Nanokaolin reinforced carboxylated nitrile butadiene rubber/polyurethane blend-based latex with enhanced tensile properties and chemical resistance

The demand for gloves (e.g., disposable gloves, medical gloves) is increasing due to the Coronavirus disease 2019 (COVID-19) pandemic. Stability in the supply chain in the glove industry is important, and thus strategies are used to solve the problem of the shortage of nitrile gloves. The blending of nitrile butadiene rubber (NBR) with polyurethane (PU) and the use of the nanocomposite concept is among the feasible approaches. The present study aims to investigate the effects of nanokaolin (NK) on the tensile and chemical properties of carboxylated nitrile butadiene rubber (NBR)/polyurethane (PU) latex blends. Three different loadings of NK (10, 20, and 30 parts per hundred rubber) were added to the NBR/PU (at a blending ratio of 85/15). The zeta potential showed that all the NBR compounds exhibit good colloidal stability. The incorporation of NK increased the crosslink density and tensile strength of the NBR/PU latex blends. The highest tensile strength was achieved when the NK loading was 20 phr. All the NBR blends and nanocomposites (NBR/PU-based) possess tensile properties that fulfill the requirements for glove application. The chemical resistance of NBR compounds was increased by the incorporation of NK due to the higher crosslink density and barrier properties contributed by the NK. © The Author(s) 2023.

A Short Commentary of the Quality Control on Radix Salvia miltiorrhiza and its Application for COVID-19

Radix Salvia miltiorrhiza (Danshen) is a Chinese herbal used in China to treat irregular menstruation, dysmenorrhea, insomnia, swelling liver, and angina pectoris. It also has various pharmacological activities, including anti-inflammation, anti-oxidation, anti-tumor, anti-atherogenesis, and anti-diabetes. However, traditional Chinese medicine (TCM), e.g., Danshen, lacks quality control. Pesticide residues and heavy metals are the most important problems, although Danshen may cure many diseases, even SARS-CoV-2 in a COVID-19 pandemic. Hence, the present short commentary discusses the background of Danshen, quality management, and its application to COVID-19.

A Short Commentary of the Quality Control on Radix Salvia miltiorrhiza and its Application for COVID-19

Radix Salvia miltiorrhiza (Danshen) is a Chinese herbal used in China to treat irregular menstruation, dysmenorrhea, insomnia, swelling liver, and angina pectoris. It also has various pharmacological activities, including anti-inflammation, anti-oxidation, anti-tumor, anti-atherogenesis, and anti-diabetes. However, traditional Chinese medicine (TCM), e.g., Danshen, lacks quality control. Pesticide residues and heavy metals are the most important problems, although Danshen may cure many diseases, even SARS-CoV-2 in a COVID-19 pandemic. Hence, the present short commentary discusses the background of Danshen, quality management, and its application to COVID-19. © 2022 by the authors.

Evaluation Of The Impact Of Covid-19 Vaccines On Thyroid Function And Autoimmunity And The Potential Influence Of Pre-existing Thyroid Autoimmunity On Neutralizing Antibody Responses

Objectives: There are concerns for COVID-19 vaccination in causing thyroid dysfunction and triggering thyroid autoimmunity. Also, data on the impact of pre-existing thyroid autoimmunity on COVID-19 vaccination efficacy are limited. We evaluated the impact of COVID-19 vaccination on thyroid function and antibodies, and the influence of pre-existing thyroid autoimmunity on neutralizing antibody (NAb) responses. Methods: Adults without history of COVID-19 or thyroid disorders who received COVID-19 vaccination between 14 June 2021 and 8 August 2021 at three vaccination centers were recruited. All participants received two doses of vaccines. Thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies were measured at baseline and 8 weeks after the first dose of vaccination. Post-vaccination NAb against SARS-CoV-2 receptor-binding domain was measured. Results: In total, 215 individuals were included (129 BNT162b2 [60%] and 86 CoronaVac [40%] recipients): mean age 49.6 years, 37.2% men, and 12.1% positive for anti-TPO/anti-Tg at baseline. After vaccination, TSH levels did not change (p=0.225), but fT4 slightly increased (from 12. 0±1.1 to 12.2±1.2 pmol/L, p<0. 001) and fT3 slightly decreased (from 4.1±0.4 to 4. 0±0.4 pmol/L, p<0. 001). Only 3 patients (1.4%) had abnormal thyroid function after vaccination: two occurred among BNT162b2 recipients - both were subclinical thyrotoxicosis (TSH 0.32mIU/L, fT4 11.51pmol/L and fT3 4.40pmol/L;TSH 0.34mIU/L, fT4 12.67pmol/L and fT3 4.22pmol/L;both were anti-TPO and anti-Tg negative before and after vaccination);one occurred among CoronaVac recipients - isolated mild low fT3 (TSH 0.90mIU/L, fT4 9.94pmol/L and fT3 2.33pmol/L;anti-TPO/Tg negative before and after vaccination). All three recipients were asymptomatic. Both anti-TPO and anti-Tg titers increased modestly after vaccination (anti-TPO: from 7.50 [IQR: 5.90-11.2] to 9.80 IU/mL [IQR: 7.80-13.1], p<0. 001;anti-Tg: from 12.4 [IQR: 11.1-14.9] to 15.7 IU/mL [IQR: 14.2-18.2], p<0. 001), without significant changes in anti-TPO/Tg positivity. Changes in thyroid function and anti-thyroid antibodies were generally consistent between BNT162b2 and CoronaVac recipients, although anti-TPO titer rise was greater after BNT162b2 (p<0. 001). NAb responses were similar between individuals with and without pre-existing thyroid autoimmunity (p=0.855). Conclusion: COVID-19 vaccination was associated with a modest increase in anti-thyroid antibody titers. Anti-TPO increase was greater among BNT162b2 recipients. However, there was no clinically significant thyroid dysfunction 8 weeks post-vaccination. NAb responses were not influenced by pre-existing thyroid autoimmunity. Our results provided important reassurance to people to proceed to COVID-19 vaccination.Presentation: No date and time listed

