Risk Of Cross-infection Research Articles

Aerosol transmission in queuing and dining scenarios in canteens and the effectiveness of control measures

This study investigates the aerosol transmission in queuing and dining scenarios in canteens and explores the effectiveness of control measures. An improved Wells-Riley equation is adopted to calculate the infection risk. The dilution of exhaled aerosols is difficult in the crowded queuing scenario, where the replacement of queuing positions increases the cross-infection risk. The highest infection risk is 1.16% and 1.08% for the linear-queue and cross-queue condition, respectively. Shortening the queuing duration, increasing the separation distance, and wearing masks can considerably reduce the infection risk. In the dining scenario, the effect of increasing ACH is limited on reducing the local concentration. An exhaust vent installed close to the top of the partition can effectively remove the local high-concentration aerosols. Intermittent occupation of a seat can considerably reduce the transmission risk between the consecutive dinners taking that seat. These findings should contribute to improved control of infectious transmission in canteens.

Evaluation of the Effectiveness of Overheated Dry-Saturated Steam Disinfection in the Control of the Dental Chair Contamination by Bioluminescence Analysis: A Pilot In Vitro Study

This study aimed to evaluate, through Adenosine triphosphate (ATP) bioluminescence analysis, the effectiveness of an overheated dry-saturated steam device (Polti Sani System) in decreasing the superficial microbial contamination on dental chairs’ surfaces after 30 s steam disinfection (T1) in comparison to baseline (T0), i.e., at the end of an aerosol-generating procedure (AGDP), and to investigate any differences in the tested surfaces’ contamination at T0 in relation to the surface’s type. Three dental chair surfaces (scialytic lamp, control button panel, spit bowl), sized 10 × 10 cm each, were swabbed and analyzed before and after steam application. The procedure was repeated 20 times for a total of 60 before–after evaluations. Non-parametric tests were used to analyze Relative Light Unit (RLU) values and categorical data on the ATP molecules’ amount detected on the tested surfaces. Statistically significant differences were found for both RLU and categorical data for all surfaces, and each type of surface evaluated at T0 and T1 (p < 0.05). Differences in RLU among the tested surfaces at T0 were not significant. By reducing the microbial contamination on the evaluated surfaces, the overheated dry-saturated steam system was an effective measure for the disinfection of the dental chair’s surfaces after AGDPs, potentially reducing the risk of cross-infections.

Screen-printing of chitosan and cationised cellulose nanofibril coatings for integration into functional face masks with potential antiviral activity

Masks proved to be necessary protective measure during the COVID-19 pandemic, but they provided a physical barrier rather than inactivating viruses, increasing the risk of cross-infection. In this study, high-molecular weight chitosan and cationised cellulose nanofibrils were screen-printed individually or as a mixture onto the inner surface of the first polypropylene (PP) layer. First, biopolymers were evaluated by various physicochemical methods for their suitability for screen-printing and antiviral activity. Second, the effect of the coatings was evaluated by analysing the morphology, surface chemistry, charge of the modified PP layer, air permeability, water-vapour retention, add-on, contact angle, antiviral activity against the model virus phi6 and cytotoxicity. Finally, the functional PP layers were integrated into face masks, and resulting masks were tested for wettability, air permeability, and viral filtration efficiency (VFE). Air permeability was reduced for modified PP layers (43 % reduction for kat-CNF) and face masks (52 % reduction of kat-CNF layer). The antiviral potential of the modified PP layers against phi6 showed inhibition of 0.08 to 0.97 log (pH 7.5) and cytotoxicity assay showed cell viability above 70 %. VFE of the masks remained the same (~99.9 %), even after applying the biopolymers, confirming that these masks provided high level of protection against viruses.

