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1.
PLoS One ; 16(3): e0247797, 2021.
Article in English | MEDLINE | ID: covidwho-1605332

ABSTRACT

Since the initial identification of the novel coronavirus SARS-CoV-2 in December of 2019, researchers have raced to understand its pathogenesis and begun devising vaccine and treatment strategies. An accurate understanding of the body's temporal immune response against SARS-CoV-2 is paramount to successful vaccine development and disease progression monitoring. To provide insight into the antibody response against SARS-CoV-2, plasma samples from 181 PCR-confirmed COVID-19 patients collected at various timepoints post-symptom onset (PSO) were tested for the presence of anti-SARS-CoV-2 IgM and IgG antibodies via lateral flow. Additionally, 21 donors were tracked over time to elucidate patient-specific immune responses. We found sustained levels of anti-SARS-CoV-2 antibodies past 130 days PSO, with 99% positivity observed at 31-60 days PSO. By 61-90 days PSO, the percentage of IgM-/IgG+ results were nearly equal to that of IgM+/IgG+ results, demonstrating a shift in the immune response with a decrease in IgM antibody levels. Results from this study not only provide evidence that the antibody response to COVID-19 can persist for over 4 months, but also demonstrates the ability of Easy Check™ to monitor seroconversion and antibody response of patients. Easy Check was sufficiently sensitive to detect antibodies in patient samples as early as 1-4 days PSO with 86% positivity observed at 5-7 days PSO. Further studies are required to determine the longevity and efficacy of anti-SARS-CoV-2 antibodies, and whether they are protective against re-infection.


Subject(s)
Antibodies, Viral/blood , COVID-19/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19 Serological Testing/instrumentation , COVID-19 Serological Testing/methods , Equipment Design , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Longitudinal Studies , Male , Middle Aged , SARS-CoV-2/isolation & purification , Young Adult
2.
J Nanobiotechnology ; 20(1): 6, 2022 Jan 04.
Article in English | MEDLINE | ID: covidwho-1608546

ABSTRACT

BACKGROUND: Gold nanoparticles (AuNPs) have been widely used in local surface plasmon resonance (LSPR) immunoassays for biomolecule sensing, which is primarily based on two conventional methods: absorption spectra analysis and colorimetry. The low figure of merit (FoM) of the LSPR and high-concentration AuNP requirement restrict their limit of detection (LOD), which is approximately ng to µg mL-1 in antibody detection if there is no other signal or analyte amplification. Improvements in sensitivity have been slow in recent for a long time, and pushing the boundary of the current LOD is a great challenge of current LSPR immunoassays in biosensing. RESULTS: In this work, we developed spectral image contrast-based flow digital nanoplasmon-metry (Flow DiNM) to push the LOD boundary. Comparing the scattering image brightness of AuNPs in two neighboring wavelength bands near the LSPR peak, the peak shift signal is strongly amplified and quickly detected. Introducing digital analysis, the Flow DiNM provides an ultrahigh signal-to-noise ratio and has a lower sample volume requirement. Compared to the conventional analog LSPR immunoassay, Flow DiNM for anti-BSA detection in pure samples has an LOD as low as 1 pg mL-1 within only a 15-min detection time and 500 µL sample volume. Antibody assays against spike proteins of SARS-CoV-2 in artificial saliva that contained various proteins were also conducted to validate the detection of Flow DiNM in complicated samples. Flow DiNM shows significant discrimination in detection with an LOD of 10 pg mL-1 and a broad dynamic detection range of five orders of magnitude. CONCLUSION: Together with the quick readout time and simple operation, this work clearly demonstrated the high sensitivity and selectivity of the developed Flow DiNM in rapid antibody detection. Spectral image contrast and digital analysis further provide a new generation of LSPR immunoassay with AuNPs.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Surface Plasmon Resonance/methods , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19 Serological Testing/instrumentation , Equipment Design , Gold/chemistry , Humans , Immunoassay/instrumentation , Immunoassay/methods , Metal Nanoparticles/chemistry , SARS-CoV-2/immunology , Saliva/virology , Spike Glycoprotein, Coronavirus/immunology , Surface Plasmon Resonance/instrumentation
3.
Acta Orthop ; 93: 198-205, 2022 01 03.
Article in English | MEDLINE | ID: covidwho-1607747

