Performance of helmet CPAP using different configurations: Turbine-driven ventilators vs Venturi devices.

BACKGROUND: Traditionally, Venturi-based flow generators have been preferred over mechanical ventilators to provide continuous positive airway pressure (CPAP) through the helmet (h-CPAP). Recently, modern turbine-driven ventilators (TDVs) showed to be safe and effective in delivering h-CPAP. We aimed to compare the pressure stability during h-CPAP delivered by Venturi devices and TDVs and assess the impact of High Efficiency Particulate Air (HEPA) filters on their performance. METHODS: We performed a bench study using an artificial lung simulator set in a restrictive respiratory condition, simulating two different levels of patient effort (high and low) with and without the interposition of the HEPA filter. We calculated the average of minimal (Pmin), maximal (Pmax) and mean (Pmean) airway pressure and the time product measured on the airway pressure curve (PTPinsp). We defined the pressure swing (Pswing) as Pmax - Pmin and pressure drop (Pdrop) as End Expiratory Pressure - Pmin. RESULTS: Pswing across CPAP levels varied widely among all the tested devices. During "low effort", no difference in Pswing and Pdrop was found between Venturi devices and TDVs; during high effort, Pswing (p<0.001) and Pdrop (p<0.001) were significantly higher in TDVs compared to Venturi devices, but the PTPinsp was lower (1.50 SD 0.54 vs 1.67 SD 0.55, p<0.001). HEPA filter addition almost doubled Pswing and PTPinsp (p<0.001) but left unaltered the differences among Venturi and TDVs systems in favor of the latter (p<0.001). CONCLUSIONS: TDVs performed better than Venturi systems in delivering a stable positive pressure level during h-CPAP in a bench setting.

Aerosol Medication Use in COVID-19 Pandemic

Administration of aerolized drugs to patients diagnosed with COVID-19 leads to the risk of transmission of patient-generated infectious aerosols to healthcare providers.While the COVID-19 pandemic is ongoing, in order to provide the best treatment for patients and at the same time to protect healthcare providers at the highest level, it is necessary to increase access to information and pay maximum attention to preventive measures.Copyright © 2020 Bilimsel Tip Yayinevi. All rights reserved.

Development of reusable cloth mask with nanoparticle filtration efficiency greater than 95%

ABSRACT: After the rapid spread of SARS-Cov-2 virus, the use of masks was suggested by the world health organization (WHO) to reduce the virus transmission, whose primary mode of transmission was suggested to be through respiratory droplets. The recommended face coverings were single use surgical and respirator masks made of non-woven materials. With the increased demand for masks worldwide, the environmental impacts of mask disposal and the pollution caused by microplastic fibers of the non-woven materials were presented. This challenge necessitates the need for the development of a novel reusable mask reducing the environmental effects, while providing the necessary personal protective properties. Based on the ASTM F2299 standard test method, the performance, i.e., particle-size dependent filtration efficiency and pressure drop were studied for 20 samples with multilayer knit fabrics of natural and synthetic fibers (inner layer of pure cotton, cotton-nylon and cotton-polyester, middle layer of Lycra, and outer layer of superhydrophobic polyester). The results show that all the samples had an efficiency of >94% and 87–99% for large (250 (Formula presented.) –1 (Formula presented.) m) and small (100–250 nm) particles, respectively. The best performing structure has a material composition of 41% superhydrophobic polyester, 26% natural cotton, 24% nylon and 9% Lycra. The filtration efficiency, pressure drop, and quality factor for this sample are 97.8% (for 100 nm particles), 4.04 mmH2O/cm2 and 4.77 kPa−1, respectively. It was also demonstrated that the developed mask maintains its performance after 50 wash/dry cycles, verifying its reusability. It should be noted that charge neutralizer was not used in the experimental setup of this study which might have led to enhanced results for the filtration efficiency of small (100–250 nm) particles due to the dominance of electrostatic attraction. However, several samples were tested by the third-party company who uses a certified testing equipment based on ASTM F2299, and similar results were obtained. Copyright © 2022 American Association for Aerosol Research.