Mitigation of breathing contaminants: Exhaust location optimization for indoor space with impinging jet ventilation supply

Densely occupied spaces (e.g., classrooms) are generally over-crowded and pose a high risk of cross-infection during the pandemic of COVID-19. Among various ventilation systems, impinging jet ventilation (IJV) system might be promising for such spaces. However, the exhaust location of the IJV system used for densely occupied classrooms is unclear. This study aims to investigate the effects of exhaust location on the removal of exhaled contaminants in a classroom (15 × 7 × 5 m3) occupied by 50 students. Exhaled contaminants are modeled by a tracer gas released at the top of each manikin. The reference case has three exhausts evenly distributed in the ceiling. The results indicate that: a) a recirculation airflow entraining exhaled contaminants exists above the occupied zone; b) this recirculation air flow entrains contaminants and accumulates them at the upper part of the room near the diffuser; c) locating merely one exhaust on the same side of the supply diffuser leads to the best indoor air quality, i.e., it reduces the mean age of air from 278 s to 243 s, the mass fraction of CO2 from 753 ppm to 726 ppm, and the concentration of tracer gas from 305 ppm to 266 ppm; d) this layout still performs the best when the supply velocity drops to 0.5 m/s. It is worth noting that the proposed layout has fewer exhausts than the reference case but performs better. These results conclude that the exhaust for large spaces is not evenly distributed but depends on the indoor airflow pattern: the key is locating the exhaust near the region with high contaminant concentration. Factors determining the recirculation airflow are suggested to be further studied.

Personalized displacement ventilation as an energy-efficient solution for airborne disease transmission control in offices

There is evidence to suggest that airborne droplets play an important role in the transmission of respiratory diseases. The highest risk of exposure to these pathogens is in indoor environments, where airflow control has been recognized as one of the most effective engineering means to combat its spread. However, this can contribute to a significant increase in energy costs, as conventional ventilation is often not designed to remove contaminants efficiently. In this study, Computational Fluid Dynamics simulations were used to analyze how a novel ventilation approach, called Personalized Displacement Ventilation (PerDiVent), can simultaneously reduce both pathogenic airborne transmission and reduce energy costs in an open office. In addition, thermal comfort and noise were investigated to assess the practicality of the concept. PerDiVent was found to reduce the risk of cross infection by a factor of 1.08–2.0 compared to mixing ventilation in the worst and best case scenarios analyzed, and lead to savings in mechanical power of at least 30%. Furthermore, there is great potential to further improve the system and to increase the stated numbers substantially with relatively simple alterations to the design. Tools that can be used to great advantage for such optimization are also proposed in this work. These include a simple integral model and analytical metrics to estimate the reduction in cross-infection risk and energy savings as a function of PerDiVent’s effectiveness in removing contaminants. Finally, the system has a modular and highly flexible arrangement, which makes it suitable for retrofitting purposes in various indoor environments and integration with current ventilation systems. The concept shows great promise for the future, where ventilation is required to create healthier and more sustainable environments.

CFD Simulations of Ventilation and Interunit Dispersion in Dormitory Complex: A Case Study of Epidemic Outbreak in Shanghai.

Since the beginning of March 2022, a new round of COVID-19 outbreaks in Shanghai has led to a sharp increase in the number of infected people. It is important to identify possible pollutant transmission routes and predict potential infection risks for infectious diseases. Therefore, this study investigated the cross-diffusion of pollutants caused by natural ventilation, including external windows and indoor ventilation windows, under three wind directions in a densely populated building environment with the CFD method. In this study, CFD building models were developed based on an actual dormitory complex and surrounding buildings under realistic wind conditions to reproduce the airflow fields and transmission paths of pollutants. This paper adopted the Wells-Riley model to assess the risk of cross-infection. The biggest risk of infection was when a source room was located on the windward side, and the risk of infection in other rooms on the same side as the source room was large in the windward direction. When pollutants were released from room 8, north wind resulted in the highest concentration of pollutants in room 28, reaching 37.8%. This paper summarizes the transmission risks related to the indoor and outdoor environments of compact buildings.

Risk Perception on Covid 19 and Biosecurity Practices in Private Dental Practice

The arrival of SARS-COV-2 brought new positions on biological risks in dental practice, based on emerging and preconceived perceptions about the risk of cross-infection and COVID 19, as well as on the sociopolitical conditions of each context.

