This study aims to deepen knowledge of the biodegradation of plastics, focusing on polypropylene (PP) fabric from surgical masks and polystyrene (PS) by larvae of Zophobas atratus as well as of specialized bacterial consortia from their gut, which were obtained in different enrichment conditions (aerobic, anaerobic, presence or absence of combined nitrogen). Plastics ingested by larvae obtained in Spain did not show any signs of oxidation but only limited depolymerization, preferably from the lowest molecular weight chains. Gut microbiota composition changed as an effect of plastic feeding. Such differences were more evident in bacterial enrichment cultures, where the polymer type influenced the composition more than by culture conditions, with an increase in the presence of nitrogen-fixers in anaerobic conditions. PS and PP degradation by different enrichment cultures was confirmed under aerobic and anaerobic conditions by respirometry tests, with anaerobic conditions favouring a more active plastic degradation. In addition, exposure to selected bacterial consortia in aerobiosis induced limited surface oxidation of PS. This possibly indicates that different biochemical routes are being utilized in the anaerobic gut and in aerobic conditions to degrade the polymer.

The efficacy of face masking for the public is not convincing to prevent the transmission of respiratory tract viruses such as SARS-CoV-2 when the criteria of evidence-based medicine are applied. This finding is mainly explained by the results from randomized-controlled trials (RCTs) when a high prevalence of the infection and a high compliance in mask wearing was assured. Throughout these studies no significant protective effect was observed. Observational studies with surgical masks describe a significant protective effect, but are prone to confounders such as physical distance. Respirators do not provide an additional health benefit compared to surgical or medical masks (RCTs). Community masks can even increase the risk of infection (RCTs). Based on the categories of evidence-based medicine, the efficacy results can best be categorized as conflicting evidence. Many relevant adverse events are described when masks are worn for hours such as dyspnea (12.2-52.8%), headache (3.9-73.4%), pruritus (0.0-60.0%), and skin reactions (0.0-85.0%). Their frequency is often higher with respirators. In future pandemics, masks should only be recommended or mandated for settings in which a clinically relevant health benefit can be expected, defined as the prevention of severe, critical or fatal disease, that clearly outweighs the expectable associated adverse reactions.

Face masks are crucial parts of personal protective equipment (PPE) to reduce the risk of respiratory infections. The COVID-19 outbreak has increased healthcare workers’ use of face masks. This study aimed to evaluate changes in cerebrovascular response among healthcare workers using surgical and N95 respirator masks. 

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90 healthcare workers: 30 wearing surgical masks, 30 wearing N95 respirators, and 30 without masks were included. After two-hour of face mask use, the baseline mean flow velocity (MFV) and the mean breath-holding index (BHI) of the bilateral middle cerebral arteries (MCAs) were evaluated with transcranial Doppler ultrasound. The presence of de-novo headache was recorded. BHI values ​​below 0.69 were evaluated as a sign of impaired cerebrovascular reactivity (CVR). 

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The rate of de-novo headache was significantly higher in the N95 respirator mask group (p = 0.004). Compared to the control and surgical mask groups, the N95 respirator mask group had significantly lower values of the baseline MFV of the right MCA (p = 0.003 and p = 0.021, respectively) and mean BHI (p = 0.003 and p = 0.012, respectively). Still, only one N95 respirator mask user had a mean BHI value below 0.69.

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Surgical masks did not signi­fi­cantly affect cerebral hemodynamics. Although N95 respirator mask use significantly decreased BHI values, the CVR is still within normal limits, and the development of de-novo headache is not directly associated with low CVR. 

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Az arcmaszkok a légzőszervi fertőzések kockázatának csökkentésére alkalmazott személyes védőfelszerelés (PPE) elengedhetetlen részét képezik. A Covid-19-járvány hatására fokozódott az egészségügyi dolgozók arcmaszkhasználata. Tanulmányunk célja az volt, hogy értékeljük a sebészeti és az N95 respirátor maszkot viselő egészségügyi dolgozók körében bekövetkező cerebrovascularis válasz változásait.

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Összesen 90 egészségügyi dolgozót vontunk be a tanulmányba: 30-an sebészeti maszkot és 30-an N95 respirátor maszkot viseltek, míg 30-an nem viseltek maszkot. Kétórás maszkhasználat után trans­cranialis Doppler-ultrahanggal értékeltük a bilaterális középagyi artériák (MCA) átlagos áramlási sebességét (MFV) és átlagos légzéstartási indexét (BHI). Rögzítettük a de novo fejfájás jelenlétét. A 0,69 alatti BHI-értékeket a károsodott cerebrovascularis reaktivitás (CVR) jelének tekintettük. 

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A de novo fejfájás előfor­dulási aránya szignifikánsan magasabb volt az N95 légzőmaszkot viselő csoportban (p = 0,004). Az N95 légzőmaszkot viselő csoportban a jobb MCA átlagos áramlási sebességének kiindulási értéke (p = 0,003, illetve p = 0,021) és az átlagos BHI-értékek (p = 0,003 és p = 0,012) szignifikánsan alacsonyabbak voltak a kontroll- és a sebészeti maszkot viselő csoportok értékeihez képest. Mindazonáltal, csak egy N95 légzőmaszkot viselő személy esetében volt az átlagos BHI-érték 0,69 alatt.