A description of ventilation system design in public hospitals: Health provider perspective

Introduction: Ventilation system serves as one of the methods for infection control within patient treatment areas amongst patients and staff. The High infectivity in confined areas raised concerns for patients and staff safety especially during the COVID-19 pandemic. Objective(s): To describe the ventilation system design approach applied in patient areas of a public hospital. Material(s) and Method(s): Four (4) patient-related areas in a 76 bed non-specialist hospital was assessed. The variables included are the airflow, supply air, return air and air filtration. Result(s) and Conclusion(s): The airborne infection isolation room has air flow from the staff area to the patient area. The air inlet provides 100% non-circulating fresh air with 12 air change rate per hour (ACH) located at entrance. The outlet is located on the lower left side of the patient's head. High-efficiency particulate air (HEPA) filter placed at the outlet with negative room pressure. The air conditioned multi bed area has air inlet at the entry point and outlet located farther away from patients and staff. While, the clinical examination room air inlet was placed near the staff area and outlet above the patient treatment area. Both the common multi-bed inpatient and clinical examination rooms have normal pressure. The ventilation system is served from central Air Handling Unit (AHU) and recirculated, however, MERV 13 grade filter is employed as recommended by American Standard Heating and Refrigeration Engineer (ASHRAE) in both multi-bed inpatient area and clinical examination room. Finally, the operation room was provided with laminar air flow from above the patient towards the lower four corners of the room. The room pressure would be relatively positive compared to the surrounding rooms. The HEPA filter is placed at the inlet. The ventilation system design approach in the public hospital assessed caters for airborne-related infectious diseases control. However, further assessment of its effectiveness is required particularly in the operation theater where the room pressure is relatively positive.

Design of IoT Based Indoor Air Purifier

An IoT-based system for monitoring the quality of the air within a building, which includes a "Smart-Air"air quality sensor on a web server. IoT and cloud storage are used to evaluate the quality of the air at any time and from any place. Smart-Air is a product of the Internet of Things (IoT), a device that uses LTE to broadcast real-time data on air quality to a web server. Today, air pollution is a leading cause of preventable mortality and disease across the world. Pollution has become a major concern all around the globe. The discharge of chemicals or unfriendly compounds has a devastating impact on human, animal, and plant life. This is referred to as pollution. Many studies have been conducted on different air purification techniques because of this. Air purifiers that utilize HEPA filters, activated carbon, and UV light are discussed in this paper. The water and chemicals that an air purifier sprays into the air will spread out contaminants. © 2022 IEEE.

HEPA filters of portable air cleaners as a tool for the surveillance of SARS-CoV-2.

Studies about the identification of SARS-CoV-2 in indoor aerosols have been conducted in hospital patient rooms and to a lesser extent in nonhealthcare environments. In these studies, people were already infected with SARS-CoV-2. However, in the present study, we investigated the presence of SARS-CoV-2 in HEPA filters housed in portable air cleaners (PACs) located in places with apparently healthy people to prevent possible outbreaks. A method for detecting the presence of SARS-CoV-2 RNA in HEPA filters was developed and validated. The study was conducted for 13 weeks in three indoor environments: school, nursery, and a household of a social health center, all in Ciudad Real, Spain. The environmental monitoring of the presence of SARS-CoV-2 was conducted in HEPA filters and other surfaces of these indoor spaces for a selective screening in asymptomatic population groups. The objective was to limit outbreaks at an early stage. One HEPA filter tested positive in the social health center. After analysis by RT-PCR of SARS-CoV-2 in residents and healthcare workers, one worker tested positive. Therefore, this study provides direct evidence of virus-containing aerosols trapped in HEPA filters and the possibility of using these PACs for environmental monitoring of SARS-CoV-2 while they remove airborne aerosols and trap the virus.

Effectiveness of HEPA Filters at Removing Infectious SARS-CoV-2 from the Air.