ABSTRACT

Background and purpose - Facemasks play a role in preventing the respiratory spread of SARS-CoV-2, but their impact on the physician-patient relationship in the orthopedic outpatient clinic is unclear. We investigated whether the type of surgeons' facemask impacts patients' perception of the physician-patient relationship, influences their understanding of what the surgeon said, or affects their perceived empathy. Patients and methods - All patients with an appointment in the orthopedic outpatient clinic of a tertiary university hospital during the 2-week study period were included. During consultations, all surgeons wore a non-transparent (first study week) or transparent facemask (second study week). Results of 285 of 407 eligible patients were available for analysis. The doctor-patient relationship was evaluated using the standardized Patient Reactions Assessment (PRA) and a 10-point Likert-scale questionnaire ranging from 0 (strongly disagree) to 10 (strongly agree). Results - A non-transparent facemask led to more restrictions in the physician-patient communication and a worse understanding of what the surgeon said. Patients' understanding improved with a transparent facemask with greatest improvements reported by patients aged 65 years and older (non-transparent: 6 [IQR 5-10] vs. transparent: 10 [IQR 9-10], p < 0.001) and by patients with a self-reported hearing impairment (non-transparent: 7 [IQR 3-7] vs. transparent: 9 [IQR 9-10], p < 0.001). The median PRA score was higher when surgeons wore a transparent facemask (p= 0.003). Interpretation - Surgeons' non-transparent facemasks pose a new communication barrier that can negatively affect the physician-patient relationship. While emotional factors like affectivity and empathy seem to be less affected overall, the physician-patient communication and patients' understanding of what the surgeon said seem to be negatively affected.


Subject(s)
COVID-19/prevention & control , Equipment Design , Masks , Orthopedic Surgeons , Pandemics/prevention & control , Physician-Patient Relations , Adult , Aged , Cohort Studies , Female , Hospitals, University , Humans , Male , Middle Aged , Prospective Studies , SARS-CoV-2 , Surveys and Questionnaires
4.
Drug Deliv ; 29(1): 10-17, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1577575

ABSTRACT

Aerosol therapy is used to deliver medical therapeutics directly to the airways to treat respiratory conditions. A potential consequence of this form of treatment is the release of fugitive aerosols, both patient derived and medical, into the environment and the subsequent exposure of caregivers and bystanders to potential viral infections. This study examined the release of these fugitive aerosols during a standard aerosol therapy to a simulated adult patient. An aerosol holding chamber and mouthpiece were connected to a representative head model and breathing simulator. A combination of laser and Schlieren imaging was used to non-invasively visualize the release and dispersion of fugitive aerosol particles. Time-varying aerosol particle number concentrations and size distributions were measured with optical particle sizers at clinically relevant positions to the simulated patient. The influence of breathing pattern, normal and distressed, supplemental air flow, at 0.2 and 6 LPM, and the addition of a bacterial filter to the exhalation port of the mouthpiece were assessed. Images showed large quantities of fugitive aerosols emitted from the unfiltered mouthpiece. The images and particle counter data show that the addition of a bacterial filter limited the release of these fugitive aerosols, with the peak fugitive aerosol concentrations decreasing by 47.3-83.3%, depending on distance from the simulated patient. The addition of a bacterial filter to the mouthpiece significantly reduces the levels of fugitive aerosols emitted during a simulated aerosol therapy, p≤ .05, and would greatly aid in reducing healthcare worker and bystander exposure to potentially harmful fugitive aerosols.


