A rigorous theoretical and numerical analysis of a nonlinear reaction-diffusion epidemic model pertaining dynamics of COVID-19.

The spatial movement of the human population from one region to another and the existence of super-spreaders are the main factors that enhanced the disease incidence. Super-spreaders refer to the individuals having transmitting ability to multiple pathogens. In this article, an epidemic model with spatial and temporal effects is formulated to analyze the impact of some preventing measures of COVID-19. The model is developed using six nonlinear partial differential equations. The infectious individuals are sub-divided into symptomatic, asymptomatic and super-spreader classes. In this study, we focused on the rigorous qualitative analysis of the reaction-diffusion model. The fundamental mathematical properties of the proposed COVID-19 epidemic model such as boundedness, positivity, and invariant region of the problem solution are derived, which ensure the validity of the proposed model. The model equilibria and its stability analysis for both local and global cases have been presented. The normalized sensitivity analysis of the model is carried out in order to observe the crucial factors in the transmission of infection. Furthermore, an efficient numerical scheme is applied to solve the proposed model and detailed simulation are performed. Based on the graphical observation, diffusion in the context of confined public gatherings is observed to significantly inhibit the spread of infection when compared to the absence of diffusion. This is especially important in scenarios where super-spreaders may play a major role in transmission. The impact of some non-pharmaceutical interventions are illustrated graphically with and without diffusion. We believe that the present investigation will be beneficial in understanding the complex dynamics and control of COVID-19 under various non-pharmaceutical interventions.

EACVI survey on radiation exposure in interventional echocardiography.

AIMS: The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey on radiation exposure in interventional echocardiography. The survey aimed to collect data on local practices for radioprotection in interventional echocardiography and to assess the awareness of echocardiography operators about radiation-related risks. METHODS AND RESULTS: A total of 258 interventional echocardiographers from 52 different countries (48% European) responded to the survey. One hundred twenty-two (47%) participants were women. Two-thirds (76%) of interventional echocardiographers worked in tertiary care/university hospitals. Interventional echocardiography was the main clinical activity for 34% of the survey participants. The median time spent in the cath-lab for the echocardiographic monitoring of structural heart procedures was 10 (5-20) hours/month. Despite this, only 28% of interventional echocardiographers received periodic training and certification in radioprotection and 72% of them did not know their annual radiation dose. The main adopted personal protection devices were lead aprons and thyroid collars (95% and 92% of use, respectively). Dedicated architectural protective shielding was not available for 33% of interventional echocardiographers. Nearly two-thirds of responders thought that the radiation exposure of interventional echocardiographers was higher than that of interventional cardiologists and 72% claimed for an improvement in the radioprotection measures. CONCLUSION: Radioprotection measures for interventional echocardiographers are widely variable across centres. Radioprotection devices are often underused by interventional echocardiographers, portending an increased radiation-related risk. International scientific societies working in the field should collaborate to endorse radioprotection training, promote reliable radiation dose assessment, and support the adoption of radioprotection shielding dedicated to interventional echocardiographers.

Surgical team member's application of personal protective equipment: an observational study.

Background: Personal protective equipment (PPE) is a term used to refer to clothing or equipment that creates a barrier to protect an individual from work-place hazards, thereby protecting the worker against work-related injuries and illnesses. This study was aimed at determining the compliance of application of personal protective equipment against the standards. Methods: One hundred surgical personnel were included in this study from 21 March 2023 to 23 April 2023. Data were collected through direct observation. The standards were directly changed into question forms with two integral checking components, "Yes", and "No". Data were entered and analyzed by statistical package of social sciences (SPSS) version 25. Result: A total of 100 surgical personnel involved in surgical procedures were assessed for how they applied PPE. Majority of healthcare workers, 61.2%, were compliant with the communicable disease control standard on the application of PPE. The highest compliance rate was observed for the put-on gloves over the gown, while the lowest compliance rate was observed for wearing eye protection. Conclusion and recommendation: The practice of PPE usage by surgical personnel was suboptimal. Healthcare facilities can better protect their staff and patients from the spread of infections and other hazards through PPE use protocols. Donning and doffing must always be methodical and supervised by another staff member, especially during surgical emergencies. PPE should be used in accordance with infection prevention and control guidelines and the level of risk involved in the specific procedure.