Stoppage of exercise during the COVID-19 pandemic results in worsening liver enzymes in patients with metabolic associated fatty liver disease

Objectives: Worldwide, the COVID-19 pandemic has resulted in lifestyle disruptions, with lockdowns and curtailed activities. This was acutely felt in Asia from February 2020 onwards. Such drastic changes in lifestyle habits may impact negatively on metabolic related diseases. We explored these changes and their effects in patients with metabolic associated fatty liver disease (MAFLD). Materials and Methods: The data of MAFLD patients who were prospectively enrolled from eleven Asian centres in a longitudinal cohort study were analyzed. The data from 1st January 2019 (pre- COVID-19), were compared with the data from 1st February 2020 onwards (during COVID-19). Patients were stratified by physical activity level and whether they met target recommendation of[ 150 min of moderate/vigorous exercise per week. Results: A total of 229 patients were evaluated. Mean age was 59 ± 9.6 years with 136 (59.4%) males. During the COVID-19 pandemic, 50 (21.8%) patients maintained moderate/vigorous exercise, while 28 (12.2%) and 33 (14.4%) patients started and stopped moderate/vigorous exercising respectively. 118 patients (51.5%) did not participate in moderate/vigorous exercise either before or during the pandemic. Seventy-eight (34.1%) patients achieved[150 min moderate/vigorous exercise per week at the last visit. With the onset of COVID-19, reduction of physical activity of any kind was demonstrated in the majority (65.9%) of patients. There was a reduction of any physical activity including walking amongst those who stopped moderate/vigorous exercise and those without moderate/ vigorous exercise throughout. No significant changes in BMI, waist or hip circumference were observed in any activity level group. In patients who stopped moderate/vigorous exercise, alanine transaminase and aspartate transaminase significantly increased by 18.5% and 14.8% respectively. Conclusion: Stoppage of moderate/vigorous exercise leads to worsening of liver enzymes in patients with MAFLD and may have deleterious effects long term. As we adapt to live with COVID endemicity, novel modified healthy lifestyle habits would be needed to manage MAFLD.

Development of a prediction score (ThyroCOVID) for identifying abnormal thyroid function in COVID-19 patients.

PURPOSE: Thyroid dysfunction in COVID-19 carries clinical and prognostic implications. In this study, we developed a prediction score (ThyroCOVID) for abnormal thyroid function (TFT) on admission amongst COVID-19 patients. METHODS: Consecutive COVID-19 patients admitted to Queen Mary Hospital were prospectively recruited during July 2020-May 2021. Thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) were measured on admission. Multivariable logistic regression analysis was performed to identify independent determinants of abnormal TFTs. ThyroCOVID was developed based on a clinical model with the lowest Akaike information criteria. RESULTS: Five hundred and forty six COVID-19 patients were recruited (median age 50 years, 45.4% men, 72.9% mild disease on admission). 84 patients (15.4%) had abnormal TFTs on admission. Patients with abnormal TFTs were more likely to be older, have more comorbidities, symptomatic, have worse COVID-19 severity, higher SARS-CoV-2 viral loads and more adverse profile of acute-phase reactants, haematological and biochemical parameters. ThyroCOVID consisted of five parameters: symptoms (malaise), comorbidities (ischaemic heart disease/congestive heart failure) and laboratory parameters (lymphocyte count, C-reactive protein, and SARS-CoV-2 cycle threshold values). It was able to identify abnormal TFT on admission with an AUROC of 0.73 (95% CI 0.67-0.79). The optimal cut-off of 0.15 had a sensitivity of 75.0%, specificity of 65.2%, negative predictive value of 93.5% and positive predictive value of 28.1% in identifying abnormal TFTs on admission amongst COVID-19 patients. CONCLUSION: ThyroCOVID, a prediction score to identify COVID-19 patients at risk of having abnormal TFT on admission, was developed based on a cohort of predominantly non-severe COVID-19 patients.

