Synthesis and characterization of Au-decorated graphene oxide nanocomposite for magneto-electrochemical detection of SARS-CoV-2 nucleocapsid gene.

Fast and effective diagnosis is the first step in monitoring the current coronavirus 2 (CoV-2) pandemic. Herein, we establish a simple and sensitive electrochemical assay using magnetic nanocomposite and DNA sandwich probes to rapidly quantify the CoV-2 nucleocapsid (N) gene down to the 0.37 fM level. This assay uses a pair of specific DNA probes. The capture probe is covalently conjugated to Au-decorated magnetic reduced graphene oxide (AMrGO) nanocomposite for efficiently capturing target RNA. In contrast, the detection probe is linked to peroxidase for signal amplification. The probes target the COV-2 gene, allowing for specific magnetic separation, enzymatic signal amplification, and subsequent generation of voltammetric current with a total assay time of 45 min. The developed biosensor has high selectivity and can discriminate non-specific gene sequences. Synthetic COV-2 N-gene can be detected efficiently in serum and saliva, while 1-bp mismatch gene yielded a low response. The performance of the genosensor was good in an extensive linear range of 5 aM-50 pM. For synthetic N-gene, we achieved the detection limit of 0.37, 0.33, and 0.19 fM in human saliva, urine, and serum. This simple, selective, and sensitive genosensor could have various genetics-based biosensing and diagnostic applications.

Spatiotemporal evolution of online attention to vaccines since 2011: An empirical study in China.

Since the outbreak of Coronavirus Disease 2019 (COVID-19), the Chinese government has taken a number of measures to effectively control the pandemic. By the end of 2021, China achieved a full vaccination rate higher than 85%. The Chinese Plan provides an important model for the global fight against COVID-19. Internet search reflects the public's attention toward and potential demand for a particular thing. Research on the spatiotemporal characteristics of online attention to vaccines can determine the spatiotemporal distribution of vaccine demand in China and provides a basis for global public health policy making. This study analyzes the spatiotemporal characteristics of online attention to vaccines and their influencing factors in 31 provinces/municipalities in mainland China with Baidu Index as the data source by using geographic concentration index, coefficient of variation, GeoDetector, and other methods. The following findings are presented. First, online attention to vaccines showed an overall upward trend in China since 2011, especially after 2016. Significant seasonal differences and an unbalanced monthly distribution were observed. Second, there was an obvious geographical imbalance in online attention to vaccines among the provinces/municipalities, generally exhibiting a spatial pattern of "high in the east and low in the west." Low aggregation and obvious spatial dispersion among the provinces/municipalities were also observed. The geographic distribution of hot and cold spots of online attention to vaccines has clear boundaries. The hot spots are mainly distributed in the central-eastern provinces and the cold spots are in the western provinces. Third, the spatiotemporal differences in online attention to vaccines are the combined result of socioeconomic level, socio-demographic characteristics, and disease control level.

Voltammetric biosensor for coronavirus spike protein using magnetic bead and screen-printed electrode for point-of-care diagnostics.

The rapid spread of the novel human coronavirus 2019 (COVID-19) and its morbidity have created an urgent need for rapid and sensitive diagnostics. The real-time polymerase chain reaction is the gold standard for detecting the coronavirus in various types of biological specimens. However, this technique is time consuming, labor intensive, and expensive. Screen-printed electrodes (SPEs) can be used as point-of-care devices because of their low cost, sensitivity, selectivity, and ability to be miniaturized. The ability to detect the spike protein of COVID-19 in serum, urine, and saliva was developed using SPE aided by magnetic beads (MBs) and a portable potentiostat. The antibody-peroxidase-loaded MBs were the captured and catalytic units for the electrochemical assays. The MBs enable simple washing and homogenous deposition on the working electrode using a magnet. The assembly of the immunological MBs and the electrochemical system increases the measuring sensitivity and speed. The physical and electrochemical properties of the layer-by-layer modified MBs were systematically characterized. The performance of these immunosensors was evaluated using spike protein in the range 3.12-200 ng mL-1. We achieved a limit of detection of 0.20, 0.31, and 0.54 ng mL-1 in human saliva, urine, and serum, respectively. A facile electrochemical method to detect COVID-19 spike protein was developed for quick point-of-care testing.

Exchange rate dynamics with crash risk and interventions

An exchange rate model with crash risk is developed with the exchange rate confined in a wide moving band. A currency crash occurs when its exchange rate breaches a boundary. Using an asymmetric mean-reverting fundamental shock to incorporate intervention policy in the model, the log-normalised exchange rate follows a mean-reverting square-root process, which generates left-skewed exchange rate distributions consistent with outlier negative returns in carry trades. The exchange rates of nine major currencies against the US dollar can be calibrated according to the model, where the mean reversion in the exchange rate dynamic is negatively cointegrated with the risk reversals.

Guidelines on Setting Up Stations for Remote Viewing of Nuclear Medicine and Molecular Imaging Studies During COVID-19.

The current pandemic has created a situation where nuclear medicine practitioners and medical physicists read or process nuclear medicine images remotely from their home office. This article presents recommendations on the components and specifications when setting up a remote viewing station for nuclear medicine imaging.