Design optimization and validation of UV-C illumination chamber for filtering facepiece respirators.

In this study, we constructed an UV-C illumination chamber using commercially available germicidal lamps and other locally available low-cost components for general-purpose biological decontamination purposes. The illumination chamber provides uniform illumination of around 1 J/cm2 in under 5 min across the chamber. The control mechanism was developed to automate the on/off process and make it more secure minimizing health and other electrical safety. To validate the decontamination efficacy of the UV-C Illumination Chamber we performed the Geobacillus spore strip culture assay. Additionally, we performed the viral load measurement by identifying the COVID-19-specific N-gene and ORF1 gene on surgical masks. The gold standard RT-qPCR measurement was performed to detect and quantify the COVID-19-specific gene on the mask sample. The biochemical assay was conducted on the control and test group to identify the presence of different types of bacteria, and fungi before and after exposure under the illumination chamber. The findings of our study revealed satisfactory decontamination efficacy test results. Therefore, it could be an excellent device in healthcare settings as a disinfection tool for biological decontamination such as SAR-CoV-2 virus, personal protection equipment (PPE), (including n95, k95 respirators, and surgical masks), and other common pathogens.

[Sociodemographic and environmental factors associated with mask use during the COVID-19 pandemic]. / Factores sociodemográficos y ambientales relacionados con el uso de mascarillas en la población durante la pandemia por la COVID-19.

OBJECTIVE: During COVID-19 pandemic, prevention measures were implemented to mitigate the community transmission of SARS-CoV-2. Compliance with these measures was influenced by several sociodemographic and environmental factors. However, literature addressing compliance with these prevention measures among the general population remains limited. The study aimed to assess the association of sociodemographic and environmental factors and mask usage during close contact situations. METHODS: A cross-sectional study was conducted with a sample of 1,778 individuals identified through close contact tracing of individuals diagnosed with SARS-CoV-2 by the COVID-19 Coordination Center of Mallorca, from February to June 2021. A descriptive analysis was conducted, and a logistic regression model was utilized to evaluate factors associated with mask non-compliance. RESULTS: The mean age of the participants was 42.8±17.4 years, with 53.6% being female. Among close contacts, 60.8% (95% CI: 57.8-62.3) did not use masks during their contact. No significant differences were observed between genders or across age groups (p=0.497 and p=0.536, respectively). Factors linked to mask non-compliance included the home setting, indoor spaces without ventilation, and closer physical distances (p<0.001). CONCLUSIONS: Our findings indicate that mask adherence was notably lower among close contacts exposed to higher risk. In future public health crises, interventions should be developed to raise awareness about risks and promote adherence to preventive and control measures.

OBJECTIVE: Durante la pandemia de la COVID-19 se implementaron medidas de prevención con el propósito de reducir su transmisión comunitaria. El grado de cumplimiento con estas medidas estuvo influenciado por diversos factores sociodemográficos y ambientales. Sin embargo, existe escasa literatura científica que aborde el cumplimiento de las medidas preventivas en la población general. El objetivo de este estudio fue analizar la asociación entre factores sociodemográficos y ambientales, así como la adhesión al uso de mascarillas en contactos estrechos. METHODS: Se realizó un estudio transversal con 1.778 individuos, identificados mediante el rastreo de contactos estrechos de personas con SARS-CoV-2 por la Central de Coordinación de la COVID-19 de Mallorca, entre febrero y junio de 2021. Se realizó un análisis descriptivo y se utilizó un modelo de regresión logística para determinar los factores asociados al incumplimiento del uso de mascarillas. RESULTS: La edad media de los participantes fue de 42,8±17,4 años (53,6% de mujeres). El 60,8% (IC 95%: 57,8-62,3) de los contactos estrechos no utilizó mascarilla durante su contacto. No se observaron diferencias estadísticamente significativas en función del sexo o grupo etario (p=0,497 y p=0,536, respectivamente). Las situaciones de mayor incumplimiento con el uso de mascarillas se dieron en el entorno domiciliario, espacios cerrados sin ventilación y al mantener distancias cortas (p<0,001). CONCLUSIONS: Nuestros hallazgos indican una menor adhesión al uso de mascarillas en escenarios de mayor riesgo. Frente a futuras situaciones de crisis sanitaria, se deberían diseñar intervenciones que realcen la conciencia sobre los riesgos y que promuevan una mayor adhesión a medidas de prevención y control.

