lowest risk, respectively. Tracer gas was dosed into the air exhaled by the “infected” manikin to simulate the droplet nuclei. A newly developed average exposure index was used to evaluate the exposure risk. The time-averaged exposure index increases over time, but the increasing rate depends strongly on the duration of exposure time, e.g., the exposure index increases much faster during the first 5 minutes than during the period after 5 minutes. The exposure index during short-term events does not always decrease with the increase of separation distance. These findings imply that the control measures formulated based on steady-state conditions are not necessarily effective to short-term events.
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Ma, She Xiang, Jin Sun, and Yong Qiang Guan. "Detection Probability of Airborne AIS." Applied Mechanics and Materials 401-403 (September 2013): 1204–7. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.1204.
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Aiming at the small coverage of shore-based AIS and complicated structure of space-based AIS, airborne AIS is chosen to increase the coverage effectively. This paper gives the calculation method of the maximum transmission distance, and then establishes the detection probability model of the airborne AIS. The relationship between reporting interval, ship densities and detection probabilities is established. At the end of the paper, simulation results of the model are given.
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Stabile, Luca, Antonio Pacitto, Giorgio Buonanno, and Marco Dell’Isola. "Ventilation System Operation to Minimize the COVID-19 Airborne Transmission in Schools." Tecnica Italiana-Italian Journal of Engineering Science 65, no. 2-4 (July 30, 2021): 300–306. http://dx.doi.org/10.18280/ti-ijes.652-424.
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Minimizing the SARS-CoV-2 virus transmission is essential to face the COVID-19 pandemic. This is even more important for highly crowded indoor environments, e.g. schools, where the mitigation solutions based on social distancing and hand washing seem to be not effective to reduce the virus airborne transmission mode, which is the main route of transmission. To minimize the airborne virus transmission a proper ventilation is necessary. In the study, a simplified mass balance equation (box-model) was applied to school scenarios in order to determine the required conditions to maintain the infection risk below an acceptable level. In particular, the required air exchange rates for mechanically-ventilated classrooms and the adequate airing procedures for naturally ventilated classrooms were determined. Moreover, for naturally ventilated classrooms, a control strategy based on the measurement of CO2 indoor concentration was also developed.
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Lloret, Maria Gavila, Fabian Duvigneau, Gregor Müller, and Hermann Rottengruber. "Computer-aided Prediction of Airborne Sound Transmission through the Front Car End." ATZ worldwide 120, no. 7-8 (July 2018): 76–79. http://dx.doi.org/10.1007/s38311-018-0078-8.
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Gavila Lloret, Maria, Fabian Duvigneau, Ulrich Gabbert, and Hermann Rottengruber. "Prediction of the airborne sound transmission through the front end of a vehicle." Automotive and Engine Technology 4, no. 3-4 (September 10, 2019): 169–78. http://dx.doi.org/10.1007/s41104-019-00051-z.
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Cavallo, Alessandro, and Jasmine Rita Petriglieri. "Naturally Occurring Asbestos in Valmalenco (Central Alps, Northern Italy): From Quarries and Mines to Stream Sediments." Environmental and Engineering Geoscience 26, no. 1 (February 20, 2020): 47–52. http://dx.doi.org/10.2113/eeg-2270.
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ABSTRACT The Valmalenco area (central Alps, northern Italy) is an excellent case study for naturally occurring asbestos (NOA) because of the huge outcrops of serpentinites and widespread quarrying and mining activities. Extensive sampling of rocks, soils, stream sediments, and airborne asbestos has been in progress since 2004. The combined use of scanning electron microscopy and transmission electron microscopy has proven to be effective for the correct discrimination between asbestiform and non-asbestiform mineralogical varieties (but falling into the World Health Organization fiber definition), whereas phase contrast microscopy has not proven suitable because of the very small size of fibrils after strong mechanical fragmentation. The quantitative analysis of “massive” samples (rocks, soils, and sediments) requires accurate and representative sampling as well as specific counting and discrimination criteria to determine NOA. Over a decade of experience has allowed us to identify critical issues and adopt effective preventive measures.
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Szudrowicz, Barbara, and Elżbieta Nowicka. "Factors affecting the sound insulation in the prefabricated buildings." Budownictwo i Architektura 13, no. 4 (December 9, 2014): 049–56. http://dx.doi.org/10.35784/bud-arch.1692.
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The sound insulation in buildings is affected by many factors related to various sound transmission paths between rooms. Among them the following paths can be distinguished: the so called direct path dependent on the sound insulation of the partition between rooms, the structural flanking transmission paths and additional airborne paths due to sound transmission though leaks and ducts linking the rooms (e.g. ventilation ducts). The paper analyzes the influence of these factors on sound insulation in multifamily, prefabricates buildings. Laboratory and field measurement results made by ITB’s Acoustic Department in the period of 1975-85 are presented.
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Buysse, Marie, Maxime Duhayon, Franck Cantet, Matteo Bonazzi, and Olivier Duron. "Vector competence of the African argasid tick Ornithodoros moubata for the Q fever agent Coxiella burnetii." PLOS Neglected Tropical Diseases 15, no. 1 (January 6, 2021): e0009008. http://dx.doi.org/10.1371/journal.pntd.0009008.
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Q fever is a widespread zoonotic disease caused by the intracellular bacterium Coxiella burnetii. While transmission is primarily but not exclusively airborne, ticks are usually thought to act as vectors on the basis of early microscopy studies. However, recent observations revealed that endosymbionts of ticks have been commonly misidentified as C. burnetii, calling the importance of tick-borne transmission into question. In this study, we re-evaluated the vector competence of the African soft tick Ornithodoros moubata for an avirulent strain of C. burnetii. To this end, we used an artificial feeding system to initiate infection of ticks, specific molecular tools to monitor further infections, and culture assays in axenic and cell media to check for the viability of C. burnetii excreted by ticks. We observed typical traits associated with vector competence: The exposure to an infected blood meal resulted in viable and persistent infections in ticks, trans-stadial transmissions of infection from nymphs to adults and the ability of adult ticks to transmit infectious C. burnetii. However, in contrast to early studies, we found that infection differed substantially between tick organs. In addition, while adult female ticks were infected, we did not observe C. burnetii in eggs, suggesting that transovarial transmission is not effective. Finally, we detected only a sporadic presence of C. burnetii DNA in tick faeces, but no living bacterium was further isolated in culture assays, suggesting that excretion in faeces is not a common mode of transmission in O. moubata.
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Anchordoqui, Luis Alfredo, and Eugene M. Chudnovsky. "A Physicist View of COVID-19 Airborne Infection through Convective Airflow in Indoor Spaces." SciMedicine Journal 2 (August 28, 2020): 68–72. http://dx.doi.org/10.28991/scimedj-2020-02-si-5.
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General Idea: Naturally produced droplets from humans (such as those produced by breathing, talking, sneezing, and coughing) include several types of cells (e.g., epithelial cells and cells of the immune system), physiological electrolytes contained in mucous and saliva (e.g. Na+, K+, Cl-), as well as, potentially, several infectious agents (e.g. bacteria, fungi, and viruses). In response to the novel coronavirus SARS-CoV-2 epidemic, which has become a major public health issue worldwide, we provide a concise overview of airborne germ transmission as seen from a physics perspective. We also study whether coronavirus aerosols can travel far from the immediate neighbourhood and get airborne with the convective currents developed within confined spaces. Methodology: Methods of fluid dynamics are utilized to analyse the behavior of various-size airborne droplets containing the virus. Study Findings: We show that existing vortices in the air can make a location far away from the source of the virus be more dangerous than a nearby (e.g., 6 feet away) location. Practical Implications: Our study reveals that it seems reasonable to adopt additional infection-control measures to the recommended 6 feet social distancing. We provide a recommendation that could help to slow down the spread of the virus.
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Cocârţă, Diana M., Cristina A. Gogoncea, and Constantin Streche. "An important challenge in occupational health: sampling indoor airborne viruses." MATEC Web of Conferences 343 (2021): 10022. http://dx.doi.org/10.1051/matecconf/202134310022.
