Effects of medical waste incineration fly ash on the promotion of heavy metal chlorination volatilization from incineration residues.

High contents of heavy metals and Cl are major challenges for incineration residue disposal. Classification by the Chinese government and the coronavirus disease 2019 pandemic have changed the characteristics of incineration residues, thereby increasing the difficulty of disposal. In this study, medical waste incineration fly ash (MWI FA) was proposed as an additive to promote chlorination volatilization of heavy metals from municipal solid waste incineration fly ash (MSWI FA) and medical waste incineration slag (MWI S). When the mixing ratio of MWI FA to MSWI FA was 1:3, the chlorination volatilization efficiencies of Cu, Zn, Pb, and Cd at 1000 °C for 60 min were 50.2%, 99.4%, 99.7%, and 97.9%, respectively. When MWI FA was mixed with MWI S at a ratio of 1:1, the chlorination volatilization efficiencies of Cu, Zn, Pb, and Cd at 1200 °C for 40 min were 88.9%, 99.7%, 97.3%, and 100%, respectively. Adding MWI FA can replenish Cl in MSWI FA and MWI S while increasing the surface area and forming pore structures by sublimation of NaCl and decomposition of CaSO4, or can reduce the melting point and viscosity by Na2O destroying the glass matrix. Therefore, MWI FA can be co-disposed with MSWI FA and MWI S respectively to enhance the chlorination volatilization of heavy metals.

Empirical Examination on the Drivers of the U.S. Equity Returns in the During the COVID-19 Crisis.

This study investigates the drivers of the Standard & Poor's (S&P) 500 equity returns during the COVID-19 crisis era. The paper considers various determinants of the equity returns from December 31, 2019, to February 19, 2021. It is observed that the United States Dollar (USD) and the volatility indices (VIX) negatively affect the S&P 500 equity returns. However, the newspaper-based infectious disease "equity market volatility tracker" is positively associated with the stock market returns. These results are robust to consider both the ordinary least squares (OLS) and the least angle regression (LARS) estimators.

Epidemics, Public Sentiment, and Infectious Disease Equity Market Volatility.

Background: This article studies the relationship between the COVID-19 epidemic, public sentiment, and the volatility of infectious disease equities from the perspective of the United States. We use weekly data from January 3, 2020 to March 7, 2021. This provides a sufficient dataset for empirical analysis. Granger causality test results prove the two-way relationship between the fluctuation of infectious disease equities and confirmed cases. In addition, confirmed cases will cause the public to search for COVID-19 tests, and COVID-19 tests will also cause fluctuations in infectious disease equities, but there is no reverse correlation. The results of this research are useful to investors and policy makers. Investors can use the number of confirmed cases to predict the volatility of infectious disease equities. Similarly, policy makers can use the intervention of retrieved information to stabilize public sentiment and equity market fluctuations, and integrate a variety of information to make more scientific judgments on the trends of the epidemic.

"Don, doff, discard" to "don, doff, decontaminate"-FFR and mask integrity and inactivation of a SARS-CoV-2 surrogate and a norovirus following multiple vaporised hydrogen peroxide-, ultraviolet germicidal irradiation-, and dry heat decontaminations.

BACKGROUND: As the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens. AIM: We provide information on the effect of time-dependent passive decontamination (infectivity loss over time during room temperature storage in a breathable bag) and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination. METHODS: Masks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations. RESULTS AND DISCUSSION: Infectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused.

Perceiving Social-Emotional Volatility and Triggered Causes of COVID-19.

