With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst sele...With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.展开更多
Owing to the significant increase in air pollutants and the spread of infectious diseases,it seems that the use of face masks will become an essential item in human societies.Therefore,there is a need to conduct more ...Owing to the significant increase in air pollutants and the spread of infectious diseases,it seems that the use of face masks will become an essential item in human societies.Therefore,there is a need to conduct more research to develop novel types of respirators utilizing upto-date science such as nanotechnology.In this study,we fabricated a nanocomposite fibrous filter containing modified graphene oxide(GO)and zinc oxide(ZnO)nanoparticles.This layer was used as an active filter for absorbing and removing air pollutants,such as suspended submicron particles(below 2.5 microns)and CO_(2),NO_(2),and SO_(2)gases.The synthesized nanostructures and fibrous filters were characterized by different analysis(FTIR,XRD,TGA,and FESEM),and the performance of the filters was surveyed by tests such as pressure drop,CO_(2),NO_(2),SO_(2)gas rejection,and particulate removal.The results showed that the stabilization of the modified GO and ZnO nanostructures on the fibrous filter improved the effectiveness of this filter as a mask for removing toxic particles and gases,and the filter containing nanoparticles had the best performance.展开更多
The objective was to measure the effect of various face masks on speech recognition threshold and the word recognition score in the presence of varying background noise levels.20 normal-hearing adult subjects(a total ...The objective was to measure the effect of various face masks on speech recognition threshold and the word recognition score in the presence of varying background noise levels.20 normal-hearing adult subjects(a total of 40 ears)participated.Pure tone audiometry followed by speech recognition threshold and word recognition score at the most comfortable level in varying signal-to-noise ratios(SNR0,SNR10,and SNR15)using surgical,pleated cloth,and N95 masks.Using surgical,cloth,and N95 masks,speech recognition thresholds increased by 1.8 dB,4.4 dB,and 5.05 dB,respectively.Word recognition scores decreased by 32%without a mask,43.7%in a surgical mask,46.3%in a cloth mask,and 46.7%in N95 mask conditions,between SNR15 and SNR0.The speech recognition threshold was negatively affected with cloth and N95 masks.Surgical masks do not affect the word recognition scores at lower background noise levels.However,as the signal-to-noise ratio decreased,even the surgical,cloth,and N95 masks significantly impacted the word recognition score even in normal-hearing individuals.展开更多
Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-po...Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-posable masks will be generated every day in the world,causing great pressure on the environment.Herein,con-ductive polymer composites are fabricated by simple melt blending of mask fragments(mask polypropylene,short for mPP)and multi-walled carbon nanotubes(MWNTs).MWNTs were used as modifiers for composites because of their high strength and high conductivity.The crystalline structure,mechanical,electrical and thermal enhancement effect of the composites were investigated.MWNTs with high thermal stability acted the role of promoting the crystallisation of mPP by expediting the crystalline nucleation,leading to the improvement of amount for crystalline nucleus.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.With 2.0 wt% MWNTs loading,the tensile strength and electrical conductivity of the composites were increased by 809% and 7 orders of magnitude.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.Thus,more conducting paths were constructed to transport carriers.The findings may open a way for high value utilization of the disposable masks.展开更多
Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a ...Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a pandemic.The use of face masks and respirators is an important public health measure to reduce or prevent transmission of SARS-CoV-2.Here we discuss the hypothetical mechanisms by which exercise with face masks or respirators can induce detrimental effects on the cardiovascular system,potentially explaining adverse events such as cardiac arrhythmias and spontaneous pneumothorax.Although sudden death associated with the wearing of a face mask during running is a rare event,the risk is higher especially in those with existing cardiac comorbidities.In such cases,a mask designed specifi cally for runners with no or few side effects of oxygen defi ciency should be considered instead.展开更多
Introduction: Two spread methods of Covid-19, namely airborne and respiratory droplets, can be prevented by proper use of face masks. However, it has been reported an inadequate knowledge attitude and practice of prop...Introduction: Two spread methods of Covid-19, namely airborne and respiratory droplets, can be prevented by proper use of face masks. However, it has been reported an inadequate knowledge attitude and practice of proper use of face masks among school students. Therefore, the knowledge, attitude, and practice of school students should be improved. Different approaches are used to improve knowledge, attitude, and practice. However, e-posters are rare, and the effect of e-posters on improving the knowledge, attitude, and practice of school students on the proper use of face masks has not been studied. Objectives: The objective of this study was to determine the effect of an e-educational poster on knowledge, attitude, and practice of the proper use of face masks among school students. Method: This study was conducted as a pre-test and post-test design. The sample was 364 grade 11 students of the Gampaha educational division, Sri Lanka. Data were collected using self-administered questionnaires distributed pre and post to the interventional e-education poster. Data analyses were conducted by using SPSS Software. Results: Results show no significant demographic difference (p = 0.446) between the pre and post-test groups. A significant increase was observed between the pre and post-test mean scores of knowledge (p ≤ 0.05), attitude (p ≤ 0.05), and practice (p ≤ 0.05) on the proper use of face masks. In pre-group knowledge (p = 0.155), attitude (p = 0.258) and practice (p = 0.211) shows no significant difference due to gender. Also post group knowledge (p = 0.079), attitude (p = 0.835) and practice (p = 0.435) shows no significant difference due to gender. Conclusions: The results suggest that e-educational posters may be useful to improve the knowledge, attitude, and practice on the proper use of face masks among school students. The improvement of knowledge, attitude, and practice on the proper use of face masks by e-educational posters among school students occurs irrespective of gender.展开更多