Factores sociodemográficos y ambientales relacionados con el uso de mascarillas en la población durante la pandemia por la COVID-19 / Sociodemographic and environmental factors associated with mask use during the COVID-19 pandemic

Fundamentos: Durante la pandemia de la COVID-19 se implementaron medidas de prevención con el propósito de reducir su transmisión comunitaria. El grado de cumplimiento con estas medidas estuvo influenciado por diversos factores sociodemográficos y ambientales. Sin embargo, existe escasa literatura científica que aborde el cumplimiento de las medidas preventivas en la población general. El objetivo de este estudio fue analizar la asociación entre factores sociodemográficos y ambientales, así como la adhesión al uso de mascarillas en contactos estrechos. Métodos: Se realizó un estudio transversal con 1.778 individuos, identificados mediante el rastreo de contactos estrechos de personas con SARS-CoV-2 por la Central de Coordinación de la COVID-19 de Mallorca, entre febrero y junio de 2021. Se realizó un análisis descriptivo y se utilizó un modelo de regresión logística para determinar los factores asociados al incumplimiento del uso de mascarillas.Resultados: La edad media de los participantes fue de 42,8±17,4 años (53,6% de mujeres). El 60,8% (IC 95%: 57,8-62,3) de los contactos estrechos no utilizó mascarilla durante su contacto. No se observaron diferencias estadísticamente significativas en función del sexo o grupo etario (p=0,497 y p=0,536, respectivamente). Las situaciones de mayor incumplimiento con el uso de mascarillas se dieron en el entorno domiciliario, espacios cerrados sin ventilación y al mantener distancias cortas (p<0,001). Conclusiones: Nuestros hallazgos indican una menor adhesión al uso de mascarillas en escenarios de mayor riesgo. Frente a futuras situaciones de crisis sanitaria, se deberían diseñar intervenciones que realcen la conciencia sobre los riesgos y que promuevan una mayor adhesión a medidas de prevención y control.(AU)

Background: During COVID-19 pandemic, prevention measures were implemented to mitigate the community transmission of SARS-CoV-2. Compliance with these measures was influenced by several sociodemographic and environmental factors. However, literature addressing compliance with these prevention measures among the general population remains limited. The study aimed to assess the association of sociodemographic and environmental factors and mask usage during close contact situations. Methods: A cross-sectional study was conducted with a sample of 1,778 individuals identified through close contact tracing of indivi-duals diagnosed with SARS-CoV-2 by the COVID-19 Coordination Center of Mallorca, from February to June 2021. A descriptive analysis was conducted, and a logistic regression model was utilized to evaluate factors associated with mask non-compliance. Results: The mean age of the participants was 42.8±17.4 years, with 53.6% being female. Among close contacts, 60.8% (95% CI: 57.8-62.3) did not use masks during their contact. No significant differences were observed between genders or across age groups (p=0.497 and p=0.536, respectively). Factors linked to mask non-compliance included the home setting, indoor spaces without venti-lation, and closer physical distances (p<0.001). Conclusions: Our findings indicate that mask adherence was notably lower among close contacts exposed to higher risk. In future public health crises, interventions should be developed to raise awareness about risks and promote adherence to preventive and control measures.(AU)

Evaluation of novel radiation protection devices during radiologically guided interventions.

