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At present, the filtration of virus and other small particles in the air by meltblown cloth produced by electret treatment mainly depends on its electrostatic adsorption mechanism. However, because the surface charge of melt blown fabric can not be maintained for a long time, it can not maintain high efficiency filtration for a long time. Therefore, there is no guarantee for the medical staffs to not be infected by COVID-19. Therefore, it is necessary to improve the mechanical filtration efficiency of melt blown fabric in the situation of an electric charge loss. In this paper, nylon 6 (PA6) nanofibers were electrospun on melt blown cloth by electrospinning technology, and a sandwich material with melt blown cloth as surface layer and PA6 nanofibers as middle layer was made by hot- pressing technology;the surface morphology, thermal and mechanical properties of the sandwich material were characterized, and its filtration performance was tested. The experimental results show that the surface integrity of the sandwich material is high, and the diameter of nanofibers can reach about 67 nm;without the electret treatment, the filtration efficiency of the sandwich material for particles in an size of 0.2 μm is more than 95%,while the filtration efficiency of non-woven fabric is zero;the filtration resistance of the material is about 284 Pa, which is suitable for personal protection. © 2023 Chengdu University of Science and Technology. All rights reserved.
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Extracorporeal membrane oxygenator (ECMO) is a valuable technology to support people with acute respiratory distress syndrome (ARDS) and is recommended for COVID-19 patients. This study aims to fabricate polymer-based composite membranes coated with ethylcellulose nanoparticles from waste paper and identify the performance of the composite as ECMO candidates. Composite membranes were made from four types of polymers, namely, nylon, PTFE (polytetrafluoroethylene), Pebax® MH-1657, and SBS (poly-(styrene-b-butadiene-b-styrene)). PDMS (polydimethylsiloxane) 1 wt.% and ethylcellulose nanoparticles (3% and 10 wt.%) were used as membrane coatings to increase their hydrophobic properties. The success of cellulose isolation and ethylcellulose synthesis from waste paper was confirmed by the FTIR and XRD analysis. The size of the synthesized ethylcellulose nanoparticles was 32.68 nm. The coating effect on composite membranes was studied by measuring the contact angle, membrane porosity, protein quantification tests, and single gas permeation of O2 and CO2. Based on the protein quantification test, the protein could not pass through the Pebax/PDMS and SBS/PDMS composites coated with 10 wt.% ethylcellulose;this indicated less risk of plasma leakage. The gas permeation test on nylon/PDMS, PTFE/PDMS, and SBS/PDMS composites coated with 10% ethylcellulose resulted high CO2/O2 selectivity, respectively, 2.17, 3.48, and 3.22 as good indication for extracorporeal oxygenation membrane.
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Goats may suffer from rumen bloat for many reasons, e.g. improperly concentrated ratio or obstruction. The disease can be caused by eating undigested items, e.g. plastic rope or bags. Since the COVID-19 pandemic, it has often become mandatory for people to wear medical masks. People are generally unaware that masks left on the ground pose a risk to goats who may eat them. This case report describes the rumen bloat caused by medical masks in a male goat reared in an elementary school. After physical examination, the goat showed a bloated rumen, anorexia, depression, and weakness. The heart rate was normal, but respiratory patterns were fast and deep. Fewer defecated feces were noted by the owner. Furthermore, the owner's complaints and ultrasound images revealed that undigested items in the rumen were the cause. After performing a standard rumenotomy, we scooped out four medical masks, one plastic bag, and one high-density nylon rope from the rumen. We believe this was the first report describing the risk of medical masks in goats. Promoting life and animal welfare education is essential to inform others of the harm medical masks pose to animals.Copyright © 2023 World Scientific Publishing Co. Pte Ltd. All rights reserved.