This research introduces an innovative approach to address the management of waste baby diapers(BDs)and face masks(FMs)in order to mitigate environmental risks associated with the indiscriminate disposal of BD and FM ...This research introduces an innovative approach to address the management of waste baby diapers(BDs)and face masks(FMs)in order to mitigate environmental risks associated with the indiscriminate disposal of BD and FM waste.The study focuses on using BDs and FMs in road pavement hot mix asphalt(HMA)to enhance bitumen and aggregate per-formance,respectively.The approach involves the direct incorporation of 4%shredded BD during the bitumen melting process,while varying percentages of shredded FM(0%,0.5%,1%,and 1.5%relative to aggregate weight)are utilized as aggregate coating through a melt-ing process.The inclusion of BD enhances the resistance of modified bitumen(MB)to per-manent deformations under high temperatures compared to conventional bitumen.Simultaneously,the treatment of FM significantly improves the physical and mechanical attributes of the aggregates.The combination of 4%BD and 1.5%FM results in improved densification,fostering robust bonding between aggregates and asphalt paste.This enhancement leads to a 39%increase in stability,an 18%increase in indirect tensile strength(ITS),and a 27%reduction in permanent deformations.Notably,there is a remark-able 53%increase in resistance to rut depth and a 33%increase in resilient modulus.Ultimately,the implementation of 4%BD as a bitumen enhancer and 1.5%FM as an aggre-gate modifier demonstrates the potential to achieve waste reductions of 36%and 61%,respectively.This approach extends beyond pavement enhancement,contributing to the broader societal mitigation of adverse effects associated with BD and FM waste.展开更多
Textiles have proved to be very important materials to human beings since the time immemorial.And,fibers are the basic building units of these materials.In this perspective we substantiate the uniqueness and capabilit...Textiles have proved to be very important materials to human beings since the time immemorial.And,fibers are the basic building units of these materials.In this perspective we substantiate the uniqueness and capability of nanofibers as active layers in face masks,to protect people against the novel coronavirus disease(COVID-19).This time-sensitive letter introduces the mechanisms based on which their active filters function,the uniqueness of electrospun nanofibers in face masks and do-it-yourself(DIY)steps to realize a fully functional face mask at home.展开更多
Importance:Despite the high burden of respiratory infections among children,the production of exhaled particles during common activities and the efficacy of face masks in children have not been sufficiently studied.Ob...Importance:Despite the high burden of respiratory infections among children,the production of exhaled particles during common activities and the efficacy of face masks in children have not been sufficiently studied.Objective:To determine the effect of type of activity and mask usage on exhaled particle production in children.Methods:Healthy children were asked to perform activities that ranged in intensity(breathing quietly,speaking,singing,coughing,and sneezing)while wearing no mask,a cloth mask,or a surgical mask.The concentration and size of exhaled particles were assessed during each activity.Results:Twenty-three children were enrolled in the study.Average exhaled particle concentration increased by intensity of activity,with the lowest particle concentration during tidal breathing(1.285 particles/cm^(3)[95%CI 0.943,1.627])and highest particle concentration during sneezing(5.183 particles/cm^(3)[95%CI 1.911,8.455]).High-intensity activities were associated with an increase primarily in the respirable size(≤5μm)particle fraction.Surgical and cloth masks were associated with lower average particle concentration compared to no mask(P=0.026 for sneezing).Surgical masks outperformed cloth masks across all activities,especially within the respirable size fraction.In a multivariable linear regression model,we observed significant effect modification of activity by age and by mask type.Interpretation:Similar to adults,children produce exhaled particles that vary in size and concentration across a range of activities.Production of respirable size fraction particles(≤5μm),the dominant mode of transmission of many respiratory viruses,increases significantly with coughing and sneezing and is most effectively reduced by wearing surgical face masks.展开更多
Despite cities being recognized as being potential sources of microplastic pollution to the wider environment, most surveys of COVID-19 plastic-based litter have been undertaken through linear transects of marine beac...Despite cities being recognized as being potential sources of microplastic pollution to the wider environment, most surveys of COVID-19 plastic-based litter have been undertaken through linear transects of marine beaches. For the far fewer number of studies conducted on inland and urban locations, the site-specific focus has primarily been surveys along the length of streets. The present study is the first to specifically assess the standing stock (i.e., moment-in-time) of littered face masks for the entire surface area of urban parking lots. The density of face masks in 50 parking lots in a Canadian coastal town (0.00054 m2 ± 0.00051 m2) was found to be significantly greater than the background level of littering of town streets. Face mask density was significantly related to visitation “usage” of parking lots as gauged by the areal size of the lots and of their onsite buildings, as well as the number of vehicles present. Neither parking lot typology nor estimates of inferred export (various measures of wind exposure) and entrapment (various metrics of obstruction) of face masks had a significant influence on the extent of whole-lot littering. In consequence, modelling of the potential input of mask-derived microplastics to the marine environment from coastal communities can use the areal density of face masks found here in association with the total surface area of lots for individual municipalities as determined through GIS analysis.展开更多
Reusable face masks are an important alternative for minimizing costs of disposable and surgical face masks during pan-demics.Often complementary to washing,a prolonged lifetime of face masks relies on the incorporati...Reusable face masks are an important alternative for minimizing costs of disposable and surgical face masks during pan-demics.Often complementary to washing,a prolonged lifetime of face masks relies on the incorporation of self-cleaning materials.The development of self-cleaning face mask materials requires the presence of a durable catalyst to deactivate contaminants and microbes after long-term use without reducing filtration efficiency.Herein,we generate self-cleaning fibers by functionalizing silicone-based(polydimethylsiloxane,PDMS)fibrous membranes with a photocatalyst.Coaxial electro-spinning is performed to fabricate fibers with a non-crosslinked silicone core within a supporting shell scaffold,followed by thermal crosslinking and removal of the water-soluble shell.Photocatalytic zinc oxide nanoparticles(ZnO NPs)are immo-bilized on the PDMS fibers by colloid-electrospinning or post-functionalization procedures.The fibers functionalized with ZnO NPs can degrade a photo-sensitive dye and display antibacterial properties against Gram-positive and Gram-negative bacteria(Escherichia coli and Staphylococcus aureus)due to the generation of reactive oxygen species upon irradiation with UV light.Furthermore,a single layer of functionalized fibrous membrane shows an air permeability in the range of 80-180 L/m^(2)s and 65%filtration efficiency against fine particulate matter with a diameter less than 1.0µm(PM_(1.0)).展开更多