Coronavirus disease 2019 (COVID-19) spreads by airborne transmission; therefore, the development and functional evaluation of air-cleaning technologies are essential for infection control. Air filtration using high-efficiency particulate air (HEPA) filters may be effective; however, no quantitative assessment of the effectiveness of these filters in the removal of infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the air has been reported. To evaluate the removal effect of HEPA filtration on airborne SARS-CoV-2, here, we disseminated infectious SARS-CoV-2 aerosols in a test chamber in a biosafety level 3 facility and filtered the air with a HEPA-filtered air cleaner in the chamber. The air cleaner with the HEPA filter continuously removed the infectious SARS-CoV-2 from the air in a running-time-dependent manner, and the virus capture ratios were 85.38%, 96.03%, and >99.97% at 1, 2, and 7.1 ventilation volumes, respectively. The air-cleaning performance of a HEPA filter coated with an antiviral agent consisting mainly of a monovalent copper compound was also evaluated, and the capture ratio was found to be comparable to that of the conventional HEPA filter. This study provides insights into the proper use and performance of HEPA-filtered air cleaners to prevent the spread of COVID-19. IMPORTANCE Air filtration simulation experiments quantitatively showed that an air cleaner equipped with a HEPA filter can continuously remove SARS-CoV-2 from the air. The capture ratios for SARS-CoV-2 in the air when the air cleaner was equipped with an antiviral-agent-coated HEPA filter were comparable to those with the conventional HEPA filter, and there was little effect on SARS-CoV-2 in the air that passed through the antiviral-reagent-coated HEPA filter.

Protecting healthcare workers against COVID-19: A fast-track ventilation system for hospitals

Clinical problem: The novel coronavirus disease 2019 (COVID-19) puts the healthcare workers (HCWs) at a high risk of infection. So many aerosol-generating medical procedures, including endotracheal intubation, non-invasive ventilation, and exhaled air dispersion, exacerbate the exponential infection rate as COVID-19 is highly infective and primarily transmitted through aerosols, especially when medical care systems have been overwhelmed by the COVID-19 surge, resulting from the shortage of personal protective equipment (PPE), hospital wards, and negative pressure rooms. Hence, we develop an ultra-fast-track and effective technology utilizing vented enclosures for individual patients to protect HCWs. The concept of innovation and how it works: We aim to minimize the airborne cross-infection risk in hospitals by limiting the spread of virus and decreasing the encounters between infected patients and HCWs to effectively protect the HCWs by reducing small droplets and aerosol emission from patients. Our system mainly consists of transparent hood, polyvinyl chloride (PVC) pipes, pump, filter, and antiviral materials. When negative pressure is introduced by the pump, the suction at several extraction ports is induced. The contaminated air is conveyed through an exit port at the base of the hood. The extracted contaminated air is cleaned by high-efficiency particulate air (HEPA) filters and UVC light, and then released back into the ward. Besides, the hood is coated by anti-viral and anti-bacterial coating. Feasibility and usability for clinical application: (1) Quickly assembled in 5 min: our system can solve the urgent demand when the healthcare system is overwhelmed. (2) Excellent performance: almost 100% aerosol removal efficiency validated by simulations, experiments, and trials in local hospitals. (3) Achieve 26 air changes per hour (ACH) while the Centers for Disease Control and Prevention (USA) suggests a minimum ACH of 12: our system can provide sufficient air for individual patients in the hood. (4) Highly adjustable, flexible, portable, and low-cost. Scalability and sustainability: Our frame is constructed from PVC materials, which can be readily purchased and manufactured. Our system is highly adjustable, flexible, portable and low-cost, indicating that it can be installed or removed easily in hospitals wards, intensive care unit (ICU), hospital waiting rooms, and clinics without modifying the heating, ventilation, and air conditioning (HVAC) systems.

Methodical Approach to Inactivate Any Microbial Element like SARS-CoV2.

The proposed paper discusses Far UVC could assassinate microbes without harming healthy tissues. The plasma ion generation will increase the ion (O2 -) generation in abundance along with hydrogen ion (H+), and at the same time, the negative hydroxyl radical (OH-) formed will merge with the positive (H+) ion of the virus to break the structure of it. The silver nanoparticle which is present in the diffuser with thermostat support is very effective for destroying the microbial elements by heating the gel present within the diffuser. The gel will mix in the environment, and it will also increase the activity of T cell generation and act as an immunoglobulin booster in the human body while inhaling it. In the proposed device, we are using warm humidified CO2 strategic therapy in low dose which is able to suppress any microbial element like SARS-CoV2.

