Respirator Research Articles

Analysis of Vessel Segmentation Based on Various Enhancement Techniques for Improvement of Vessel Intensity Profile.

It is vital to develop an appropriate prediction model and link carefully to measurable events such as clinical parameters and patient outcomes to analyze the severity of the disease. Timely identifying retinal diseases is becoming more vital to prevent blindness among young and adults. Investigation of blood vessels delivers preliminary information on the existence and treatment of glaucoma, retinopathy, and so on. During the analysis of diabetic retinopathy, one of the essential steps is to extract the retinal blood vessel accurately. This study presents an improved Gabor filter through various enhancement approaches. The degraded images with the enhancement of certain features can simplify image interpretation both for a human observer and for machine recognition. Thus, in this work, few enhancement approaches such as Gamma corrected adaptively with distributed weight (GCADW), joint equalization of histogram (JEH), homomorphic filter, unsharp masking filter, adaptive unsharp masking filter, and particle swarm optimization (PSO) based unsharp masking filter are taken into consideration. In this paper, an effort has been made to improve the performance of the Gabor filter by combining it with different enhancement methods and to enhance the detection of blood vessels. The performance of all the suggested approaches is assessed on publicly available databases such as DRIVE and CHASE_DB1. The results of all the integrated enhanced techniques are analyzed, discussed, and compared. The best result is delivered by PSO unsharp masking filter combined with the Gabor filter with an accuracy of 0.9593 for the DRIVE database and 0.9685 for the CHASE_DB1 database. The results illustrate the robustness of the recommended model in automatic blood vessel segmentation that makes it possible to be a clinical support decision tool in diabetic retinopathy diagnosis.

Diagnosis of Vertical Root Fracture by Digital Radiography With and Without Unsharp Masking Filter: An In-vitro Study

Background and Objectives The digital radiography offers a variety of image processing techniques. Due to the importance of the accuracy of this method and its widespread applications, in this study we aim to investigate the diagnose of vertical root fracture (VRF) by conventional digital radiography with and without unsharp masking (UM) filter. Subjects and Methods Radiographs were taken from 24 extracted anterior teeth before and after VRF induction. The root canal was prepared with passive step-back technique, and then the teeth were divided into two halves buccolingually with a very thin disk. The two halves were re-attached to each other and mounted in a mixture of gypsum and sawdust. After processing by the UM filter, the radiographs were evaluated by two observers to detect the presence or absence of VRF. Results For the first observer, the sensitivity of both methods was the same, while the specificity of the UM filtering mode was higher. For the second observer, the sensitivity of the unfiltered mode was higher, while the specificity of the two methods was the same. Conclusion There is no significant difference between digital radiography with and without the UM filter in diagnosing VRF. Due to the high sensivity and specifity of the UM filtering method, the specialist can use this filter based on personal preferences.

Bi Histogram Equalization Based Image Enhancement with Bicubic Interpolation

In image processing, enhancement histogram equalization is the widely used technique for contrast enhancement. However, this technique tends to change the brightness of the image. Here, the contrast and resolution of image were enhanced using the proposed Bi Histogram Equalization Based Image Enhancement with Bicubic Interpolation (BHBI) technique. Bi Histogram for contrast enhancement and bicubic interpolation for resolution enhancement has taken. Bi Histogram Equalization separates the input image's histogram into two based on input mean before equalizing them independently. Bicubic Interpolation can generate bigger or high-resolution image from one or more low resolution or smaller images. The performance of the BHBI method can be compared for some typical image’s cameraman lens that are applied to some existing enhancement methods like Adaptive Gamma Correction with Weighting Distribution (AGCWD), Adaptive Scale Adjustment Design of Unsharp Masking Filters (ASAUMF), Averaging Histogram Equalization (AVGHEQ), and Median-Mean Based Sub-Image-Clipped Histogram Equalization (MMSICHE). The performance of these existing techniques can be evaluated subjectively in terms of person illustration observation and measurably using Discrete Entropy (DE), Image Quality Index (IQI), Normalized Correlation Coefficient (NCC), Contrast Improvement Index (CII), and Absolute Mean Brightness Error (AMBE). The results obtained from the BHBI technique shows better when compared with respect to the various existing techniques.