Ensemble Learning for Interpretable Concept Drift and Its Application to Drug Recommendation

During the COVID-19 epidemic, the online prescription pattern of Internet healthcare provides guarantee for the patients with chronic diseases and reduces the risk of cross-infection, but it also raises the burden of decision-making for doctors. Online drug recommendation system can effectively assist doctors by analysing the electronic medical records (EMR) of patients. Unlike commercial recommendations, the accuracy of drug recommendations should be very high due to their relevance to patient health. Besides, concept drift may occur in the drug treatment data streams, handling drift and location drift causes is critical to the accuracy and reliability of the recommended results. This paper proposes a multi-model fusion online drug recommendation system based on the association of drug and pathological features with online-nearline-offline architecture. The system transforms drug recommendation into pattern classification and adopts interpretable concept drift detection and adaptive ensemble classification algorithms. We apply the system to the Percutaneous Coronary Intervention (PCI) treatment process. The experiment results show our system performs nearly as good as doctors, the accuracy is close to 100%

The Spread of Exhaled Air and Aerosols during Physical Exercise

Physical exercise demonstrates a special case of aerosol emission due to its associated elevated breathing rate. This can lead to a faster spread of airborne viruses and respiratory diseases. Therefore, this study investigates cross-infection risk during training. Twelve human subjects exercised on a cycle ergometer under three mask scenarios: no mask, surgical mask, and FFP2 mask. The emitted aerosols were measured in a grey room with a measurement setup equipped with an optical particle sensor. The spread of expired air was qualitatively and quantitatively assessed using schlieren imaging. Moreover, user satisfaction surveys were conducted to evaluate the comfort of wearing face masks during training. The results indicated that both surgical and FFP2 masks significantly reduced particles emission with a reduction efficiency of 87.1% and 91.3% of all particle sizes, respectively. However, compared to surgical masks, FFP2 masks provided a nearly tenfold greater reduction of the particle size range with long residence time in the air (0.3-0.5 μm). Furthermore, the investigated masks reduced exhalation spreading distances to less than 0.15 m and 0.1 m in the case of the surgical mask and FFP2 mask, respectively. User satisfaction solely differed with respect to perceived dyspnea between no mask and FFP2 mask conditions.

Continuously-deformable and stiffness-tunable soft manipulator achieving unmanned COVID-19 pandemic sampling

In recent years, COVID-19 has spread across the whole world, and manpowered collection of pharyngeal samples undoubtedly increases the possibility of cross-infections. In this article, based on our previous fabricated soft manipulator (Cell Reports Physical Science, 2021, 2, 100600), we performed the COVID-19 sampling on real human volunteers by exploiting a pre-programmed unmanned system. The unmanned sampling system mainly includes a soft manipulator and a rigid motion platform, which are adjusted by pneumatic control box and the motor control modules, respectively. Drawn on the lead-through teaching method, the unmanned sampling of COVID-19 is realized by recording the applied pressure in soft manipulator and the feed motion of rigid platform. This research provides a potential approach for unmanned COVID-19 sampling, solving the risk of cross-infection during manual collection.

Comparison of Flexible Ureteroscope Performance between Reusable and Single-Use Models.

Single-use flexible ureteroscopes for urinary retention have been developed in recent years as an alternative to reusable ureteroscopes in order to eliminate the risk of cross-infections and to solve the primary limitations of traditional reusable flexible ureteroscopes for urinary retention. In this study, we evaluated and contrasted three of the most recent types of flexible ureteroscopes, including two digital reusable versions (Olympus URF-V and Olympus URF-V2) and one single-use model (Pusen Medi-calUscope UE3022), in both ex vivo and in vivo scenarios. The influence of a variety of instruments on the flow of irrigation and its deflection was investigated ex vivo. In the in vivo investigation, a total of 40 patients were treated with retrograde fURS utilizing URF-V, 20 patients were treated with URF-V2, and 20 patients were treated with single-use fURS. The visibility and maneuverability of each fURS were evaluated by the same urologist during the procedures, and the results were compared. Intraoperatively, we compared the image quality of reusable (URF-V and URF-V2) and single-use fURS USCOPE UE3022 cameras and found that there was no statistically significant difference between the two types of camera. The score for maneuverability was the same (4.2) regardless of whether we used the UscopeUE3022 or the URF-V2, but it was significantly lower (3.8, p = 0.03) when we utilized the URF-V. Irrigation was about the same when utilizing reused scopes, whereas employing a single-use scope was more than fifty percent more effective. The findings of our research indicate that reusable and single-use fURs have visibility and maneuverability characteristics that are at least comparable to one another. The possibilities of the single-use type in terms of irrigation flow and deflection are superior.