Face masks play a pivotal role in preventing infection transmission.However,the capture of infection-sourced particles in face masks poses challenges related to reuse,necessitating proper disposal.We developed a self-...Face masks play a pivotal role in preventing infection transmission.However,the capture of infection-sourced particles in face masks poses challenges related to reuse,necessitating proper disposal.We developed a self-sterilizable polypropylene-based membrane for face masks to address challenges associated with infection transmission prevention.The membrane,created using 3D printing,underwent functionalization with zinc oxide(ZnO)and polydopamine(PDA)-TEMPO to achieve broad-spectrum light absorption and facilitate self-sterilization through photocatalytic and photothermal effects upon light exposure.The hydrophobic surface(water contact angle:133±2°)minimized moisture accumulation,and the membrane exhibited robust mechanical properties,including shear strength(1.25±0.5kPa)and peel resistance strength(112.8±11.2kPa).The evaluation demonstrated stability in airflow(0-500cm^(3)/s)and excellent aerosol filtration efficiency(94.8±0.6%)for particles(PM 0.3,PM 2.5,PM 10),comparable to commercial masks.The membrane showed antibacterial efficacy over five uses in a simulated respiratory environment.Safety assessments confirmed biocompatibility through cytocompatibility and skin irritation assays.In conclusion,this membrane offers efficient filtration and photo-triggered sterilization,presenting a promising solution for next-generation face masks to address concerns related to reuse,disposal,and infection control.展开更多
BACKGROUND There have been increased reports of dry eyes in the coronavirus disease 2019(COVID-19) pandemic era.AIM To analyze the differences in tear film properties from pre-and post-pandemic of the COVID-19 era.MET...BACKGROUND There have been increased reports of dry eyes in the coronavirus disease 2019(COVID-19) pandemic era.AIM To analyze the differences in tear film properties from pre-and post-pandemic of the COVID-19 era.METHODS It was a retrospective comparative study.Patients were divided into three groups according to the data of multimodal ocular surface evaluation:(1) Group 1 if it was before Portugal lockdown decision(from August 2019 to March 2020);(2) Group 2 if it was after Portugal lockdown decision but without mask mandate(from April 2020 to October 2020);and(3) Group 3 if it was after Portugal lockdown but with mask mandate in health public highway(from November 2020 to April 2021).The following variables were analyzed:Lipid layer thickness,blink rate,Schirmer test,tear meniscus height,tear osmolarity,non-invasive break-up time,and loss area of the meibomian glands.RESULTS The study included 548 eyes of 274 patients,aged 18 years to 89 years,with a mean age of 66.15 ± 13.40 years at the time of multimodal ocular surface evaluation.Compared to group 1:(1) Mean lipid layer thickness was better in group 2(P = 0.001) and group 3(P < 0.001);(2) Schirmer test was similar in group 2(P = 0.576) and better in group 3(P = 0.002);(3) Tear osmolarity and loss area of the meibomian glands were worse in group 2(P = 0.031 and P < 0.001,respectively) and in group 3(both with P < 0.001);(4) Blink rate and tear meniscus height were similar in group 2(P = 0.821 and P = 0.370,respectively) and worse in group 3(P < 0.001 and P = 0.038,respectively);and(5) Non-invasive break-up time was worse in group 2(P = 0.030) and similar in group 3(P = 0.263).CONCLUSION Our study demonstrated that differences existed in tear film properties comparing data from the pre-and post-pandemic of the COVID-19 era.展开更多
To reduce the impact of the novel SARS-CoV-2 virus, popularly known as the Coronavirus, many public health-related rules have been established around the world. Along with social distancing and lockdowns, most countri...To reduce the impact of the novel SARS-CoV-2 virus, popularly known as the Coronavirus, many public health-related rules have been established around the world. Along with social distancing and lockdowns, most countries have mandatory wearing of face masks in public areas to limit the spread of the virus during the COVID-19 pandemic. However, because people are free to choose any method to make their masks, some are being fabricated from materials that can be toxic to the environment and human health. This paper discusses how inks and dyes used in face masks are causing major environmental degradation and health issues in industry workers and the general mask-wearing public. The goal fixed for the present study is to raise the alarm with authorities and decision-makers regarding the toxic nature of some colors (dyes and inks) and fabrics in the masks being worn every day.展开更多
To automatically detecting whether a person is wearing mask properly,we propose a face mask detection algorithm based on hue-saturation-value(HSV)+histogram of oriented gradient(HOG)features and support vector machine...To automatically detecting whether a person is wearing mask properly,we propose a face mask detection algorithm based on hue-saturation-value(HSV)+histogram of oriented gradient(HOG)features and support vector machines(SVM).Firstly,human face and five feature points are detected with RetinaFace face detection algorithm.The feature points are used to locate to mouth and nose region,and HSV+HOG features of this region are extracted and input to SVM for training to realize detection of wearing masks or not.Secondly,RetinaFace is used to locate to nasal tip area of face,and YCrCb elliptical skin tone model is used to detect the exposure of skin in the nasal tip area,and the optimal classification threshold can be found to determine whether the wear is properly according to experimental results.Experiments show that the accuracy of detecting whether mask is worn can reach 97.9%,and the accuracy of detecting whether mask is worn correctly can reach 87.55%,which verifies the feasibility of the algorithm.展开更多