Piezoelectric Nanofiber Membrane for Reusable, Stable, and Highly Functional Face Mask Filter with Long‐Term Biodegradability

AbstractThe emergence of the SARS‐CoV‐2 pandemic and airborne particulate matter (PM) pollution has led to remarkably high demand for face masks. However, conventional respirators are intended for single use and made from nondegradable materials, causing serious concern for a plastic‐waste environmental crisis. Furthermore, these facemasks are weakened in humid conditions and difficult to decontaminate. Herein, a reusable, self‐sustaining, highly effective, and humidity‐resistant air filtration membrane with excellent particle‐removal efficiency is reported, based on highly controllable and stable piezoelectric electrospun poly (l‐lactic acid) (PLLA) nanofibers. The PLLA filter possesses a high filtration efficiency (>99% for PM 2.5 and >91% for PM 1.0) while providing a favorable pressure drop (≈91 Pa at normal breathing rate) for human breathing due to the piezoelectric charge naturally activated by respiration through the mask. The filter has a long, stable filtration performance and good humidity resistance, demonstrated by a minimal declination in the filtration performance of the nanofiber membrane after moisture exposure. The PLLA filter is reusable via common sterilization tools (i.e., an ultrasonic cleaning bath, autoclave, or microwave). Moreover, a prototype of a completely biodegradable PLLA nanofiber‐based facemask is fabricated and shown to decompose within 5 weeks in an accelerated degradation environment.

Low-Complexity Filter for Software-Defined Radio by Modulated Interpolated Coefficient Decimated Filter in a Hybrid Farrow.

Realising a low-complexity Farrow channelisation algorithm for multi-standard receivers in software-defined radio is a challenging task. A Farrow filter operates best at low frequencies while its performance degrades towards the Nyquist region. This makes wideband channelisation in software-defined radio a challenging task with high computational complexity. In this paper, a hybrid Farrow algorithm that combines a modulated Farrow filter with a frequency response interpolated coefficient decimated masking filter is proposed for the design of a novel filter with low computational complexity. A design example shows that the HFarrow filter bank achieved multiplier reduction of 50%, 70% and 64%, respectively, in comparison with non-uniform modulated discrete Fourier transform (NU MDFT FB), coefficient decimated filter bank (CD FB) and interpolated coefficient decimated (ICDM) filter algorithms. The HFarrow filter bank is able to provide the same number of sub-band channels as other algorithms such as non-uniform modulated discrete Fourier transform (NU MDFT FB), coefficient decimated filter bank (CD FB) and interpolated coefficient decimated (ICDM) filter algorithms, but with less computational complexity.

Astrocytoma Brain Tumor Automated Classification Procedure Based on Ki67 Expression

It is known to be a very challenging task for pathologists to perform astrocytoma biopsy analysis especially with the high demand for an accurate and precise analysis. An inaccurate diagnosis might affect the treatment decisions for the patient. Therefore, this study aims to develop an automated procedure for classification astrocytoma brain tumor. The procedure consists of four stages, namely image pre-processing, image segmentation, feature extraction and selection, and classification of Ki67 expression. Initially, the image’s quality was enhanced by using global stretching and unsharp masking filter. Then, the adaptive color thresholding technique was used to segment the Ki67 expression. The process was followed by extracting the features related to the positive and negative Ki67 cells. ReliefF feature selection algorithm was used to select the best features in defining the positive and negative cells. In the classification stage, two classifiers, namely Support Vector Machine (SVM) and Multilayer Perceptron (MLP) were used to differentiate between the positive and negative cells. From 81 samples images, both classifiers yielded promising results, with an accuracy of 98.5% for SVM and 99.6% for MLP respectively.

Respiratory virus deterrence induced by modified mask filter.

Airborne transmission of infectious respiratory pathogens is a significant health hazard for the general public as well as healthcare professionals. Face masks have been frequently utilized as safety measures to limit the transmission of these infectious aerosolized particles. However, the efficacy of face masks in reducing respiratory virus infectivity and pathogenicity is unknown. Improving the effectiveness of masks in blocking viruses is urgently needed. In this study, surgical mask filters were modified by coating the filters with 1, 3, or 5 M of sodium dihydrogen phosphate, and subsequently exposed to the aerosolized respiratory influenza viruses (A/H3N2, A/H5N1) generated by a nebulizer set. Mask filter modification significantly reduced the size and counts of filter pores, which enabled entrapment of 40–60% of aerosolized viruses (captured viruses) with more than 90% of the captured viruses losing their infectivity. Upon contact with the coated mask filters, both the captured viruses and the viruses that managed to bypass the filter pore (passed viruses) were found to be inactivated. Passed viruses demonstrated significantly reduced pathogenicity in mice as indicated by significantly reduced lung virus titers, bodyweight loss, and prolonged survival compared to bare control. These findings highlight the potential of modified mask filters for reducing viral activity and pathogenicity, which contributes to improving facial mask efficacy as well as limiting airborne pathogen transmission.

