i-Comments: On-screen Individualized Comments for Online Learning Support

With the rapid development of digitization in education, online learning has become an alternative and promising way to enable flexible learning scenarios. Especially after COVID-19, online learning draws more and more attention. However, online learning has inherent disadvantages and problems. One of them is that learners have difficulty in concentrating, and the other one is that they may feel lonely during lessons. In this study, a new model of on-screen individualized comments, namely i-Comments, is proposed for online learning support. In the proposed model, three elements, i.e., timing, content, and quantity of i-Comments, are defined respectively, which are used to help learners improve concentration and decrease the feeling of loneliness. Furthermore, an experiment is designed to evaluate the model and verify whether the proposed model can help learners gain a better learning experience and improve their learning effectiveness. © 2022 IEEE.

Inactivation Effect of All-Solid-State 228 nm Far-UVC Pulsed Laser

Objective The ongoing coronavirus pandemic has propelled the need for new approaches to disinfection, especially for airborne viruses. The 254 nm emission of low-pressure vacuum lamps is known for its antimicrobial effect;however, its radiation is harmful to human health, causing skin cancer and cataracts. Some studies have shown that short-wavelength ultraviolet (UV) light in the spectral region of 200-230 nm (far-UVC) can inactivate pathogens without harming human cells. Thus, it has great prospects for many applications. Sufficient studies have proved the antibacterial performance of far-UVC band range in an excimer lamp emitting a peak wavelength of 222 nm light. Furthermore, laser light sources can realize long-distance transmission and complement the deficiency of excimer lamps in remote sterilization and disinfection. This study investigates the antibacterial effect of a self-developed far-UVC laser with a peak wavelength of 228 nm and hopes to provide a new technical approach for the inactivation of the novel coronavirus and other microbial pathogens. Methods Bacterial sample preparation: Escherichia coli (E. coli) widely exists naturally and is a pathogen of major focus in human public health defense. It is also one of the most drug-resistant species in the enterobacterium group. Therefore, it is often used in ultraviolet disinfection and environmental health research. Bacillus cereus (B. cereus), which is closely related to humans, causes food poisoning and cannot be eliminated by pasteurization or normal hygiene procedures due to the heat and acid resistance of its spores. Therefore, the strains used in this experiment are E. coli and B. cereus. E. coli and B. cereus are provided by the Ministry of Education Key Laboratory for Ecology of Tropical Islands, Hainan Normal University, and subsp. Kustaki HD-1, provided by the Environmental Microbial Ecology Laboratory of Hainan Normal University. Both strains are cultured in a nutrient agar medium and placed in an incubator at 35 degrees C for 1 day. Nutrient agar medium is provided by Guangdong Huankai Microbial Technology Co., LTD, China. UV irradiation source: the irradiation source is a self-developed all-solid-state 228 nm far-UVC laser, which provides UV irradiance of up to 35 mW/cm(2), and its spectral linewidth is less than 0.1 nm. The laser is realized by LD-pumped Nd3+ laser crystal, Q-switched technology, and nonlinear optical frequency conversion technology. All-solid-state lasers have the advantages of small size, high efficiency, good beam quality, high reliability, long life, and portability. 228 nm far-UVC laser sterilization: we input a certain concentration of 1 mL bacterial suspension sample into a high permeability UVC cuvette. The 228 nm laser irradiance of 0.1 mW/cm(2) is obtained by adjusting the laser output power and the placement of the colorimeter. E. coli suspension samples are irradiated for 5, 10, 15, and 20 s [Fig. 1 (b), and B. cereus suspension samples are irradiated for 15, 30, 45, and 60 s [Fig. 1(c)] at 228 nm far-UV light of 0.1 mW/cm(2). The experiment is repeated three times for each sample at the same irradiation dose. Results and Discussions Figs. 1 (b) and (c) show the distribution of bacteria before and after 228 nm laser irradiation. The concentration of bacterial suspension samples in the control and irradiated groups is determined using the nutrient agar plate counting method. The detection results are shown in Table 1. When the E. coli suspension is irradiated by 228 nm laser for 10, 15, and 20 s (1, 1.5, and 2 mJ/cm(2)), the inactivation rates are 90. 7 %, 96.9 %, and 100 yo, respectively. When the B. cereus suspension is irradiated by 228 nm laser for 30, 45, and 60 s (3, 4. 5, and 6 mJ/cm(2)), the inactivation rates are 88. 4%, 98.6 %, and 100 %, respectively. Conclusions This experimental study shows that the use of several mJ/cm(2) doses of far-UVC 228 nm pulsed laser irradiation can effectively inactivate E. coli and B. cereus, whereas the use of excimer lamps requires dozens of mJ/cm(2) doses. Compared with the excimer light source, the far-UVC pulsed laser light source shows a stronger sterilization effect. The next step is to conduct experimental research on the inactivation of the influenza virus using a far-UVC 228 nm pulsed laser.