Subject(s)
Aerosols , COVID-19 , Drug Delivery Systems , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Nebulizers and Vaporizers , Respiratory Therapy , Aerosols/administration & dosage , Aerosols/adverse effects , COVID-19/prevention & control , COVID-19/transmission , Computer Simulation , Drug Delivery Systems/instrumentation , Drug Delivery Systems/methods , Equipment Design , Humans , Infection Control/methods , Models, Biological , Particle Size , Respiratory Therapy/adverse effects , Respiratory Therapy/instrumentation , Respiratory Therapy/methods , SARS-CoV-2
5.
PLoS One ; 16(3): e0247575, 2021.
Article in English | MEDLINE | ID: covidwho-1573727

ABSTRACT

INTRODUCTION: The COVID-19 pandemic has led to widespread shortages of N95 respirators and other personal protective equipment (PPE). An effective, reusable, locally-manufactured respirator can mitigate this problem. We describe the development, manufacture, and preliminary testing of an open-hardware-licensed device, the "simple silicone mask" (SSM). METHODS: A multidisciplinary team developed a reusable silicone half facepiece respirator over 9 prototype iterations. The manufacturing process consisted of 3D printing and silicone casting. Prototypes were assessed for comfort and breathability. Filtration was assessed by user seal checks and quantitative fit-testing according to CSA Z94.4-18. RESULTS: The respirator originally included a cartridge for holding filter material; this was modified to connect to standard heat-moisture exchange (HME) filters (N95 or greater) after the cartridge showed poor filtration performance due to flow acceleration around the filter edges, which was exacerbated by high filter resistance. All 8 HME-based iterations provided an adequate seal by user seal checks and achieved a pass rate of 87.5% (N = 8) on quantitative testing, with all failures occurring in the first iteration. The overall median fit-factor was 1662 (100 = pass). Estimated unit cost for a production run of 1000 using distributed manufacturing techniques is CAD $15 in materials and 20 minutes of labor. CONCLUSION: Small-scale manufacturing of an effective, reusable N95 respirator during a pandemic is feasible and cost-effective. Required quantities of reusables are more predictable and less vulnerable to supply chain disruption than disposables. With further evaluation, such devices may be an alternative to disposable respirators during public health emergencies. The respirator described above is an investigational device and requires further evaluation and regulatory requirements before clinical deployment. The authors and affiliates do not endorse the use of this device at present.


Subject(s)
COVID-19/prevention & control , Equipment Design/instrumentation , Filtration/instrumentation , Pandemics/prevention & control , Personal Protective Equipment , Respiratory Protective Devices , Ventilators, Mechanical , Equipment Reuse , Face , Humans , Materials Testing/instrumentation , N95 Respirators , Occupational Exposure/prevention & control , Printing, Three-Dimensional/instrumentation , SARS-CoV-2/pathogenicity
6.
Br J Radiol ; 95(1129): 20210835, 2022 Jan 01.
Article in English | MEDLINE | ID: covidwho-1575206

ABSTRACT

OBJECTIVE: To evaluate the efficacy of a barrier shield in reducing droplet transmission and its effect on image quality and radiation dose in an interventional suite. METHODS: A human cough droplet visualisation model in a supine position was developed to assess efficacy of barrier shield in reducing environmental contamination. Its effect on image quality (resolution and contrast) was evaluated via image quality test phantom. Changes in the radiation dose to patient post-shield utilisation was measured. RESULTS: Use of the shield prevented escape of visible fluorescent cough droplets from the containment area. No subjective change in line-pair resolution was observed. No significant difference in contrast-to-noise ratio was measured. Radiation dosage to patient was increased; this is predominantly attributed to the increased air gap and not the physical properties of the shield. CONCLUSION: Use of the barrier shield provided an effective added layer of personal protection in the interventional radiology theatre for aerosol generating procedures. ADVANCES IN KNOWLEDGE: This is the first time a human supine cough droplet visualisation has been developed. While multiple types of barrier shields have been described, this is the first systematic practical evaluation of a barrier shield designed for use in the interventional radiology theatre.