Effective strategies to control COVID-19 pandemic need high attention to mitigate negatively impacted communal health and global economy,with the brim-full horizon yet to unfold.In the absence of effective antiviral a...Effective strategies to control COVID-19 pandemic need high attention to mitigate negatively impacted communal health and global economy,with the brim-full horizon yet to unfold.In the absence of effective antiviral and limited medical resources,many measures are recommended by WHO to control the infection rate and avoid exhausting the limited medical resources.Wearing mask is among the non-pharmaceutical intervention measures that can be used as barrier to primary route of SARS-CoV2 droplets expelled by presymptomatic or asymptomatic individuals.Regardless of discourse on medical resources and diversities in masks,all countries are mandating coverings over nose and mouth in public areas.Towards contribution of public health,the aim of the paper is to devise a real-time technique that can efficiently detect non mask faces in public and thus enforce to wear mask.The proposed technique is ensemble of one stage and two stage detectors to achieve low inference time and high accuracy.We took ResNet50 as a baseline model and applied the concept of transfer learning to fuse high level semantic information in multiple feature maps.In addition,we also propose a bounding box transformation to improve localization performance during mask detection.The experiments are conducted with three popular baseline models namely ResNet50,AlexNet and MobileNet.We explored the possibility of these models to plug-in with the proposed model,so that highly accurate results can be achieved in less inference time.It is observed that the proposed technique can achieve high accuracy(98.2%)when implemented with ResNet50.Besides,the proposed model can generate 11.07%and 6.44%higher precision and recall respectively in mask detection when compared to RetinaFaceMask detector.展开更多
Since the outbreak of Coronavirus Disease 2019(COVID-19),people are recommended to wear facial masks to limit the spread of the virus.Under the circumstances,traditional face recognition technologies cannot achieve sa...Since the outbreak of Coronavirus Disease 2019(COVID-19),people are recommended to wear facial masks to limit the spread of the virus.Under the circumstances,traditional face recognition technologies cannot achieve satisfactory results.In this paper,we propose a face recognition algorithm that combines the traditional features and deep features of masked faces.For traditional features,we extract Local Binary Pattern(LBP),Scale-Invariant Feature Transform(SIFT)and Histogram of Oriented Gradient(HOG)features from the periocular region,and use the Support Vector Machines(SVM)classifier to perform personal identification.We also propose an improved Convolutional Neural Network(CNN)model Angular Visual Geometry Group Network(A-VGG)to learn deep features.Then we use the decision-level fusion to combine the four features.Comprehensive experiments were carried out on databases of real masked faces and simulated masked faces,including frontal and side faces taken at different angles.Images with motion blur were also tested to evaluate the robustness of the algorithm.Besides,the experiment of matching a masked face with the corresponding full face is accomplished.The experimental results show that the proposed algorithm has state-of-the-art performance in masked face recognition,and the periocular region has rich biological features and high discrimination.展开更多
A face-mask object detection model incorporating hybrid dilation convolutional network termed ResNet Hybrid-dilation-convolution Face-mask-detector (RHF) is proposed in this paper. Furthermore, a lightweight face-mask...A face-mask object detection model incorporating hybrid dilation convolutional network termed ResNet Hybrid-dilation-convolution Face-mask-detector (RHF) is proposed in this paper. Furthermore, a lightweight face-mask dataset named Light Masked Face Dataset (LMFD) and a medium-sized face-mask dataset named Masked Face Dataset (MFD) with data augmentation methods applied is also constructed in this paper. The hybrid dilation convolutional network is able to expand the perception of the convolutional kernel without concern about the discontinuity of image information during the convolution process. For the given two datasets being constructed above, the trained models are significantly optimized in terms of detection performance, training time, and other related metrics. By using the MFD dataset of 55,905 images, the RHF model requires roughly 10 hours less training time compared to ResNet50 with better detection results with mAP of 93.45%.展开更多
To shorten operation time and improve survival rate of rats with myocardial ischemia or myocardial infarction,we use a novel device comprised of a face mask and a head/neck retainer in this study.We report the basic d...To shorten operation time and improve survival rate of rats with myocardial ischemia or myocardial infarction,we use a novel device comprised of a face mask and a head/neck retainer in this study.We report the basic design of the novel respiratory face mask(RFM) and evaluate its performance in a rat model of myocardial ischemia.The device is cost-effective and easier to handle than other devices,such as tracheal intubation.Compared with conventional tracheal intubation,we found that RFM shortens operation time significantly while keeping blood indices normal;the mean operation time for rats in the mask group was(32±3) min,and that for the intubation group was(45±7) min(P<0.05).Moreover,the size and shape of the RFM can be changed according to the body weight of rats.In conclusion,RFM is an appropriate device for the establishment of myocardial infarction or ischemia-reperfusion in rats.展开更多
Today,due to the pandemic of COVID-19 the entire world is facing a serious health crisis.According to the World Health Organization(WHO),people in public places should wear a face mask to control the rapid transmissio...Today,due to the pandemic of COVID-19 the entire world is facing a serious health crisis.According to the World Health Organization(WHO),people in public places should wear a face mask to control the rapid transmission of COVID-19.The governmental bodies of different countries imposed that wearing a face mask is compulsory in public places.Therefore,it is very difficult to manually monitor people in overcrowded areas.This research focuses on providing a solution to enforce one of the important preventative measures of COVID-19 in public places,by presenting an automated system that automatically localizes masked and unmasked human faces within an image or video of an area which assist in this outbreak of COVID-19.This paper demonstrates a transfer learning approach with the Faster-RCNN model to detect faces that are masked or unmasked.The proposed framework is built by fine-tuning the state-of-the-art deep learning model,Faster-RCNN,and has been validated on a publicly available dataset named Face Mask Dataset(FMD)and achieving the highest average precision(AP)of 81%and highest average Recall(AR)of 84%.This shows the strong robustness and capabilities of the Faster-RCNN model to detect individuals with masked and un-masked faces.Moreover,this work applies to real-time and can be implemented in any public service area.展开更多
基金supported by the National Natural Science Foundation of China(52076099,52306257,and 72293601)。
文摘With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.