Research Progress on Moral Injury of Foreign Medical Staff under the Background of COVID-19 Pandemic

This paper reviewed the research on moral injury among foreign medical staff in the background of the COVID-19 pandemic. It was found that foreign medical staff bore multiple moral pressures and impacts in the face of the epidemic, including the collision between medical practice and utilitarian policy, the inability to meet personal needs, the rapid transformation of medical mode, and a variety of comprehensive factors. Therefore, the moral injury of foreign medical staff is particularly prominent. In order to avoid and reduce the occurrence of moral injury, it is necessary to strengthen the cultivation of moral resilience, provide psychological and social support, and carry out personalized treatment for medical staff. © 2022, Editorial department of Chinese Medical Ethics. All rights reserved.

Time Warping Clustering for the Forecast and Analysis of COVID-19

This paper presents an effective algorithm for the clustering of confirmed COVID-19 cases at the county-level in the United States. Dynamic time warping and Euclidean distance are examined as the k-means clustering distance metrics. Dynamic time warping can compare time series varying in speed, as counties often experience similar outbreak trends without the timelines matching up exactly. The effect of data preprocessing on clustering was systematically studied. Further analyses demonstrate the immediate value of our clusters for both retrospective interpretation of the pandemic and as informative inputs for case prediction models. We visualize the time progression of COVID-19 from April 5, 2020 to August 23, 2020. We proposed a Monte-Carlo dropout feedforward neural network with the ability to forecast four weeks into the future. Predictions evaluated from July 24, 2020 to August 20, 2020 demonstrate the better empirical performance of the model when trained on the clusters, in comparison with the model trained on individual counties and the model trained on counties clustered by state. © 2020 IEEE.

Release of Microplastics from Discarded Surgical Masks and Their Adverse Impacts on the Marine Copepod Tigriopus japonicus

Surgical masks (SMs) are the most commonly used personal protective equipment during the COVID-19 pandemic. Due to their vast use and inappropriate disposal worldwide, SMs could potentially cause serious microplastic (MP) pollution in coastal marine environments. This study aimed to investigate the kinetic release of MPs from polypropylene SMs (PP-SMs) in seawater and to evaluate the chronic toxicity of the released MPs to the marine copepod Tigriopus japonicus. On the basis of the results of our kinetic study and available relevant data, we estimated that SMs discarded throughout the year 2020 would lead to >137 trillion MPs entering the coastal marine environment globally, with a release rate of 396 billion MPs per day. Our results also demonstrated that the copepods ingested the MPs released from PP-SMs, causing a significant decline in their fecundity. The results clearly suggest the MPs released from improperly discarded SMs could have a long-term domino effect on coastal marine ecosystems. To minimize the risk of this emerging threat, better environmental management, policy, and law enforcement for ensuring the proper disposal of SMs are deemed to be necessary. © 2021 The Authors. Published by American Chemical Society.