3D-DOSS - Using Digital Twins and Spatiotemporal Data Mapping for Infectious Disease Surveillance and Outbreak Investigations

Background. The COVID-19 pandemic has brought to light the importance of contact tracing in outbreak management. Digital technologies have been leveraged to enhance contact tracing in community settings. However, within complex hospital environments, where patient and staff movement and interpersonal interactions are central to care delivery, tools for contact tracing and cluster detection remain limited. We aimed to develop a system to promptly, identify contacts in infectious disease exposures and detect infectious disease clusters. Methods. We prototyped a 3D mapping tool 3-Dimensional Disease Outbreak Surveillance System (3D-DOSS), to have a spatial representation of patients in the hospital inpatient locations. Based on the AutoCAD drawings, the hospital physical spaces are built within a game-development software to obtain accurate digital replicas. This concept borrows from the way gamers interact with the virtual world/space, to mimic the interactions in physical space, like the SIMS franchise. Clinical, laboratory and patient movement data is then integrated into the virtual map to develop syndromic and disease surveillance systems. Risk assignment to individuals exposed is through mathematical modeling based on distance coordinates, room type and ventilation parameters and whether the disease is transmitted via contact, droplet or airborne route. Results. We have mapped acute respiratory illness (ARI) data for the period September to December 2018. We identified an influenza cluster of 10 patients in November 2018. In a COVID-19 exposure involving a healthcare worker (HCW), we identified 44 primary and 162 secondary contacts who were then managed as per our standard exposure management protocols. MDRO outbreaks could also be mapped. Conclusion. Through early identification of at-risk contacts and detection of infectious disease clusters, the system can potentially facilitate interventions to prevent onward transmission. The system can also support security, environmental cleaning, bed assignment and other operational processes. Simulations of novel diseases outbreaks can enhance preparedness planning as health systems that had been better prepared have been more resilient in this current pandemic.

A prospective study of the impact of glycaemic status on clinical outcomes and anti-SARS-CoV-2 antibody responses among patients with predominantly non-severe COVID-19

OBJECTIVE: We aimed to evaluate the impact of glycaemic status on clinical outcomes and anti-SARS-CoV-2 antibody (Ab) response among patients with predominantly non-severe COVID-19, highly relevant to the current COVID-19 vaccination programme. METHODS: We included consecutive adults admitted to Queen Mary Hospital for COVID-19 from July 2020 to May 2021. Glycaemic status was defined by HbA1c on admission: normoglycaemia (<5.7%), prediabetes (5.7-6.4%) and diabetes (≥6.5% or known diabetes). Clinical deterioration was defined by radiological progression, new oxygen requirement, intensive care unit admission, or death. COVID-19 survivors had Ab measurements at 1-month, 2-month, 3- month and 6-month post-discharge, with a live SARS-CoV-2-based microneutralization assay which correlated well with anti-SARS-CoV-2 receptor binding domain IgG (≥1:20 defined as positive). RESULTS: Among 605 patients (age 50.2 - 17.1 years;45.1% men;96.9% non-severe COVID-19), 325 had normoglycaemia, 185 had prediabetes and 95 had diabetes. 74 had clinical deterioration (12.2%): 16 required intensive care and 4 died. Clinical deterioration was more likely with worse glycaemic status (P < 0.001) and higher HbA1c (OR 1.403, P < 0.001). Older age (P < 0.001), higher viral loads (P < 0.001), higher C-reactive protein (CRP) (P < 0.001) and symptomatic presentation (P = 0.008), but not glycaemic status/HbA1c, independently predicted clinical deterioration. 314 patients had Ab measured upon follow-up (1-month: 295;2-month: 227;3-month: 207;6-month: 122). Ab titres were comparable across glycaemic status throughout follow-up period. CRP (P = 0.003), but not glycaemic status/HbA1c, was the only positive independent determinant of Ab levels. Rate of decline of Ab titre was comparable across glycaemic status, and did not correlate with HbA1c. Furthermore, most patients remained Ab-positive throughout follow-up (1-month: 94.9%, 2-month: 93.8%, 3-month: 87.4%, 6-month 80.3%), similar across glycaemic status. CONCLUSION: Worse glycaemic status was associated with a higher chance of clinical deterioration in COVID-19, contributed by older age, more severe inflammation and higher viral loads. Importantly, glycaemic status did not adversely influence the Ab response.