Health support has been sought by the public from online social media after the outbreak of novel coronavirus disease 2019 (COVID-19). In addition to the physical symptoms caused by the virus, there are adverse impacts on psychological responses. Therefore, precisely capturing the public emotions becomes crucial to providing adequate support. By constructing a domain-specific COVID-19 public health emergency discrete emotion lexicon, we utilized one million COVID-19 theme texts from the Chinese online social platform Weibo to analyze social-emotional volatility. Based on computed emotional valence, we proposed a public emotional perception model that achieves: (1) targeting of public emotion abrupt time points using an LSTM-based attention encoder-decoder (LAED) mechanism for emotional time-series, and (2) backtracking of specific triggered causes of abnormal volatility in a cognitive emotional arousal path. Experimental results prove that our model provides a solid research basis for enhancing social-emotional security outcomes.

Reliable and highly sensitive biosensor from suspended MoS2 atomic layer on nano-gap electrodes.

The uneven morphology and the trapped charges at the surface of the traditionally used supporting substrate-based 2D biosensors produces a scattering effect, which leads to a irregular signals from individually fabricated devices. Though suspended 2D channel material has the potential to overcome scattering effects from the substrates but achieving reliability and selectivity, have been limiting the using of this biosensor technology. Here, we have demonstrated nanogap electrodes fabrication by using the self-assembly technique, which provides suspension to the 2D-MoS2. These nano-spacing electrodes not only give suspension but also provide robustness strength to the atomic layer, which remains freestanding after coating of the Hafnium oxide (HfO2) as well as linkers and antibodies. For evaluating the electrical characteristics of suspended MoS2 FET, gating potential was applied through an electrolyte on the suspended MoS2 transistor. This helped in achieved a lower subthreshold swing 70 mV/dec and ON/OFF ratio 107. Later, pH detection was conducted at room temperature, which showed an impressive sensitivity of ~880 by changing 1 unit of pH. We have also successfully shown Escherichia coli (E. coli) bacteria sensing from the suspended MoS2 transistor by functionalizing dielectric layer with E. coli antibodies. The reported biosensor has shown the ~9% of conductance changes with a lower concentration of E. coli (10 CFU/mL; colony-forming unit per mL) as well as maintain the constant sensitivity in three fabricated devices. The obtained enhancement in the sensitivity of devices and its effect on biomolecules detection can be extened to other biomolecules and this type of architecture has the potential to detect COVID-19 viruses based biomolecules.

Spikes in demand for hospital transfusion services.

INTRODUCTION: Spikes in the demand for blood components represent a substantial challenge to transfusion services. Simple metrics for characterizing volatility in blood components within the hospital transfusion service have not been established. METHODS: We measured the volatility of demand for blood services at a large academic urban general hospital over a 6-month period from July 2019 to December 2019 prior to the SARS-CoV2 pandemic. RESULTS: Among 4416 consecutive hours assessed, there were 693 h (16%) with spikes in demand for blood components with a mean (sd) of 3.8 (2.7) spikes/day. Spikes in demand were frequently clustered. The median number of hours between spikes differed by shift (6 h for days; 3 h for evenings; 3 h for nights). The percentage of shift hours with demand spikes also differed (9% day; 19% evening; 18% night). During the study, 32,447 components were distributed to 19,431 patients. Of these, 11,819 components (36%) were distributed during hours of peak demand. Hours with a simultaneous spike in both component demand and patient demand occurred in 5% of hours or approximately once each day. CONCLUSION: Demand for transfusion services was highly volatile in an unpredictable fashion. We provide an approach that could be used to benchmark spikes in demand for blood services at hospitals. Consideration of the frequency, unpredictability, and magnitude of spikes in demand may be relevant for hemovigilance programs and for strategies to determine the laboratory staffing needed for good patient care.

A narrative review of hydrogen-oxygen mixture for medical purpose and the inhaler thereof.