Functional Textile Materials for Blocking COVID-19 Transmission.

The outbreak of COVID-19 provided a warning sign for society worldwide: that is, we urgently need to explore effective strategies for combating unpredictable viral pandemics. Protective textiles such as surgery masks have played an important role in the mitigation of the COVID-19 pandemic, while revealing serious challenges in terms of supply, cross-infection risk, and environmental pollution. In this context, textiles with an antivirus functionality have attracted increasing attention, and many innovative proposals with exciting commercial possibilities have been reported over the past three years. In this review, we illustrate the progress of textile filtration for pandemics and summarize the recent development of antiviral textiles for personal protective purposes by cataloging them into three classes: metal-based, carbon-based, and polymer-based materials. We focused on the preparation routes of emerging antiviral textiles, providing a forward-looking perspective on their opportunities and challenges, to evaluate their efficacy, scale up their manufacturing processes, and expand their high-volume applications. Based on this review, we conclude that ideal antiviral textiles are characterized by a high filtration efficiency, reliable antiviral effect, long storage life, and recyclability. The expected manufacturing processes should be economically feasible, scalable, and quickly responsive.

Clinical effect of standardized nursing for lymphoma patients and the influencing factors of nosocomial infection.

To analyze the clinical effect of standardized nursing for lymphoma patients and the influencing factors of nosocomial infection, a total of 360 diffuse large B-cell lymphoma patients with disease recurrence or progression after first-line treatment were retrospectively selected from our hospital from January 2021 to July 2022. After standardized nursing, the overall infection rate of lymphoma patients was 2.50% (9/360), which was significantly lower than the overall infection rate of our hospital in 2021 (7.44%, 844/11342) (P < .05). The proportion of 3 kinds of pathogenic bacteria detected were G+ bacteria (33.5%), G- bacteria (53.3%), and fungi (13.2%). The pathogenic bacteria genus with the most G+ bacteria is Enterococcus, the pathogenic bacteria genus with the most G+ bacteria is Enterobacteriaceae, and the pathogenic bacteria with the most fungi is Candida albicans. Female infection rate was significantly higher than male (P < .05). There was no significant difference in nosocomial infection among different marital status/fertility status (P > .05). The nosocomial infection of patients with different hospitalization times was statistically significant (P < .05). The duration of hospitalization in the infected group was significantly higher than that in the non-infected group (P < .05). The clinical effect of standardized nursing for lymphoma patients is significant, and the influencing factors of nosocomial infection include patient gender, hospitalization frequency, and hospitalization duration.

The Efficacy of Three Types of Disinfectants on the Microbial Flora from the Surface of Impression Materials Used in Dentistry—In Vitro Study

During impressions, bacteria, viruses, and fungi remain on the impression material, representing a significant risk for the medical team (dentists, dental assistants, and laboratory technicians). Impression disinfectants have been introduced into dentistry to reduce the risk of cross-infection. This study was performed by examining the surface disinfection of five commonly used impression materials in prosthodontics: alginate-Tropicalgin (Zhermack®), condensation silicone-Zetaplus (Zhermack®), Oranwash L (Zhermack®); and addition silicone-Elite HD + Putty Soft (Zhermack®), Elite + Light Body (Zhermack®) after the disinfection with three disinfectants: Zeta 3 Soft (Zhermack®), Zeta 7 Spray (Zhermack®) and Zeta 7 Solution (Zhermack®). Before disinfection, the impression materials were contaminated with Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10213. Our results demonstrate the efficacy of the two examined specific disinfectants in reducing cross-infection risk. The surface disinfectant-spray is not adequate for impression disinfection. A high number of bacterial colonies were found on the surface of all impressions disinfected with this spray. The immersion-disinfection method effectively eliminates the risk of cross-infections (Kruskal–Wallis test showed a p &lt; 0.001).