Mask filtering to the Wigner-Ville distribution

The Wigner-Ville distribution (WVD) is a high-resolution time-frequency spectral analysis method for nonstationary signals; yet, it suffers from cross-term interference among signal components. We proposed applying a masking filter directly to the WVD time-frequency spectrum to suppress the cross-term interference. Conventional methods for suppressing interference include the smoothed pseudo-WVD (SP-WVD) method, which incorporates smooth filtering in the time and frequency directions. We exploited the SP-WVD spectrum as a reference to design the masking filter; thus, the mask-filtered WVD (MF-WVD) procedure is data-adaptive. The MF-WVD method preserves the high-resolution energy concentration in the spectrum portrayed by the standard WVD, while suppressing the cross-term interference cleanly as in the SP-WVD method. Applying the MF-WVD method to field 3D seismic data generates high-resolution spectral cubes for various frequencies, and these spectral cubes may be used intuitively for detecting reservoir-related characteristics.

АНАЛИЗ УПРАВЛЯЕМОСТИ НЕКОТОРЫХ ЦИФРОВЫХ ФИЛЬТРОВ С КОНЕЧНОЙ ИМПУЛЬСНОЙ ХАРАКТЕРИСТИКОЙ

This overview article covers finite impulse response filters and filter banks. The use of these filtersfor hearing aids is considered. Ways to compensate for hearing loss and ways to increase loudnessusing broadband amplification are considered. A schematic diagram of a method for digitalsignal processing using a bank of filters, as well as a technique for synthesizing interpolation filterswith low computational complexity, is presented. Also, the application of the MATLAB system for thesynthesis of narrow-band non-recursive FIR filters, their design procedure, methodology and examplesare considered. Finite Impulse Response (FIR) filters and filter banks have specific propertiesthat guarantee stability. Therefore, they are popular in many applications such as communicationsystems, audio signal processing, biomedical instruments, and so on. Unfortunately, due to the longerwavelength, the cost of implementing an FIR filter is usually not higher than an infinite impulse response(IIR) filter that meets the same requirements. It is well known that the length of an FIR filter isinversely proportional to its transition bandwidth. Therefore, the disadvantage becomes acute when agiven filter has a narrow transition band. The main goal is to consider computationally efficientmethods for designing FIR filters and filter banks. The masking method (FRM) results in significantsavings in the number of multipliers. Next, a 16-band, low group delay, non-equal-spacing digitalFIR filter bank is considered. Overall latency is significantly reduced as a result of a new filter structurethat reduces the interpolation factor for prototype filters. Masking filter may be an interpolatedfinite impulse response (IFIR) filter that helps reduce complexity.

Low complexity reconfigurable modified FRM architecture with full spectral utilization for efficient channelizers

This paper proposes a design of low complexity, reconfigurable, and narrow transition band (NTB) filter bank (FB). In our proposed Modified Frequency Response Masking (ModFRM) architecture, the modal filter and complementary filter in the conventional FRM approach are replaced by a power complementary and linear phase FB. Additionally, a new masking strategy is proposed by which an M-channel FB can be designed by alternately masking even channels and odd channels. By using this masking strategy, it is only necessary to modulate the masking filters over the multiple spectra replicas appearing in [0,2π] to generate uniform ModFRM FB. Also, the reconfigurability of filter banks can be achieved by adjusting the interpolation values appropriately, to obtain more masking responses. The results indicate that the proposed method requires substantially fewer multipliers in comparison to the reconfigurable FB existing in the literature. Finally, nonuniform FB is generated from the uniform FB by combining nearby channels and are used for the extraction of different communication standards in the software defined radio (SDR) channelizer. When more channels are to be extracted, the proposed scheme can achieve a reduced hardware complexity in comparison to other filter bank based SDR channelizers.

Cost-Effective Face Mask Filter Based on Hybrid Composite Nanofibrous Layers with High Filtration Efficiency.