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Airborne biological particles are made by bacteria, viruses, fungi, pollen, dust mites and other living organisms. Between the airborne biological contaminants, the sampling of airborne viruses is the most difficult. This technical challenge has real consequences both in limiting the studies on the aerobiology of viral diseases, and in making possible, at least for now, to establish Standards for Acceptable Bioaerosol Exposure Limits in case of viruses. The circumstances and uncertainties in which we are living from the end of 2019, have demonstrated once again, the need of having common approaches in sampling, processing, and analysis of bioaerosol samples. Results from sampling indoor airborne viruses can be used both for identifying the airborne transmission of the respiratory viruses and for providing useful information as support in human health risk assessments. On the other hand, even if there are different sampling methods and equipment used for collecting bioaerosols, there are certain elements that must be considered in choosing the most appropriate sampling method to collect airborne viruses. The main challenge in sampling indoor airborne viruses is to identify the system that allows the sampling of bioaerosols ensuring in the same time the viability of the virus and the representativeness of the sample. Keeping in mind the lack of standardization in sampling indoor airborne viruses, as well as the missing of common approaches for air sampling strategies or sample treatment and analysis, the present work is focused on providing important recommendations as support in the concentrated effort of the researchers in developing of a common strategy for indoor viable bioaerosol sampling for virus detection.
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Zerboni, Bengalli, Baeri, Fiandra, Catelani, and Mantecca. "Mixture Effects of Diesel Exhaust and Metal Oxide Nanoparticles in Human Lung A549 Cells." Nanomaterials 9, no. 9 (September 11, 2019): 1302. http://dx.doi.org/10.3390/nano9091302.
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Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to analyse the combined in vitro effects of DEP and metal oxide NPs (ZnO, CuO) on human lung A549 cells. The mixtures and the relative single NPs (DEP, ZnO, CuO) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and inductively coupled plasma-optic emission spectroscopy (ICP-OES). Cells were exposed for different times (3–72 h) to mixtures of standard DEP at a subcytotoxic concentration and ZnO and CuO at increasing concentrations. At the end of the exposure, the cytotoxicity was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and clonogenic tests, the pro-inflammatory potential was evaluated by interleukin-8 (IL-8) release and the cell morphology was investigated by fluorescence and transmission electron microscopy. The obtained results suggest that the presence of DEP may introduce new physico-chemical interactions able to increase the cytotoxicity of ZnO and to reduce that of CuO NPs.
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Yeon, Jun Oh, Kyoung Woo Kim, Kwan Seop Yang, and Myung Jun Kim. "Analysis of the Airborne Sound Insulation Performance of Floor Structures Based on the Intensity Method." Applied Mechanics and Materials 752-753 (April 2015): 796–99. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.796.
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Apartment buildings are constructed using box frame structures that integrate slabs and wall frames, and vibrations can easily travel through these integrated box frame structures. On the other hand, such a framed structure generates fewer gaps between structural elements, assuring a superior insulation performance of airborne sound compared to wooden houses. Vertically installed equipment running through different floor levels can serve as a transmission route for airborne sound of specific frequency bands. In this study, we sought to develop technical methods to improve the inter-floor airborne sound insulation performance. To this end, we measured the sound insulation performance of floor structures and intensity levels in noise penetration areas. The sound insulation performance of the living room floor structure was measured to exceed 51 dB, which was superior to that of the restroom floor by 2–7 dB. Intensity measurements identified the central and corner areas of the living room as high-level noise areas.
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Subedi, Sachin, Sulove Koirala, and Lilong Chai. "COVID-19 in Farm Animals: Host Susceptibility and Prevention Strategies." Animals 11, no. 3 (February 28, 2021): 640. http://dx.doi.org/10.3390/ani11030640.
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COVID-19 is caused by the virus SARS-CoV-2 that belongings to the family of Coronaviridae, which has affected multiple species and demonstrated zoonotic potential. The COVID-19 infections have been reported on farm animals (e.g., minks) and pets, which were discussed and summarized in this study. Although the damage of COVID-19 has not been reported as serious as highly pathogenic avian influenza (HPAI) for poultry and African Swine Fever (ASF) for pigs on commercial farms so far, the transmission mechanism of COVID-19 among group animals/farms and its long-term impacts are still not clear. Prior to the marketing of efficient vaccines for livestock and animals, on-farm biosecurity measures (e.g., conventional disinfection strategies and innovated technologies) need to be considered or innovated in preventing the direct contact spread or the airborne transmission of COVID-19.
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Dwijayanti, Fifi, Hendi Setiadi, and Martya Rahmaniati Makful. "COVID-19 and Cancer Care in Indonesia: What we have done in Dharmais Cancer Center Hospital." Indonesian Journal of Cancer 14, no. 2 (July 1, 2020): 37. http://dx.doi.org/10.33371/ijoc.v14i2.747.
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At the end of 2019, the novel coronavirus (CoV) of severe acute respiratory syndrome (SARS), named SARS- CoV-2 was approved as a microbial agent that causes viral pneumonia in patients who are linked epidemiologically to the seafood market in Wuhan (Wuhan) Hubei province, China [1]. The World Health Organization (WHO) stated the coronavirus or COVID-19 as a pandemic because it has spread globally in the world since March 11, 2020 [2]. There have been more than 8 million cases reported with more than 450 thousand deaths around the world until June 19, 2020 [3]. Indonesia reported the first cases of COVID-19 in early March 2020 and currently 43,803 cases with 2,373 deaths [4]. Indonesia has the highest cases of COVID-19 in Southeast Asia [5]. WHO stated that according to the current evidence, coronavirus is transmitted among people through respiratory droplets and contact routes [6-8]. Droplet transmission is different from airborne disease. Droplet transmission occurs when a person closely contacted (within 1 m) with someone who has respiratory symptoms (e.g. coughing or sneezing,) and was therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets. Droplet transmission may also occur through fomites in the immediate environment around the infected person [9]. Increasing cases occur continuously become alert for our institution as health care providers.
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Ray, Achintya. "Containing Airborne Transmission of COVID-19 and Its Implications for Global Economic Recovery." Business Ethics and Leadership 5, no. 1 (2021): 81–88. http://dx.doi.org/10.21272/bel.5(1).81-88.2021.
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COVID-19 was first reported in December 2019 in Wuhan, China; however, it took international health experts another six months to establish the airborne nature of transmission of the disease. The transmission of the infection through aerosolized virus particles opens a new frontier in global pandemic control initiatives. It necessitates the need for appropriate economic policies to end the COVID-19 recession in most parts of the world. Mass vaccination and herd immunity are potent tools in combatting the challenge of COVID-19. Global vaccination against the disease is also gaining momentum. However, new variants and infection surges threaten to undermine critical gains. Furthermore, complete vaccination of the world population may be many years away. Therefore, it is essential to design public policies and business strategies in a world of great uncertainty. Understanding the airborne transmission of coronavirus will help business leaders craft meaningful operational procedures to protect their stakeholders and minimize costly business disruptions. It will also help the policymakers to avoid economically costly lockdowns. International success in indoor air purification, outdoor air pollution mitigation, widespread adoption of hand hygiene, and universal mask usage can significantly help pandemic control and increase the efficacy of various pandemic control measures. Controlling the pandemic may help countries in opening their economies and kickstarting global travel in the post-COVID-19 world. Such actions may also help in lessening the global burden of many other respiratory diseases. They may, in turn, save countless lives while dramatically reducing premature deaths. Such health gains may be conducive towards boosting GDP, decreasing healthcare costs, increasing productivity, and improving health equities. Controlling the COVID-19 pandemic remains the prime directive of all global public policy measures. Investments in aerosolized virus particle transmission mitigation offer a unique opportunity to achieve health improvement goals whose positive impacts may remain potent for generations to come.
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Bailey, R. Mark. "Asbestiform Minerals of the Franciscan Assemblage in California with a Focus on the Calaveras Dam Replacement Project." Environmental and Engineering Geoscience 26, no. 1 (February 20, 2020): 21–28. http://dx.doi.org/10.2113/eeg-2264.
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ABSTRACT The San Francisco Bay Area is underlain by bedrock of the Franciscan Assemblage, which outcrops in numerous places. A significant portion of these outcrops consists of rock types that contain both regulated and unregulated asbestiform minerals, including ultra-mafic serpentinites, various greenstones, amphibolites, blueschist, and other schists (talc-tremolite, actinolite, etc.). These rocks are a legacy of tectonic activity that occurred on the west coast margin of the North American plate ∼65–150 MY ago during subduction of the East Pacific and Farallon plates. The Calaveras Dam Replacement Project (CDRP), located in Fremont, California, is an example of an area within the Franciscan Assemblage that is substantially underlain by metamorphosed oceanic sedimentary, mafic, and ultra-mafic rocks in a tectonic subduction zone mélange with highly disrupted relationships between adjoining rock bodies with different pressure/temperature metamorphic histories. In order to protect the health of workers and residents in the surrounding area, an extensive effort was taken to identify, categorize, and monitor the types, locations, and concentrations of naturally occurring asbestos at the site. Using a combination of geologic field observations and transmission electron microscopy, energy dispersive X-ray, and selected area electron diffraction analysis of airborne particulate and rock/soil samples, the CDRP was discovered to contain chrysotile-bearing serpentine. It also had as a range of amphibole-containing rocks, including blueschist, amphibolite schist, and eclogite, with at least 19 different regulated and non-regulated fibrous amphibole minerals identified. The extensive solid solution behavior of the amphiboles makes definitive identification difficult, though a scheme was created that allowed asbestos mineral fingerprinting of various areas of the project site.