A discussion on the minimum required number of tests in two common pooling test methods for SARS-CoV-2.

Pooling of samples in detecting the presence of virus is an effective and efficient strategy in screening carriers in a large population with low infection rate, leading to reduction in cost and time. There are a number of pooling test methods, some being simple and others being complicated. In such pooling tests, the most important parameter to decide is the pool or group size, which can be optimised mathematically. Two pooling methods are relatively simple. The minimum numbers required in these two tests for a population with known infection rate are discussed and compared. Results are useful for identifying asymptomatic carriers in a short time and in implementing health codes systems.

A discussion on implementing pooling detection tests of novel coronavirus (SARS-CoV-2) for a large population.

A pooled sample analysis strategy for novel coronavirus (severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)) is proposed for a large population in this paper. The population to be tested is divided into divisions based on earlier observed detection rate of SARS-CoV-2 first. Samples collected are then grouped in appropriate pooled size. The number of tests per person in that population is expressed as a function of two variables: the observed detection rate and the pooled size or number of samples grouped. The minimum number of tests per person can be further shown to be a function of only one of these two variables, because these two parameters are found to be related at this minimum. A management scheme on grouping the samples is proposed in order to reduce the number of tests, to save time, which is of utmost importance in fighting an epidemic. The proposed testing scheme will be useful for supporting the government in making decisions to handle regular routine detection tests for identifying asymptomatic patients and implementing health code system in large population of millions of citizens. Another important point is to use smaller number of test kits, allowing more resources to speed up the mass screening tests, particularly in places not so rich.

A proposed two-stage quarantine containment scheme against spreading of novel coronavirus (SARS-CoV-2)

Novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading rapidly all over the world with over 23 million infected near the end of August 2020. There are also asymptomatic patients (APs) who are difficult to identify, but they are infectious and believed to be one of the transmission sources. No specific medicine, no vaccine and even no reliable quick identification tests on SARS-CoV-2 are available yet. Workable safety management must be implemented to stop such global pandemic resulting from disease transmission, including those infected through APs. A two-stage containment scheme is proposed with quarantining people into units within blocks. The units inside a block is to be open after being closed for quarantine for an agreed period such as 14?days. The blocks would then be sealed for another period before opening. Argument of the proposal was supported by a simple mathematical approach with parameters deduced from observations on a cruise ship to estimate the infection constant. The proposed containment scheme is believed to be effective in controlling the spreading of SARS-CoV-2 and identifying APs by a more targeted screening test for the suspected group with a more acceptable environment at the second stage of containment.

Upskilling the surgical workforce for vascular access provision during the COVID-19 pandemic - The Salisbury experience.

A vascular access device is defined as a catheter inserted into veins allowing fluids and medicines to be delivered intravenously1. The need for such devices in acutely unwell patients has remained steady throughout the COVID-19 pandemic. We describe here our experience of up-skilling the resident plastic surgery and maxillofacial surgical registrars to provide a vascular access service to reduce the workload on our intensive care colleagues. We hope that our practice and an 'all hands on deck' approach to the utilisation of baseline skills within the existing workforce will inform other departments to help ease the burden on critical care departments as we progress through the next stages of the COVID-19 pandemic.

Trajectories of large respiratory droplets in indoor environment: A simplified approach.

The recent pandemic of COVID-19 has brought about tremendous impact on every aspect of human activities all over the world. The main route of transmission is believed to be through coronavirus-bearing respiratory droplets. The respiratory droplets have a wide spectrum in droplet size, ranging from very small droplets (aerosol droplets) to large droplets of tens and even hundreds of µm in size. The large droplets are expected to move like projectiles under the action of gravity force, buoyancy force and air resistance. Droplet motion is complicated by droplet evaporation, which reduces droplet size in its trajectory and affects the force acting on it. The present work attempts to determine the trajectories of the large droplets by using a simplified single-droplet approach. It aims at providing a clear physical picture to elucidate the mechanics involved in single droplet motion and the various factors affecting the range. Assuming an indoor environment with an air temperature of 18 °C and relative humidity of 50%, the horizontal range L x of large respiratory droplets (diameter 120 µm-200 µm) in common respiratory activities are as follows: Speaking, L x ≈ 0.16 m-0.68 m, coughing, L x ≈ 0.58 m-1.09 m, and sneezing, L x ≈ 1.34 m-2.76 m. For the smaller droplets (diameter < 100 µm), the droplets are reduced to aerosol droplets (≤5 µm) due to evaporation, and will remain suspended in the air instead of falling onto the ground like a projectile.