文摘Owing to the significant increase in air pollutants and the spread of infectious diseases,it seems that the use of face masks will become an essential item in human societies.Therefore,there is a need to conduct more research to develop novel types of respirators utilizing upto-date science such as nanotechnology.In this study,we fabricated a nanocomposite fibrous filter containing modified graphene oxide(GO)and zinc oxide(ZnO)nanoparticles.This layer was used as an active filter for absorbing and removing air pollutants,such as suspended submicron particles(below 2.5 microns)and CO_(2),NO_(2),and SO_(2)gases.The synthesized nanostructures and fibrous filters were characterized by different analysis(FTIR,XRD,TGA,and FESEM),and the performance of the filters was surveyed by tests such as pressure drop,CO_(2),NO_(2),SO_(2)gas rejection,and particulate removal.The results showed that the stabilization of the modified GO and ZnO nanostructures on the fibrous filter improved the effectiveness of this filter as a mask for removing toxic particles and gases,and the filter containing nanoparticles had the best performance.
文摘The objective was to measure the effect of various face masks on speech recognition threshold and the word recognition score in the presence of varying background noise levels.20 normal-hearing adult subjects(a total of 40 ears)participated.Pure tone audiometry followed by speech recognition threshold and word recognition score at the most comfortable level in varying signal-to-noise ratios(SNR0,SNR10,and SNR15)using surgical,pleated cloth,and N95 masks.Using surgical,cloth,and N95 masks,speech recognition thresholds increased by 1.8 dB,4.4 dB,and 5.05 dB,respectively.Word recognition scores decreased by 32%without a mask,43.7%in a surgical mask,46.3%in a cloth mask,and 46.7%in N95 mask conditions,between SNR15 and SNR0.The speech recognition threshold was negatively affected with cloth and N95 masks.Surgical masks do not affect the word recognition scores at lower background noise levels.However,as the signal-to-noise ratio decreased,even the surgical,cloth,and N95 masks significantly impacted the word recognition score even in normal-hearing individuals.
基金M.Xiang and S.Dong wishes to thank the National Natural Science Foundation of China(21908086 and 51801083)Changzhou Sci&Tech Program(CJ20190035)+1 种基金Jiangsu Higher Education Institutions in China(19KJB610011)Natural Science Foundation of Jiangsu Province(BK20181044).
文摘Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-posable masks will be generated every day in the world,causing great pressure on the environment.Herein,con-ductive polymer composites are fabricated by simple melt blending of mask fragments(mask polypropylene,short for mPP)and multi-walled carbon nanotubes(MWNTs).MWNTs were used as modifiers for composites because of their high strength and high conductivity.The crystalline structure,mechanical,electrical and thermal enhancement effect of the composites were investigated.MWNTs with high thermal stability acted the role of promoting the crystallisation of mPP by expediting the crystalline nucleation,leading to the improvement of amount for crystalline nucleus.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.With 2.0 wt% MWNTs loading,the tensile strength and electrical conductivity of the composites were increased by 809% and 7 orders of magnitude.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.Thus,more conducting paths were constructed to transport carriers.The findings may open a way for high value utilization of the disposable masks.
文摘Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a pandemic.The use of face masks and respirators is an important public health measure to reduce or prevent transmission of SARS-CoV-2.Here we discuss the hypothetical mechanisms by which exercise with face masks or respirators can induce detrimental effects on the cardiovascular system,potentially explaining adverse events such as cardiac arrhythmias and spontaneous pneumothorax.Although sudden death associated with the wearing of a face mask during running is a rare event,the risk is higher especially in those with existing cardiac comorbidities.In such cases,a mask designed specifi cally for runners with no or few side effects of oxygen defi ciency should be considered instead.
文摘Introduction: Two spread methods of Covid-19, namely airborne and respiratory droplets, can be prevented by proper use of face masks. However, it has been reported an inadequate knowledge attitude and practice of proper use of face masks among school students. Therefore, the knowledge, attitude, and practice of school students should be improved. Different approaches are used to improve knowledge, attitude, and practice. However, e-posters are rare, and the effect of e-posters on improving the knowledge, attitude, and practice of school students on the proper use of face masks has not been studied. Objectives: The objective of this study was to determine the effect of an e-educational poster on knowledge, attitude, and practice of the proper use of face masks among school students. Method: This study was conducted as a pre-test and post-test design. The sample was 364 grade 11 students of the Gampaha educational division, Sri Lanka. Data were collected using self-administered questionnaires distributed pre and post to the interventional e-education poster. Data analyses were conducted by using SPSS Software. Results: Results show no significant demographic difference (p = 0.446) between the pre and post-test groups. A significant increase was observed between the pre and post-test mean scores of knowledge (p ≤ 0.05), attitude (p ≤ 0.05), and practice (p ≤ 0.05) on the proper use of face masks. In pre-group knowledge (p = 0.155), attitude (p = 0.258) and practice (p = 0.211) shows no significant difference due to gender. Also post group knowledge (p = 0.079), attitude (p = 0.835) and practice (p = 0.435) shows no significant difference due to gender. Conclusions: The results suggest that e-educational posters may be useful to improve the knowledge, attitude, and practice on the proper use of face masks among school students. The improvement of knowledge, attitude, and practice on the proper use of face masks by e-educational posters among school students occurs irrespective of gender.