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Pasquier, Jorge, Oscar Villalta, Sunaymy Sarria Lamorú, Carmen Balagué, Ramon Vilallonga, and Eduardo M. Targarona. "Are Smoke and Aerosols Generated During Laparoscopic Surgery a Biohazard? A Systematic Evidence-Based Review." Surgical Innovation 28, no. 4 (February 11, 2021): 485–95. http://dx.doi.org/10.1177/1553350621992309.
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Background. Laparoscopic surgery generates end products that can have potentially harmful effects for the surgical team from short- or long-time exposure. In view of the current SARS-CoV-2 circumstances, controversy has risen concerning the safety of surgical smoke (SS) and aerosols and the perception of an increased risk of exposure during laparoscopic surgery. Methods. The present qualitative systematic review was conducted according to Meta-Analyses and Systematic Reviews of Observational Studies (MOOSE). A literature search was performed from March 2020 up to May 10, 2020, using the PubMed database, Cochrane, and Google Scholar to assess the risk of airborne transmission of viruses and the potential health risk of surgical smoke- and aerosol-generating procedures produced during laparoscopic surgery. The keywords were introduced in combination to obtain better search results. Application of the inclusion and exclusion criteria identified 44 relevant articles. Results. Genetic material from certain viruses, or the virus itself, has been detected in SS and aerosols. However, in the current SARS-CoV-2, as in other coronavirus situations, studies analyzing the presence of airborne transmission of viruses in surgical smoke are lacking. Conclusion. Despite the lack of clear evidence regarding the risk of diseases as the result of smoke- and aerosol-generating procedures during laparoscopic surgery, further investigation is needed. Meanwhile, all available precautions must be taken.
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Yao, Gang. "To Improve the Real-Time Performance of Airborne Data Link Communication System." Mathematical Problems in Engineering 2021 (February 23, 2021): 1–11. http://dx.doi.org/10.1155/2021/5558089.
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Ground-to-air data link communication has the advantages of fast transmission rate, strong anti-interference ability, and large data communication volume and has been widely used in the field of civil aviation. This article mainly studies the measures to improve the real-time performance of the airborne data link communication system. The design of the hardware platform of the jamming environment simulator needs to comprehensively consider the implementation complexity of the jamming environment model and the real-time simulation method adopted by the UAV data link system. This paper uses the multicore and multithread in the Linux operating system to simulate the functions of the original data link communication system and uses the TFT screen to display the data communication process in the multicore and multithread design scheme. When evaluating and scoring the evaluation indicators, it must be carried out in accordance with certain standards. However, most of the indicators cannot be directly assessed quantitatively only through certain specific values. This article mainly uses the AHP method to analyze the weight of indicators. In the simulation, user information is generated by a random code generator and then distributed to each branch through serial-to-parallel conversion (S/P), and the spreading process is completed by long-code spreading on each branch, respectively, by BPSK. It is modulated on different carriers to form a transmission signal; the signal passes through a Gaussian white noise channel, and a certain frequency offset noise is added at the same time to reach the receiving end; the receiving end uses correlated demodulation, and after despreading, the error rate is counted. The data shows that under different distances, the frame loss rate of the data link is different. The frame loss rate in the 500 m range is about 1%, and the frame loss rate in the 2 km range is about 2.3%. The results show that the real-time performance of the data link communication system in this paper has been greatly improved.
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Wang, Jie, Ke-Hong Zhu, Li-Na Wang, Xing-Dong Liang, and Long-Yong Chen. "A Novel Orthogonal Waveform Separation Scheme for Airborne MIMO-SAR Systems." Sensors 18, no. 10 (October 22, 2018): 3580. http://dx.doi.org/10.3390/s18103580.
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In recent years, multi-input multi-output (MIMO) synthetic aperture radar (SAR) systems, which can promote the performance of 3D imaging, high-resolution wide-swath remote sensing, and multi-baseline interferometry, have received considerable attention. Several papers on MIMO-SAR have been published, but the research of such systems is seriously limited. This is mainly because the superposed echoes of the multiple transmitted orthogonal waveforms cannot be separated perfectly. The imperfect separation will introduce ambiguous energy and degrade SAR images dramatically. In this paper, a novel orthogonal waveform separation scheme based on echo-compression is proposed for airborne MIMO-SAR systems. Specifically, apart from the simultaneous transmissions, the transmitters are required to radiate several times alone in a synthetic aperture to sense their private inner-aperture channels. Since the channel responses at the neighboring azimuth positions are relevant, the energy of the solely radiated orthogonal waveforms in the superposed echoes will be concentrated. To this end, the echoes of the multiple transmitted orthogonal waveforms can be separated by cancelling the peaks. In addition, the cleaned echoes, along with original superposed one, can be used to reconstruct the unambiguous echoes. The proposed scheme is validated by simulations.
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Kurz, F., D. Rosenbaum, H. Runge, D. Cerra, G. Mattyus, and P. Reinartz. "LONG-TERM TRACKING OF A SPECIFIC VEHICLE USING AIRBORNE OPTICAL CAMERA SYSTEMS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 8, 2016): 521–25. http://dx.doi.org/10.5194/isprs-archives-xli-b2-521-2016.
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In this paper we present two low cost, airborne sensor systems capable of long-term vehicle tracking. Based on the properties of the sensors, a method for automatic real-time, long-term tracking of individual vehicles is presented. This combines the detection and tracking of the vehicle in low frame rate image sequences and applies the lagged Cell Transmission Model (CTM) to handle longer tracking outages occurring in complex traffic situations, e.g. tunnels. The CTM model uses the traffic conditions in the proximities of the target vehicle and estimates its motion to predict the position where it reappears. <br><br> The method is validated on an airborne image sequence acquired from a helicopter. Several reference vehicles are tracked within a range of <i>500m</i> in a complex urban traffic situation. An artificial tracking outage of <i>240m</i> is simulated, which is handled by the CTM. For this, all the vehicles in the close proximity are automatically detected and tracked to estimate the basic density-flow relations of the CTM model. Finally, the real and simulated trajectories of the reference vehicles in the outage are compared showing good correspondence also in congested traffic situations.
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Kurz, F., D. Rosenbaum, H. Runge, D. Cerra, G. Mattyus, and P. Reinartz. "LONG-TERM TRACKING OF A SPECIFIC VEHICLE USING AIRBORNE OPTICAL CAMERA SYSTEMS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 8, 2016): 521–25. http://dx.doi.org/10.5194/isprsarchives-xli-b2-521-2016.
Full textAbstract:
In this paper we present two low cost, airborne sensor systems capable of long-term vehicle tracking. Based on the properties of the sensors, a method for automatic real-time, long-term tracking of individual vehicles is presented. This combines the detection and tracking of the vehicle in low frame rate image sequences and applies the lagged Cell Transmission Model (CTM) to handle longer tracking outages occurring in complex traffic situations, e.g. tunnels. The CTM model uses the traffic conditions in the proximities of the target vehicle and estimates its motion to predict the position where it reappears. <br><br> The method is validated on an airborne image sequence acquired from a helicopter. Several reference vehicles are tracked within a range of <i>500m</i> in a complex urban traffic situation. An artificial tracking outage of <i>240m</i> is simulated, which is handled by the CTM. For this, all the vehicles in the close proximity are automatically detected and tracked to estimate the basic density-flow relations of the CTM model. Finally, the real and simulated trajectories of the reference vehicles in the outage are compared showing good correspondence also in congested traffic situations.
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Wathes, C. M., and H. E. Johnson. "Physical protection against airborne pathogens and pollutants by a novel animal isolator in a level 3 containment laboratory." Epidemiology and Infection 107, no. 1 (August 1991): 157–70. http://dx.doi.org/10.1017/s0950268800048780.