Subject(s)
Infectious Disease Transmission, Patient-to-Professional/prevention & control , Protective Devices , Radiology, Interventional/instrumentation , Adult , COVID-19/transmission , Cough , Equipment Design , Fluorescence , Humans , Male , Phantoms, Imaging , Radiation Dosage , Signal-To-Noise Ratio , Supine Position
7.
J Emerg Manag ; 19(7): 193-202, 2021.
Article in English | MEDLINE | ID: covidwho-1551756

ABSTRACT

INTRODUCTION: Having an adequate supply of personal protective equipment during the COVID-19 pandemic has been a constant challenge for hospitals across the United States. In the event of shortages, our assembled mask might offer noninferior protection compared to an N95 respirator. OBJECTIVE: To study the ability of an assembled mask to pass a quantitative fit testing. METHODS: We conducted a feasibility study at the Oklahoma City Veteran Affairs Health Care System. Volunteers were fitted with an assembled mask made of either a Hans Rudolph half-face mask or a Respironics Performax full-face mask, attached to an Iso-Gard HEPA light Filter 28022 through a Performax SE elbow hinge. Quantitative fit testing was conducted using the Occupation Safety and Health Administration fit testing protocol. The primary outcome was the percentage of participants who pass the quantitative fit test. Secondary outcomes included the overall fit factor (FF), average FF for different exercises, changes in pulse oximetry and end-tidal CO2 at 0 and 15 minutes, willingness to use the mask, and visibility assessment. RESULTS: Twenty participants completed the study, and all (100 percent) passed the quantitative fit testing. The overall FF had a geometric mean of 2,317 (range: 208-16,613) and a geometric standard deviation of 3.8. The lowest FF was recorded while the subjects were talking. Between time 0 and 15 minutes, there was no clinically significant change in pulse oximetry and end-tidal CO2 levels. Most participants reported "very good" visibility and were "highly likely" to use the Hans Rudolph half-face mask in the case of shortage. CONCLUSION: Our assembled respirator offers noninferior protection to N95 respirators in the setting of hypothetical protective equipment shortage.


Subject(s)
COVID-19 , Pandemics , Equipment Design , Feasibility Studies , Humans , N95 Respirators , Pandemics/prevention & control , Personal Protective Equipment , SARS-CoV-2 , United States
8.
Anesthesiology ; 135(6): 951-962, 2021 12 01.
Article in English | MEDLINE | ID: covidwho-1546049

ABSTRACT

Respiratory viruses are transmitted via respiratory particles that are emitted when people breath, speak, cough, or sneeze. These particles span the size spectrum from visible droplets to airborne particles of hundreds of nanometers. Barrier face coverings ("cloth masks") and surgical masks are loose-fitting and provide limited protection from airborne particles since air passes around the edges of the mask as well as through the filtering material. Respirators, which fit tightly to the face, provide more effective respiratory protection. Although healthcare workers have relied primarily on disposable filtering facepiece respirators (such as N95) during the COVID-19 pandemic, reusable elastomeric respirators have significant potential advantages for the COVID-19 and future respiratory virus pandemics. However, currently available elastomeric respirators were not designed primarily for healthcare or pandemic use and require further development to improve their suitability for this application. The authors believe that the development, implementation, and stockpiling of improved elastomeric respirators should be an international public health priority.


Subject(s)
COVID-19/epidemiology , Elastomers/standards , Equipment Design/standards , Health Personnel/standards , Occupational Exposure/standards , Ventilators, Mechanical/standards , COVID-19/prevention & control , COVID-19/transmission , Equipment Design/methods , Equipment Reuse/standards , Humans , Occupational Exposure/prevention & control , Pandemics/prevention & control
9.
Blood Purif ; 50(3): 290-297, 2021.
Article in English | MEDLINE | ID: covidwho-1533118

ABSTRACT

The principles and use of plasmapheresis are often little understood by intensivists. We propose to review the principles, the main indications, and the methods of using this technique.


Subject(s)
Critical Care/methods , Plasma Exchange/methods , Animals , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/therapy , COVID-19/therapy , Equipment Design , Guillain-Barre Syndrome/therapy , Humans , Liver Failure, Acute/therapy , Membranes, Artificial , Plasma Exchange/instrumentation , Purpura, Thrombotic Thrombocytopenic/therapy
10.
Sci Rep ; 11(1): 21979, 2021 11 09.
Article in English | MEDLINE | ID: covidwho-1510615