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• Pd/ m- Al 2 O 3 -Si catalyst exhibited high efficiency in converting α- amino -ε- caprolactam (α- ACL) to dimethyl-protected cyclic lysine (DMCL). • The lack of Brönsted acid sites on Pd/ m- Al 2 O 3 -Si surface facilitated the formation of DMCL and suppressed undesirable reaction process. • Pd/ m- Al 2 O 3 -Si catalyst with microspherical morphology performed excellent stability and physical strength during the catalytic process. • The nylon‑6 copolymers produced from the as-synthesized DMCL exhibited a great potential in the synthesis of self-cleaning antibacterial materials. Antibacterial monomers are prerequisites for synthesizing antibacterial polymers, especially during the current COVID-19 pandemic. Dimethyl-protected cyclic lysine (DMCL) is a promising functional monomer for nylon-6 based self-cleaning antibacterial polymers. However, the production of DMCL still faces formidable challenges, such as harsh reaction conditions and low catalyst activities. In this study, we developed a Pd/ m -Al 2 O 3 -Si catalyst, which exhibited high efficiency in converting α -amino- ε -caprolactam (α -ACL) to DMCL, affording a yield of as high as 97.1% at 100 °C and 1 MPa H 2. The lack of Brönsted acid sites on the catalyst surface facilitated the formation of DMCL and suppressed undesirable hydrolysis or cracking by-products from the lactam-based reactant. The recycled experiments showed that Pd/ m -Al 2 O 3 -Si performed excellent stability and physical strength with essentially no damage to its microspheres after the reaction. The nylon‑6 copolymers produced from the as-synthesized DMCL exhibited similar structure and thermal stability with pure nylon-6, showing great potential in synthesizing the self-cleaning antibacterial polymers. This work provides a sustainable and efficient method for producing DMCL and other lysine-based antibacterial monomers, showing a great prospect for the utilization of bio-based chemicals in synthesizing functional polymers. [ FROM AUTHOR] Copyright of Chemical Engineering Journal is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)
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Maintaining reduction of a calcaneal tuberosity avulsion fracture is challenged by the powerful force exerted upon the bone fragment by the Achilles tendon. Low-demand, elderly patients with osteoporotic bone usually undergo a low-energy mechanism when this fracture pattern occurs. Likely attributable to poor bone quality, the rate of early fixation failure has been documented to be as high as 40%. We present the cases of two 65-year-old female patients who each sustained a calcaneal tuberosity avulsion fracture. Both patients underwent a low-energy mechanism of injury and had a medical history of many comorbidities. The first patient underwent a partial calcaneal ostectomy and tenotomy after failing open reduction internal fixation (ORIF). The second patient primarily underwent a partial calcaneal ostectomy and tenotomy. Postoperatively, after the incision site was fairly healed, both patients could bear weight as tolerated. This method of excision and release may allow for decreased risk of skin compromise and return trips to the operating room for failed ORIF. In low-demand patients with low-energy calcaneal avulsion type fractures and osteoporotic bone, this technique may be the preferred surgical option.Copyright © 2022 The Author(s)
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ABSRACT: After the rapid spread of SARS-Cov-2 virus, the use of masks was suggested by the world health organization (WHO) to reduce the virus transmission, whose primary mode of transmission was suggested to be through respiratory droplets. The recommended face coverings were single use surgical and respirator masks made of non-woven materials. With the increased demand for masks worldwide, the environmental impacts of mask disposal and the pollution caused by microplastic fibers of the non-woven materials were presented. This challenge necessitates the need for the development of a novel reusable mask reducing the environmental effects, while providing the necessary personal protective properties. Based on the ASTM F2299 standard test method, the performance, i.e., particle-size dependent filtration efficiency and pressure drop were studied for 20 samples with multilayer knit fabrics of natural and synthetic fibers (inner layer of pure cotton, cotton-nylon and cotton-polyester, middle layer of Lycra, and outer layer of superhydrophobic polyester). The results show that all the samples had an efficiency of >94% and 87–99% for large (250 (Formula presented.) –1 (Formula presented.) m) and small (100–250 nm) particles, respectively. The best performing structure has a material composition of 41% superhydrophobic polyester, 26% natural cotton, 24% nylon and 9% Lycra. The filtration efficiency, pressure drop, and quality factor for this sample are 97.8% (for 100 nm particles), 4.04 mmH2O/cm2 and 4.77 kPa−1, respectively. It was also demonstrated that the developed mask maintains its performance after 50 wash/dry cycles, verifying its reusability. It should be noted that charge neutralizer was not used in the experimental setup of this study which might have led to enhanced results for the filtration efficiency of small (100–250 nm) particles due to the dominance of electrostatic attraction. However, several samples were tested by the third-party company who uses a certified testing equipment based on ASTM F2299, and similar results were obtained. Copyright © 2022 American Association for Aerosol Research.
