1. Bacterial filtration efficiency of different masksTamara Košir, Katja Fric, Arijana Filipić, Polona Kogovšek, 2022, original scientific article Abstract: Face coverings, such as surgical masks and respirators, have an important role in preventing bacterial and viral transmission, especially during a global pandemic like COVID-19. Therefore, to secure their availability, new manufacturers and the use of novel materials must be encouraged. However, masks and their materials must first be properly tested for safety and efficiency, as required by the relevant standard, valid in a specific region. All standards prescribe determination of the bacterial filtration efficiency (BFE) of masks. In this study, we report the establishment of a test method for the BFE of face masks in accordance with European standard EN 14683:2019, by which we tested 52 samples, each composed of 3 to 5 subsamples, of surgical and cloth masks, respirators, filters, and mask materials. Forty-seven out of the 52 samples reached a BFE above 75 %. Of these, 16 samples had a BFE of 75 % to 95 %, 3 had a BFE of 95 % to 98 %, while 28 reached a filtration efficiency above 98 %. Our findings show that all tested samples provided some level of protection, most of which met the requirements for the national or European market.
Keywords: bacterial filtration efficiency, face coverings, masks, respirators, Andersen Cascade Impactor, EN 14683:2019
Published in DiRROS: 26.02.2025; Views: 889; Downloads: 714
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2. Antiviral respiratory masks with plasma-functionalized polypropylene textiles for optimal adsorption of antiviral substanceMark Zver, David Dobnik, Rok Zaplotnik, Miran Mozetič, Alenka Vesel, Arijana Filipić, Polona Kogovšek, Katja Fric, Alja Štern, Gregor Primc, 2024, original scientific article Abstract: During the COVID-19 pandemic, face masks were the first line of defense against the spread of infection. However, infectious viruses may remain on medical textiles, potentially serving as an additional source of infection. Due to their chemical inertness, many textiles cannot be enhanced with antiviral functionalities. Through treatment with low-pressure gaseous plasma, we have activated the surface of a medical-grade melt-blown, non-woven polypropylene textile so that it can absorb sodium dodecyl sulfate, an antimicrobial surfactant. Within two hours of contact time, the functionalized textile has been able to inactivate over 7 log10 PFU mL−1 of bacteriophage phi6, a surrogate of enveloped viruses such as SARS-CoV-2, and it has retained its antiviral properties for over 100 days. The functionalized material has not disrupted facial mask filtration efficiency or breathability. In addition, the in vitro biocompatibility testing in accordance with ISO 10993-5 for testing of medical devices has demonstrated that the selected formulation causes no adverse effects on the mouse fibroblast cell line L-929. With the treatment processes that have been completed within seconds, the method seems to have great potential to produce antiviral textiles against future outbreaks.
Keywords: surgical face masks, plasma functionalization, antiviral materials, virus filtration, breathability
Published in DiRROS: 07.10.2024; Views: 1280; Downloads: 900
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3. Assessment of different experimental setups to determineviral filtration efficiency of face masksArijana Filipić, Katja Fric, Maja Ravnikar, Polona Kogovšek, 2022, original scientific article Abstract: Abstract
As a result of the COVID-19 pandemic, many new materials and masks came onto the market. To determine their suitability, several standards specify which properties to test, including bacterial filtration efficiency (BFE), while none describe how to determine viral filtration efficiency (VFE), a property that is particularly important in times of pandemic. Therefore, we focused our research on evaluating the suitability and efficiency of different systems for determining VFE. Here, we evaluated the VFE of 6 mask types (e.g., a surgical mask, a respirator, material for mask production, and cloth masks) with different filtration efficiencies in four experimental setups and compared the results with BFE results. The study included 17 BFE and 22 VFE experiments with 73 and 81 mask samples tested, respectively. We have shown that the masks tested had high VFE (>99% for surgical masks and respirators, ≥98% for material, and 87–97% for cloth masks) and that all experimental setups provided highly reproducible and reliable VFE results (coefficient of variation < 6%). Therefore, the VFE tests described in this study can be integrated into existing standards for mask testing.
Keywords: face masks, virus filtration efficiency, bacterial filtration efficiency, EN 14683:2019+AC:2019, air sampler
Published in DiRROS: 17.07.2024; Views: 1342; Downloads: 748
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4. On stifling a transcendental breath : an Italian contribution to the philosophy of breathingMichael Lewis, 2023, original scientific article Abstract: The article contends that respiratory philosophy has, thus far, laid predominant stress upon the empirical form of breathing, as opposed to the transcendental; or at least it has used breath precisely as an occasion to elide or deconstruct this very opposition. Breath is then conceived primarily as material, bodily, and natural: as binding us together with the animals and with all living things.and yet this apparently benign ecological gesture is not without its deleterious side-effects: by contrasting this gesture with a more humanistic and transcendental conception of breath, inspired by Giorgio agamben’s work on the voice, we might begin to gain some clarity as to the jarring contrast that sprang up between the friendly valorisation of a shared con-spiration that has characterised this young philosophy up to now, and the intense, even violent, hostility to the breath of the other which the developed world exhibited from at least 2020 to 2022.We consider whether an overly empiricistic conception of breath and of the human might have played a part in this reversal of values. In conclusion, the article urges upon us a certain turn towards the transcendental form of the breath, and indeed to a certain human exceptionalism in this regard.
Keywords: Agamben, language, voice, breath, animal, human, humanism, transcendental, empirical, masks, stifling, identity, invisibility, virus, pandemic
Published in DiRROS: 14.05.2024; Views: 1231; Downloads: 736
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