ABSTRACT

Respirators, medical masks, and barrier face coverings all filter airborne particles using similar physical principles. However, they are tested for certification using a variety of standardized test methods, creating challenges for the comparison of differently certified products. We have performed systematic experiments to quantify and understand the differences between standardized test methods for N95 respirators (NIOSH TEB-APR-STP-0059 under US 42 CFR 84), medical face masks (ASTM F2299/F2100), and COVID-19-related barrier face coverings (ASTM F3502-21). Our experiments demonstrate the role of face velocity, particle properties (mean size, size variability, electric charge, density, and shape), measurement techniques, and environmental preconditioning. The measured filtration efficiency was most sensitive to changes in face velocity and particle charge. Relative to the NIOSH method, users of the ASTM F2299/F2100 method have commonly used non-neutralized (highly charged) aerosols as well as smaller face velocities, each of which may result in approximately 10% higher measured filtration efficiencies. In the NIOSH method, environmental conditioning at elevated humidity increased filtration efficiency in some commercial samples while decreasing it in others, indicating that measurement should be performed both with and without conditioning. More generally, our results provide an experimental basis for the comparison of respirators certified under various international methods, including FFP2, KN95, P2, Korea 1st Class, and DS2.


Subject(s)
COVID-19 , Equipment Design , Filtration
11.
Sci Rep ; 11(1): 21449, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1500502

ABSTRACT

The World Health Organisation has called for a 40% increase in personal protective equipment manufacturing worldwide, recognising that frontline workers need effective protection during the COVID-19 pandemic. Current devices suffer from high fit-failure rates leaving significant proportions of users exposed to risk of viral infection. Driven by non-contact, portable, and widely available 3D scanning technologies, a workflow is presented whereby a user's face is rapidly categorised using relevant facial parameters. Device design is then directed down either a semi-customised or fully-customised route. Semi-customised designs use the extracted eye-to-chin distance to categorise users in to pre-determined size brackets established via a cohort of 200 participants encompassing 87.5% of the cohort. The user's nasal profile is approximated to a Gaussian curve to further refine the selection in to one of three subsets. Flexible silicone provides the facial interface accommodating minor mismatches between true nasal profile and the approximation, maintaining a good seal in this challenging region. Critically, users with outlying facial parameters are flagged for the fully-customised route whereby the silicone interface is mapped to 3D scan data. These two approaches allow for large scale manufacture of a limited number of design variations, currently nine through the semi-customised approach, whilst ensuring effective device fit. Furthermore, labour-intensive fully-customised designs are targeted as those users who will most greatly benefit. By encompassing both approaches, the presented workflow balances manufacturing scale-up feasibility with the diverse range of users to provide well-fitting devices as widely as possible. Novel flow visualisation on a model face is presented alongside qualitative fit-testing of prototype devices to support the workflow methodology.


Subject(s)
Face/physiology , Personal Protective Equipment , Photogrammetry/methods , COVID-19/prevention & control , COVID-19/virology , Computer-Aided Design , Equipment Design , Face/anatomy & histology , Humans , Printing, Three-Dimensional , SARS-CoV-2/isolation & purification
12.
Proc Natl Acad Sci U S A ; 118(45)2021 11 09.
Article in English | MEDLINE | ID: covidwho-1475573

ABSTRACT

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other pathogens with pandemic potential requires safe, protective, inexpensive, and easily accessible vaccines that can be developed and manufactured rapidly at a large scale. DNA vaccines can achieve these criteria, but induction of strong immune responses has often required bulky, expensive electroporation devices. Here, we report an ultra-low-cost (<1 USD), handheld (<50 g) electroporation system utilizing a microneedle electrode array ("ePatch") for DNA vaccination against SARS-CoV-2. The low cost and small size are achieved by combining a thumb-operated piezoelectric pulser derived from a common household stove lighter that emits microsecond, bipolar, oscillatory electric pulses and a microneedle electrode array that targets delivery of high electric field strength pulses to the skin's epidermis. Antibody responses against SARS-CoV-2 induced by this electroporation system in mice were strong and enabled at least 10-fold dose sparing compared to conventional intramuscular or intradermal injection of the DNA vaccine. Vaccination was well tolerated with mild, transient effects on the skin. This ePatch system is easily portable, without any battery or other power source supply, offering an attractive, inexpensive approach for rapid and accessible DNA vaccination to combat COVID-19, as well as other epidemics.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , Electroporation/instrumentation , SARS-CoV-2 , Vaccines, DNA/administration & dosage , Animals , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Costs and Cost Analysis , Electroporation/economics , Electroporation/methods , Equipment Design , Female , Genes, Reporter , Humans , Mice , Mice, Inbred BALB C , Microelectrodes , Needles , Pandemics/prevention & control , Proof of Concept Study , Rats , Rats, Wistar , Skin/immunology , Skin/metabolism , Transfection , Vaccination/economics , Vaccination/instrumentation , Vaccination/methods , Vaccines, DNA/genetics , Vaccines, DNA/immunology
15.
Sci Rep ; 11(1): 19970, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462030