Progress of concentrated growth factors in the treatment of jaw cysts

The activation of platelets can release multiple growth factors associated with wound healing and bone regeneration. With the development of autologous platelet concentrate preparation techniques, significant progress has been made in the repair of bone defects in oral and jaw cysts. Concentrated growth factors (CGF)are the latest generation of platelet concentrates obtained by differential centrifugation, rich in growth factors without the addition of anticoagulants, and with no risk of cross-infection and immune rejection. CGF is convenient for material preparation, simple preparation, high efficiency, and has a certain anti-inflammatory effect, and the surrounding soft tissue structure is better recovered. This paper briefly reviews the promoting effect of CGF in the treatment of jaw cysts on soft and hard tissue healing and its related clinical applications, and aims to provide some theoretical basis for the further application of CGF in promoting osteogenesis, which can be better applied in clinical practice and play its maximum value.

Detection of abnormal chicken droppings based on improved Faster R-CNN

The characteristics of chicken droppings are closely related to the health of chickens. Veterinarians often judge the health of a chicken by looking at whether the chicken poop is normal. At present, the inspection of abnormal chicken droppings in chicken coops relies on manual observation, which is inefficient, accurate varies from person to person, labor-intensive, and has the risk of cross-infection. To achieve efficient, accurate, and intelligent identification of abnormal chicken droppings, an abnormal chicken droppings detection method based on improved Faster Region-based Convolutional Neural Network (Faster R-CNN) was proposed in this study. In the feature extraction network stage, deformable convolution was used and combined with Path Augmentation-Feature Pyramid Network (PA-FPN) to improve the extraction ability of features at different scales. In the Region Proposal Network (RPN) stage, the K-means++ algorithm was used to cluster the dataset and obtain the Anchor-ratio which is more suitable for the chicken poop object, and the FocalLoss classification loss function was used to improve the classification ability of difficult samples. In the regional convolutional network stage, the region of interest calibration algorithm was used instead to obtain more accurate localization information. The experimental results show that the improved Faster R-CNN structure can reach an accuracy of 98.8% for abnormal chicken poop detection, and the average accuracy mean value was improved by 27.8%. The results can provide a key core technology support for establishing an efficient abnormal chicken droppings online detection system. Keywords: abnormal chicken droppings, Faster R-CNN, detection, non-destructive monitoring, PA-FPN DOI: 10.25165/j.ijabe.20231601.7732 Citation: Zhu J H, Cui Z H, Wang H Y, Zhou M, Sun X Q. Detection of abnormal chicken droppings based on improved Faster R-CNN. Int J Agric & Biol Eng, 2023; 16(1): 243–249.

Transmission of monkeypox virus through the saliva and air that need careful management.

Transmission of monkeypox virus through the saliva and air that need careful management.

Ceiling-Fan-Integrated Air Conditioning (CFIAC): Age-of-air, Air Pollution, and Airflow Distribution

Ceiling-Fan-Integrated-Air Conditioning (CFIAC) is a heating ventilation and air conditioning (HVAC) design approach that jets supply air into the vicinity of ceiling fans to be mixed and distributed within the room. This eliminates terminal ductwork and diffusers and provides very efficient cooling for the occupants. Two previously published papers have described the air velocity, temperature, and thermal comfort fields in a space conditioned by CFIAC. This paper is the third in this series, to evaluate CFIAC ventilation effectiveness and its effect on air pollution. In a test chamber, HVAC supply air was jetted from a high-sidewall vent into the centreline of a ceiling fan. The ceiling fan was operated at various conditions (off, level 2-downward, level 4-downward, and blowing upward). Carbon dioxide (CO2) was used as a tracer gas for the age-of-air evaluation, and as a proxy for an indoor air pollutant. For the age-of-air measurement, the CO2 source was injected into the side wall jet, and the age-of-air was monitored in various locations in the chamber. For the air pollution test, CO2 as the pollution source was released near a thermal manikin’s nose that was located in the middle of the chamber. The CO2 concentrations were measured at different locations around the ceiling fan and the thermal manikin. The ventilation effectiveness and health exposure are represented by the age-of-air and intake fraction (IF). At level 2 and level 4 downward fan operations, the age-of-air is reduced in the measured locations compared to the fan-off operation. The age-of-air for upward fan operation is equal to the age-of-air in fan-off operation, except for one location that is farthest from the fan. The IF results are very similar among all 4 fan operations, with level-4-downward and upward-fan operations slightly lower than the fan level-2 downward and fan-off operations. The study is considered preliminary, but at this point, we can say that fans reduce age-of-air and cross-infection risk.

