ABSTRACT
Recently, inspired by natural biological motor behavior, various actuators emerge at the historic moment. Actuator is a kind of device that converts input energy into mechanical motion, and the input energy can be triggered by various stimuli such as heat, light, and electric fields. However, present actuators usually are driven by a single stimulus, often showing poor performance with high power consumption. Here, a MXene and Low-Density Polyethylene based actuator with multiresponsive functions was fabricated via a facile drop-casting method. The electrically driven actuator shows a large offset distance (20 mm), with a low driving voltage of 1.5 V. The heat driven actuator can sense temperature gradient and capture object in the same way that flytraps do. Especially, finite element analysis was used to successfully verify the working mechanism. The light driven actuator is able to perform like a walking robot with a speed up to 16.52 mm min-1. It can perform as a light-controlled (or heat-controlled) switch and be integrated into a circuit being applied to some extreme occasions that require non-contact switches, for example, the current need for non-contact scenarios with COVID-19. This work also provides a new paradigm for expanding MXene applications.
ABSTRACT
Background: Coronavirus disease 2019 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 is highly transmissible. Early and rapid testing is necessary to effectively prevent and control the outbreak. Detection of SARS-CoV-2 antibodies with lateral flow immunoassay can achieve this goal. Antibody detection is especially effective for the detection of asymptomatic infection.Methods: In this study, SARS-CoV-2 nucleoprotein was expressed by E. coli and purified by affinity chromatography. We used the highly stable and sensitive selenium nanoparticle as the labeling probe coupled with the SARS-CoV-2 nucleoprotein to prepare a new SARS-CoV-2 antibody (IgM and IgG) detection kit. The sensitivity and specificity of the kit were verified by plasma of COVID-19 patients and health persons. Separate detection of IgM and IgG, such as in this assay, was performed in order to reduce mutual interference and improve the accuracy of the test results.Results: The SARS-CoV-2 nucleoprotein was purified on a nickel column, and the final purity was greater than 90%. The sensitivity of the kit was 94.74% and the specificity was 95.12% by 41 negative plasma samples and 19 positive plasma samples detection.Conclusions: The assay kit does not require any special device for reading the results and the readout is a simple color change that can be evaluated with the naked eye. This kit is suitable for rapid and real-time detection of the SARS-CoV-2 antibody.
Subject(s)
COVID-19 , Communicable DiseasesABSTRACT
Background The outbreak and the rampant spread of SARS-CoV-2-infected pneumonia (COVID-19) first identified in Wuhan, China, has infected thousands of patients and killed more than two thousand. We aimed to find indicators that could predict the progression of SARS-CoV-2 pneumonia. Methods Medical history, clinical features, laboratory and radiological results were retrospectively reviewed from 112 patients with clinically diagnosed SARS-CoV-2 pneumonia in Renmin Hospital of Wuhan University from Jan 1 to Jan 31, 2020. Clinical outcomes were followed up to Feb 9, 2020. Results Based on their outcomes, we divided these patients into groups of remission, deterioration and death respectively, and analyzed the counts of lymphocyte and its subsets. A decreased combination of CD3+, CD4+ and CD8+ T lymphocyte counts was observed as the SARS-CoV-2 pneumonia progressed. Among them, the CD4+ T lymphocyte counts were reduced at the early stage, while CD8+ counts were decreased at advanced stage or end stage. Conclusions We identified in our study of 112 hospitalized patients that CD3+, CD4+ and CD8+ T lymphocyte counts were useful markers to predict the clinical progression of SARS-CoV-2 pneumonia at different stages. Considering the large number of patients with severe pneumonia, and the urgency of this ongoing global public health emergency, the counts of lymphocyte and its subsets from laboratory examinations could be easy and useful indicators for physicians to determine a timely and proper therapeutic strategy for patients and an early warning sign for predicting or reducing mortality in SARS-CoV-2-infected pneumonia.