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In this paper we report two applications of a subcategory of air cleaning devices based on soft ionization that do not cause molecular fragmentation. A system that includes two unipolar ionizing modules has been used to simultaneously produce positive and negative ions in the air. In one set of experiments a large chamber (28 m3) was used to study the effect of ions on reducing PM1.0 particles produced by a research grade calibrated cigarette. The data presented in this paper were obtained using a carbon-brush-based bipolar ionizer and a MERV 10 filter with electret media in a recirculating HVAC system. Significant improvement in removal rate of fine and ultrafine particles was achieved when using the bipolar ionizer in conjunction with the MERV 10 filter. The second set of experiments were conducted using a 36 m3 chamber, following BSL-3 standards, to study the effect of ions on aerosolized SARS-CoV-2. Results of these investigations reveal the inactivation rate of SARS-CoV-2 are enhanced when ions are introduced in the air;inactivation rates were increased by more than 60%and 90%for ion densities of 10,000/cc and 18,000/cc. IEEE
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Infectious diseases (e.g., coronavirus disease 2019) dramatically impact human life, economy and social development. Exploring the low-cost and energy-saving approaches is essential in removing infectious virus particles from indoors, such as in classrooms. The application of air purification devices, such as negative ion generators (ionizers), gains popularity because of the favorable removal capacity for particles and the low operation cost. However, small and portable ionizers have potential disadvantages in the removal efficiency owing to the limited horizontal diffusion of negative ions. This study aims to investigate the layout strategy (number and location) of ionizers based on the energy-efficient natural ventilation in the classroom to improve removal efficiency (negative ions to particles) and decrease infection risk. Three infected students were considered in the classroom. The simulations of negative ion and particle concentrations were performed and validated by the experiment. Results showed that as the number of ionizers was 4 and 5, the removal performance was largely improved by combining ionizer with natural ventilation. Compared with the scenario without an ionizer, the scenario with 5 ionizers largely increased the average removal efficiency from around 20% to 85% and decreased the average infection risk by 23%. The setup with 5 ionizers placed upstream of the classroom was determined as the optimal layout strategy, particularly when the location and number of the infected students were unknown. This work can provide a guideline for applying ionizers to public buildings when natural ventilation is used. Electronic Supplementary Material ESM: the Appendix is available in the online version of this article at 10.1007/s12273-022-0959-z.
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Mimusops elengi Linn. Secondary metabolites of flavonoids, phenolic acids, coumarin classes and stilbene were identified by UPLC/ESI-QTOF-HRMS/MS technique with negative ion detection. Major Mimusops elengi flavonoids included Myricitrin, Myricetin, and Kaempferol-3-O-alpha-L-rhamnoside. The most abundant Coumarin and phenolic acids detected in the chromatogram included aesculin and quinic acid respectively. Down regulation of NLRP3 inflammasome activation inhibits the severe inflammatory responses caused by virus infection. Studying in silicobinding affinity of flavonoids, coumarins and phenolic acid in M. elengi leaves extract against the ADP binding site of NLRP3 protein (PDB code: 6NPY) demonstrated that investigated compounds have docking scores ranged from −6.20 to −12.30 kcal/mol. The best score was achieved by kaempferol-3-O-(6-p-coumaroyl) -glucoside(Compound 9) followed by aesculin (Compound 25) while Quinic acid (Compound 20) showed the lowest affinity toward ADP-binding site of NLRP3. © 2023 The Authors
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Ozone is a highly effective and broad-spectrum non-residual gas disinfectant.The global COVID-19 pandemic has significantly affected public safety and health, and low concentrations of ozone can inactivate the novel coronavirus.The negative ion generator is a safe and efficient method to generate ozone.Through corona discharge on the needle plate, an ion current can be formed between the needle-plate electrodes and a certain concentration of ozone can be released.In the research on the relationship between the electrode-to-plate distance and ozone release in the negative ion generator, different experimental observations show contradictory results, making the theoretical explanation very difficult and complicated.As the needle-to-plate electrode distance increases, the continuous exponential decreasing trend of ozone emission rate changes to a non-continuous step-wised decreasing pattern, which is defined as the Quantum Ozone Emission Effect (QOEE).The QOEE was observed in all negative ion generators when the plate material was aluminium, stainless steel, yellow brass, or copper.The observed quantum ozone emission effect in negative ion generators may be related to the gas ionization potential of the oxygen molecule and to the electron avalanche theory.The quantum effect of ozone emission is a manifestation of the quantum behavior of the microscopic electron world in the macroscopic world.The ozone emission quantum effect provides a novel technical method for measuring the microscopic properties and corona discharge characteristics of materials. © 2022, Editorial Department of Journal of Xidian University. All right reserved.