Scope of Teledentistry during the Trying Times of COVID-19 Pandemic: A Patient Perspective Questionnaire Survey

Introduction: Teledentistry has provided a glimmer of hope for patients who require treatment, but are limited to their homes owing to Coronavirus Disease-2019 (COVID-19) restrictions. Like any other professional careers, dentistry also had to switch to a new normal mode of consultation and teledentistry came to its aid. With the support of advanced technologies dental care was made possible even though face to face interactions were to be refrained due to the curfew restrictions. Aim: To assess the scope of teledentistry from a patient’s perspective. Materials and Methods: The survey was designed as a descriptive cross-sectional study conducted in the Department of Periodontics, Karpaga Vinayaga Institute of Dental Sciences, Chengelpet, Tamil Nadu, on dental patients of Chennai, India, from April 2021 to May 2021 who made use of Telemedicine for dental consultation. The study population included those who sought teledentistry and the study included 100 participants. A computer aided self-administered questionnaire was designed and validated. Practicing dentists were requested to circulate a questionnaire containing 10 questions that assessed scope of teledentistry from patient’s perspective, to their patients at the end of their teleconsultation after obtaining consent. A total of 94 responses were obtained successfully out of 100 participants. Descriptive analysis of the obtained data was done using International Business Machines Statistical Package for the Social Sciences (IBM SPSS) software version 22.0. Results: The mean±Standard Deviation (SD) age of the study participants was 33±2.5 years, there were 51 males and 43 females. A 57.5% (n=54) of individuals made the best use of teledentistry during the lockdown and 59.6% (n=56) of the respondents felt that teledentistry was safe as it prevented the risk of unnecessary exposure and cross-infection. Of all, 79 (84.04%) respondents answered that they support teledentistry in the future. Suggestions were received requesting reduction in consultation fee and to increase consultation timings. Conclusion: Teledentistry proved to be an excellent alternate mode of dental service during the COVID-19 pandemic crisis. Moreover, it helped to bring down the cross-infection and made health services available to people caught up in inaccessible areas thus, making teledentistry a valuable tool that can be used on a day to day basis

An Article Review Step by Step About Preventive Measures to Prevent Infection by Covid-19 in Dental Clinic

A huge public health concern is the advent of the COVID-19 pandemic. As dentists, both our dental staff and our patients have significant roles in reducing their susceptibility to infection. The team is at a high risk of infectious infection and likely spread of viruses because of the existence of our job. One of the best strategies to combat this pandemic is to facilitate successful social isolation. As dental professionals, though, we are confronting the double task of shielding our staff and shielding our patients from exposure to the environment from all sides by ensuring that our patients continue to be able to receive urgency / emergency dental services. Both the dentist / dental staff and the patient are at a strong risk of cross-infection because of their existence, and this is for many reasons, the most two important reasons which are 1) the needed distancing between dental worker and the patient (which is about one to two meters) that we can’t save it during dental treatment. 2) The dental treatment is applied inside the oral cavity which is the biggest source of contamination with the virus especially when we use high speed hand piece with cooling water that lead to highly spread of aerosols, which are loaded by blood and saliva droplet containing viruses, that spread to the environment of dental room and surfaces. Therefor the COVID-19 pandemic, has led to the absolute requirement for strict and effective infection control protocols beyond those that already exist within the dental setting. The purpose of this position statement is to establish a standard operating protocol for dental practice