BACKGROUND: In radiologically guided interventions, medical practitioners are subjected to radiation exposure, which may lead to radiation-induced diseases. In this study, novel radiation shields for the head and neck were evaluated for their potential to reduce radiation exposure. METHOD: An anthropomorphic phantom was exposed on its left side to scattered radiation from beneath to simulate the exposure of an operator in a x-ray operating room. Thermoluminescent dosimeters (TLDs) were positioned at different depths in five slices in the phantom, measuring personal dose equivalent. Two different set up situations were evaluated: a head protector designed to reduce radiation in the upper section of the head; and a novel thyroid protector prototype extended in the front and on both sides, designed to reduce radiation in the lower and middle sections of the head. A standard thyroid collar prototype and a ceiling mounted lead glass shield were used as comparisons. Furthermore, the head protector was evaluated in a clinical study in which TLDs were positioned to measure scattered radiation exposure to the heads of operators during endovascular interventions. RESULTS: The extended thyroid protector reduced the scattered radiation in the throat, chin, and ear slices. Some shielding effect was seen in the brain and skull slices. The head protector showed a shielding effect in the skull slice up to two cm depth where it covered the phantom head. As expected, the ceiling mounted lead glass shield reduced the scattered radiation in all measuring points. CONCLUSIONS: A ceiling mounted lead glass shield is an effective radiation protection for the head, but in clinical practice, optimal positioning of a ceiling mounted lead shield may not always be possible, particularly during complex cases when radiation protection may be most relevant. Added protection using these novel guards may compliment the shielding effect of the ceiling mounted lead shield. The head protector stand-alone did not provide sufficient protection of the head. The extended thyroid protector stand-alone provided sufficient protection in the lower and middle sections of the head and neck.

Inference for entomological semi-field experiments: Fitting a mathematical model assessing personal and community protection of vector-control interventions.

The effectiveness of vector-control tools is often assessed by experiments as a reduction in mosquito landings using human landing catches (HLCs). However, HLCs alone only quantify a single characteristic and therefore do not provide information on the overall impacts of the intervention product. Using data from a recent semi-field study which used time-stratified HLCs, aspiration of non-landing mosquitoes, and blood feeding, we suggest a Bayesian inference approach for fitting such data to a stochastic model. This model considers both personal protection, through a reduction in biting, and community protection, from mosquito mortality and disarming (prolonged inhibition of blood feeding). Parameter estimates are then used to predict the reduction of vectorial capacity induced by etofenpox-treated clothing, picaridin topical repellents, transfluthrin spatial repellents and metofluthrin spatial repellents, as well as combined interventions for Plasmodium falciparum malaria in Anopleles minimus. Overall, all interventions had both personal and community effects, preventing biting and killing or disarming mosquitoes. This led to large estimated reductions in the vectorial capacity, with substantial impact even at low coverage. As the interventions aged, fewer mosquitoes were killed; however the impact of some interventions changed from killing to disarming mosquitoes. Overall, this inference method allows for additional modes of action, rather than just reduction in biting, to be parameterised and highlights the tools assessed as promising malaria interventions.

Controlled human infection trials: Legitimacy and conditions of implementation in France.

This round table is the result of an observation. The observation being that controlled human infection clinical trials (also called "infectious challenge" trials or "Controlled Human Infection Models", "CHIM") recommended or even encouraged in the context of vaccine developments in particular, are not carried out in France. However, there are no formal prohibitions within regulations or ethical principles, which point to the prior assessment of risks and benefits for individuals and for society. The participants in this Round Table thus wished to examine, through the prism of their respective disciplines, the scientific and medical relevance of conducting such trials in France and, if possible, to imagine the conditions under which they would be carried out, thus resulting in recommendations on (1) the advisability of their conduct in France (2), the conditions under which they would be implemented in terms of logistics and regulations, and (3) their social acceptability. The recommendations on which the participants of the Round Table came to an agreement are presented as the analysis progresses.

Personal protection equipment: Preliminary evidence of effectiveness from a three-phase simulation program.

Background: Healthcare providers carry the occupational risk of being exposed to pathogens. Personal Protection Equipment (PPE) requires proficiency whenever used. Yet, evidence shows significant errors and variation in competency when applying PPE. Objective: In this study, we developed a three-phase intervention to promote PPE proficiency. Methods: Education and assessment of participants' PPE knowledge and skills occurred at a large academic university in Western Canada. Participants first completed an online module; second, they experienced one-on-one coaching and deliberate practice with infection control professionals; and third, participants managed a COVID-19 clinical simulation scenario. The measured outcomes include a 15-item pre- and post-knowledge test and a pre- and post-skills assessment of donning and doffing behaviors. These behaviors were observed from video recordings and were assessed using two standardized checklists. Results: Knowledge and donning/doffing post-test scores (11.73, 0.95, and 0.96, respectively) were significantly higher after completing all three phases of the educational intervention, p < .001. Conclusions: An online module alone is insufficient for PPE knowledge and skill development. Rather, a module followed by practice and simulation allows learners to gain proficiency.

