Discrimination of the H1N1 and H5N2 Variants of Influenza A Virus Using an Isomeric Sialic Acid-Conjugated Graphene Field-Effect Transistor.

There has been a continuous effort to fabricate a fast, sensitive, and inexpensive system for influenza virus detection to meet the demand for effective screening in point-of-care testing. Herein, we report a sialic acid (SA)-conjugated graphene field-effect transistor (SA-GFET) sensor designed using α2,3-linked sialic acid (3'-SA) and α2,6-linked sialic acid (6'-SA) for the detection and discrimination of the hemagglutinin (HA) protein of the H5N2 and H1N1 viruses. 3'-SA and 6'-SA specific for H5 and H1 influenza were used in the SA-GFET to capture the HA protein of the influenza virus. The net charge of the captured viral sample led to a change in the electrical current of the SA-GFET platform, which could be correlated to the concentration of the viral sample. This SA-GFET platform exhibited a highly sensitive response in the range of 101-106 pfu mL-1, with a limit of detection (LOD) of 101 pfu mL-1 in buffer solution and a response time of approximately 10 s. The selectivity of the SA-GFET platform for the H1N1 and H5N2 influenza viruses was verified by testing analogous respiratory viruses, i.e., influenza B and the spike protein of SARS-CoV-2 and MERS-CoV, on the SA-GFET. Overall, the results demonstrate that the developed dual-channel SA-GFET platform can potentially serve as a highly efficient and sensitive sensing platform for the rapid detection of infectious diseases.

Fluorophore-encapsulated nanobeads for on-site, rapid, and sensitive lateral flow assay.

Since December 2019, the rapid and sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a priority for public health. Although the lateral flow assay (LFA) sensor has emerged as a rapid and on-site SARS-CoV-2 detection technique, the conventional approach of using gold nanoparticles for the signaling probe had limitations in increasing the sensitivity of the sensor. Herein, our newly suggested methodology to improve the performance of the LFA system could amplify the sensor signal with a facile fabrication method by concentrating fluorescent organic molecules. A large Stokes shift fluorophore (single benzene) was encapsulated into polystyrene nanobeads to enhance the fluorescence intensity of the probe for LFA sensor, which was detected on the test line with a longpass filter under ultraviolet light irradiation. This approach provides comparatively high sensitivity with the limit of detection of 1 ng mL-1 for the SARS-CoV-2 spike protein and a fast detection process, which takes less than 20 min. Furthermore, our sensor showed higher performance than gold nanoparticle-based commercial rapid diagnostics test kits in clinical tests, proving that this approach is more suitable and reliable for the sensitive and rapid detection of viruses, bacteria, and other hazardous materials.

A Pilot Study of Virtual Reality (VR) Tai Chi Program on Mental Health among Older Adults during the COVID-19 Pandemic.

OBJECTIVES: Tai Chi, an ancient Chinese martial art, has been credited for improving the physical and mental health of community-dwelling older adults. Virtual reality (VR) has developed as a therapeutic technique for improving health and well-being in older adults. Previous research on exercise-based VR interventions in older adults has focused primarily on the physical and cognitive health effects. The extent to which a program integrating the ancient practice of Tai Chi with virtual reality might benefit older individuals' physical and mental health is an unknown entity. In this pilot study, we examined potential advantages of the virtual Tai Chi program in terms of health outcomes, as well as to gather qualitative data on the barriers to VR program participation. METHODS: We conducted semi-structured, in-depth interviews with 5 participants who had participated at least 5 years in traditional Tai Chi. RESULTS: Three key salient themes emerged as beneficial results of VR experiences: (1) mindfulness/ meditation, (2) enjoyment, and (3) physical exercise. Participants also reported 3 main challenges: (1) some difficulties with controllers and functions, (2) cybersickness/pain, and (3) absence of group synergy. CONCLUSIONS: These challenges suggest further avenues of investigation for researchers in refining this approach.

Treatment delay and outcomes of ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention during the COVID-19 era in South Korea.