Recent development regarding mixture of H2 (concentration of ~66%) with O2 (concentration of ~34%) for medical purpose, such as treatment of coronavirus disease-19 (COVID-19) patients, is introduced. Furthermore, the design principles of a hydrogen inhaler which generates mixture of hydrogen (~66%) with oxygen (~34%) for medical purpose are proposed. With the installation of the liquid blocking module and flame arresters, the air pathway of the hydrogen inhaler is divided by multiple isolation zones to prevent any unexpected explosion propagating from one zone to the other. An integrated filtering/cycling module is utilized to purify the impurity, and cool down the temperature of the electrolytic module to reduce the risk of the explosion. Moreover, a nebulizer is provided to selectively atomize the water into vapor which is then mixed with the filtered hydrogen-oxygen mix gas, such that the static electricity of a substance hardly occurs to reduce the risk of the explosion. Furthermore, hydrogen concentration detector is installed to reduce the risk of hydrogen leakage. Result shows that the hydrogen inhaler implementing the aforesaid design rules could effectively inhibit the explosion, even ignition at the outset of the hydrogen inhaler which outputs hydrogen-oxygen gas (approximately 66% hydrogen: 34% oxygen).

Decontaminating N95 respirators during the COVID-19 pandemic: simple and practical approaches to increase decontamination capacity, speed, safety and ease of use.

BACKGROUND: The COVID-19 pandemic has caused a severe shortage of personal protective equipment (PPE), especially N95 respirators. Efficient, effective and economically feasible methods for large-scale PPE decontamination are urgently needed. AIMS: (1) to develop protocols for effectively decontaminating PPE using vaporized hydrogen peroxide (VHP); (2) to develop novel approaches that decrease set-up and take-down time while also increasing decontamination capacity; (3) to test decontamination efficiency for N95 respirators heavily contaminated by make-up or moisturizers. METHODS: We converted a decommissioned Biosafety Level 3 laboratory into a facility that could be used to decontaminate N95 respirators. N95 respirators were hung on metal racks, stacked in piles, placed in paper bags or covered with make-up or moisturizer. A VHP® VICTORY™ unit from STERIS was used to inject VHP into the facility. Biological and chemical indicators were used to validate the decontamination process. FINDINGS: N95 respirators individually hung on metal racks were successfully decontaminated using VHP. N95 respirators were also successfully decontaminated when placed in closed paper bags or if stacked in piles of up to six. Stacking reduced the time needed to arrange N95 respirators for decontamination by approximately two-thirds while almost tripling facility capacity. Make-up and moisturizer creams did not interfere with the decontamination process. CONCLUSIONS: Respirator stacking can reduce the hands-on time and increase decontamination capacity. When personalization is needed, respirators can be decontaminated in labelled paper bags. Make up or moisturizers do not appear to interfere with VHP decontamination.

Use, re-use or discard? Quantitatively defined variance in the functional integrity of N95 respirators following vaporized hydrogen peroxide decontamination during the COVID-19 pandemic.

BACKGROUND: Coronavirus disease 2019 has stretched the ability of many institutions to supply needed personal protective equipment, especially N95 respirators. N95 decontamination and re-use programmes provide one potential solution to this problem. Unfortunately, a comprehensive evaluation of the effects of decontamination on the fit of various N95 models using a quantitative fit test (QNFT) approach is lacking. AIMS: To investigate the effects of up to eight rounds of vaporized hydrogen peroxide (VHP) decontamination on the fit of N95 respirators currently in use in a hospital setting, and to examine if N95 respirators worn by one user can adapt to the face shape of a second user with no compromise to fit following VHP decontamination. METHODS: The PortaCount Pro+ Respirator Fit Tester Model 8038 was used to quantitatively define functional integrity, measured by fit, of N95 respirators following decontamination with VHP. FINDINGS: There was an observable downward trend in the functional integrity of Halyard Fluidshield 46727 N95 respirators throughout eight cycles of decontamination with VHP. Functional integrity of 3M 1870 N95 respirators was reduced significantly after the respirator was worn, decontaminated with VHP, and then quantitatively fit tested on a second user. Furthermore, inconsistencies between qualitative fit test and QNFT results were uncovered that may have strong implications on the fit testing method used by institutions. CONCLUSIONS: The data revealed variability in the functional integrity of different N95 models after VHP decontamination, and exposed potential limitations of N95 decontamination and re-use programmes.

