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In the search for treatment schemes of COVID-19, we start by examining the general weakness of coronaviruses and then identify approved drugs attacking that weakness. The approach, if successful, should identify drugs with a specific mechanism that is at least as effective as the best drugs proposed and are ready for clinical trials. All coronaviruses translate their non-structural proteins (∼16) in concatenation, resulting in a very large super-protein. Homo-harringtonine (HHT), which has been approved for the treatment of leukemia, blocks protein elongation very effectively. Hence, HHT can repress the replication of many coronaviruses at the nano-molar concentration. In two mouse models, HHT clears SARS-CoV-2 in 3 days, especially by nasal dripping of 40 ug per day. We also use dogs to confirm the safety of HHT delivered by nebulization. The nebulization scheme could be ready for large-scale applications at the onset of the next epidemics. For the current COVID-19, a clinical trial has been approved by the Ditan hospital of Beijing but could not be implemented for want of patients. The protocol is available to qualified medical facilities.

A clock network is not only difficult to design, but also challenging to test. For high-performance designs with a rigorous clock-skew requirement, small defects in a clock tree network could lead to unexpected failures in the field and thus need to be identified during the manufacturing test. In this paper, we present a novel flush test procedure to determine if a clock network has any small delay faults. This method does not require any change of the clock network, but it does require a “special test clock signal,” which can be generated on the chip by using only standard cells. Experimental results of transistor-level simulation on benchmark circuits injected with resistive open defects in the layout show that the proposed method is capable of detecting a delay fault as small as 52.8 ps.

Middle East respiratory syndrome coronavirus (MERS-CoV), a member of the Coronaviridae family, is the causative pathogen for MERS that is characterized by high fever, pneumonia, acute respiratory distress syndrome (ARDS), as well as extrapulmonary manifestations. Currently, there are no approved treatment regimens or vaccines for MERS. Here, we generated recombinant nonvirulent Newcastle disease virus (NDV) LaSota strain expressing MERS-CoV S protein (designated as rLa-MERS-S), and evaluated its immunogenicity in mice and Bactrian camels. The results revealed that rLa-MERS-S showed similar growth properties to those of LaSota in embryonated chicken eggs, while animal immunization studies showed that rLa-MERS-S induced MERS-CoV neutralizing antibodies in mice and camels. Our findings suggest that recombinant rLa-MERS-S may be a potential MERS-CoV veterinary vaccine candidate for camels and other animals affected by MERS.

In order to improve the citrus grading accuracy, fractal dimensions which characterize the color and shape features of citrus fruit were analyzed. Samples were from Citrus unshiu Marc.cv.unbergii Nakai. For each sample, images from peduncle, calyx and two opposite sides were collected. These four images were cut, removed backgrounds, and converted from RGB space to HSI one, then by the following methods, the color and shape features of citrus were extracted 1) HSI images were segmented according to hue value of 0°~20°, 20°~40°, 40°~60°, 60°~80°and 80°~100°. And each segment image was converted to binary image to retrieve box dimension, which character the color feature of fruit. 2) HSI images were converted to binary images, and then the imagines were edge detected and the box dimension of fruits profile of peduncle and one side, which character the shape features of fruits, were retrieved. Based on the box dimensions, a wavelet neural network was constructed to model the fruit color and shape grading system. Test results showed that for 120 sample fruits, the average correctness of color and shape grading was 95.83%, which mean box dimensions of equal segmentation of hue value 0°~100° revealed the color feature, and box dimensions of peduncle and side profile revealed fruit shape information. Color and shape grading accuracy meet the requirements for auto-grading of system real-time machine-vision.

A recombinant Newcastle disease virus (NDV) expressing the green fluorescent protein (GFP) was generated by applying reverse genetics techniques. The GFP open reading frame flanked by NDV transcription start and stop sequences was inserted between the phosphoprotein (P) and matrix protein (M) in a full-length cDNA clone of NDV Lasota vaccine strain. This plasmid transcribing antigenome RNA was cotransfected with helper plasmids expressing viral nucleoprotein, phosphoprotein and large protein into cells stably expressing T7 RNA polymerase. The rescued virus was first propagated in 10-day-old embryonated eggs and the allantoic fluid was used to infect primary chicken embryo fibroblasts (CEF) cells. The appearance of GFP in live infected cells confirmed further the recovery of a recombinant NDV (rNDV-GFP) expressing this reporter gene. Nine successive passages in embryonated chicken eggs were performed. Allantoic fluid samples were then titrated by a microtiter plate HA test. HA positive ailantoic fluid were used for further egg passages. All the allantoic fluid samples were titrated by end point dilutions and infected cells were examined for the presence of GFP expression. To analyze virus growth, 10-day-old embryonated SPF chicken eggs were inoculated with 1 x 10(4) EID50 rNDV or rNDV-GFP. At 24,48,72 and 96 h p.i. the allantoic fluid of inoculated eggs containing live embryos was harvested and clarified by centrifugation. Supernatants were used for titration of EID50 in 10-day-old embryonated SPF chicken eggs. rNDV and rNDV-GFP grew to similar titers (10(9) EID50/mL). In order to test the virulence of rNDV-GFP, infectious allantoic fluid of rNDV-GFP were inoculated into embryonated SPF chicken eggs at 1 x 10(6) EID50. No dead embryonated egg was found within 96 hours. The replication kinetics and pathogenicity in SPF embryonated eggs of rNDV-GFP did not differ significantly from that of the parent virus. LaSota is a widely used NDV live vaccine strain. The reverse genetic system established for this LaSota vaccine strain provided a useful platform for development of novel live viral vector vaccines in future.