ABSTRACT

Particulate respirators such as N95s are an essential component of personal protective equipment (PPE) for front-line workers. This study describes a rapid and effective UVC irradiation system that would facilitate the safe re-use of N95 respirators and provides supporting information for deploying UVC for decontamination of SARS-CoV-2 during the COVID-19 pandemic. To assess the inactivation potential of the proposed UVC germicidal device as a function of time by using 3 M 8211-N95 particulate respirators inoculated with SARS-CoV-2. A germicidal UVC device to deliver tailored UVC dose was developed and test coupons (2.5 cm2) of the 3 M-N95 respirator were inoculated with 106 plaque-forming units (PFU) of SARS-CoV-2 and were UV irradiated. Different exposure times were tested (0-164 s) by fixing the distance between the lamp and the test coupon to 15.2 cm while providing an exposure of at least 5.43 mWcm-2. Primary measure of outcome was titration of infectious virus recovered from virus-inoculated respirator test coupons after UVC exposure. Other measures included the method validation of the irradiation protocol, using lentiviruses (biosafety level-2 agent) and establishment of the germicidal UVC exposure protocol. An average of 4.38 × 103 PFU ml-1 (SD 772.68) was recovered from untreated test coupons while 4.44 × 102 PFU ml-1 (SD 203.67), 4.00 × 102 PFU ml-1 (SD 115.47), 1.56 × 102 PFU ml-1 (SD 76.98) and 4.44 × 101 PFU ml-1 (SD 76.98) was recovered in exposures 2, 6, 18 and 54 s per side respectively. The germicidal device output and positioning was monitored and a minimum output of 5.43 mW cm-2 was maintained. Infectious SARS-CoV-2 was not detected by plaque assays (minimal level of detection is 67 PFU ml-1) on N95 respirator test coupons when irradiated for 120 s per side or longer suggesting 3.5 log reduction in 240 s of irradiation, 1.3 J cm-2. A scalable germicidal UVC device to deliver tailored UVC dose for rapid decontamination of SARS-CoV-2 was developed. UVC germicidal irradiation of N95 test coupons inoculated with SARS-CoV-2 for 120 s per side resulted in 3.5 log reduction of virus. These data support the reuse of N95 particle-filtrate apparatus upon irradiation with UVC and supports use of UVC-based decontamination of SARS-CoV-2 during the COVID-19 pandemic.


Subject(s)
COVID-19/prevention & control , Decontamination/instrumentation , N95 Respirators/virology , SARS-CoV-2/radiation effects , Ultraviolet Rays , Animals , COVID-19/virology , Chlorocebus aethiops , Decontamination/economics , Equipment Design , Equipment Reuse , HEK293 Cells , Humans , SARS-CoV-2/isolation & purification , Time Factors , Vero Cells
16.
Sci Rep ; 11(1): 19930, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462026

ABSTRACT

Transmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.


Subject(s)
Coronavirus 229E, Human/radiation effects , Coronavirus Infections/prevention & control , Coronavirus OC43, Human/radiation effects , Disinfection/methods , Ultraviolet Rays , Virus Inactivation/radiation effects , Aerosols/isolation & purification , Air Microbiology , COVID-19/prevention & control , Computer Simulation , Coronavirus 229E, Human/isolation & purification , Coronavirus 229E, Human/physiology , Coronavirus OC43, Human/isolation & purification , Coronavirus OC43, Human/physiology , Disinfection/instrumentation , Equipment Design , Humans , Models, Biological
17.
Sci Rep ; 11(1): 19910, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462025