Full textAbstract:
SUMMARYA containment laboratory unit for research with aerosols of group 2 pathogenic microorganisms is described. The design criteria are based on current UK guidelines, which imply containment at group 3 level during aerosol production, storage, exposure of animals and sampling. Within the aerosol laboratory, primary containment is provided by a Henderson apparatus operating at a negative pressure to the external environment. Flexible film isolators under negative pressure are used for all hazardous microbiological work, e.g. tissue homogenization, and for housing infected laboratory rodents. A novel feature of the animal isolator is the separate ventilation of each cage, which minimizes the risk of cross-infection by aerosol transmission and ensures a similar environment within each cage. The results of an intentional release of a cloud of non-pathogenic microorganisms are presented to show the effectiveness of the containment barriers. Recommendations are given for the safe operation of a containment unit based upon practical experience.
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Chua, Ming Hui, Weiren Cheng, Shermin Simin Goh, Junhua Kong, Bing Li, Jason Y. C. Lim, Lu Mao, et al. "Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives." Research 2020 (August 7, 2020): 1–40. http://dx.doi.org/10.34133/2020/7286735.
Full textAbstract:
The increasing prevalence of infectious diseases in recent decades has posed a serious threat to public health. Routes of transmission differ, but the respiratory droplet or airborne route has the greatest potential to disrupt social intercourse, while being amenable to prevention by the humble face mask. Different types of masks give different levels of protection to the user. The ongoing COVID-19 pandemic has even resulted in a global shortage of face masks and the raw materials that go into them, driving individuals to self-produce masks from household items. At the same time, research has been accelerated towards improving the quality and performance of face masks, e.g., by introducing properties such as antimicrobial activity and superhydrophobicity. This review will cover mask-wearing from the public health perspective, the technical details of commercial and home-made masks, and recent advances in mask engineering, disinfection, and materials and discuss the sustainability of mask-wearing and mask production into the future.
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Munir, Nosheen, Mohammad Awrangjeb, and Bela Stantic. "Automatic Extraction of High-Voltage Bundle Subconductors Using Airborne LiDAR Data." Remote Sensing 12, no. 18 (September 20, 2020): 3078. http://dx.doi.org/10.3390/rs12183078.
Full textAbstract:
Overhead high-voltage conductors are the chief components of power lines and their safety has a strong influence on social and daily life. In the recent decade, the airborne laser scanning (ALS) technique has been widely used to capture the three-dimensional (3D) information of power lines and surrounding objects. Most of the existing methods focused on extraction of single conductors or extracted all conductors as one object class by applying machine learning techniques. Nevertheless, power line corridors (PLCs) are built with multi-loop, multi-phase structures (bundle conductors) and exist in intricate environments (e.g., mountains and forests), and thus raise challenges to process ALS data for extraction of individual conductors. This paper proposes an automated method to extract individual subconductors in bundles from complex structure of PLCs using a combined image- and point-based approach. First, the input point cloud data are grouped into 3D voxel grid and PL points and separated from pylon and tree points using the fact that pylons and trees are vertical objects while power lines are non-vertical objects. These pylons are further separated from trees by employing a statistical analysis technique and used to extract span points between two consecutive pylons; then, by using the distribution properties of power lines in each individual span, the bundles located at different height levels are extracted using image-based processing; finally, subconductors in each bundle are detected and extracted by introducing a window that slides over the individual bundle. The orthogonal plane transformation and recursive clustering procedures are exploited in each window position and a point-based processing is conducted iteratively for extraction of complete individual subconductors in each bundle. The feasibility and validity of the proposed method are verified on two Australian sites having bundle conductors in high-voltage transmission lines. Our experiments show that the proposed method achieves a reliable result by extracting the real structure of bundle conductors in power lines with correctness of 100% and 90% in the two test sites, respectively.
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Kotsilkov, Stanislav, Evgeni Ivanov, and Nikolay Vitanov. "Release of Graphene and Carbon Nanotubes from Biodegradable Poly(Lactic Acid) Films during Degradation and Combustion: Risk Associated with the End-of-Life of Nanocomposite Food Packaging Materials." Materials 11, no. 12 (November 22, 2018): 2346. http://dx.doi.org/10.3390/ma11122346.
Full textAbstract:
Nanoparticles of graphene and carbon nanotubes are attractive materials for the improvement of mechanical and barrier properties and for the functionality of biodegradable polymers for packaging applications. However, the increase of the manufacture and consumption increases the probability of exposure of humans and the environment to such nanomaterials; this brings up questions about the risks of nanomaterials, since they can be toxic. For a risk assessment, it is crucial to know whether airborne nanoparticles of graphene and carbon nanotubes can be released from nanocomposites into the environment at their end-life, or whether they remain embedded in the matrix. In this work, the release of graphene and carbon nanotubes from the poly(lactic) acid nanocomposite films were studied for the scenarios of: (i) biodegradation of the matrix polymer at the disposal of wastes; and (ii) combustion and fire of nanocomposite wastes. Thermogravimetric analysis in air atmosphere, transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscope (SEM) were used to verify the release of nanoparticles from nanocomposite films. The three factors model was applied for the quantitative and qualitative risk assessment of the release of graphene and carbon nanotubes from nanocomposite wastes for these scenarios. Safety concern is discussed in respect to the existing regulations for nanowaste stream.
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Chaintoutis, Serafeim C., Zoi Thomou, Evangelia Mouchtaropoulou, George Tsiolas, Taxiarchis Chassalevris, Ioanna Stylianaki, Maria Lagou, et al. "Outbreaks of SARS-CoV-2 in naturally infected mink farms: Impact, transmission dynamics, genetic patterns, and environmental contamination." PLOS Pathogens 17, no. 9 (September 7, 2021): e1009883. http://dx.doi.org/10.1371/journal.ppat.1009883.
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SARS-CoV-2 infection outbreaks in minks have serious implications associated with animal health and welfare, and public health. In two naturally infected mink farms (A and B) located in Greece, we investigated the outbreaks and assessed parameters associated with virus transmission, immunity, pathology, and environmental contamination. Symptoms ranged from anorexia and mild depression to respiratory signs of varying intensity. Although the farms were at different breeding stages, mortality was similarly high (8.4% and 10.0%). The viral strains belonged to lineages B.1.1.218 and B.1.1.305, possessing the mink-specific S-Y453F substitution. Lung histopathology identified necrosis of smooth muscle and connective tissue elements of vascular walls, and vasculitis as the main early key events of the acute SARS-CoV-2-induced broncho-interstitial pneumonia. Molecular investigation in two dead minks indicated a consistently higher (0.3–1.3 log10 RNA copies/g) viral load in organs of the male mink compared to the female. In farm A, the infected farmers were responsible for the significant initial infection of 229 out of 1,000 handled minks, suggesting a very efficient human-to-mink transmission. Subsequent infections across the sheds wherein animals were being housed occurred due to airborne transmission. Based on a R0 of 2.90 and a growth rate equal to 0.293, the generation time was estimated to be 3.6 days, indicative of the massive SARS-CoV-2 dispersal among minks. After the end of the outbreaks, a similar percentage of animals were immune in the two farms (93.0% and 93.3%), preventing further virus transmission whereas, viral RNA was detected in samples collected from shed surfaces and air. Consequently, strict biosecurity is imperative during the occurrence of clinical signs. Environmental viral load monitoring, in conjunction with NGS should be adopted in mink farm surveillance. The minimum proportion of minks that need to be immunized to avoid outbreaks in farms was calculated at 65.5%, which is important for future vaccination campaigns.
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Edoror, Faith I., Elizabeth O. Oloruntoba, and Shade J. Akinsete. "Knowledge and perception of the role of water, sanitation and hygiene in containment of Ebola virus disease among secondary school students in Ibadan, Nigeria." Journal of Water, Sanitation and Hygiene for Development 9, no. 4 (July 29, 2019): 635–43. http://dx.doi.org/10.2166/washdev.2019.132.
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Abstract This study assessed the knowledge and perception of the role of water supply, sanitation and hygiene (WASH) in the containment of Ebola virus disease (EVD) among secondary school students in Ibadan, Nigeria. A cross-sectional study of 420 students from eight schools (public and private) in Ibadan was conducted. A semi-structured questionnaire and an observational checklist were used to collect data. Data were analysed using descriptive statistics, Chi-square test and logistic regression at 5% level of significance. Overall, 60% reported EVD was airborne. A majority (71%) of the respondents had good knowledge of EVD, while a majority (92%) had a good perception of the role of WASH in EVD containment. Class of respondents was significantly (p = 0.045) associated with knowledge of WASH. Although schools had satisfactory sanitary facilities, only a few (21%) sustained good hygiene practices at the end of the Ebola outbreak in Nigeria. Our findings revealed suboptimal knowledge on transmission of EVD, and unsustainable hygiene practices among secondary students post-Nigeria's EVD outbreak. High priority should be given to hygiene education among educators and students. Implementation of monitoring and evaluation of hygiene behaviour among secondary school students should also be a priority.