Air management techniques in dental office in post COVID era: Literature Review

The neoteric coronavirus outburst has jeopardised the health care system globally. As a result, practising dentistry has severe constraints due to production of aerosols and splatter in a large quantity. Air management gains foremost importance in reducing the transmission of SARS-COV-2 in a dental operatory. A variety of air filtration techniques have been put forth to optimize the air quality by removing the pollutants and pathogens. Amidst the blowing wave of information accessible online and on social media, it is puzzling to identify dependable research data and guidance to equip the operatory to minimize the risk of disease by aerosol, droplet and contact transmission. This paper presents comprehensive review on the different air purification technologies, their mechanism and utility in reducing viral load with the aim of providing information in regards to setting up a dental operatory with reduced risk of disease transmission in the post COVID-19 era. © 2022, Universidade Estadual Paulista, Institute of Science and Technology of Sao Jose dos Campos. All rights reserved.

Is hydrogen peroxide an effective mouthwash for reducing the viral load of SARS-CoV-2 in dental clinics?

BACKGROUND: Previous studies have demonstrated that SARS-CoV-2 is mainly transmitted by inhalation of aerosols and can remain viable in the air for hours. Viruses can spread in dental settings and put professionals and patients at high risk of infection due to proximity and aerosol-generating procedures, and poor air ventilation. OBJECTIVES: The aim of this study was to investigate the effects of a 1% hydrogen peroxide (H2O2) mouth rinse on reducing the intraoral SARS-CoV-2 load. METHODS: Portable air cleaners with HEPA filters exposed for 3 months were analysed to test for virus presence in a waiting room (where patients wore a face mask but did not undergo mouth rinsing) and three treatment rooms (where patients wore no mask but carried out mouth rinsing). As CO2 is co-exhaled with aerosols containing SARS-CoV-2 by COVID-19 infected people, we also measured CO2 as a proxy of infection risk indoors. Specific primer and probe RT-PCR were applied to detect viral genomes of the SARS-CoV-2 virus in the filters. Specifically, we amplified the nucleocapsid gene (Nuclv) of SARS-CoV-2. RESULTS: CO2 levels ranged from 860 to 907 ppm, thus indicating low ventilation and the risk of COVID-19 transmission. However, we only found viral load in filters from the waiting room and not from the treatment rooms. The results revealed the efficiency of 1-minute mouth rinsing with 1% H2O2 since patients rinsed their mouths immediately after removing their mask in the treatment rooms. CONCLUSIONS: Our findings suggest that dental clinics would be safer and more COVID-19 free by implementing mouth rinsing 1 min with 1% H2O2 immediately after the patients arrive at the clinic.

The Usage of an Air Purifier Device with HEPA 14 Filter during Dental Procedures in COVID-19 Pandemic: A Randomized Clinical Trial.

The aim of the present study was to evaluate the efficacy of an air purifier device (professional XXl inn-561 innoliving) with HEPA 14 filter in reducing the number of suspended particles generated during dental procedures as a vector of COVID-19 transmission. The survey was conducted on 80 individuals who underwent Oral Surgery with dental Hygiene Procedures, divided into two groups based on the operational risk classification related to dental procedures: a Test Group (with application of filtering device) and a Control Group (without filtering device). All procedures were monitored throughout the clinical controls, utilising professional tools such as molecular particle counters (Lasair III 350 L 9.50 L/min), bacteriological plates (Tryptic Soy Agar), sound meters for LAFp sound pressure level (SPL) and LCpk instantaneous peak level. The rate of suspended particles, microbiological pollution and noise pollution were calculated. SPSS software was used for statistical analysis method. The results showed the higher efficacy of the TEST Group on pollution abatement, 83% more than the Control fgroup. Additionally, the contamination was reduced by 69-80%. Noise pollution was not noticeable compared to the sounds already present in the clinical environment. The addition of PAC equipment to the already existing safety measures was found to be significantly effective in further microbiological risk reduction.

Use of portable air purifiers as local exhaust ventilation during COVID-19.