基金supported by National University of Sciences and Technology(NUST),Sector H-12,Islam-abad 44000,Pakistan.
文摘This research introduces an innovative approach to address the management of waste baby diapers(BDs)and face masks(FMs)in order to mitigate environmental risks associated with the indiscriminate disposal of BD and FM waste.The study focuses on using BDs and FMs in road pavement hot mix asphalt(HMA)to enhance bitumen and aggregate per-formance,respectively.The approach involves the direct incorporation of 4%shredded BD during the bitumen melting process,while varying percentages of shredded FM(0%,0.5%,1%,and 1.5%relative to aggregate weight)are utilized as aggregate coating through a melt-ing process.The inclusion of BD enhances the resistance of modified bitumen(MB)to per-manent deformations under high temperatures compared to conventional bitumen.Simultaneously,the treatment of FM significantly improves the physical and mechanical attributes of the aggregates.The combination of 4%BD and 1.5%FM results in improved densification,fostering robust bonding between aggregates and asphalt paste.This enhancement leads to a 39%increase in stability,an 18%increase in indirect tensile strength(ITS),and a 27%reduction in permanent deformations.Notably,there is a remark-able 53%increase in resistance to rut depth and a 33%increase in resilient modulus.Ultimately,the implementation of 4%BD as a bitumen enhancer and 1.5%FM as an aggre-gate modifier demonstrates the potential to achieve waste reductions of 36%and 61%,respectively.This approach extends beyond pavement enhancement,contributing to the broader societal mitigation of adverse effects associated with BD and FM waste.
基金M.T.acknowledges scholarship support from the Australian Government Research Training Program(RTP)Z.X.acknowledges the support from the China Scholarship Council(CSC)The Shanghai“Belt&Road”International Joint Laboratory Program(18520750400)administrated by the Science and Technology Commission of Shanghai Municipality is also acknowledged for its support.
文摘Textiles have proved to be very important materials to human beings since the time immemorial.And,fibers are the basic building units of these materials.In this perspective we substantiate the uniqueness and capability of nanofibers as active layers in face masks,to protect people against the novel coronavirus disease(COVID-19).This time-sensitive letter introduces the mechanisms based on which their active filters function,the uniqueness of electrospun nanofibers in face masks and do-it-yourself(DIY)steps to realize a fully functional face mask at home.
基金supported by the National Institutes of Health:K23ES030399-04(PPM),K08HL143183(LMY),U24ES026946(PD)the COVID Corps Program at Massachusetts General Hospital.
文摘Importance:Despite the high burden of respiratory infections among children,the production of exhaled particles during common activities and the efficacy of face masks in children have not been sufficiently studied.Objective:To determine the effect of type of activity and mask usage on exhaled particle production in children.Methods:Healthy children were asked to perform activities that ranged in intensity(breathing quietly,speaking,singing,coughing,and sneezing)while wearing no mask,a cloth mask,or a surgical mask.The concentration and size of exhaled particles were assessed during each activity.Results:Twenty-three children were enrolled in the study.Average exhaled particle concentration increased by intensity of activity,with the lowest particle concentration during tidal breathing(1.285 particles/cm^(3)[95%CI 0.943,1.627])and highest particle concentration during sneezing(5.183 particles/cm^(3)[95%CI 1.911,8.455]).High-intensity activities were associated with an increase primarily in the respirable size(≤5μm)particle fraction.Surgical and cloth masks were associated with lower average particle concentration compared to no mask(P=0.026 for sneezing).Surgical masks outperformed cloth masks across all activities,especially within the respirable size fraction.In a multivariable linear regression model,we observed significant effect modification of activity by age and by mask type.Interpretation:Similar to adults,children produce exhaled particles that vary in size and concentration across a range of activities.Production of respirable size fraction particles(≤5μm),the dominant mode of transmission of many respiratory viruses,increases significantly with coughing and sneezing and is most effectively reduced by wearing surgical face masks.
文摘Despite cities being recognized as being potential sources of microplastic pollution to the wider environment, most surveys of COVID-19 plastic-based litter have been undertaken through linear transects of marine beaches. For the far fewer number of studies conducted on inland and urban locations, the site-specific focus has primarily been surveys along the length of streets. The present study is the first to specifically assess the standing stock (i.e., moment-in-time) of littered face masks for the entire surface area of urban parking lots. The density of face masks in 50 parking lots in a Canadian coastal town (0.00054 m2 ± 0.00051 m2) was found to be significantly greater than the background level of littering of town streets. Face mask density was significantly related to visitation “usage” of parking lots as gauged by the areal size of the lots and of their onsite buildings, as well as the number of vehicles present. Neither parking lot typology nor estimates of inferred export (various measures of wind exposure) and entrapment (various metrics of obstruction) of face masks had a significant influence on the extent of whole-lot littering. In consequence, modelling of the potential input of mask-derived microplastics to the marine environment from coastal communities can use the areal density of face masks found here in association with the total surface area of lots for individual municipalities as determined through GIS analysis.
基金Funding Open Access funding provided by Lib4RI-Library for the Research Institutes within the ETH Domain:Eawag,Empa,PSI&WSL.