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Jablonska, M., J. Janeczek, and F. J. M. Rietmeijer. "Seasonal changes in the mineral compositions of tropospheric dust in the industrial region of Upper Silesia, Poland." Mineralogical Magazine 67, no. 6 (December 2003): 1231–41. http://dx.doi.org/10.1180/0026461036760161.
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AbstractThe tropospheric dust loading in Upper Silesia (Poland) shows a steady, annually averaged supply of minerals from natural and anthropogenic sources, industrial dust emitters, domestic heating, transportation, but with superimposed seasonal changes for some dust types. Samples of airborne and deposited particles were collected at monthly intervals between 1996 and 2001 in several cities of Upper Silesia. Dust samples were examined by X-ray powder diffraction, analytical transmission electron microscopy, analytical scanning electron microscopy, and electron microprobe microanalysis. The most common dust included quartz, gypsum, coke, soot, hematite, magnetite, wüstite, bassanite, graphite and various K-, Fe- and Mg-bearing aluminosilicates, in order of decreasing abundance. Minor phases included α-iron, sulphur, sphalerite, halite, sylvite, hercynite, franklinite, baryte, dolomite, ankerite, apatite, olivine and feldspars. Quartz, and specific industrial minerals, e.g. spinels, sphalerite, olivine and iron, occurred throughout the year in almost constant abundances. The amounts of all other dust components show seasonal variations; gypsum, baryte and other sulphates are particularly abundant in winter. In general, minerals related to low-emission sources are abundant in the winter time, while both natural dusts and dust from high-emission sources are predominant during the summer.
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Anghel, Larisa, Cătălin-George Popovici, Cristian Stătescu, Radu Sascău, Marina Verdeș, Vasilică Ciocan, Ionela-Lăcrămioara Șerban, Minela Aida Mărănducă, Sebastian-Valeriu Hudișteanu, and Florin-Emilian Țurcanu. "Impact of HVAC-Systems on the Dispersion of Infectious Aerosols in a Cardiac Intensive Care Unit." International Journal of Environmental Research and Public Health 17, no. 18 (September 10, 2020): 6582. http://dx.doi.org/10.3390/ijerph17186582.
Full textAbstract:
At the end of 2019, a variation of a coronavirus, named SARS-CoV-2, has been identified as being responsible for a respiratory illness disease (COVID-19). Since ventilation is an important factor that influences airborne transmission, we proposed to study the impact of heating, ventilation and air-conditioning (HVAC) with a variable air volume (VAV) primary air system, on the dispersion of infectious aerosols, in a cardiac intensive care unit, using a transient simulation with computational fluid dynamics (CFD), based on the finite element method (FEM). We analyzed three scenarios that followed the dispersion of pathogen carrying expiratory droplets particles from coughing, from patients possibly infected with COVID-19, depending on the location of the patients in the intensive care unit. Our study provides the mechanism for spread of infectious aerosols, and possibly of COVID-19 infection, by air conditioning systems and also highlights important recommendations for disease control and optimization of ventilation in intensive care units, by increasing the use of outdoor air and the rate of air change, decreasing the recirculation of air and using high-efficiency particulate air (HEPA) filters. The CFD-FEM simulation approach that was applied in our study could also be extended to other targets, such as public transport, theaters, philharmonics and amphitheaters from educational units.
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Feld, Louise, Hans Bay, Øystein Angen, Anders Rhod Larsen, and Anne Mette Madsen. "Survival of LA-MRSA in Dust from Swine Farms." Annals of Work Exposures and Health 62, no. 2 (January 20, 2018): 147–56. http://dx.doi.org/10.1093/annweh/wxx108.
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AbstractDust is suspected to be an important factor in transmission of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) between pigs and pig farmers and their families. The aim of this study was to determine the rate of decay for Staphylococcus aureus and LA-MRSA in dust from swine farms. Electrostatic dust fall collectors (EDCs) were used for passive sampling of settling airborne dust in 11 stable sections from six swine farms. Extraction, plating, identification, and enumeration of cultivable S. aureus and LA-MRSA from the EDCs were performed after storage for 0–30 days postsampling. The survival of S. aureus was measured in 196 dust samples from all farms, and data were used to estimate the decay constant λ according to a model for exponential decay: N(t) = N0 × e−λt. The number of S. aureus colonies was up to 600-fold higher than the number of LA-MRSA colonies on MRSA selective agar. The data showed a good fit to the model (λ = 0.13, r2 = 0.86) even with a large difference in initial concentrations of S. aureus between stables. The loads of S. aureus and LA-MRSA in the dust were significantly reduced by storage time, and the half-life was 5 days for both S. aureus and LA-MRSA. In dust samples with high initial concentrations, LA-MRSA and S. aureus could still be cultivated 30 days after sampling. On all farms MRSA isolates belonged to the clonal complex (CC) 398, and at one farm some isolates also belonged to CC30. A screening for other Staphylococcus species in the farm dust revealed 13 different species numerically dominated by Staphylococcus equorum. Based on the exponential decay model, S. equorum had a half-life of 4 days. In conclusion, the presence of MRSA in airborne dust from five of six farms indicates that dust might be an important vehicle for transmission of LA-MRSA. LA-MRSA and S. aureus was found to survive well in farm dust with half-lives of 5 days, and dependent on the initial concentration they could be found in farm dust for weeks. The 99.9% die-off rate was 66 days for LA-MRSA. Thus, farm dust can pose an exposure risk for humans in the farm environment, but also when transported to other environments. On the other hand, the risk will decrease by time. These results provide important knowledge to diminish spread from farm environments to other environments on, e.g., tools or clothing, and in relation to cleaning of emptied LA-MRSA-positive stables.
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Cao, Rui, and J. Stuart Bolton. "Experimental Investigation of Tire Slap Noise." Tire Science and Technology 46, no. 1 (January 1, 2018): 38–52. http://dx.doi.org/10.2346/tire.18.460101.
Full textAbstract:
ABSTRACT Tire noise is an important issue both in the vehicle interior and to the vehicle exterior, since it affects passenger comfort and environmental noise levels, respectively. Such noise is increased when a tire encounters discontinuities on the road surface, the discontinuity being either a gap or a bump. The relatively high frequency (e.g., approximately 1 kHz and above) airborne tire noise generated by such discontinuities is defined as tire slap noise in this study. Most previous research on noise generated by surface discontinuities has been focused on lower frequency tire noise, typically below 600 Hz, and, in particular, on structural-borne noise transmitted from the tire into the vehicle associated with the acoustic modes of the tire interior. Here, instead, the focus is on higher frequency airborne transmission. Further, the study here is conducted from the perspective of tire structural vibration, which concerns the vibration of and sound radiation from the tire treadband structure, rather than tire pattern noise, for example. The high frequency tire slap noise was investigated in a laboratory environment. The measurements were conducted by using the Ray W. Herrick Laboratories' Tire Pavement Test Apparatus (TPTA), on which a loaded tire can be run on realistic road surfaces at speeds up to 50 km/h; the resulting tire noise was measured using the On-Board Sound Intensity (OBSI) method. A gap between two different concrete surfaces was chosen as the road discontinuity, and both narrow band and one-third-octave band spectra were recorded over the gap and over the adjacent smooth road surface segments. Several tires were tested on the TPTA, and their slap noise was recorded. Surface noise and slap noise were compared up to 1600 Hz to show the impact of the discontinuity on the tire noise radiation. Generally, slap noise is of a higher level than the surface noise, especially between 800 and 1400 Hz, but some tires showed distinct differences between the noise response on the surface and over the gap, while other tires radiated similar noise on both the surface and over the gap. Moreover, static tire mobility measurements were performed to investigate the wave type responsible for the different responses on the gap and the surface.
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Miller, Arthur L., Andrew Todd Weakley, Peter R. Griffiths, Emanuele G. Cauda, and Sean Bayman. "Direct-on-Filter α-Quartz Estimation in Respirable Coal Mine Dust Using Transmission Fourier Transform Infrared Spectrometry and Partial Least Squares Regression." Applied Spectroscopy 71, no. 5 (September 19, 2016): 1014–24. http://dx.doi.org/10.1177/0003702816666288.