The purpose of this study was to determine if strategic placement of portable air purifiers would improve effectiveness of aerosol reduction in a space as compared to use as a general room air purifier. Two sizes of portable air purifiers were placed in two different positions intended to function similar to either a local exhaust ventilation hood or an air curtain to determine if strategic placement would lead to a reduction of particles in a worker's position at a desk in an office environment. Particle generators were used to introduce particulate into the air and personal aerosol monitors measured particles during each test condition. Results showed that when the medium room portable air purifiers used in this study were set to high, corresponding to 98 CFM, and placed near the breathing zone of each office worker with the unit's filter cover removed, the particle concentration was reduced 35% beyond the reduction that would be expected if the same units were placed on the floor behind the occupant's workstation. Results also indicated that the larger portable air purifier tested, positioned as close as reasonable to each occupant's breathing zone with the largest capture area possible (i.e., removing the unit's filter cover), delivers the best aerosol reduction performance. The authors concluded that as a layer of protection against transmission of airborne infectious organisms for office occupants, installing a portable air purifier, sized and operated similar to the units tested in this study on the desk 12 inches from the breathing zone of the worker, has the potential to reduce airborne particulate to a greater degree than if the same units were placed outside of the breathing zone, in the general cubicle area.

Probable Cases Evacuation-Body Top Jacket with Portable Hepa Filter

Introduction: In view of the latest covid-19 pandemic condition worldwide, it affects greatly on paramedical colleagues daily practice especially on the suspected or not yet confirmed case transfer or evacuation. Unlike those server deadly infectious diseases case which goanna to have strict isolation devices, and most patients condition are ambulatory or transfer for isolation purposes only. Objectives: To develop a head to abdomen enclosed well covered jacket for transfer purposes in order to reduce the chance of droplets and aerosols spread whilst patient transfer to strict isolation areas. Thus, patient should feel comfortable and acceptable during the process. Methods: Soft plastic core shell on back and with hard transparent front was built;and loosely tight seal on all sides via elastic wrapper. Besides, airs will be sucked through HEPA filter to eliminate any infectious droplets or aerosols leak out to open air and infect those paramedical colleagues who simply escort the case to major Hospitals or strict isolation facility. Results: Laboratory test conducted for its antimicrobial activities against Pseudomonas Aeruginosa (ATCC No. 9027), Enterobacteriaceae (Escherichia coli ATCC No. 8739);Staphylococcus aureus (ATCC No. 6538P);ISO 22196: 2011 Measurement of antibacterial activity on plastics and other non-porous surfaces methodology adopted and result indicated with its compliance of the antimicrobial activities. Trial run successfully with the simulated patient transfer and the safety standards as HEPA filter efficiency minimal standard well-kept in order to maintain the air seal internal environment via HEPA suctioning. In order to maintain the front shape for easy observation and comfort, it remodeled into hard shell. Jacket shell is used environmental friendly materials for disposable, combustible as of non-polyvinylchloride material. Conclusion: Transfer Jacket enhances safety for health care providers as well as transportation vehicles immediate environment plus peoples nearby with an extra protection. Besides comfort of the evacuee can be enhanced and safety ranges and aspects consideration are also being well taken care of.

Mitigation of Aerosols Generated During Exercise Testing With a Portable High-Efficiency Particulate Air Filter With Fume Hood.

BACKGROUND: The role of portable high-efficiency particulate air (HEPA) filters for supplemental aerosol mitigation during exercise testing is unknown and might be relevant during COVID-19 pandemic. RESEARCH QUESTION: What is the effect of portable HEPA filtering on aerosol concentration during exercise testing and its efficiency in reducing room clearance time in a clinical exercise testing laboratory? STUDY DESIGN AND METHODS: Subjects were six healthy volunteers aged 20 to 56 years. In the first experiment, exercise was performed in a small tent with controlled airflow with the use of a stationary cycle, portable HEPA filter with fume hood, and particle counter to document aerosol concentration. Subjects performed a four-stage maximal exercise test that lasted 12 min plus 5 min of pretest quiet breathing and 3 min of active recovery. First, they exercised without mitigation then with portable HEPA filter running. In a separate experiment, room aerosol clearance time was measured in a clinical exercise testing laboratory by filling it with artificially generated aerosols and measuring time to 99.9% aerosol clearance with heating, ventilation, and air conditioning (HVAC) only or HVAC plus portable HEPA filter running. RESULTS: In the exercise experiment, particle concentrations reached 1,722 ± 1,484/L vs 96 ± 124/L (P < .04) for all particles (>0.3 µm), 1,339 ± 1,281/L vs 76 ± 104/L (P < .05) for smaller particles (0.3 to 1.0 µm), and 333 ± 209/L vs 17 ± 19/L (P < .01) for larger particles (1.0 to 5.0 µm) at the end of the protocol in a comparison of mitigation vs portable HEPA filter. Use of a portable HEPA filter in a clinical exercise laboratory clearance experiment reduced aerosol clearance time 47% vs HVAC alone. INTERPRETATION: The portable HEPA filter reduced the concentration of aerosols generated during exercise testing by 96% ± 2% for all particle sizes and reduced aerosol room clearance time in clinical exercise testing laboratories. Portable HEPA filters therefore might be useful in clinical exercise testing laboratories to reduce the risk of COVID-19 transmission.