Synergistic effects of anionic surfactants on coronavirus (SARS-CoV-2) virucidal efficiency of sanitizing fluids to fight COVID-19.

Our surrounding environment, especially often-touched contaminated surfaces, plays an important role in the transmission of pathogens in society. The shortage of effective sanitizing fluids, however, became a global challenge quickly after the coronavirus disease-19 (COVID-19) outbreak in December 2019. In this study, we present the effect of surfactants on coronavirus (SARS-CoV-2) virucidal efficiency in sanitizing fluids. Sodium dodecylbenzenesulfonate (SDBS), sodium laureth sulfate (SLS), and two commercial dish soap and liquid hand soap were studied with the goal of evaporation rate reduction in sanitizing liquids to maximize surface contact time. Twelve fluids with different recipes composed of ethanol, isopropanol, SDBS, SLS, glycerin, and water of standardized hardness (WSH) were tested for their evaporation time and virucidal efficiency. Evaporation time increased by 17-63% when surfactant agents were added to the liquid. In addition, surfactant incorporation enhanced the virucidal efficiency between 15 and 27% according to the 4-field test in the EN 16615:2015 European Standard method. Most importantly, however, we found that surfactant addition provides a synergistic effect with alcohols to inactivate the SARS-CoV-2 virus. This study provides a simple, yet effective solution to improve the virucidal efficiency of commonly used sanitizers.

Impact of extended use and decontamination with vaporized hydrogen peroxide on N95 respirator fit.

BACKGROUND: To address the shortage of N95 respirators in the wake of the COVID-19 pandemic, some organizations have recommended the decontamination of respirators using vaporized hydrogen peroxide (VHP) sterilizer for up to 10 times. However, these recommendations are based on studies that did not take into account the extended use of respirators, which can degrade respirator fit. METHODS: We investigated the impact of extended use and decontamination with VHP on N95 Respirator Fit. We performed a prospective cohort study to determine the number of times respirators can be decontaminated before respirator fit test failure. The primary outcome was the overall number of cycles required for half of the respirators to fail (either mechanical failure or fit test failure). RESULTS: Thirty-six participants completed 360 hours of respirator usage across 90 cycles. The median number of cycles completed by participants before respirator failure was 2. The overall number of cycles required for half of respirators to fail was 1, 3, 5, and 4 for the 3M 1860(S), 3M 1870+, Moldex 151X and ProGear 88020 respirators, respectively. CONCLUSIONS: The combination of prolonged usage and VHP decontamination was associated with early failure. Decontamination and prolonged usage of respirators must be done cautiously.

Extent of infectious SARS-CoV-2 aerosolisation as a result of oesophagogastroduodenoscopy or colonoscopy.

BACKGROUND: COVID-19 has caused an unprecedented pandemic and medical emergency that has changed routine care pathways. This article discusses the extent of aerosolisation of severe acute respiratory syndrome coronavirus 2, the virus that causes COVID-19, as a result of oesophagogastroduodenoscopy and colonoscopy. METHODS: PubMed and Google Scholar were searched for relevant publications, using the terms COVID-19 aerosolisation, COVID-19 infection, COVID-19 transmission, COVID-19 pandemic, COVID-19 and endoscopy, Endoscopy for COVID-19 patients. RESULTS: A total of 3745 articles were identified, 26 of which were selected to answer the question of the extent of SARS-CoV-2 aerosolisation during upper and lower gastrointestinal endoscopy. All studies suggested high infectivity from contact and droplet spread. No clinical study has yet reported the viral load in the aerosol and therefore the infective dose has not been accurately determined. However, aerosol-generating procedures are potentially risky and full personal protective equipment should be used. CONCLUSIONS: As it is a highly infectious disease, clinicians treating patients with COVID-19 require effective personal protective equipment. The main routes of infection are direct contact and droplets in the air and on surfaces. Aerosolisation carries a substantial risk of infection, so any aerosol-producing procedure, such as endoscopy, should be performed wearing personal protective equipment and with extra caution to protect the endoscopist, staff and patients from cross-infection via the respiratory system.