Full textAbstract:
In order to help reduce silicosis in miners, the National Institute for Occupational Health and Safety (NIOSH) is developing field-portable methods for measuring airborne respirable crystalline silica (RCS), specifically the polymorph α-quartz, in mine dusts. In this study we demonstrate the feasibility of end-of-shift measurement of α-quartz using a direct-on-filter (DoF) method to analyze coal mine dust samples deposited onto polyvinyl chloride filters. The DoF method is potentially amenable for on-site analyses, but deviates from the current regulatory determination of RCS for coal mines by eliminating two sample preparation steps: ashing the sampling filter and redepositing the ash prior to quantification by Fourier transform infrared (FT-IR) spectrometry. In this study, the FT-IR spectra of 66 coal dust samples from active mines were used, and the RCS was quantified by using: (1) an ordinary least squares (OLS) calibration approach that utilizes standard silica material as done in the Mine Safety and Health Administration's P7 method; and (2) a partial least squares (PLS) regression approach. Both were capable of accounting for kaolinite, which can confound the IR analysis of silica. The OLS method utilized analytical standards for silica calibration and kaolin correction, resulting in a good linear correlation with P7 results and minimal bias but with the accuracy limited by the presence of kaolinite. The PLS approach also produced predictions well-correlated to the P7 method, as well as better accuracy in RCS prediction, and no bias due to variable kaolinite mass. Besides decreased sensitivity to mineral or substrate confounders, PLS has the advantage that the analyst is not required to correct for the presence of kaolinite or background interferences related to the substrate, making the method potentially viable for automated RCS prediction in the field. This study demonstrated the efficacy of FT-IR transmission spectrometry for silica determination in coal mine dusts, using both OLS and PLS analyses, when kaolinite was present.
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Dmytryszyn, Mark, Matthew Crook, and Timothy Sands. "Preparing for Satellite Laser Uplinks and Downlinks." Sci 2, no. 1 (March 18, 2020): 16. http://dx.doi.org/10.3390/sci2010016.
Full textAbstract:
The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, even lasers as weapons (e.g., Airborne Laser). Lasers in support of telecommunications is also not new. The use of laser light in fiber optics shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers rather than traditional radio frequency sources for satellite uplink and downlink signal carriers, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploitation (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.
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Dmytryszyn, Mark, Matthew Crook, and Timothy Sands. "Lasers for Satellite Uplinks and Downlinks." Sci 2, no. 2 (June 12, 2020): 44. http://dx.doi.org/10.3390/sci2020044.
Full textAbstract:
The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, even lasers as weapons (e.g., Airborne Laser). Lasers in support of telecommunications is also not new. The use of laser light in fiber optics shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers rather than traditional radio frequency sources for satellite uplink and downlink signal carrier, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploitation (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.
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Dmytryszyn, Mark, Matthew Crook, and Timothy Sands. "Lasers for Satellite Uplinks and Downlinks." Sci 2, no. 3 (September 9, 2020): 71. http://dx.doi.org/10.3390/sci2030071.
Full textAbstract:
The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, even lasers as weapons (e.g., Airborne Laser). Lasers in support of telecommunications is also not new. The use of laser light in fiber optics shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers rather than traditional radio frequency sources for satellite uplink and downlink signal carrier, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploitation (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.
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Dmytryszyn, Mark, Matthew Crook, and Timothy Sands. "Lasers for Satellite Uplinks and Downlinks." Sci 3, no. 1 (January 4, 2021): 4. http://dx.doi.org/10.3390/sci3010004.
Full textAbstract:
The use of Light Amplification by Stimulated Emission of Radiation (i.e., LASERs or lasers) by the U.S. Department of Defense is not new and includes laser weapons guidance, laser-aided measurements, and even lasers as weapons (e.g., Airborne Laser). Lasers in the support of telecommunications is also not new. The use of laser light in fiber optics has shattered thoughts on communications bandwidth and throughput. Even the use of lasers in space is no longer new. Lasers are being used for satellite-to-satellite crosslinking. Laser communication can transmit orders-of-magnitude more data using orders-of-magnitude less power and can do so with minimal risk of exposure to the sending and receiving terminals. What is new is using lasers as the uplink and downlink between the terrestrial segment and the space segment of satellite systems. More so, the use of lasers to transmit and receive data between moving terrestrial segments (e.g., ships at sea, airplanes in flight) and geosynchronous satellites is burgeoning. This manuscript examines the technological maturation of employing lasers as the signal carrier for satellite communications linking terrestrial and space systems. The purpose of the manuscript is to develop key performance parameters (KPPs) to inform the U.S. Department of Defense initial capabilities documents (ICDs) for near-future satellite acquisition and development. By appreciating the history and technological challenges of employing lasers, rather than traditional radio frequency sources for satellite uplink and downlink signal carriers, this manuscript recommends ways for the U.S. Department of Defense to employ lasers to transmit and receive high bandwidth, and large-throughput data from moving platforms that need to retain low probabilities of detection, intercept, and exploit (e.g., carrier battle group transiting to a hostile area of operations, unmanned aerial vehicle collecting over adversary areas). The manuscript also intends to identify commercial sector early-adopter fields and those fields likely to adapt to laser employment for transmission and receipt.
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Hein, Daniel, Thomas Kraft, Jörg Brauchle, and Ralf Berger. "Integrated UAV-Based Real-Time Mapping for Security Applications." ISPRS International Journal of Geo-Information 8, no. 5 (May 8, 2019): 219. http://dx.doi.org/10.3390/ijgi8050219.
Full textAbstract:
Security applications such as management of natural disasters and man-made incidents crucially depend on the rapid availability of a situation picture of the affected area. UAV-based remote sensing systems may constitute an essential tool for capturing aerial imagery in such scenarios. While several commercial UAV solutions already provide acquisition of high quality photos or real-time video transmission via radio link, generating instant high-resolution aerial maps is still an open challenge. For this purpose, the article presents a real-time processing tool chain, enabling generation of interactive aerial maps during flight. Key element of this tool chain is the combination of the Terrain Aware Image Clipping (TAC) algorithm and 12-bit JPEG compression. As a result, the data size of a common scenery can be reduced to approximately 0.4% of the original size, while preserving full geometric and radiometric resolution. Particular attention was paid to minimize computational costs to reduce hardware requirements. The full workflow was demonstrated using the DLR Modular Airborne Camera System (MACS) operated on a conventional aircraft. In combination with a commercial radio link, the latency between image acquisition and visualization in the ground station was about 2 s. In addition, the integration of a miniaturized version of the camera system into a small fixed-wing UAV is presented. It is shown that the described workflow is efficient enough to instantly generate image maps even on small UAV hardware. Using a radio link, these maps can be broadcasted to on-site operation centers and are immediately available to the end-users.
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Herrmann, Michael, Rainer Jöst, Florian Kehl, Ali Özkan, Simon Pless, and Frank Gauterin. "Importance of Vehicle Body Elements and Rear Axle Elements for Describing Road Booming Noise." Vehicles 2, no. 4 (November 25, 2020): 589–603. http://dx.doi.org/10.3390/vehicles2040034.
Full textAbstract:
For investigating influences of vehicle components on the acoustic comfort at low frequencies, e.g., the booming noise behavior of a vehicle, building a whole car simulation model is useful. To reduce the model’s complexity and to save resources in the validation process, we first identify relevant components before building the model. Based on previous studies, we focus on the vehicle’s body and the rear axle. In this paper, we analyze which axle and body elements are crucial for describing road booming noise. For this purpose, we use impact measurements to examine noise transfer functions of the body and a vibro-acoustical modal analysis to identify coupled modes between the body’s structure and the interior cavity. For investigating relevant force paths from the rear axle to the body, we used a chassis test bench. We identify the main transmission paths of road booming noise and highlight which axle and body components have an influence on them. Mainly the rear axle in its upright direction in combination with a rigid body movement of the rear tailgate coupled with the first longitudinal mode of the airborne cavity causes road booming noise. Furthermore, the rear axle steering, the active roll stabilization and the trim elements of the vehicle’s body are essential to describe road booming noise. The results can be used to set priorities in the validation of individual axle and body components for future simulation models. We found that the ventilation openings, the front seats, the headliner, and the cockpit of a vehicle have little influence on its noise transfer functions from the rear axle connection points to the driver’s ear between 20 and 60 Hz.