Refocusing on work-based hazards for the anaesthesiologist in a post-pandemic era.

The coronavirus pandemic has raised public awareness of one of the many hazards that healthcare workers face daily: exposure to harmful pathogens. The anaesthesia workplace encompasses the operating room, interventional radiology suite, and other sites that contain many other potential occupational and environmental hazards. This review article highlights the work-based hazards that anaesthesiologists and other clinicians may encounter in the anaesthesia workplace: ergonomic design, physical, chemical, fire, biological, or psychological hazards. As the anaesthesia work environment enters a post-COVID-19 pandemic phase, anaesthesiologists will do well to review and consider these hazards. The current review includes proposed solutions to some hazards and identifies opportunities for future research.

Association of known SARS-CoV-2 serostatus and adherence to personal protection measures and the impact of personal protective measures on seropositivity in a population-based cross-sectional study (MuSPAD) in Germany.

BACKGROUND: In 2020/2021 in Germany, several non-pharmacological interventions were introduced to lower the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated to what extent knowledge of prior infection with SARS-CoV-2 or vaccination status influenced the use of personal protection measures (PPM). Further, we were interested in the effect of compliance with PPM on SARS-CoV-2 serostatus. METHODS: Data was based on a sequential, multilocal seroprevalence study (MuSPAD), carried out in eight locations from July 2020 to August 2021. We estimated the association between a known SARS-CoV-2 serostatus (reported positive PCR test or vaccination) and self-reported PPM behavior (hand hygiene, physical distancing, wearing face mask), just as the association of PPM compliance with seropositivity against nucleocapsid (NC), receptor-binding domain (RBD), and spike protein (S) antigens. We identified relevant variables and deduced adjustment sets with directed acyclic graphs (DAG), and applied mixed logistic regression. RESULTS: Out of the 22,297 participants (median age: 54 years, 43% male), 781 were classified as SARS-CoV-2-infected and 3,877 had a vaccinated immune response. Vaccinated individuals were less likely to keep 1.5 m distance [OR = 0.74 (95% CI: 0.57-0.97)] and only partly physically distanced [OR = 0.71 (95% CI: 0.58-0.87)]. Participants with self-reported positive PCR test had a lower chance of adhering partly to physical distancing [OR = 0.70 (95% CI: 0.50-0.99)] in comparison to the reference group. Higher odds of additionally wearing a face mask was observed in vaccinated [OR = 1.28 (95% CI: 1.08-1.51)] even if it was not obligatory. Overall, among unvaccinated participants, we found little evidence of lower odds of seropositivity given mask wearing [OR: 0.91 (95% CI: 0.71-1.16)], physical distancing [OR: 0.84 (95% CI: 0.59-1.20)] and no evidence for completely adhering to hand cleaning [OR: 0.97 (95% CI: 0.29-3.22)]. CONCLUSIONS: A known confirmed prior infection and vaccination may have the potential to influence adherence to PPM.

Avoiding SARS-CoV-2 infection in healthcare workers: is behavioral change the answer?

Background: The COVID-19 pandemic has become an important cause of morbimortality, and healthcare workers are at the highest risk of infection. As a result, policies and guidelines have been issued, and behavioral changes have been crucial in hospitals. Among these measures, the implementation of personal protective equipment (PPE) and its appropriate use in the workplace is key to avoiding contagion, as is understanding new measures regarding patient admission, distribution, constant education on virtual platforms, among others, and changing conduct to reduce contagion. However, behavioral change interventions in healthcare workers are challenging as contextual characteristics, attributes of the intervention, and psychological factors are involved. Study objectives: The issue under investigation is the impact of COVID-19 on frontline healthcare workers in the emergency department of the Fundación Cardioinfantil (FCI). The objective was to describe their behavioral changes by studying and monitoring SARS-CoV-2 infection and their relationship through the tracing process in 2020. Methods: We conducted a case study to identify and relate the SARS-CoV-2 infection rate within the personnel in the department and the response of healthcare workers to the implementation and adherence to the use of PPE through the analysis of the different variables that contributed to behavioral change. Data were collected by a single author and analyzed by two authors using both the individual-level logic model technique and the triangulation of information, with approval from the institutional review board. Discussion: Several interventions for behavior change were registered in the data collection process. The data obtained indicated that implementation, embedding, and integration were perceived as collective and individual behavioral processes. This was supported by evidence from healthcare interventions, such as education, incentivization, training, restriction, environmental restructuring, modeling, and enablement. Conclusion: Behavioral science should be part of public health responses, as the theoretical basis suggests that change may modify the response to avoid the transmission of infectious diseases. Therefore, individuals at the highest risk appear to adopt guidance with targeted behavior adaptation interventions. Efforts to inform, instruct, and motivate healthcare workers must be continuous, and actions at the community level must be strengthened, as it is human behavior that determines the spread and mortality of infectious diseases, where community compliance to preventive behaviors plays a crucial role.