文摘Reusable face masks are an important alternative for minimizing costs of disposable and surgical face masks during pan-demics.Often complementary to washing,a prolonged lifetime of face masks relies on the incorporation of self-cleaning materials.The development of self-cleaning face mask materials requires the presence of a durable catalyst to deactivate contaminants and microbes after long-term use without reducing filtration efficiency.Herein,we generate self-cleaning fibers by functionalizing silicone-based(polydimethylsiloxane,PDMS)fibrous membranes with a photocatalyst.Coaxial electro-spinning is performed to fabricate fibers with a non-crosslinked silicone core within a supporting shell scaffold,followed by thermal crosslinking and removal of the water-soluble shell.Photocatalytic zinc oxide nanoparticles(ZnO NPs)are immo-bilized on the PDMS fibers by colloid-electrospinning or post-functionalization procedures.The fibers functionalized with ZnO NPs can degrade a photo-sensitive dye and display antibacterial properties against Gram-positive and Gram-negative bacteria(Escherichia coli and Staphylococcus aureus)due to the generation of reactive oxygen species upon irradiation with UV light.Furthermore,a single layer of functionalized fibrous membrane shows an air permeability in the range of 80-180 L/m^(2)s and 65%filtration efficiency against fine particulate matter with a diameter less than 1.0µm(PM_(1.0)).
基金supported by Key Scientific Research Projects of Colleges and Universities in Henan Province(No.23ZX016)University Innovation Research and Training Program(No.202110467004)the Distinguished Professor Program of Institutions of Higher Learning in Henan Province,National Key R&D Program of China(No.2019YFE0101200).
文摘Face masks play a pivotal role in preventing infection transmission.However,the capture of infection-sourced particles in face masks poses challenges related to reuse,necessitating proper disposal.We developed a self-sterilizable polypropylene-based membrane for face masks to address challenges associated with infection transmission prevention.The membrane,created using 3D printing,underwent functionalization with zinc oxide(ZnO)and polydopamine(PDA)-TEMPO to achieve broad-spectrum light absorption and facilitate self-sterilization through photocatalytic and photothermal effects upon light exposure.The hydrophobic surface(water contact angle:133±2°)minimized moisture accumulation,and the membrane exhibited robust mechanical properties,including shear strength(1.25±0.5kPa)and peel resistance strength(112.8±11.2kPa).The evaluation demonstrated stability in airflow(0-500cm^(3)/s)and excellent aerosol filtration efficiency(94.8±0.6%)for particles(PM 0.3,PM 2.5,PM 10),comparable to commercial masks.The membrane showed antibacterial efficacy over five uses in a simulated respiratory environment.Safety assessments confirmed biocompatibility through cytocompatibility and skin irritation assays.In conclusion,this membrane offers efficient filtration and photo-triggered sterilization,presenting a promising solution for next-generation face masks to address concerns related to reuse,disposal,and infection control.
文摘BACKGROUND There have been increased reports of dry eyes in the coronavirus disease 2019(COVID-19) pandemic era.AIM To analyze the differences in tear film properties from pre-and post-pandemic of the COVID-19 era.METHODS It was a retrospective comparative study.Patients were divided into three groups according to the data of multimodal ocular surface evaluation:(1) Group 1 if it was before Portugal lockdown decision(from August 2019 to March 2020);(2) Group 2 if it was after Portugal lockdown decision but without mask mandate(from April 2020 to October 2020);and(3) Group 3 if it was after Portugal lockdown but with mask mandate in health public highway(from November 2020 to April 2021).The following variables were analyzed:Lipid layer thickness,blink rate,Schirmer test,tear meniscus height,tear osmolarity,non-invasive break-up time,and loss area of the meibomian glands.RESULTS The study included 548 eyes of 274 patients,aged 18 years to 89 years,with a mean age of 66.15 ± 13.40 years at the time of multimodal ocular surface evaluation.Compared to group 1:(1) Mean lipid layer thickness was better in group 2(P = 0.001) and group 3(P < 0.001);(2) Schirmer test was similar in group 2(P = 0.576) and better in group 3(P = 0.002);(3) Tear osmolarity and loss area of the meibomian glands were worse in group 2(P = 0.031 and P < 0.001,respectively) and in group 3(both with P < 0.001);(4) Blink rate and tear meniscus height were similar in group 2(P = 0.821 and P = 0.370,respectively) and worse in group 3(P < 0.001 and P = 0.038,respectively);and(5) Non-invasive break-up time was worse in group 2(P = 0.030) and similar in group 3(P = 0.263).CONCLUSION Our study demonstrated that differences existed in tear film properties comparing data from the pre-and post-pandemic of the COVID-19 era.
文摘To reduce the impact of the novel SARS-CoV-2 virus, popularly known as the Coronavirus, many public health-related rules have been established around the world. Along with social distancing and lockdowns, most countries have mandatory wearing of face masks in public areas to limit the spread of the virus during the COVID-19 pandemic. However, because people are free to choose any method to make their masks, some are being fabricated from materials that can be toxic to the environment and human health. This paper discusses how inks and dyes used in face masks are causing major environmental degradation and health issues in industry workers and the general mask-wearing public. The goal fixed for the present study is to raise the alarm with authorities and decision-makers regarding the toxic nature of some colors (dyes and inks) and fabrics in the masks being worn every day.
基金National Natural Science Foundation of China(No.519705449)。
文摘To automatically detecting whether a person is wearing mask properly,we propose a face mask detection algorithm based on hue-saturation-value(HSV)+histogram of oriented gradient(HOG)features and support vector machines(SVM).Firstly,human face and five feature points are detected with RetinaFace face detection algorithm.The feature points are used to locate to mouth and nose region,and HSV+HOG features of this region are extracted and input to SVM for training to realize detection of wearing masks or not.Secondly,RetinaFace is used to locate to nasal tip area of face,and YCrCb elliptical skin tone model is used to detect the exposure of skin in the nasal tip area,and the optimal classification threshold can be found to determine whether the wear is properly according to experimental results.Experiments show that the accuracy of detecting whether mask is worn can reach 97.9%,and the accuracy of detecting whether mask is worn correctly can reach 87.55%,which verifies the feasibility of the algorithm.