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Uprety, Sirish, Changyong Cao, Xiaoxiong Xiong, Slawomir Blonski, Aisheng Wu, and Xi Shao. "Radiometric Intercomparison between Suomi-NPP VIIRS and Aqua MODIS Reflective Solar Bands Using Simultaneous Nadir Overpass in the Low Latitudes." Journal of Atmospheric and Oceanic Technology 30, no. 12 (December 1, 2013): 2720–36. http://dx.doi.org/10.1175/jtech-d-13-00071.1.
Full textAbstract:
Abstract On-orbit radiometric performance of the Suomi National Polar-Orbiting Partnership (Suomi-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) is studied using the extended simultaneous nadir overpass (SNO-x) approach. Unlike the traditional SNO analysis of data in the high latitudes, this study extends the analysis to the low latitudes—in particular, over desert and ocean sites with relatively stable and homogeneous radiometric properties—for intersatellite comparisons. This approach utilizes a pixel-by-pixel match with an efficient geospatial matching algorithm to map VIIRS data into the Moderate Resolution Imaging Spectroradiometer (MODIS). VIIRS moderate-resolution bands M-1 through M-8 are compared with Aqua MODIS equivalent bands to quantify radiometric bias over the North African desert and over the ocean. Biases exist between VIIRS and MODIS in several bands, primarily because of spectral differences as well as possible calibration uncertainties, residual cloud contamination, and bidirectional reflectance distribution function (BRDF). The impact of spectral differences on bias is quantified by using the Moderate Resolution Atmospheric Transmission (MODTRAN) and hyperspectral measurements from the Earth Observing-1 (EO-1) Hyperion and the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS). After accounting for spectral differences and bias uncertainties, the VIIRS radiometric bias over desert agrees with MODIS measurements within 2% except for the VIIRS shortwave infrared (SWIR) band M-8, which indicates a nearly 3% bias. Over ocean, VIIRS agrees with MODIS within 2% by the end of January 2013 with uncertainty less than 1%. Furthermore, VIIRS bias relative to MODIS is also computed at the Antarctica Dome C site for validation and the result agrees well within 1% with the bias estimated using SNO-x over desert.
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Zhao, Yang, Lilong Chai, Brad Richardson, and Hongwei Xin. "Field Evaluation of an Electrostatic Air Filtration System for Reducing Incoming Particulate Matter of a Hen House." Transactions of the ASABE 61, no. 1 (2018): 295–304. http://dx.doi.org/10.13031/trans.12533.
Full textAbstract:
Abstract. As a result of the unprecedented highly pathogenic avian influenza (HPAI) outbreak in the U.S. in 2014-2015, some egg producers in the U.S. started using inlet air filtration to reduce the risk of disease transmission by air into hen houses. The removal efficiency of particulate matter (PM), the carrier of airborne pathogens, by such filtration systems has not been investigated. Therefore, this field study was conducted to evaluate the PM removal efficacy of an electrostatic air filtration system (consisting of a low-grade air filter and an electrostatic particle ionization, or EPI, system) installed at the inlet of a commercial high-rise hen house. The evaluation was performed in two test rounds over a one-year period. Results showed that average PM removal efficiencies in round 1 (spring to summer) and round 2 (late fall to spring) were respectively 66% and 29% for PM1, 66% and 30% for PM2.5, 66% and 31% for PM4, 68% and 36% for PM10, and 68% and 45% for total PM. Removal efficiency became unstable when the EPI system was inactive (i.e., when solely relying on the filter for PM removal). House static pressure and ventilation rate indicated considerable clogging of the filter media by dust accumulation and the need for replacement after ~16 weeks of use in the spring-to-summer sampling period (round 1); however, clogging was not an issue during the entire late fall-to-spring sampling period (24 weeks, round 2). The appearance of the filter changed gradually as dust accumulated with time, which can be captured by image analysis and used to judge filter dirtiness and lifespan. The findings of this field study provide insight into the efficacy of PM removal by such a low-cost air filtration system, which will help egg producers in their decision-making for disease prevention strategies. Keywords: Electrostatic particle ionization, Filtration, Hen house, Particulate matter, Reduction.
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Ghani, Fazal. "Editorial Fallow Time and Managing Aerosol Generation in Dental Clinics–Current Evidence and Financial Investment Implications." Journal of Rawalpindi Medical College 24, no. 4 (December 30, 2020): 290–91. http://dx.doi.org/10.37939/jrmc.v24i4.1492.
Full textAbstract:
Recently, the Scottish Dental Clinical Effectiveness Programme (SDCEP) was tasked to perform a rapid review on the guidelines related to factors mitigating the effect of aerosol generation during dental procedures and reduction in fallow-time. Review1, reflecting the tireless work by the SDCEP review board can be truly considered as a report that the profession has been looking for. The SDCEP’s review comes at a time when the science has not been comprehensive and doesn’t outline how to best ensure public and staff safety in the dental clinic.2 He hopes that the government policy and any new instructions will now reflect the recommendations made in this review.Considering the issues of continued frustration of the dental profession, towards the end of June, the Office of the Chief Dental Officers (CDOs) in the UK tasked the SDCEP to get to grips with the matter. It is worth-noting that SDECP3 has been held in high regard for its outstanding work on antimicrobial resistance, antibiotic prophylaxis, dental amalgam, and periodontal care, and has been praised by all the CDOs in the UK four countries including England, Scotland, Wales, and Northern Ireland. In response, the SDCEP immediately convened a multidisciplinary working group to identify and appraise all the available evidence concerning the generation and mitigation of aerosol dentistry and the associated risk of COVID-19 transmission. The aim was to reach a number of agreed position statements informing policy and clinical guidance.The review members’ dedication, commitment, and clinical and academic expertise have been hugely impressive.2 All worked for almost three months and there were; remarkable academics, virologists, physicists, public health officials, and other wet-fingered dentists. The process required hours of virtual meetings piled on top of intensive review work. To complete the review, everyone almost felt like being a student again waking up to spend hours on physics of relevance to aerosol and epidemiology of airborne viral diseases.
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Ghani, Fazal. "Editorial Fallow Time and Managing Aerosol Generation in Dental Clinics–Current Evidence and Financial Investment Implications." Journal of Rawalpindi Medical College 24, no. 4 (December 30, 2020): 290–91. http://dx.doi.org/10.37939/jrmc.v24i4.1492.
Full textAbstract:
Recently, the Scottish Dental Clinical Effectiveness Programme (SDCEP) was tasked to perform a rapid review on the guidelines related to factors mitigating the effect of aerosol generation during dental procedures and reduction in fallow-time. Review1, reflecting the tireless work by the SDCEP review board can be truly considered as a report that the profession has been looking for. The SDCEP’s review comes at a time when the science has not been comprehensive and doesn’t outline how to best ensure public and staff safety in the dental clinic.2 He hopes that the government policy and any new instructions will now reflect the recommendations made in this review.Considering the issues of continued frustration of the dental profession, towards the end of June, the Office of the Chief Dental Officers (CDOs) in the UK tasked the SDCEP to get to grips with the matter. It is worth-noting that SDECP3 has been held in high regard for its outstanding work on antimicrobial resistance, antibiotic prophylaxis, dental amalgam, and periodontal care, and has been praised by all the CDOs in the UK four countries including England, Scotland, Wales, and Northern Ireland. In response, the SDCEP immediately convened a multidisciplinary working group to identify and appraise all the available evidence concerning the generation and mitigation of aerosol dentistry and the associated risk of COVID-19 transmission. The aim was to reach a number of agreed position statements informing policy and clinical guidance.The review members’ dedication, commitment, and clinical and academic expertise have been hugely impressive.2 All worked for almost three months and there were; remarkable academics, virologists, physicists, public health officials, and other wet-fingered dentists. The process required hours of virtual meetings piled on top of intensive review work. To complete the review, everyone almost felt like being a student again waking up to spend hours on physics of relevance to aerosol and epidemiology of airborne viral diseases.
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Cocârţă, Diana Mariana, Mariana Prodana, Ioana Demetrescu, Patricia Elena Maria Lungu, and Andreea Cristiana Didilescu. "Indoor Air Pollution with Fine Particles and Implications for Workers’ Health in Dental Offices: A Brief Review." Sustainability 13, no. 2 (January 10, 2021): 599. http://dx.doi.org/10.3390/su13020599.