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The pandemic of respiratory diseases, such as coronavirus disease 2019 (COVID-19) and influenza, has imposed significant public health and economic burdens on the world. Wearing masks is an effective way to cut off the spread of the respiratory virus. However, due to cultural differences and uncomfortable wearing experiences, not everyone is willing to wear masks; there is an urgent need to find alternatives to masks. In this study, we tested the disinfection effect of a portable ionizer on pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (strain V34) and influenza A virus (strain CA04). Negative ions significantly reduced the concentration of particulate matter in the air above and effectively disinfected viruses stuck to the solid plate at the level of both nucleic acid and virus titer. The disinfection efficiency was >99.8% after 1-h exposure. Moreover, negative ions effectively disinfected aerosolized viruses; the disinfection efficiency was more than 87.77% after purification for 10 min. Furthermore, negative ions had a significant protective effect on susceptible animals exposed to viral aerosols. When the negative ionizer was switched from off to on, the inhalation 50% infective dose (ID50) for golden hamsters challenged with SARS-CoV-2 rose from 9.878 median tissue culture infective dose (TCID50) [95% confidence interval (CI), 6.727-14.013 TCID50] to 43.891 TCID50 (95% CI, 29.31-76.983 TCID50), and the inhalation ID50 for guinea pigs challenged with influenza A virus rose from 6.696 TCID50 (95% CI, 3.251-9.601 TCID50) to 28.284 TCID50 (95% CI, 19.705-40.599 TCID50). In the experiment of transmission between susceptible animals, negative ions 100% inhibited the aerosol transmission of SARS-CoV-2 and influenza A virus. Finally, we tested the safety of negative ion exposure. Balb/c mice exposed to negative ions for 4 weeks showed no abnormalities in body weight, blood routine analysis, and lung pathology. Our study demonstrates that air ions can be used as a safe and effective means of blocking respiratory virus transmission and contribute to pandemic prevention and control.
Subject(s)
COVID-19 , Influenza A virus , Aerosols , Animals , COVID-19/prevention & control , Cricetinae , Guinea Pigs , Ions , Mice , Pandemics/prevention & control , SARS-CoV-2ABSTRACT
The 19th International Conference on Ion Sources was hosted by TRIUMF in Vancouver, BC, Canada, September 20 to September 24, 2021.The biennial conference series covers the physics and technology of ion sources for scientific research and applications. With the conference being the main event within the ion sources community, it offers a forum for the exchange of ideas and the establishing of collaborations. New developments and advancements have been presented and discussed. As in previous conferences of this series, all aspects of ion sources have been covered in the categories• Fundamental processes in ion sources and plasmas• Production of high intensity ion beams• Production of highly charged ion beams• Negative ion sources• Ion sources for fusion• Radioactive ion sources, charge breeders and polarized beams• Beam formation, extraction, transport, and diagnostics• Applications of ion sources• Key technologies for ion sourcesDue to restrictions on traveling and meeting sizes caused by health regulations during the COVID-19 pandemic, the conference was held as a virtual conference. Talks have been presented via ZOOM and two poster sessions were held within the remote meeting platform “Gather town”, which was also open for discussions among participants outside the plenary sessions.The main session on electron beam ion sources was dedicated to the memory of Professor Dr. Evgeny Denisovich Donets who, to our great regret, passed away in June 2021. Professor Donets was the inventor of the electron beam ion source and one of the initiators of this conference series. He was a longtime member of the international advisory committee. His memory will be highly regarded within the ion source community.List of International advisory committee, Scientific program committee, Local organizing committee are available in this pdf.
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The purpose of this study was to develop a simple electrostatic apparatus to precipitate virus particles spread via droplet transmission, which is especially significant in the context of the recent coronavirus disease 2019 (COVID-19) pandemic. The bacteriophage φ6 of Pseudomonas syringae was used as a model of the COVID-19 virus because of its similar structure and safety in experiments. The apparatus consisted of a spiked, perforated stainless plate (S-PSP) linked to a direct-current voltage generator to supply negative charge to the spike tips and a vessel with water (G-water) linked to a ground line. The S-PSP and G-water surface were paralleled at a definite interval. Negative charge supplied to the spike tips positively polarised the G-water by electrostatic induction to form an electric field between them in which ionic wind and negative ions were generated. Bacteriophage-containing water was atomised with a nebuliser and introduced into the electric field. The mist particles were ionised by the negative ions and attracted to the opposite pole (G-water). This apparatus demonstrated a prominent ability to capture phage-containing mist particles of the same sizes as respiratory droplets and aerosols regardless of the phage concentration of the mist particles. The trapped phages were successfully sterilised using ozone bubbling. Thus, the present study provides an effective system for eliminating droplet transmission of viral pathogens from public spaces.