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Rapid diagnostics for the diagnosis of COVID-19 are urgently needed in offices, residences, and other public places due to the new Covid epidemic stages. A portable and easy-to-use immunosensing platform was developed and evaluated for a point-of-care and self-detection of SARS-CoV-2 spike protein without the need for extraction, separation, or amplification steps using clinically isolated samples (n = 40 samples). The sensing platform was fabricated based on functionalized nylon nanofibrous membranes and a commercial glucose meter to enable easy deployment of the sensing technology. The fabrication of the immunoreaction vial using nylon nanofibrous membranes as a support matrix for the tethering of antibodies significantly improved the sensitivity of the detection platform in contrast to the use of conventional nylon casted membranes. The sensitivity of the nanofibrous membrane attached antibody was at least an order of magnitude higher (∼12 times) compared to the sensitivity of detection with regular casted membrane-based immunoreaction vial. The feasibility of the designed sensing platform was investigated using saliva as a non-invasive and self-administered sample for the diagnosis of SARS-CoV-2. With a detection limit of 9 ng mL−1 and no pretreatment processes required, the sensing platform demonstrated its suitability for the direct detection of SARS-CoV-2 spike protein in the spiked saliva samples. In addition, the developed platform depicted high agreement with RT-qPCR data in the analysis of the clinical samples with good stability over the storage time and reusability for three cycles with maintaining more than 95% of its original activity. [Display omitted] • Diagnosis of COVID-19 in human saliva using commercial glucose meter. • High sensitivity with broad dynamic range was achieved using nanofibrous membrane. • Successfully analyzing of clinical samples in agreement with RT-qPCR. • Potential application for self- and on-site diagnosis without sample pretreatment. • The sensing platform depicted reusability for 3 cycles and good storage stability. [ FROM AUTHOR]
ABSTRACT
Rapid diagnostics for the diagnosis of COVID-19 are urgently needed in offices, residences, and other public places due to the new Covid epidemic stages. A portable and easy-to-use immunosensing platform was developed and evaluated for a point-of-care and self-detection of SARS-CoV-2 spike protein without the need for extraction, separation, or amplification steps using clinically isolated samples (n = 40 samples). The sensing platform was fabricated based on functionalized nylon nanofibrous membranes and a commercial glucose meter to enable easy deployment of the sensing technology. The fabrication of the immunoreaction vial using nylon nanofibrous membranes as a support matrix for the tethering of antibodies significantly improved the sensitivity of the detection platform in contrast to the use of conventional naylon casted membranes. The sensitivity of the nanofibrous membrane attached antibody was at least an order of magnitude higher (∼12 times) compared to the sensitivity of detection with regular casted membrane-based immunoreaction vial. The feasibility of the designed sensing platform was investigated using saliva as a non-invasive and self-administered sample for the diagnosis of SARS-CoV-2. With a detection limit of 9 ng mL−1 and no pretreatment processes required, the sensing platform demonstrated its suitability for the direct detection of SARS-CoV-2 spike protein in the spiked saliva samples. In addition, the developed platform depicted high agreement with RT-qPCR data in the analysis of the clinical samples with good stability over the storage time and reusability for three cycles with maintaining more than 95% of its original activity.