The hidden inequality: the disparities in the quality of daily use masks associated with family economic status.

Wearing high-quality masks plays a critical role in reducing COVID-19 transmission. However, no study has investigated socioeconomic inequality in the quality of masks. Addressing this gap, this paper explored the relationships between mask's quality and family economic status. The cross-sectional survey was conducted in two Chinese universities by distributing structured questionnaires to assess participants' characteristics including family economic status, and meanwhile collecting their masks to evaluate the quality by measuring particle filtration efficiency. The valid responses were obtained from 912 students with mean age of 19.556 ± 1.453 years and were analyzed by using fractional or binary logistic regression. Three main findings were presented. First, inequality existed in the quality of masks. 36.07% of students were using unqualified masks with average filtration efficiency of 0.795 ± 0.119, which was much lower than China's national standard (0.9). Of those masks with identified production date, 11.43% were manufactured during COVID-19 outbreak when market was flooded with counterfeit production, and thus were of poor quality with average filtration efficiency of 0.819 ± 0.152. Second, better family economic status was associated with better masks' filtration efficiency and greater probability of using qualified masks. Third, students with better family economic status tend to use masks with individual packaging, and unique patterns and special designs, which may lead to inequality on a psychological level. Our analysis reveals the hidden socioeconomic inequality that exist behind cheap masks. In facing the challenges of future emerging infectious diseases, it is important to address the inequity to ensure equal access to affordable qualified personal protection equipment.

Application of Inorganic Nanomaterials in Cultural Heritage Conservation, Risk of Toxicity, and Preventive Measures.

Nanotechnology has allowed for significant progress in architectural, artistic, archaeological, or museum heritage conservation for repairing and preventing damages produced by deterioration agents (weathering, contaminants, or biological actions). This review analyzes the current treatments using nanomaterials, including consolidants, biocides, hydrophobic protectives, mechanical resistance improvers, flame-retardants, and multifunctional nanocomposites. Unfortunately, nanomaterials can affect human and animal health, altering the environment. Right now, it is a priority to stop to analyze its advantages and disadvantages. Therefore, the aims are to raise awareness about the nanotoxicity risks during handling and the subsequent environmental exposure to all those directly or indirectly involved in conservation processes. It reports the human-body interaction mechanisms and provides guidelines for preventing or controlling its toxicity, mentioning the current toxicity research of main compounds and emphasizing the need to provide more information about morphological, structural, and specific features that ultimately contribute to understanding their toxicity. It provides information about the current documents of international organizations (European Commission, NIOSH, OECD, Countries Normative) about worker protection, isolation, laboratory ventilation control, and debris management. Furthermore, it reports the qualitative risk assessment methods, management strategies, dose control, and focus/receptor relationship, besides the latest trends of using nanomaterials in masks and gas emissions control devices, discussing their risk of toxicity.

Role of the European Pharmacist in the Implementation of the Latest WHO Guidelines for Malaria.

Following the publication a few months ago of the new WHO guidelines for malaria, the European pharmacist, even out of endemic areas, as a health care professional and advisor, has a major role to play in their effective implementation and in the interest of public health. The pharmacist is central in the health care system to ensure the correct application of these recommendations and to perform a decisive role in the prevention of malaria infections, both in the adapted pharmaceutical advice on personal protection against biting vector insects on the one hand, and in the pharmaceutical analysis and recommendations concerning antimalarial chemoprophylaxis prescriptions on the other hand. Physicians and pharmacist biologists, as well as hospital pharmacists, are also important for the analysis and treatment of effective malaria cases, particularly in the management of the diagnostic and therapeutic emergency that a P. falciparum infection represents.