One of the main protective measures against COVID-19's spread is the use of face masks. It is therefore of the utmost importance for face masks to be high functioning in terms of their filtration ability and comfort. Notwithstanding the prevalence of the commercial polypropylene face masks, its effectiveness is under contention, leaving vast room for improvement. During the pandemic, the use of at least one mask per day for each individual results in a massive number of masks that need to be safely disposed of. Fabricating biodegradable filters of high efficiency not only can protect individuals and save the environment but also can be sewed on reusable/washable cloth masks to reduce expenses. Wearing surgical masks for long periods of time, especially in hot regions, causes discomfort by irritating sensitive facial skin and warmed inhaled air. Herein, we demonstrate the fabrication of novel electrospun composites layers as face mask filters for protection against pathogens and tiny particulates. The combinatorial filter layers are made by integrating TiO2 nanotubes as fillers into chitosan/poly(vinyl alcohol) polymeric electrospun nanofibers as the outer layer. The other two filler-free layers, chitosan/poly(vinyl alcohol) and silk/poly(vinyl alcohol) as the middle and inner composite layers, respectively, were used for controlled protection, contamination prevention, and comfort for prolonged usage. The ASTM standards evaluation tests were adopted to evaluate the efficacy of the assembled filter, revealing high filtration efficiency compared to that of commercial surgical masks. The TiO2/Cs/PVA outer layer significantly reduced Staphylococcus aureus bacteria by 44.8% compared to the control, revealing the dual effect of TiO2 and chitosan toward the infectious bacterial colonies. Additionally, molecular dynamics calculations were used to assess the mechanical properties of the filter layers.

Use of Allophane as Face Mask Filter for Coronaviruses (Sars-Cov-2)

The traditional mouth cover masks can be made by hand. But with the arrival of the Coronavirus pandemic, these masks have special requirements and we will have to use these until at least 2022. Therefore, the current technological problem is what must be the appropriate filter nanomaterial (cuprum, zinc, zeolite or Allophane) to absorb and/or destroy coronaviruses. In addition, the preparation of this specific purpose mask must be certified, easy to manufacture and inexpensive. Taking these requirements into account, there is a suitable nanomaterial called Allophane, which has active centers of silicon and aluminum (Si / Al), which rapidly absorb micro droplets and nanodrops of water [3, 5] nm. Coronaviruses are microscopically embedded in water droplets. To build an absorbent filter that also destroys coronaviruses, we can use some organic surfactant in optimal proportions and that works cooperatively with Allophane. The physicochemical properties of natural Allophane were studied. For the characterization, analytical techniques were used: Fourier transform infrared spectroscopy (FTIR), BET surface area, X-ray diffraction (XRD), Chemisorption and Atomic Force Microscopy (AFM). In addition, the Navier Stokes 3D equations were studied, which allow us studying molecular dynamics contributing substantively to chemical kinetics describing the process of absorption of water and decomposition of water + coronavirus.

Statistical Analysis of Image with Various Noises and Filters

Research displays an extensive investigation for different factual statistical estimates and their practical implementation in picture handling with various noises and filter channel procedures. Noise is very challenging to take out it from the digital images. The purpose of image filtering is to eliminate the noise from the image in such a way that the new image is detectible. We have clarified different calculations and systems for channel the pictures and which calculation is the best for sifting the picture. Signal and maximum Peak proportion parameters are utilized for execution for factual estimating, Wiener channel performs preferred in evacuating clamor over different channels. Wiener channel functions admirably for a wide range of clamors. The exhibition of Gaussian channel is superior to anything Mean channel, Mask Filter and Wiener channel as per MSE results. In picture setting up, a Gaussian fog generally called Gaussian smoothing is the result of darkening an image by a Gaussian limit. We reason that Gaussian separating approach is the best method that can be effectively actualized with the assistance of the MSE of picture. The Gaussian channel is certifiably superior to different calculations at expelling clamor. The outcomes have been looked at for channels utilizing SNR, PSNR and Mean Square Error esteem.