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A sebészeti maszk hasz­nálata nem befolyásolta szignifikánsan a ce­rebralis hemodinamikát. Habár az N95 lég­zőmaszk használata szignifikánsan csökkentette a BHI-értékeket, a CVR-értékek továbbra is a normáltartományban voltak, és a de novo fejfájás kialakulása nem volt közvetlen összefüggésben az alacsony CVR-rel.

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Purpose: The study examined the benefits of transparent versus non-transparent surgical masks on the speech intelligibility in quiet of adult cochlear implant (CI) users, in conjunction with patient preferences and the acoustic effects of the different masks on the speech signal.
Methods: Speech tracking test (STT) scores and acoustical characteristics were measured in quiet for live speech in three different conditions, without mask, with a non-transparent surgical mask and with a transparent surgical mask. Patients were asked about their experience with the face masks. The study sample consists of 30 patients using a cochlear implant.
Results: We found a significant difference in speech perception among all conditions, with the speech tracking scores revealing a significant advantage when switching from the non-transparent surgical mask to the transparent one. The transparent surgical mask, although it does not transmit high frequencies effectively, seems to have minimal effect on speech comprehension in practice when lip movements are visible. This substantial benefit is further emphasized in the questionnaire, where 82% of the patients express a preference for the transparent surgical mask.
Conclusion: The study highlights significant benefits for patients in speech intelligibility in quiet with the use of medically safe transparent facemasks. Transitioning from standard surgical masks to transparent masks demonstrates highly significant effectiveness and patient satisfaction for patients with hearing loss. This research strongly advocates for the implementation of transparent masks in broader hospital and perioperative settings.
In scenarios mandating mask usage, it’s advisable for caregivers to opt for transparent surgical masks. Specifically within perioperative settings, where patients might not be able to utilise their hearing aids or cochlear implants, it becomes imperative for all caregivers to consistently wear transparent surgical masks to prevent communication impediments.When utilising a transparent surgical mask, caregivers must recognise that sound may be altered and maintaining a clear view of the face and lips is crucial for effective communication.

UNASSIGNED: To evaluate possible temporomandibular disorders (TMD) symptoms that may occur due to mask use in dentists during the coronavirus disease-2019 pandemic period and identify potentially effective factors.
UNASSIGNED: An online questionnaire consisting of three parts was sent to dentists and clinical dental students. The first part included questions regarding sociodemographic information. In the second part, questions were asked to evaluate stress levels, TMD symptoms, and treatment of TMD, if any, before (T0) and during the pandemic (T1). In the last part, professional mask choice, mask-related parafunctional movements, and breathing patterns while wearing a mask were evaluated.
UNASSIGNED: TMD symptoms and stress levels were significantly higher at T1. An increase in mouth breathing and mask-related parafunctional movements was reported during the use of N95 masks compared with daily life in dentists whose professional mask selection was an N95 respirator. The change in temporomandibular joints pain and muscle pain at rest between T0 and T1 was higher in those whose professional mask choice was N95 respirators than in those who chose to wear one surgical mask.
UNASSIGNED: The increase in mouth breathing and mask-related parafunctional movements during the use of N95 respirators may increase TMD.

BACKGROUND: In certain situations, masks are worn during sleep to prevent respiratory infections. However, the effects of mask wearing on cardiopulmonary function during sleep are unknown. This study aimed to determine whether wearing masks during sleep has an impact on cardiopulmonary function, including in patients with obstructive sleep apnea.
METHODS: This was a prospective, randomized crossover-controlled trial. The effects of wearing surgical masks or N95 respirators on cardiopulmonary function were measured in healthy subjects and patients with mild-moderate obstructive sleep apnea. Sleep breathing parameters were monitored during nocturnal sleep using a sleep monitor, and subjective feelings about mask wearing were assessed using a questionnaire.
RESULTS: Wearing masks during sleep at night did not significantly impact sleep breathing parameters. Furthermore, there were no significant differences in heart rate, blood oxygenation, and blood pressure before and after wearing masks. However, wearing masks wearing, especially the N95 mask, had an adverse impact on sleep quality, and masks were found to be subjectively uncomfortable.
CONCLUSIONS: Wearing masks during sleep at night does not adversely affect cardiopulmonary function but they can be uncomfortable, especially the N95 mask. Thus, in circumstances where wearing N95 masks during nocturnal sleep proves intolerable, we recommend the use of surgical masks as a more comfortable alternative.