Halochromic Textiles for Real-Time Sensing of Hazardous Chemicals and Personal Protection.

Chemical protective clothing (CPC) has become mandatory when performing various tasks to ensure user protection and prevent chemicals from contacting the skin and causing severe injuries. In addition to protection, there is a need to develop a simple mechanism that can be attached to CPC and be capable of detecting and alerting the user to the presence of harmful chemical agents. In this study, a double-sensor strategy was investigated, using six different pH indicators stamped on cotton and polyester knits to detect acidic and alkaline substances, both liquid and gaseous. Functionalized knits underwent microscopic characterization, air permeability and contact angle evaluation. All samples exhibited hydrophobic behavior (contact angle > 90°) and air permeability values above 2400 L/min/cm2/bar, with the best condition demonstrating a contact angle of 123° and an air permeability of 2412.5 L/min/cm2/bar when the sensor methyl orange and bromocresol purple (MO:BP) was stamped on polyester. The performed tests proved the functionality of the sensors and showed a visible response of all knits when contacting with different chemicals (acids and bases). Polyester functionalized with MO:BP showed the greatest potential, due to its preeminent color change. Herein, the fiber coating process was optimized, enabling the industrial application of the sensors via a stamping method, an alternative to other time- and resource-consuming techniques.

Hydrophobic/oleophobic nanofibrous filter media with bead-on-string structure for efficient personal protection of dust in mines.

Pneumoconiosis in mines occupied more than 90% of the total number of occupational diseases, poses tremendous pressure and challenges on the development of personal protection materials with high dust filtration efficiency and long-lasting comfortable wearing. In this study, a kind of polyethylene terephthalate (PET) based filter media with the bead-on-string structure and hydrophobic/oleophobic property was designed and fabricated by electrospinning technology. Nanoscale silicon dioxide (SiO2NPs) and fluorinated polyurethane (PU) used in this work were benefited for the microstructure, surface energy and hydrophobic/oleophobic property, respectively. The morphology and composition of the membranes were conducted by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR). Furthermore, the filtration performance, pressure drop, moisture permeability and breathing comfortable performance were measured for the study of personal protection of dust. The results showed that at the air flow of 85 L min-1, PET/SiO2/FPU double-layer nanofibrous membrane showed high filtration efficiency and low pressure drop with the filtration efficiency of 99.96%, pressure drop of 142.5 Pa and quality factor of 0.055 Pa-1, respectively. A long term of 24 h water vapor test had proved that this membrane held an outstanding moisture permeability ability of 5296.325 g (m2 24 h)-1. Compared with the commercial 3701CN filter media, the advantages of the regular breathing frequency and strong heart rate control ability indicated that this PET/SiO2/FPU double-layer membrane had the better wearing comfortable performance with broad application prospects in the personal protection of dust in mines.

Efficacy Evaluation of Medium-Chain Fatty Acids as Skin and Spatial Repellents Against Aedes aegypti (Diptera:Culicidae) Mosquitoes.

Fatty acids derived from natural oils are considered as perspective products for adoption as repellents. Fatty acids derived from coconut oil have shown promise as repellents. This study consisted of an olfactometer evaluation of new formulations containing medium-chain fatty acids for spatial repellency and an in laboratory arm-in cage study for contact repellency against Aedes aegypti L. mosquitoes. Six formulations each of capric acid and lauric acid were evaluated for spatial repellency. These formulations contained 0.28-10% of either capric acid or lauric acid as the active ingredients in a consumer friendly skin care formulation. Base formula without fatty acids was evaluated as control in spatial repellency evaluation. For the arm-in cage evaluations, six formulations of capric acid, one base formulation, and a 7% N,N-diethyl-m-toluamide (DEET) product were tested for contact repellency. For contact repellency, United States Department of Agriculture (USDA) standard repellent test cages were used to determine the complete protection time (CPT) of the different formulated repellents. Among all capric acid formulations tested, the concentration of 2.25% (wt) indicated the best level of spatial repellency, but not significantly different from other concentrations. None of the lauric acid concentrations showed any level of spatial repellency. In the arm-in-cage evaluations, the highest contact repellency resulted from 4.5% capric acid, which was significantly higher than 7% DEET and base formula.