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Body fluid identification at crime scenes can be crucial in retrieving the appropriate evidence that leads to the perpetrator and, in some cases, the victim. For this purpose, immunochromatographic tests are simple, fast and suitable for crime scenes. The potential sample is retrieved with a swab, normally a cotton swab, moistened in a specific buffer. Nonetheless, there are other swab types available, which have been proven to be efficient for DNA isolation and analysis. The aim of this study is to evaluate the efficiency of different swab types for body fluid identification as well as DNA isolation and characterization. Fifty microliters of human saliva were deposited in three different types of fabric (denim, cotton, and polyester). After 24 h at room temperature, samples were recovered by applying three different swab types, and the tests were performed. Subsequently, total DNA was recovered from the sample buffer. Cotton swabs performed worse in denim and cotton fabrics in both immunochromatography tests and DNA yield. No differences were observed for polyester. In contrast, and except for two replicates, it was possible to obtain a full DNA profile per fabric and swab type, and to identify the mtDNA haplogroup. In this paper, the impact of swab types on body fluid identification through the application of immunochromatographic tests is analyzed for the first time. This work corroborates previous research related to the influence of swab types in nuclear DNA isolation and characterization.
Subject(s)
DNA Fingerprinting , Specimen Handling , DNA Fingerprinting/methods , DNA, Mitochondrial/analysis , Humans , Polyesters , Saliva/chemistry , Specimen Handling/methodsABSTRACT
Objectives:Nylon fiber is a synthetic polymer that possesses outstanding physical and chemical properties such as good strength, flexibility, and air permeability. Nylon fiber has been widely used worldwide for various products including bedding, wipes, clothing, surgical gowns, wig, etc. The outbreak of COVID-19 boosts a surge in consumer demand for antibacterial fabrics that have the ability of resistance to bacteria attack because textile materials are good medium for microorganism growth and breeding. The present study thus aims to develop a durable antibacterial nylon fabric that could be used as wig against householdwashing. Thiswig would provide a solution for patients need chemotherapy to increase their self-confidence. Methods: The method of pad-dry-cure process was used to treat the nylon fabric samples. The N1 finishing formulation was prepared by adding binder and cationic antibacterial agent to deionized water. N2 finishing solution was prepared by mixing binder and inorganic antibacterial agent in deionized water. The sample was first padded with the pre-prepared finishing formulation. Afterwards, the sample was dried in an oven at 100oC for 2 min and then cured at 150oC for 1 min. After antibacterial finishing, the samples were washed with shampoo for different cycles at room temperature. Each cycle lasts 1 min. Finally, the antibacterial property of treated samples was qualitatively conducted against gram-positive S. aureus and gram-negative K. pneumoniae according to AATCC TM 147-2011. Results: The antibacterial results demonstrate that both samples treated with N1 and N2 have excellent antibacterial activities, particularly against S. aureus. However, after washing with shampoo, N1 samples show a distinct decrease in the inhibition zone and the samples fail to kill bacteria. By contrast, N2 samples show satisfactory antibacterial properties after 52 washing cycles. Moreover, there is no significant change in the antibacterial activity of N2 samples after 52 washing cycles. This suggests that the inorganic antibacterial agent has stronger affinity to nylon fiber than cationic antibacterial agent treated nylon fabric presents durable antibacterial activity. Conclusions: The inorganic antibacterial agent shows strong affinity to nylon fiber and can be used for developing durable antibacterial nylon fabrics against washing.
