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DNA is commonly employed as a substrate for the building of artificial logic networks due to its excellent biocompatibility and programmability. Till now, DNA logic circuits have been rapidly evolving to accomplish advanced operations. Nonetheless, the process of creating DNA logic circuits according to personal needs (logical truth table) requires extensive knowledge on digital circuits. Moreover, even after the researchers endeavor to build a DNA circuit, it lacks field programmability and thereby being disposable and inconvenient. Herein, inspired by the Configurable Logic Block (CLB) paradigm in silicon digital circuits, we present the CLB-based field-programmable DNA circuit that uses clip strands as its operation-controlling signals. It substantially simplifies the construction of desired circuits by establishing the relationship between circuits and operation-controlling strands. Additionally, the field programmability enables users to realize diverse functions with limited hardware. We firstly constructed CLB-based basic logic gates (OR and AND), and effectively demonstrate their eras ability and field programmability. Furthermore, by simply adding the appropriate operation-controlling strands, we achieved multiple rounds of switch among 5 different logic operations on a single two-layer circuit. In addition, we successfully built a circuit to implement two fundamental binary calculators: half-adder and half-subtractor, proving that our design could imitate silicon-based binary circuits. Finally, we built a comprehensive CLB-based circuit that enabled multiple rounds of switch among 7 different logic operations including half-adding and half-subtracting. Overall, the CLB-based field-programmable circuit greatly streamlines the process to build DNA circuits and immensely enhances their practicability. We believe our design could be widely used in DNA logic networks due to its efficiency and convenience.

Cataract causes more than half of all blindness worldwide. The most effective treatment is surgery, where cataract is often replaced by intraocular lens (IOL). Beyond saving vision, toric IOL implantation is becoming increasingly popular to correct corneal astigmatism. It is important to precisely position and align the axis of IOL during surgery to achieve optimal post-operative astigmatism correction. Comparing with conventional manual marking, automated markerless IOL alignment can be faster, more accurate and non-invasive. Here we propose a framework for computer-assisted intraoperative IOL positioning and alignment based on detection and tracking. Firstly, the iris boundary was segmented and the eye center was determined. A statistical sampling method was developed to segment iris and generate training labels, and both conventional algorithms and deep convolutional neural network (CNN) methods were evaluated. Then, regions of interests (ROIs) containing high density of scleral capillaries were used for tracking eye rotations. Both correlation filter and CNN methods were evaluated for tracking. Cumulative errors during long-term tracking were corrected using a reference image. Validation studies against manual labeling using 7 clinical cataract surgical videos demonstrated that the proposed algorithm achieved an average position error around 0.2 mm, an axis alignment error of $^{\circ}$ , and a frame rate of > 25 FPS, and can be potentially used intraoperatively for markerless IOL positioning and alignment during cataract surgery.

Background: COVID-19 has become one of the most serious global epidemics in the 21st Century. This study aims to explore the distribution of research capabilities of countries, institutions, and researchers, and the hotspots and frontiers of coronavirus research in the past two decades. In it, references for funding support of urgent projects and international cooperation among research institutions are provided. Method: the Web of Science core collection database was used to retrieve the documents related to coronavirus published from 2003 to 2020. Citespace.5.6.R2, VOSviewer1.6.12, and Excel 2016 were used for bibliometric analysis. Results: 11,036 documents were retrieved, of which China and the United States have contributed the most coronavirus studies, Hong Kong University being the top contributor. Regarding journals, the Journal of Virology has contributed the most, while in terms of researchers, Yuen Kwok Yung has made the most contributions. The proportion of documents published by international cooperation has been rising for decades. Vaccines for SARS-CoV-2 are under development, and clinical trials of several drugs are ongoing. Conclusions: international cooperation is an important way to accelerate research progress and achieve success. Developing corresponding vaccines and drugs are the current hotspots and research directions.

Dark septate endophytes (DSEs) are one of the most studied groups of root fungal endophytes in recent years. However, the effects of DSE on host plant are still under debate, and the molecular mechanisms are poorly understood. In this study, we identified a DSE fungus of the genus Anteaglonium, named T010, from the wild blueberry. When inoculated into Vaccinium corymbosum L. plants, T010 could enhance root growth and promote shoot branching, leading to increased plant growth. By comparative transcriptome analysis, we obtained 1948 regulated differentially expressed genes (DEGs) from the V. corymbosum plants treated by T010. Further functional enrichment analysis identified a series of DEGs enriched in transcriptional regulation, material transport, phytohormone biosynthesis and flavonoid biosynthesis. Moreover, the comparative analysis of liquid chromatography–mass spectrometry verified that T010 treatment induced the changes in the contents of various phytohormones and flavonoids. This is the first report on the isolation of DSE fungi of the genus Anteaglonium from blueberry roots. Moreover, our results suggested that T010 colonization could result in a series of changes in cell metabolism, biosynthesis and signal pathways, thereby promoting plant growth. Particularly, the changes of phytohormone and flavonoid metabolism induced by T010 colonization might contribute to the promotion of blueberry growth. Our results will provide new insights into understanding of the interaction of DSE fungi and host plants, as well as the development and utilization of DSE preparations.

Buckle propagation is an essential concern in offshore pipeline design. Once the propagation occurs, it may cause unavoidable failure of an entire pipeline. With the consideration of both longitudinal and hoop deformation behavior of pipeline, a ring-truss theory was analytically established in this study. Laboratory experiments were conducted in full-scale hyperbaric chamber in order to verify the analytical equation. It was observed that the length of transition zone has great influence on determination of propagation pressure. Due to the difficulties of measurement during test process, the length of transition zone was obtained using the finite element simulation. The comparison of propagation pressure between the current study and published model shows that for small diameter to thickness ratio, the ring-truss model is the one that is closest to the actual situation.

DRM has been widely used for digital content protection over Internet. Regular DRM systems bundle “user, rights, and content” together during license delivery. Thus, it will be easy to cause the overload of license server when licenses need to be updated frequently. In this work, we present a scheme based on “rights claim”, separating the bundled one into “user - rights”, “content - rights claim”, and “rights - rights claim”. We also propose a new DRM system based on our proposal, applying a tag scheme for user grouping and license updating, which especially suitable for large scale live streaming scenario. Comparing with regular DRM systems, it is a simple and secure scheme whose performance and overhead is significantly better.