Design of Reconfigurable FRM Channelizer using Resource Shared Non-maximally Decimated Masking Filters

This paper presents a reconfigurable frequency response masking (FRM) wideband channelizer architecture which is characterized by low computational and hardware complexity. The proposed hardware efficient architecture is realized by incorporating resource shared non-maximally decimated filter bank in the implementation of the FRM wideband channelizer structure. The coefficients of the proposed architecture are optimized and made multiplier-free using Pareto based meta-heuristic algorithm in the canonic signed digit (CSD) space for reducing the total power consumption of the architecture. The architecture is finally designed and synthesized using Xilinx Vivado and Cadence RTL Encounter compiler for the area and power analysis and is compared with existing channnelizer architectures. The comparison highlights the advantages of the proposed architecture in terms of hardware complexity, power and workload in realizing sharp wideband channel filters.

Automatic segmentation and classification of lung tumour using advance sequential minimal optimisation techniques

A chronic disorder caused by abnormal growth of the lung cells in the pulmonary tumour. This study suggests a modern automated approach to improve efficiency and decrease the difficulty of lung tumour diagnosis. The proposed algorithm for lung tumour sensing consists of four phases: pre-processing, segmentation, extraction, and characteristics classification. The first stage is the image acquisition here input lung image is read and then resized. The second stage is the image pre-processing here Perona–Malik diffusion with unsharp masking filter is proposed for enhancement purposes. The third stage is the segmentation here the improved histogram–based fast 2D Otsu's thresholding is proposed for lung tumour segmentation purposes. Finally, linear discriminant analysis classifier, support vector machine (SVM) classifier, SVM–sequence minimal optimisation classifier, Naive Bayes classifier, SVM–advance sequence minimal optimisation (SVM–ASMO) classification [proposed] included in the various classifier groups adopted in this report. Overall performance accuracy of 0.962 is obtained using the proposed SVM–ASMO method that helps to diagnose the cancer cells using the feature extraction process, which is done automatically. The specificity, precision, recall, and F1 score of the proposed method is found to be a value of 0.984, 0.974, 0.98, and 0.984,respectively.

Criação de respiradores mecânicos em tempos de COVID-19 no Brasil: uma revisão narrativa

A pandemia da COVID-19 tem se apresentado como desafio para o Brasil, ao registrar mais de 134 mil óbitos em sete meses e mais de 4,4 milhões de infectados. Pesquisadores de várias instituições de ensino e empresas se empenharam para desenvolver respiradores mecânicos alternativos devido ao seu alto custo e demanda. Este estudo objetiva analisar iniciativas da comunidade científica no desenvolvimento de respiradores mecânicos no Brasil. É uma revisão narrativa subdivida em duas etapas: 1) identificação dos modelos de respiradores mecânicos desenvolvidos durante a pandemia e 2) realização de um fórum de discussão com profissionais de diversas áreas acadêmicas do Nordeste, onde foram destacados temas sobre o impacto da COVID-19 no Brasil, necessidade e diagnóstico para utilização de respiradores mecânicos e critérios de autenticidade científica. Acredita-se que os projetos de respiradores mecânicos são relevantes não apenas para o momento vigente, mas também para o pós-pandemia.

Automatic multi-class intertrochanteric femur fracture detection from CT images based on AO/OTA classification using faster R-CNN-BO method.

Intertrochanteric (IT) femur fractures are the most common fractures in elderly people, and they lead to significant morbidity, mortality, and reduced quality of life. The different types of fractures require a careful definition to ensure accurate surgical planning and reduce the operation time, healing time, and number of surgical failures. In this study, a deep learning-based automatic multi-class IT fracture detection model was developed using computed tomography (CT) images and based on the AO/OTA classification method. The original CT image was resized and rearranged according to the fracture location and an unsharp masking filter was applied. A multi-class classification of nine different types of IT fractures and no fracture was performed using the faster regional-convolutional neural network (R-CNN). Bayesian optimization was also implemented to determine the optimal hyperparameter values for the faster R-CNN algorithm. In our proposed model, IT fractures classified into two classes showed an average accuracy of 0.97 ± 0.02, which was 0.90 ± 0.02 when classified into ten classes. Additionally, the detected region of interest from our proposed model showed minimum root mean square error and intersection over union values of 16.34 ± 47.01 pixels and 0.87 ± 0.12, respectively. In the future, our proposed automatic multi-class IT femur fracture detection model could allow clinicians to identify the fracture region and diagnose different types of femur fractures faster and more accurately. This will increase the probability of correct surgical treatment and minimize postoperative complications.