Automated AMBU Ventilator With Negative Pressure Headbox and Transporting Capsule for COVID-19 Patient Transfer.

Purpose: It is now clear that the COVID-19 viruses can be transferred via airborne transmission. The objective of this study was to attempt the design and fabrication of an AMBU ventilator with a negative pressure headbox linked to a negative pressure transporting capsule, which could provide a low-cost construction, flexible usage unit, and also airborne prevention that could be manufactured without a high level of technology. Method: The machine consists of an automated AMBU bag ventilator, a negative pressure headbox, and a transporting capsule. The function and working duration of each component were tested. Results: The two main settings of the ventilator include an active mode that can be set at the time range of 0 s-9 h 59 min 59 s and a resting mode, which could work continuously for 24 h. The blower motor and battery system, which were used to power the ventilator, create negative air pressure within the headbox, and the transporting capsule, could run for at least 2 h without being recharged. The transporting capsule was able to create an air change rate of 21.76 ACH with-10 Pa internal pressure. Conclusion: This automated AMBU ventilator allowed flow rate, rhythm, and volume of oxygen to be set. The hazardous expired air was treated by a HEPA filter. The patient's transporting capsule is of a compact size and incorporates the air treatment systems. Further development of this machine should focus on how to link seamlessly with imaging technology, to verify standardization, to test using human subjects, and then to be the commercialized.

An unexpected COVID-19 diagnosis during emergency surgery in a neonate.

A 4-day-old, 3.3 kg infant presented with suspected intestinal malrotation, necessitating emergent diagnostic laparoscopy. Intra-operatively, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) came back positive. This is the first case report of emergency surgery and anesthesia in a positive SARS-CoV-2 newborn. This report highlights a neonate with an incidental positive SARS-CoV-2 test, no known exposure history, negative polymerase chain reaction maternal testing, and absence of respiratory symptoms who required modified pressure control ventilation settings to adequately ventilate with the high-efficiency particulate air filter in situ.

Ambient Noise Levels and Wireless Headsets for Communication in Aerosolizing Otolaryngology Surgery During COVID-19.

The objective of this short scientific communication is to describe and test a strategy to overcome communication barriers in coronavirus disease 2019 (COVID-19) era otolaryngology operating rooms. Thirteen endoscopic sinus surgeries, 4 skull base surgeries, and 1 tracheotomy were performed with powered air-purifying respirators. During these surgeries, surgical team members donned headsets with microphones linked via conference call. Noise measurements and survey responses were obtained and compared to pre-COVID-19 data. Noise was problematic and caused miscommunication as per 93% and 76% of respondents, respectively. Noise in COVID-19 era operating rooms was significantly higher compared to pre-COVID-19 era data (73.8 vs 70.2 decibels, P = .04). Implementation of this headset strategy significantly improved communication. Respondents with headsets were less likely to encounter communication problems (31% vs 93%, P < .001). Intraoperative measures to protect surgical team members during aerosolizing surgeries may impair communication. Linking team members via a conference call is a solution to improve communication.

The Use of UVC Irradiation to Sterilize Filtering Facepiece Masks Limiting Airborne Cross-Infection.

In addition to looking for effective drugs and a vaccine, which are necessary to save and protect human health, it is also important to limit, or at least to slow, the spread of coronavirus. One important element in this action is the use of individual protective devices such as filtering facepiece masks. Currently, masks that use a mechanical filter, such as a HEPA (High Efficiency Particulate Air) filter, are often used. In some countries that do not have a well-developed healthcare system or in exceptional situations, there is a real and pressing need to restore filters for reuse. This article presents technical details for a very simple device for sterilization, including of HEPA polymer filters. The results of biological and microscopic tests confirming the effectiveness of the sterilization performed in the device are presented. The compact and portable design of the device also allows its use to disinfect other small surfaces, for example a small fragment of a floor, table, or bed.