TCTAP A-007 Transradial Versus Transfemoral Access in STEMI Patients Undergoing Rescue Percutaneous Coronary Intervention Post Fibrinolytic Therapy: A 10-year Contemporary National Centre Experience

Background: It is widely known that timely percutaneous coronary intervention (PCI) is superior to fibrinolysis in patients with ST Elevation Myocardial Infarction (STEMI). However, fibrinolytic therapy is still widely used in Malaysia due to factors such as lack of PCI-capable hospitals, logistics, and financial issues. Unfortunately, there are patients who fail to achieve reperfusion after thrombolysis and hence PCI still plays a crucial role and can be life-saving for such patients. Vascular access is then a major concern as femoral access potentially carries higher bleeding risk which in turn leads to increased mortality. Therefore, radial approach has been advocated due to lower risk of bleeding events, ease of access and reduced hospital length of stay. This study aims to look at the trend of usage, compare characteristics, safety, and clinical outcomes of radial versus femoral access in this group of patients. Methods: This is an observational retrospective analysis. 498 patients with acute STEMI that underwent rescue PCI in the National Heart Institute from January 2007 till December 2016 were included in the study. These patients were referred from other hospitals due to failed thrombolysis. Patients’ demographics, risk factors, and procedural characteristics were evaluated. The yearly trend of radial versus femoral access was analyzed. Comparison of outcomes between radial and femoral approach was done categorically on in-hospital mortality rate, MACE rate (Death, reinfarction, urgent CABG, Stroke) at 30-day, 6-month, and 1-year follow up. Results: Femoral access was used in 296 patients whereas radial access was used in 202 patients. Notably, femoral access was used more frequently in patients above 50 years old. In terms of gender, predominantly male (90.6% for radial and 85.8% for femoral). A pattern was seen whereby operators were more in favor of femoral access from 2007 till 2014 but subsequently switched to predominantly radial access from 2015 onwards. This change was due to an increasing trend of usage for radial approach with concurrent decreasing trend for femoral approach throughout the past decade. Femoral approach was seen significantly more in patients with history of previous myocardial infarction and heart failure, chronic kidney disease (CKD), Killip II onwards and associated with higher IABP usage. Analysis showed that radial approach was associated with lower in-hospital mortality compared to femoral approach (3% Vs 13.2%, p≤0.001). However, there were no significant differences in terms of bleeding outcomes, length of stay, 30-day, 6-month, and 1-year mortality between both approaches. Femoral access also did not significantly increase MACE within 1 year compared to radial access in STEMI patients who underwent rescue PCI (Hazard Ratio: 1.9;95% Confidence Interval, 0.8-4.5;p = 0.164). [Formula presented] [Formula presented] [Formula presented] [Formula presented] Conclusion: The usage trend over the past decade seems likely due to the landmark studies for benefits of radial over femoral access, improving skills and experience of operators. From this study, we can then infer that radial approach confers more favorable outcome in terms of in-hospital mortality. It is likely that the femoral approach was used in group of patients which were more ill at presentation and had more co-morbidities. Otherwise, the results in this study were somewhat similar with the recent SAFARI-STEMI study whereby there were no significant differences between the MACE outcome and bleeding events. In this new era with the Covid-19 pandemic, there is a continuous debate as to whether primary PCI should be deferred with thrombolysis-first approach being adopted in many places. Hence, this study is pertinent as operators can be assured of the similar bleeding events. In conclusion, radial approach should be attempted as long it is feasible while operators still need to be facile in the femoral approach.

Economic benefit of shale gas exploitation based on back propagation neural network

Under the influence of COVID-19, the economic benefits of shale gas development are greatly affected. With the large-scale development and utilization of shale gas in China, it is increasingly important to assess the economic impact of shale gas development. Therefore, this paper proposes a method for predicting the production of shale gas reservoirs, and uses back propagation (BP) neural network to nonlinearly fit reservoir reconstruction data to obtain shale gas well production forecasting models. Experiments show that compared with the traditional BP neural network, the proposed method can effectively improve the accuracy and stability of the prediction. There is a nonlinear correlation between reservoir reconstruction data and gas well production, which does not apply to traditional linear prediction methods © 2020 - IOS Press and the authors. All rights reserved.