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Background-The COVID-19 pandemic has changed our standard practices: operating rooms were only available for functional emergencies and outpatient visits were drastically reduced in favor of telemedicine. Aim: To report the personalized "one-shot" surgery using absorbable 10-0 Vicryl (V10-0) or polyglactin 910 monofilament in mechanical corneal injuries from February 2020 to December 2021. Methods-Prospective case series with at least 12-months' follow-up, in a French university hospital. Among the overall population of open or closed-globe emergencies (n = 40), non-penetrating corneal lamellar lacerations (long axis > 2 mm) in zone 1 (OTC group) were treated with V10-0 suture(s) (n = 10), replacing traditional non-absorbable 10-0 nylon suture(s) or medical options in first line. The outpatient visits were performed on day (D)10, month (M)2, M6 then every six months. One interim visit by phone teleconsultation was scheduled between D10 and M2, and other(s) as needed. The main outcome was best-corrected visual acuity (BCVA) at M6. Secondary outcomes included mainly corneal astigmatism (CA) at M6 complications. Results-Among the ten corneal wounds, there were three children (30%), eight domestic accidents (80%), three eyes with metallic foreign bodies (30%), four open-globe injuries (40%), and nine eyes that received high-speed projectiles or sharp objects (90%). The complete V10-0 suture(s) absorption occurred in all eyes between D10 and M2. At M6, mean far and near BCVA decreased from 0.680 ± 0.753 and 0.490 ± 0.338 preoperatively to 0.050 ± 0.071 and 0.220 ± 0.063 logMAR (p = 0.019 and p = 0.025 respectively), mean CA decreased from 4.82 ± 3.86 preoperatively to 1.15 ± 0.66 diopters (p = 0.008). BCVA and CA were unchanged thereafter. No serious adverse event nor repeated surgery occurred. The mean number of teleconsultations was 1.20 ± 0.63 without an additional nonscheduled outpatient visit. Conclusions-The absorbable V10-0 sutures might be a safe and effective alternative for eligible corneal wounds, while reducing the number of outpatient visits, especially for children (no suture removal). The COVID-19 pandemic highlighted that they are ideally suited to logistical challenges.
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Long manned missions require food packaging to maintain food safety, nutrition, and acceptability for the length of 3-5 years1,2 while the shelf life assigned by NASA for current provisions is 18-24 months1. The focus of this design project was to make a polymer film specifically to function as a high oxygen barrier to later be included in an improved multi-layer packaging system of other specialized polymers with capabilities to allow for a 5-year shelf-life. To qualify as a high oxygen barrier film and to be a successful design for the future packaging, the resulting film is required to have an oxygen transmission rate (OTR) less than 0.06 cc/ m2/24 hr/atm, the standard for the current packaging3. This new film was designed to have a decreased permeability by increasing the “tortuous path” a gas molecule travels to permeate through a film. The increase in the “tortuous path” of a gas molecule is accomplished by introducing a 2D material additive. The additive chosen for this project was hexagonal boron nitride (h-BN) which exfoliates into boron nitride nanosheets (BNNs). Nylon 6 was chosen as the candidate for the matrix. This project is required to determine the best methods to synthesize the sample film and then to test the OTR of the film to determine if this design was successful. This project examined methods for pulverizing polymer resin pellets, h-BN exfoliation, and film fabrication using a hot press. This report includes the exfoliation and analysis of h-BN, procedural preparations for films, and a modeling study of estimated OTR of the h-BN/Nylon. The work in this report did not yield a high barrier composite film because of the laboratory closure in response to COVID -19 guidance but provides a concise method of the additive preparation and film synthesis. This gives a good starting point for future research in high barrier films by 2D additive composites.