Full textAbstract:
(1) Background: Indoor air pollution can affect the well-being and health of humans. Sources of indoor pollution with particulate matter (PM) are outdoor particles and indoor causes, such as construction materials, the use of cleaning products, air fresheners, heating, cooking, and smoking activities. In 2017, according to the Global Burden of Disease study, 1.6 million people died prematurely because of indoor air pollution. The health effects of outdoor exposure to PM have been the subject of both research and regulatory action, and indoor exposure to fine particles is gaining more and more attention as a potential source of adverse health effects. Moreover, in critical situations such as the current pandemic crisis, to protect the health of the population, patients, and staff in all areas of society (particularly in indoor environments, where there are vulnerable groups, such as people who have pre-existing lung conditions, patients, elderly people, and healthcare professionals such as dental practitioners), there is an urgent need to improve long- and short-term health. Exposure to aerosols and splatter contaminated with bacteria, viruses, and blood produced during dental procedures performed on patients rarely leads to the transmission of infectious agents between patients and dental health care staff if infection prevention procedures are strictly followed. On the other hand, in the current circumstances of the pandemic crisis, dental practitioners could have an occupational risk of acquiring coronavirus disease as they may treat asymptomatic and minimally symptomatic patients. Consequently, an increased risk of SARS-CoV-2 infection could occur in dental offices, both for staff that provide dental healthcare and for other patients, considering that many dental procedures produce droplets and dental aerosols, which carry an infectious virus such as SARS-CoV-2. (2) Types of studies reviewed and applied methodology: The current work provides a critical review and evaluation, as well as perspectives concerning previous studies on health risks of indoor exposure to PM in dental offices. The authors reviewed representative dental medicine literature focused on sources of indoor PM10 and PM2.5 (particles for which the aerodynamic diameter size is respectively less than 10 and 2.5 μm) in indoor spaces (paying specific attention to dental offices) and their characteristics and toxicological effects in indoor microenvironments. The authors also reviewed representative studies on relations between the indoor air quality and harmful effects, as well as studies on possible indoor viral infections acquired through airborne and droplet transmission. The method employed for the research illustrated in the current paper involved a desk study of documents and records relating to occupational health problems among dental health care providers. In this way, it obtained background information on both the main potential hazards in dentistry and infection risks from aerosol transmission within dental offices. Reviewing this kind of information, especially that relating to bioaerosols, is critical for minimizing the risk to dental staff and patients, particularly when new recommendations for COVID-19 risk reduction for the dental health professional community and patients attending dental clinics are strongly needed. (3) Results: The investigated studies and reports obtained from the medical literature showed that, even if there are a wide number of studies on indoor human exposure to fine particles and health effects, more deep research and specific studies on indoor air pollution with fine particles and implications for workers’ health in dental offices are needed. As dental practices are at a higher risk for hazardous indoor air because of exposure to chemicals and microbes, the occupational exposures and diseases must be addressed, with special attention being paid to the dental staff. The literature also documents that exposure to fine particles in dental offices can be minimized by putting prevention into practice (personal protection barriers such as masks, gloves, and safety eyeglasses) and also keeping indoor air clean (e.g., high-volume evacuation, the use of an air-room-cleaning system with high-efficiency particulate filters, and regularly maintaining the air-conditioning and ventilation systems). These kinds of considerations are extremely important as the impact of indoor pollution on human health is no longer an individual issue, with its connections representing a future part of sustainability which is currently being redefined. These kinds of considerations are extremely important, and the authors believe that a better situation in dentistry needs to be developed, with researchers in materials and dental health trying to understand and explain the impact of indoor pollution on human health.
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Cocârţă, Diana Mariana, Mariana Prodana, Ioana Demetrescu, Patricia Elena Maria Lungu, and Andreea Cristiana Didilescu. "Indoor Air Pollution with Fine Particles and Implications for Workers’ Health in Dental Offices: A Brief Review." Sustainability 13, no. 2 (January 10, 2021): 599. http://dx.doi.org/10.3390/su13020599.
Full textAbstract:
(1) Background: Indoor air pollution can affect the well-being and health of humans. Sources of indoor pollution with particulate matter (PM) are outdoor particles and indoor causes, such as construction materials, the use of cleaning products, air fresheners, heating, cooking, and smoking activities. In 2017, according to the Global Burden of Disease study, 1.6 million people died prematurely because of indoor air pollution. The health effects of outdoor exposure to PM have been the subject of both research and regulatory action, and indoor exposure to fine particles is gaining more and more attention as a potential source of adverse health effects. Moreover, in critical situations such as the current pandemic crisis, to protect the health of the population, patients, and staff in all areas of society (particularly in indoor environments, where there are vulnerable groups, such as people who have pre-existing lung conditions, patients, elderly people, and healthcare professionals such as dental practitioners), there is an urgent need to improve long- and short-term health. Exposure to aerosols and splatter contaminated with bacteria, viruses, and blood produced during dental procedures performed on patients rarely leads to the transmission of infectious agents between patients and dental health care staff if infection prevention procedures are strictly followed. On the other hand, in the current circumstances of the pandemic crisis, dental practitioners could have an occupational risk of acquiring coronavirus disease as they may treat asymptomatic and minimally symptomatic patients. Consequently, an increased risk of SARS-CoV-2 infection could occur in dental offices, both for staff that provide dental healthcare and for other patients, considering that many dental procedures produce droplets and dental aerosols, which carry an infectious virus such as SARS-CoV-2. (2) Types of studies reviewed and applied methodology: The current work provides a critical review and evaluation, as well as perspectives concerning previous studies on health risks of indoor exposure to PM in dental offices. The authors reviewed representative dental medicine literature focused on sources of indoor PM10 and PM2.5 (particles for which the aerodynamic diameter size is respectively less than 10 and 2.5 μm) in indoor spaces (paying specific attention to dental offices) and their characteristics and toxicological effects in indoor microenvironments. The authors also reviewed representative studies on relations between the indoor air quality and harmful effects, as well as studies on possible indoor viral infections acquired through airborne and droplet transmission. The method employed for the research illustrated in the current paper involved a desk study of documents and records relating to occupational health problems among dental health care providers. In this way, it obtained background information on both the main potential hazards in dentistry and infection risks from aerosol transmission within dental offices. Reviewing this kind of information, especially that relating to bioaerosols, is critical for minimizing the risk to dental staff and patients, particularly when new recommendations for COVID-19 risk reduction for the dental health professional community and patients attending dental clinics are strongly needed. (3) Results: The investigated studies and reports obtained from the medical literature showed that, even if there are a wide number of studies on indoor human exposure to fine particles and health effects, more deep research and specific studies on indoor air pollution with fine particles and implications for workers’ health in dental offices are needed. As dental practices are at a higher risk for hazardous indoor air because of exposure to chemicals and microbes, the occupational exposures and diseases must be addressed, with special attention being paid to the dental staff. The literature also documents that exposure to fine particles in dental offices can be minimized by putting prevention into practice (personal protection barriers such as masks, gloves, and safety eyeglasses) and also keeping indoor air clean (e.g., high-volume evacuation, the use of an air-room-cleaning system with high-efficiency particulate filters, and regularly maintaining the air-conditioning and ventilation systems). These kinds of considerations are extremely important as the impact of indoor pollution on human health is no longer an individual issue, with its connections representing a future part of sustainability which is currently being redefined. These kinds of considerations are extremely important, and the authors believe that a better situation in dentistry needs to be developed, with researchers in materials and dental health trying to understand and explain the impact of indoor pollution on human health.
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Dillon, Charles F., and Michael B. Dillon. "Multi-Scale Airborne Infectious Disease Transmission." Applied and Environmental Microbiology, December 4, 2020. http://dx.doi.org/10.1128/aem.02314-20.
Full textAbstract:
Airborne disease transmission is central to many scientific disciplines including agriculture, veterinary biosafety, medicine, and public health. Legal and regulatory standards are in place to prevent agricultural, nosocomial, and community airborne disease transmission. However, the overall importance of the airborne pathway is underappreciated, e.g.,, US National Library of Medicine’s Medical Subjects Headings (MESH) thesaurus lacks an airborne disease transmission indexing term. This has practical consequences as airborne precautions to control epidemic disease spread may not be taken when airborne transmission is important, but unrecognized. Publishing clearer practical methodological guidelines for surveillance studies and disease outbreak evaluations could help address this situation. To inform future work, this paper highlights selected, well-established airborne transmission events - largely cases replicated in multiple, independently conducted scientific studies. Methodologies include field experiments, modeling, epidemiology studies, disease outbreak investigations and mitigation studies. Collectively, this literature demonstrates that airborne viruses, bacteria, and fungal pathogens have the capability to cause disease in plants, animals, and humans over multiple distances – from near range (< 5 m) to continental (> 500 km) in scale. The plausibility and implications of undetected airborne disease transmission are discussed, including the notable underreporting of disease burden for several airborne transmitted diseases.