OBJECTIVE: This study aimed to determine the impact of different types of masks on the voices of healthcare professionals who had to wear masks for an extended amount of time during the pandemic period and had a healthy voice.
METHODS: Our research included 41 healthcare workers. The participants were separated into two groups: surgical (n = 21) and N95 mask users (n = 20). Healthcare workers evaluated masks before and after wearing them for at least 8 hours throughout the workday. All subjects had a videolaryngoscopic examination; the Voice Handicap Index-10 (VHI-10), GRBAS, acoustic voice analysis (F0, jitter%, shimmer%, noise/harmonic ratio, relative average perturbation [RAP]), aerodynamic measures (maximum phonation time, MPT), and blood oxygen saturation were evaluated.
RESULTS: Although both groups\' VHI-10 scores increased after using the mask, this rise was not statistically significant in our research. According to the GRBAS classification, voice quality deterioration was identified in 9.6% (mild-moderate) of the group using surgical masks and 15% (mild) of the group wearing N95. Only the jitter and RAP values of individuals wearing both surgical and N95 masks were determined to be statistically significant. There was no significant change in MPT following mask wear in either group. Both the surgical and N95 mask-using groups showed a substantial drop in blood oxygen saturation before and after mask usage.
CONCLUSIONS: There was no change in voice quality between healthcare workers wearing surgical and N95 masks. It has been noticed that voice perception and quality are affected by the mask\'s barrier effect rather than the kind of mask.

Respiratory droplets, naturally produced during expiration, can transmit pathogens from infected individuals. Wearing a face mask is crucial to prevent such transmission, yet the perception of dyspnea and uncomfortable breathing remains a common concern, particularly during epidemics. The aim of this study was to investigate the impact of face mask use on the perception of dyspnea, cardiopulmonary parameters, and facial temperature during physical activity. A randomized crossover study was conducted on healthy adults at a physiology laboratory located in the Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia, in November 2022. Participants underwent five stages of physical exercise tests based on the Bruce Protocol under three conditions: without any face mask (control), wearing a surgical mask, and an N95 mask, forming the study\'s main groups. Dyspnea perception (measured by the Modified Borg Dyspnea Scale), cardiopulmonary parameters (heart rate, oxygen saturation, respiratory rate, blood pressure, and mean arterial pressure) and facial temperature were measured before the exercise test (pre-workout), at the end of stage 1, 2, 3, 4, 5, and after the whole exercise test (post-workout). A two-way repeated measures ANOVA was conducted, considering two factors: the type of mask (control, surgical mask, N95 mask) and the various stages of the exercise test. A total of 36 healthy adults were included in the study. We found that dyspnea perception was much worse in the N95 mask group, particularly during vigorous exercise. There was no significant difference between groups in cardiopulmonary parameters. However, participants wearing N95 had a greater supralabial temperature than those wearing surgical masks or no mask at all. It is recommended to undertake a more in-depth evaluation of cardiopulmonary physiological measures.

UNASSIGNED: The widespread use of surgical masks during the COVID-19 pandemic has posed challenges in interpreting facial emotions. As the mouth is known to play a crucial role in decoding emotional expressions, its covering is likely to affect this process. Recent evidence suggests that facial expressions impact behavioral responses only when their emotional content is relevant to subjects\' goals. Thus, this study investigates whether and how masked emotional faces alter such a phenomenon.
UNASSIGNED: Forty participants completed two reaching versions of the Go/No-go task in a counterbalanced fashion. In the Emotional Discrimination Task (EDT), participants were required to respond to angry, fearful, or happy expressions by performing a reaching movement and withholding it when a neutral face was presented. In the Gender Discrimination Task (GDT), the same images were shown, but participants had to respond according to the poser\'s gender. The face stimuli were presented in two conditions: covered by a surgical mask (masked) or without any covering (unmasked).
UNASSIGNED: Consistent with previous studies, valence influenced behavioral control in the EDT but not in the GDT. Nevertheless, responses to facial emotions in the EDT exhibited significant differences between unmasked and masked conditions. In the former, angry expressions led to a slowdown in participants\' responses. Conversely, in the masked condition, behavioral reactions were impacted by fearful and, to a greater extent, by happy expressions. Responses to fearful faces were slower, and those to happy faces exhibited increased variability in the masked condition compared to the unmasked condition. Furthermore, response accuracy to masked happy faces dramatically declined compared to the unmasked condition and other masked emotions.
UNASSIGNED: In sum, our findings indicate that surgical masks disrupt reactions to emotional expressions, leading people to react less accurately and with heightened variability to happy expressions, provided that the emotional dimension is relevant to people\'s goals.

The outbreak of COVID-19 has created renewed attention on research and large scale manufacturing of face masks. In the last two decades, usage of face masks for respiratory protection has gained increased importance as a measure to control the maladies and fatalities due to exposure to particulate pollutants and toxic pathogens. Numerous variants of surgical and high-performance respirator masks are available in the market, and yet the fibrous materials science researchers, manufacturers and public health agencies are making concerted efforts towards improvising them with respect to self-sterilisability, facial fit, thermo-physiological comfort, reusability and biodegradability, while maintaining or rather enhancing the filtration efficiency. This review article presents a compendium of materials, design and performance standards of existing face masks, as well as elaborates on developments made for their performance enhancement. The criticality of inculcation of good hygiene habits and earnest compliance to correct mask donning and doffing practices has also been highlighted. This review is expected to make valuable contributions in the present COVID-19 scenario when donning a face mask has become mandatory.