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Background:Droplet transmission is the main mode of transmission for SARS-CoV-2. Contact transmission through fom- ites is another important mode of transmission. Amongst fomites, currency notes carry a high risk of SARS-CoV-2 trans- mission because of frequent handling. They also provide ample surface area to harbor micro -organisms. As there is lim- ited data currently available on this subject, the study was planned to determine the presence of SARS -COV-2 on com- monly circulating currency notes by detecting viral RNA using real time PCR. Methods:A total of 71 creased and visibly well circulated notes of monetary value Rs. 10, 100 and 500 were included in the study, collected through normal monetary transaction from the busy shops in designated areas in Delhi (inside and outside containment zones). Two nylon flocked swabs moistened with viral transport medium were rubbed on the ob- verse and reverse sides of the notes and then kept in screw capped tubes containing 1 ml of VTM till further processing at 2-8. RNA extracted was tested for the presence of SARS-CoV-2 by real time PCR as per NIV protocol. Results:Among the 71 currency notes tested for the presence of SARS-CoV-2 RNA by RT-PCR, three samples tested posi- tive for SARS-CoV-2 RNA (4.2%). All the three positive samples were collected from containment zones. Conclusions:Currency notes may be a potential mode of human-to-human transmission. Considering the widespread magnitude of the pandemic and the remarkable stability of the virus on smooth surfaces, caution is warranted while handling currency notes. Hence, contactless transactions/ digital transactions should be recommended as the best op- tions in the ongoing pandemic
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Introduction: During COVID-19, due to the worldwide shortages of medical masks, homemade cloth masks became a mainstay of the pandemic. The CDC and WHO recommend the use of homemade cloth masks. However, there is insufficient evidence on the performance: respiratory droplet blocking ability, water-resistant capacity, breathability, and washability of commonly used fabrics to design high-performing cloth masks that can outperform medical masks. Material and Methods: We conducted a series of experiments on aerosol blocking (using healthy volunteers sneeze, image-based flow measurement technique), water-resistant, breathability, and washability to evaluate all dimensions of protection of 17 different commonly available fabrics and their layered combinations. Results: The research provides a blueprint for the optimal design of a high-performing cloth mask that can outperform a 3-layered surgical mask. A minimum of 3 layers is recommended to provide the performance of surgical masks. A combination of cotton/linen for the inner layer, blends for the middle–layer, and polyester/nylon for the outer–layer. The average thread count (threads contained in one square inch) should be greater than 200, and the porosity (percent of pores in a fabric) should be less than 2 %. Increasing the number of layers increases the droplet blocking efficiency by approximately 20 times per additional fabric layer. Machine washing at 60 °C did not affect the performance of cloth masks. Conclusions: These results and visualizations can assist people in preparing effective homemade cloth masks during the ongoing COVID-19 pandemic and future epidemics.
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PurposeThe aim of this study is to report the use of Vicryl 10‐0 (polyglactin 910) resorbable monofilament in corneal trauma during COVID‐19 pandemic: structural and functional results, and follow‐up adaptation during health crisis.MethodsDuring the COVID‐19 pandemic, nine patients were selected from the overall population of open or closed globe surgical emergencies (n = 37) in a french University Hospital. Selected patients were eligible for corneal sutures with Vicryl 10‐0, thus replacing the traditional 10‐0 nonabsorbable monofilament nylon suture. Postoperative treatment combined anti‐inflammatory drugs, topical antibiotics and lubricating drops. Outpatient visits were performed at D10, M2, M6 then every six month. Interim visits were performed if needed between D10 and M2 by teleconsultation. Patients received complete examination including different imaging. The main outcome was best corrected visual acuity. Secondary outcomes included average corneal astigmatism and the occurrence of complications.ResultsMean distance and near acuity improved from 0.711 ± 0.805 & 0.556 ± 0.305 logMAR preoperatively to 0.056 ± 0.073 & 0.333 ± 0.100 logMAR postoperatively (p = 0.032 and p = 0.043 respectively). Mean astigmatism decreased from 4.91 ± 4.21 diopters preoperatively to 0.99 ± 0.57 after suture resorption (p = 0.020). There were no serious adverse events or repeated surgery.ConclusionsPolyglactin 910 10‐0 could provide a maximum infectious risk reduction;a shorter topical treatment and antibiotic prophylaxis. The absorbable nature of the sutures simplifies logistics by reducing the number of early outpatient visits before M2. It avoids suture removal, especially for the pediatric population. Interim teleconsultation(s) on demand are interesting to evaluate the need for an additional face‐to‐face consultation. Vicryl 10‐0 sutures are ideally suited to the COVID‐19 pandemic logistical constraints, as a safe and effective alternative to nylon 10‐0 for the management of eligible corneal wounds.