N95 reprocessing by low temperature sterilization with 59% vaporized hydrogen peroxide during the 2020 COVID-19 pandemic.

BACKGROUND: Response to the COVID-19 pandemic by hospital systems has been strained by severe shortages in personal protective equipment (PPE), particularly N95 respirators. Recently, the Centers for Disease Control and Prevention endorsed decontamination strategies to prolong the lifespan of single use respirators. Battelle and Duke University have validated hospital protocols to decontaminate respirators using vaporized hydrogen peroxide (VHP) at 30%-35% concentrations. To prolong our supply of respirators, we evaluated and implemented VHP decontamination at 59% hydrogen peroxide concentration while detailing the effects of this process on the filtration efficiency and quantitative fit of single-use respirators. This study may help other health systems develop local solutions to their N95 mask shortage during this COVID-19 pandemic. METHODS: N95 respirators (3M 8211 FF and 9210 FF) that were treated with 5 and 10 cycles of VHP by the V-PRO maX Low Temperature Sterilization System were evaluated quantitatively for filtration efficiency as well as with quantitative fit testing per Occupational Safety and Health Administration standards. A decontamination protocol was concurrently implemented at our institution. This process involved depositing used masks, reprocessing, and re-distributing treated masks efficiently back to frontline providers. Furthermore, we implemented patient safety officers on COVID-19/person under investigation units to ensure optimized donning/doffing of respirators through frontline provider education. RESULTS: There were no statistically significant changes in mean filtration efficiency between the control and VHP-treated respirators. Furthermore, both treated and untreated respirators demonstrated fit factors above the minimum pass requirement. CONCLUSIONS: We have successfully demonstrated that N95 respirator decontamination with VHP at 59% hydrogen peroxide can be safely utilized to decontaminate single-use N95 respirators without significant effects on filtration efficiency or quantitative fit testing. With the COVID-19 pandemic and N95 respirator shortage, health systems without access to commercial decontamination processes should investigate the viability of such a process in their facilities.

Ultraviolet-C and other methods of decontamination of filtering facepiece N-95 respirators during the COVID-19 pandemic.

During global health emergencies such as the current COVID-19 pandemic, the decontamination of single-use personal protective equipment (PPE) becomes a necessary means to keep up with the growing demand from healthcare workers and patients alike. Many unverified methods are being considered, which can pose the risk of incomplete decontamination and lead to catastrophic results. Several factors come into play when determining the suitability of such methods including the quality of the decontamination technique, the targeted pathogen, cost, ease of installation and use, rate of sterilization, and the surface or material to be sterilized. The germicidal properties of ultraviolet-C are well known. This review will cover the most commonly described methods for the sterilization of N95 respirators, namely, ultraviolet germicidal irradiation, hydrogen peroxide vaporization, microwave-generated steaming, and dry heating. These techniques have been tested previously and have demonstrated efficacy in reducing or inactivating viral and bacterial pathogens, although testing against SARS-CoV-2 specifically has not been done. Moreover, it must be emphasized that proper disposal after a single use is still ideal under normal circumstances.

Vaporization, bioactive formulations and a marine natural product: different perspectives on antivirals.

This article examines three aspects of antivirals, such as hydroxychloroquine, chloroquine, and remdesvir, as they might relate to the treatment of a viral infection such as COVID-19: (i) the use of vaporization for the delivery of antivirals, with the bulk constituents having mild antiviral efficacy; (ii) the application of a marine natural product extract as opposed to a single molecule as an antiviral agent; and (iii) a counter intuitive approach to formulation that is, in part, based on delivering multiple species that fall into three categories: building blocks for the virus to accelerate replication; an energy source for the infected cell to boost its immune response; and the species that antagonize or provide toxicity to the virus.