ABSTRACT

Face masks are a primary preventive measure against airborne pathogens. Thus, they have become one of the keys to controlling the spread of the COVID-19 virus. Common examples, including N95 masks, surgical masks, and face coverings, are passive devices that minimize the spread of suspended pathogens by inserting an aerosol-filtering barrier between the user's nasal and oral cavities and the environment. However, the filtering process does not adapt to changing pathogen levels or other environmental factors, which reduces its effectiveness in real-world scenarios. This paper addresses the limitations of passive masks by proposing ADAPT, a smart IoT-enabled "active mask". This wearable device contains a real-time closed-loop control system that senses airborne particles of different sizes near the mask by using an on-board particulate matter (PM) sensor. It then intelligently mitigates the threat by using mist spray, generated by a piezoelectric actuator, to load nearby aerosol particles such that they rapidly fall to the ground. The system is controlled by an on-board micro-controller unit that collects sensor data, analyzes it, and activates the mist generator as necessary. A custom smartphone application enables the user to remotely control the device and also receive real-time alerts related to recharging, refilling, and/or decontamination of the mask before reuse. Experimental results on a working prototype confirm that aerosol clouds rapidly fall to the ground when the mask is activated, thus significantly reducing PM counts near the user. Also, usage of the mask significantly increases local relative humidity levels.


Subject(s)
COVID-19/prevention & control , Inhalation Exposure/prevention & control , Masks , Particulate Matter/isolation & purification , Respiratory Protective Devices , SARS-CoV-2/isolation & purification , Aerosols/isolation & purification , Air Microbiology , Equipment Design , Filtration/instrumentation , Humans , Mobile Applications , Particle Size , Smart Materials/chemistry , Smartphone
18.
Clin Respir J ; 14(3): 214-221, 2020 Mar.
Article in English | MEDLINE | ID: covidwho-1455532

ABSTRACT

BACKGROUND: Patients with neuromuscular disorders (NMDs) are likely to develop respiratory failure which requires noninvasive ventilation (NIV). Ventilation via a mouthpiece (MPV) is an option to offer daytime NIV. OBJECTIVES: To determine the preferred equipment for MPV by patients with NMDs. METHODS: Two MPV equipment sets were compared in 20 patients with NMDs. Set 1, consisted of a non-dedicated ventilator for MPV (PB560, Covidien) with a plastic angled mouthpiece. Set 2, consisted of a dedicated MPV ventilator (Trilogy 100, Philips Respironics) without backup rate and kiss trigger combined with a silicone straw mouthpiece. The Borg dyspnea score, ventilator free time, transcutaneous oxygen saturation (SpO2) and carbon dioxide tension (TcCO2 ) were recorded with and without MPV. Patient perception was assessed by a 17-items list. RESULTS: Carbon dioxide tension measurements and total perception score were not different between the two MPV sets. Dyspnea score was lower with the non-dedicated versus dedicated equipment, 1 (0.5) versus 3 (1-6), P < 0.01. All patients with a ventilator free time lower than 6 hours preferred a set backup rate rather than a kiss trigger. Sixty five percent of patients preferred the commercial arm support and 55% preferred the plastic angled mouthpiece. CONCLUSIONS: Dedicated and non-dedicated MPV equipment are deemed effective and comfortable. Individualization of arm support and mouthpiece is advised to ensure success of MPV. A ventilator free time lower than 6 hours seems to be a useful indicator to a priori set a backup rate rather than a rate at zero associated to the kiss trigger.


Subject(s)
Neuromuscular Diseases/complications , Noninvasive Ventilation/instrumentation , Respiratory Insufficiency/therapy , Ventilators, Mechanical/statistics & numerical data , Adolescent , Adult , Blood Gas Monitoring, Transcutaneous/methods , Carbon Dioxide/metabolism , Case-Control Studies , Cross-Over Studies , Dyspnea/diagnosis , Equipment Design , Female , Humans , Male , Perception , Time Factors , Ventilators, Mechanical/trends , Young Adult
19.
Sci Rep ; 10(1): 5189, 2020 03 23.
Article in English | MEDLINE | ID: covidwho-1454803