BACKGROUND/AIMS: Little is known about the clinical characteristics and treatment outcomes of ST-segment elevation myocardial infarction (STEMI) in Korea during the coronavirus disease 2019 (COVID-19) era. We aimed to evaluate the clinical characteristics and treatment outcomes of patients with STEMI in the COVID-19 era. METHODS: A total of 588 consecutive patients with STEMI who underwent primary percutaneous coronary intervention were included in this study. The patients were categorized into the COVID-19 (from January 20, 2020 to December 31, 2020) and control groups (from January 20, 2019 to December 31, 2019). RESULTS: The COVID-19 group showed pre-hospital and in-hospital delays than the control group. The control group underwent more thrombus aspiration and had a higher proportion of left main coronary artery diseases, while the COVID-19 group had a higher proportion of multivessel diseases with a marked increase in the number and total length of stents than the control group. As for the prescribed medications, the COVID-19 group was administered more beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and statins than the control group. The clinical outcomes were comparable between the groups, except for higher incidences of atrioventricular block and temporary pacemaker implantation in the COVID-19 group. CONCLUSION: Reperfusion after STEMI treatment during the COVID-19 period was delayed; therefore, efforts should be made to improve on reperfusion.

Wearable Cortisol Aptasensor for Simple and Rapid Real-Time Monitoring.

The necessity of managing stress levels is becoming increasingly apparent as the world suffers from different kinds of stresses including the extent of pandemic, the corona virus disease 2019 (COVID-19). Cortisol, a clinically confirmed stress hormone related to depression and anxiety, affects individuals mentally and physically. However, current cortisol monitoring methods require expert personnel, large and complex machines, and long time for data analysis. Here, we present a flexible and wearable cortisol aptasensor for simple and rapid cortisol real-time monitoring. The sensing channel was produced by electrospinning conducting polyacrylonitrile (PAN) nanofibers (NFs) and subsequent vapor deposition of carboxylated poly(3,4-ethylenedioxythiophene) (PEDOT). The conjugation of the cortisol aptamer on the PEDOT-PAN NFs provided the critical sensing mechanism for the target molecule. The sensing test was performed with a liquid-ion gated field-effect transistor (FET) on a polyester (polyethylene terepthalate). The sensor performance showed a detection limit of 10 pM (<5 s) and high selectivity in the presence of interference materials at 100 times higher concentrations. The practical usage and real-time monitoring of the cortisol aptasensor with a liquid-ion gated FET system was demonstrated by successful transfer to the swab and the skin. In addition, the real-time monitoring of actual sweat by applying the cortisol aptasensor was also successful since the aptasensor was able to detect cortisol approximately 1 nM from actual sweat in a few minutes. This wearable biosensor platform supports the possibility of further application and on-site monitoring for changes of other numerous biomarkers.

Detection of Infectious Viruses Using CRISPR-Cas12-Based Assay.

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease-19 (COVID-19), has severely influenced public health and economics. For the detection of SARS-CoV-2, clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein (Cas)-based assays have been emerged because of their simplicity, sensitivity, specificity, and wide applicability. Herein, we have developed a CRISPR-Cas12-based assay for the detection of SARS-CoV-2. In the assay, the target amplicons are produced by isothermal reverse transcription recombinase polymerase amplification (RT-RPA) and recognized by a CRISPR-Cas12a/guide RNA (gRNA) complex that is coupled with the collateral cleavage activity of fluorophore-tagged probes, allowing either a fluorescent measurement or naked-eye detection on a lateral flow paper strip. This assay enables the sensitive detection of SARS-CoV-2 at a low concentration of 10 copies per sample. Moreover, the reliability of the method is verified by using nasal swabs and sputum of COVID-19 patients. We also proved that the current assay can be applied to other viruses, such as Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV), with no major changes to the basic scheme of testing. It is anticipated that the CRISPR-Cas12-based assay has the potential to serve as a point-of-care testing (POCT) tool for a wide range of infectious viruses.

Machine Learning and Algorithmic Pairs Trading in Futures Markets

This study applies machine learning methods to develop a sustainable pairs trading market-neutral investment strategy across multiple futures markets. Cointegrated pairs with similar price trends are identified, and a hedge ratio is determined using an Error Correction Model (ECM) framework and support vector machine algorithm based upon the two-step Engle-Granger method. The study shows that normal backwardation and contango do not consistently characterize futures markets, and an algorithmic pairs trading strategy is effective, given the unique predominant price trends of each futures market. Across multiple futures markets, the pairs trading strategy results in larger risk-adjusted returns and lower exposure to market risk, relative to an appropriate benchmark. Backtesting is employed and results show that the pairs trading strategy may hedge against unexpected negative systemic events, specifically the COVID-19 pandemic, remaining profitable over the period examined.