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BackgroundThe COVID-19 pandemic has imposed a large, initially uncontrollable, public health crisis both in the US and across the world, with experts looking to vaccines as the ultimate mechanism of defense. The development and deployment of COVID-19 vaccines have been rapidly advancing via global efforts. Hence, it is crucial for governments, public health officials, and policy makers to understand public attitudes and opinions towards vaccines, such that effective interventions and educational campaigns can be designed to promote vaccine acceptance. ObjectiveThe aim of this study is to investigate public opinion and perception on COVID-19 vaccines by investigating the spatiotemporal trends of their sentiment and emotion towards vaccines, as well as how such trends relate to popular topics on Twitter in the US. MethodsWe collected over 300,000 geotagged tweets in the US from March 1, 2020 to February 28, 2021. We examined the spatiotemporal patterns of public sentiment and emotion over time at both national and state scales and identified three phases along the pandemic timeline with the significant changes of public sentiment and emotion, further linking to eleven key events and major topics as the potential drivers to induce such changes via cloud mapping of keywords and topic modelling. ResultsAn increasing trend of positive sentiment in parallel with the decrease of negative sentiment are generally observed in most states, reflecting the rising confidence and anticipation of the public towards vaccines. The overall tendency of the eight types of emotion implies the trustiness and anticipation of the public to vaccination, accompanied by the mixture of fear, sadness and anger. Critical social/international events and/or the announcements of political leaders and authorities may have potential impacts on the public opinion on vaccines. These factors, along with important topics and manual reading of popular posts on eleven key events, help identify underlying themes and validate insights from the analysis. ConclusionsThe analyses of near real-time social media big data benefit public health authorities by enabling them to monitor public attitudes and opinions towards vaccine-related information in a geo-aware manner, address the concerns of vaccine skeptics and promote the confidence of individuals within a certain region or community, towards vaccines.

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Objective To analyze the dose dependent cardiotoxicity of cyclophosphamide and thus establish the mouse models for understanding the underlying mechanisms . Methods Thirty mice ( 7 -8 weeks old) were randomly divided into 6 groups:control of one course group ,control of two courses group , one course of low dose ( 50 mg/kg) group ,two courses of low dose group ,one course of high dose ( 100 mg/kg) group ,two courses of high dose group . The changes of cardiac function and morphology were analyzed at indicated times by ultrasound and histology respectively . Results Compared with the control groups , injection of low dose cyclophosphamide either with one course or two courses ,and injection of high dose with only one course had no in statically significant changes in hair color ,physical activity ,body weight and cardiac function( P > 0 .05) . Treatment of two courses with high dose resulted in significant decrease of physical activity and body weight ( P < 0 .05 ) . Meanwhile ,cardiac systolic function was significantly decreased( P <0 .05) . Histology study revealed robust cardiac hypertrophy and fibrosis . Conclusions Two courses of intraperitoneal injection of cyclophosphamide at high dose result in obvious cardiotoxicity , especially systolic dysfunction .Intraperitoneal injection of two courses of cyclophosphamide serves as a good strategy to induce cardiotoxicity in mice ,which could be applied for future mechanism study .

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In an anti-thrombotic pressure circulatory device, relays and solenoid valves serve as core execution units. Thus the therapeutic efficacy and patient safety of the device will directly depend on their performance. A new type of testing system for relays and solenoid valves used in the anti-thrombotic device has been developed, which can test action response time and fatigue performance of relay and solenoid valve. PC, data acquisition card and test platform are used in this testing system based on human-computer interaction testing modules. The testing objectives are realized by using the virtual instrument technology, the high-speed data acquisition technology and reasonable software design. The two sets of the system made by relay and solenoid valve are tested. The results proved the universality and reliability of the testing system so that these relays and solenoid valves could be accurately used in the antithrombotic pressure circulatory equipment. The newly-developed testing system has a bright future in the aspects of promotion and application prospect.

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A new type of testing system used for antithrombotic pressure circulatory equipment has been developed, which realized a new method for the calibration of pressure sensor. Multi-path control and acquisition functions are achieved by this method based on human-computer interaction testing system. The precision of pressure sensor is ob tained by polynomial fitting for each test point using linear interpolation method. The result showed that the precision test of pressure sensor could be realized easily and efficiently, using the developed testing system, and the parameters of pressure sensor could be calibrated effectively, so that it could be accurately used in the antithrombotic pressure circulatory equipment. The developed testing system has a prosperous future in the aspects of promotion and application.

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