ABSTRACT

Stapled hemorrhoidopexy has a few advantages such as less postoperative pain and faster recovery compared with conventional hemorrhoidectomy. There are two major devices used for stapled hemorrhoidopexy, PPH stapler (Ethicon EndoSurgery) and DST stapler (Covidien). This study was conducted to investigate the postoperative outcomes among patients with grade III and IV hemorrhoids who underwent hemorrhoidopexy with either of these two devices. A total of 242 consecutive patients underwent stapled hemorrhoidopexy with either PPH stapler (110 patients) or DST stapler (132 patients) at a single center in 2017. We performed a retrospective case-control study to compare the short-term postoperative outcomes and the complications between these two groups. After matching the cases in terms of age, gender, and the grade of hemorrhoids, there were 100 patients in each group (PPH versus DST). There were no significant differences in the postoperative visual analog scale (VAS) score and analgesic usage. Among complications, the incidence of anorectal stricture was significantly higher in the DST group (p = 0.02). Evaluation of the mucosal specimen showed that the total surface area, the muscle/mucosa ratio and the surface area of the muscle were also significantly higher in the DST group (p = 0.03). Further analysis of the DST group demonstrated that patients with anorectal stricture after surgery are younger than patients without anorectal stricture, and higher muscle/mucosa ratio (p = 0.03) and a higher surface area of the muscle (p = 0.03) also measured in the surgical specimen. The two devices provide similar outcomes of postoperative recovery. Patients who underwent DST stapled hemorrhoidopexy had a higher incidence rate of stricture, larger area of muscle excision, and higher muscle/mucosa ratio in the surgical specimen. Further investigation is warranted for a better understanding of the correlation between muscle excision and anorectal stricture.


Subject(s)
Hemorrhoidectomy/instrumentation , Hemorrhoids/surgery , Surgical Staplers , Acetaminophen/therapeutic use , Anal Canal/pathology , Analgesics/therapeutic use , Anus Diseases/etiology , Constriction, Pathologic/etiology , Equipment Design , Female , Hemorrhage/etiology , Humans , Intestinal Mucosa/pathology , Isoxazoles/therapeutic use , Male , Middle Aged , Organ Size , Pain, Postoperative/drug therapy , Pain, Postoperative/etiology , Pain, Postoperative/prevention & control , Postoperative Complications/etiology , Retrospective Studies , Treatment Outcome , Urinary Retention/etiology
20.
PLoS One ; 16(9): e0257434, 2021.
Article in English | MEDLINE | ID: covidwho-1443838

ABSTRACT

Although research has shown that the COVID-19 disease is most likely caused by airborne transmission of the SARS-CoV-2 virus, disinfection of potentially contaminated surfaces is also recommended to limit the spread of the disease. Use of electrostatic sprayers (ESS) and foggers to rapidly apply disinfectants over large areas or to complex surfaces has emerged with the COVID-19 pandemic. ESSs are designed to impart an electrostatic charge to the spray droplets with the goal of increasing deposition of the droplets onto surfaces, thereby promoting more efficient use of the disinfectant. The purpose of this research was to evaluate several spray parameters for different types of sprayers and foggers, as they relate to the application of disinfectants. Some of the parameters evaluated included the spray droplet size distribution, the electrostatic charge, the ability of the spray to wrap around objects, and the loss of disinfectant chemical active ingredient due to the spray process. The results show that most of the devices evaluated for droplet size distribution had an average volume median diameter ≥ 40 microns, and that four out of the six ESS tested for charge/mass produced sprays of at least 0.1 mC/kg. A minimal wrap-around effect of the spray deposition onto a cylindrical object was observed. The loss of disinfectant active ingredient to the air due to spraying was minimal for the two disinfectants tested, and concurrently, the active ingredient concentrations of the liquid disinfectants sprayed and collected 3 feet (1 meter) away from the spray nozzle do not decrease.


Subject(s)
COVID-19/prevention & control , Disinfectants/administration & dosage , Disinfection/instrumentation , Disinfectants/pharmacology , Disinfection/methods , Equipment Design , Humans , SARS-CoV-2/drug effects , Static Electricity , Surface Properties/drug effects
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