Mascherine chirurgiche vs respiratori: proprietà e indicazioni

OBJECTIVES Many dental procedures are responsible for the creation of an aerosol capable of transporting bacteria, virus and infected particles into the surrounding environment The use of handpieces and/or ultrasonic devices creates an aerosol of particles with different diameters that present a severe risk for nasal and tracheobronchial cavities This deposition of particles occurs on different levels, depending on their dimensions: particles with larger diameter stops in the nasal cavities, while the smaller ones end up in lung alveoli These aerosol particles have their own movement, partly caused by the displacement of air masses and by the Brownian motions produced by the impact of the gaseous particles against the aerosol ones Since these droplets are able to persist continuously for long time in environments where patients and procedures follow and overlap over the course of a day, it is essential for dental clinicians to adopt personal protective equipment, among which the choice of an appropriate mask The aim of this literature overview is to clarify the terminology, the criteria for the construction of a mask, to illustrate the differences between masks and oral respirators and to provide practical support for personal and patient protection, choosing the device suitable for each clinical situation MATERIALS AND METHODS This work is a literature review of the national and international literature on this topic: the scientific data published since mask introduction to date have been collected, and the characteristics, differences and clinical indications for the use of masks and oral respirators in dentistry have been analyzed CONCLUSIONS The surgical mask and the respirator are individual devices that meet specific standards and whose use must always be combined with other PPE such as screens and protective glasses, headgear, gloves, disposable gowns and of course a careful personal hygiene The importance of examining the technical data sheet referring to the devices used, in order to check the necessary strict adherence to the reference protocols, must always be underlined To date there are still conflicting opinions on what the correct indication may be on the type of respirator to be used to prevent contagion from Sars-CoV-2 Respirators without a filter-valve seem to be the devices capable of providing the highest protection to the operator and patient but, precisely because of their high filtering capacity, they make breathing difficult if worn for a long time continuously To improve respiratory capacity and therefore to seek greater comfort, the use of a high filter respirator with exhalation valve, in association with a surgical mask to be applied on it, is conceivable However, surgical masks remain valid devices for all those services that do not involve the creation of highly infected aerosols and the consequent dispersion of potentially contaminated particles in the air Finally, to limit the spread of Covid-19 as much as possible, anyone should wear a surgical mask, so that an infected person cannot contaminate the surrounding environment and people nearby CLINICAL SIGNIFICANCE This work highlights the characteristics of surgical masks and oral respirators, providing practical indications on the most suitable devices for protection from Covid-19 infection

Máscaras de proteção e os reveses da busca por itens de proteção individual em tempos de COVID-19 - uma revisão integrativa

Introdução: A COVID-19 – doença viral que se tornou emergência em saúde pública – possui como agente etiológico o SARS-CoV-2 e é transmitida por gotículas ou aerossóis advindos de indivíduos infectados. Em virtude da alta taxa de contaminação pelo vírus e das limitações quanto ao tratamento da doença, instituições públicas e privadas passaram a recomendar o uso de máscaras como uma forma de proteção respiratória em massa. Objetivo: delinear um panorama mais amplo sobre aspectos relativos à produção, acesso, uso e manuseio das máscaras caseiras e especificar o tempo, a forma de uso e as recomendações de cada tipo de máscara profissional. Metodologia: Para tanto, foi feita uma revisão integrativa da literatura nas bases de dados PubMed, LILACS, Web of Science, Scopus, Science Direct, The BMJ e LEXML, utilizando várias combinações dos descritores principais “masks”, “personal protective equipment” e “virus diseases”. Resultados: Entre os principais achados destaca-se a maior eficácia de proteção dos respiradores N95 e FFP2, em detrimento das máscaras cirúrgicas. Ademais, evidências mostram métodos de desinfecção eficientes para os respiradores, como o uso de peróxido de hidrogênio e radiação UV, e a alternativa do uso de máscaras artesanais, de baixo custo e fácil fabricação, para a população em geral, frente a escassez de equipamentos de proteção individual. Conclusão: Em meio a uma pandemia com agente etiológico viral, é imprescindível o estudo de dispositivos de proteção respiratória, diferenciando-os de acordo com suas particularidades, com o objetivo de se conhecer o mais indicado para proteção individual e coletiva.

Eagle Filters' respirators now Covid-19 certified

Eagle Filters Oy respirator products have passed the tests required for Covid-19 certification, and the Finnish company says it can now start delivering to customers.