文摘Effective strategies to control COVID-19 pandemic need high attention to mitigate negatively impacted communal health and global economy,with the brim-full horizon yet to unfold.In the absence of effective antiviral and limited medical resources,many measures are recommended by WHO to control the infection rate and avoid exhausting the limited medical resources.Wearing mask is among the non-pharmaceutical intervention measures that can be used as barrier to primary route of SARS-CoV2 droplets expelled by presymptomatic or asymptomatic individuals.Regardless of discourse on medical resources and diversities in masks,all countries are mandating coverings over nose and mouth in public areas.Towards contribution of public health,the aim of the paper is to devise a real-time technique that can efficiently detect non mask faces in public and thus enforce to wear mask.The proposed technique is ensemble of one stage and two stage detectors to achieve low inference time and high accuracy.We took ResNet50 as a baseline model and applied the concept of transfer learning to fuse high level semantic information in multiple feature maps.In addition,we also propose a bounding box transformation to improve localization performance during mask detection.The experiments are conducted with three popular baseline models namely ResNet50,AlexNet and MobileNet.We explored the possibility of these models to plug-in with the proposed model,so that highly accurate results can be achieved in less inference time.It is observed that the proposed technique can achieve high accuracy(98.2%)when implemented with ResNet50.Besides,the proposed model can generate 11.07%and 6.44%higher precision and recall respectively in mask detection when compared to RetinaFaceMask detector.
基金Supported by the Postgraduate Research and Practice Innovation Program of Nanjing University of Aeronautics and Astronautics(XCXJH20220318)。
文摘Since the outbreak of Coronavirus Disease 2019(COVID-19),people are recommended to wear facial masks to limit the spread of the virus.Under the circumstances,traditional face recognition technologies cannot achieve satisfactory results.In this paper,we propose a face recognition algorithm that combines the traditional features and deep features of masked faces.For traditional features,we extract Local Binary Pattern(LBP),Scale-Invariant Feature Transform(SIFT)and Histogram of Oriented Gradient(HOG)features from the periocular region,and use the Support Vector Machines(SVM)classifier to perform personal identification.We also propose an improved Convolutional Neural Network(CNN)model Angular Visual Geometry Group Network(A-VGG)to learn deep features.Then we use the decision-level fusion to combine the four features.Comprehensive experiments were carried out on databases of real masked faces and simulated masked faces,including frontal and side faces taken at different angles.Images with motion blur were also tested to evaluate the robustness of the algorithm.Besides,the experiment of matching a masked face with the corresponding full face is accomplished.The experimental results show that the proposed algorithm has state-of-the-art performance in masked face recognition,and the periocular region has rich biological features and high discrimination.
文摘A face-mask object detection model incorporating hybrid dilation convolutional network termed ResNet Hybrid-dilation-convolution Face-mask-detector (RHF) is proposed in this paper. Furthermore, a lightweight face-mask dataset named Light Masked Face Dataset (LMFD) and a medium-sized face-mask dataset named Masked Face Dataset (MFD) with data augmentation methods applied is also constructed in this paper. The hybrid dilation convolutional network is able to expand the perception of the convolutional kernel without concern about the discontinuity of image information during the convolution process. For the given two datasets being constructed above, the trained models are significantly optimized in terms of detection performance, training time, and other related metrics. By using the MFD dataset of 55,905 images, the RHF model requires roughly 10 hours less training time compared to ResNet50 with better detection results with mAP of 93.45%.
基金(No.30600580) supported by the National Natural Science Foundation of China
文摘To shorten operation time and improve survival rate of rats with myocardial ischemia or myocardial infarction,we use a novel device comprised of a face mask and a head/neck retainer in this study.We report the basic design of the novel respiratory face mask(RFM) and evaluate its performance in a rat model of myocardial ischemia.The device is cost-effective and easier to handle than other devices,such as tracheal intubation.Compared with conventional tracheal intubation,we found that RFM shortens operation time significantly while keeping blood indices normal;the mean operation time for rats in the mask group was(32±3) min,and that for the intubation group was(45±7) min(P<0.05).Moreover,the size and shape of the RFM can be changed according to the body weight of rats.In conclusion,RFM is an appropriate device for the establishment of myocardial infarction or ischemia-reperfusion in rats.
基金This work was supported King Abdulaziz University under grant number IFPHI-033-611-2020.
文摘Today,due to the pandemic of COVID-19 the entire world is facing a serious health crisis.According to the World Health Organization(WHO),people in public places should wear a face mask to control the rapid transmission of COVID-19.The governmental bodies of different countries imposed that wearing a face mask is compulsory in public places.Therefore,it is very difficult to manually monitor people in overcrowded areas.This research focuses on providing a solution to enforce one of the important preventative measures of COVID-19 in public places,by presenting an automated system that automatically localizes masked and unmasked human faces within an image or video of an area which assist in this outbreak of COVID-19.This paper demonstrates a transfer learning approach with the Faster-RCNN model to detect faces that are masked or unmasked.The proposed framework is built by fine-tuning the state-of-the-art deep learning model,Faster-RCNN,and has been validated on a publicly available dataset named Face Mask Dataset(FMD)and achieving the highest average precision(AP)of 81%and highest average Recall(AR)of 84%.This shows the strong robustness and capabilities of the Faster-RCNN model to detect individuals with masked and un-masked faces.Moreover,this work applies to real-time and can be implemented in any public service area.
