Pyramiding favorable alleles in an elite wheatvariety in one generation by CRISPR-Cas9-mediated multiplex gene editing

Dear Editor,Common wheat(Triticum aestivum,2n=6x=42,AABBDD)is amajor staple crop consumed by more than 30%of the world’spopulation.It is the main source of cereal-based processed prod-ucts,such as bread,cookies,pasta,and noodles.Althoughwheat production increased by 10-fold following the Green revo-lution and maker-assisted breeding over the past decades,it isstill facing unprecedented challenges in the context of globalclimate changes,growing world population,decreased farm-lands,as well as water shortages in arid and semi-arid lands.Meanwhile,the functional redundancy of genes in hexaploidywheat makes a forward genetics approach to select a desiredphenotype,especially for pyramiding of several agronomicallyimportant traits in a modern variety,very time-consuming and in some cases,impossible because of gene linkage or genedrag.

Multiplex network reconstruction for the coupled spatial diffusion of infodemic and pandemic of COVID-19

The pandemic of COVID-19 witnessed a massive infodemic with the public being bombarded with vast quantities of information.The spreading of neutral and highly accurate reports can guide the public to self-protect and reduce the pandemic.Mis-and dis-information would intrigue panic and high exposure risk to epidemic.Although the infodemic has attracted attentions from the academia,it is still not known to what degree and in which direction the information flows contribute to the COVID-19 pandemic.To fill the gap,we apply network reconstruction techniques to rebuild the hidden multiplex network of information and COVID-19 spreading by which we aim at quantifying the interaction between the propagation of information and the spatial outbreak of COVID-19,and delineate between the positive and negative impact of information on the pandemic.By differentiating the types of media that participated in the information process,we find that in the early stage of COVID-19 pandemic,infodemic does play a critical role to amplify the risk of virus outbreak in China and the risk is even larger for those highly developed regions.Compared to the old-fashion media,the new mobile platforms impose a greater risk to reinforce the positive feedback between infodemic and COVID-19 pandemic.

Fatigue shear performance of concrete beams reinforced with hybrid(glass-fiber-reinforced polymer+steel)rebars and stirrups

Reinforced concrete beams consisting of both steel and glass-fiber-reinforced polymer rebars exhibit excellent strength,serviceability,and durability.However,the fatigue shear performance of such beams is unclear.Therefore,beams with hybrid longitudinal bars and hybrid stirrups were designed,and fatigue shear tests were performed.For specimens that failed by fatigue shear,all the glass-fiber-reinforced polymer stirrups and some steel stirrups fractured at the critical diagonal crack.For the specimen that failed by the static test after 8 million fatigue cycles,the static capacity after fatigue did not significantly decrease compared with the calculated value.The initial fatigue level has a greater influence on the crack development and fatigue life than the fatigue level in the later phase.The fatigue strength of the glass-fiber-reinforced polymer stirrups in the specimens was considerably lower than that of the axial tension tests on the glass-fiber-reinforced polymer bar in air and beam-hinge tests on the glass-fiber-reinforced polymer bar,and the failure modes were different.Glass-fiber-reinforced polymer stirrups were subjected to fatigue tension and shear,and failed owing to shear.

Monte Carlo simulation of the diffusion-limited aggregating process of particle suspension systems

The aggregating process of particle suspension systems is a very universal phenomena and crucial for various processes both in nature and in industry.In this paper,the aggregating process was simulated with offlattice diffusion-limited cluster-cluster aggregation(DLCA)Monte Carlo programs.The self-similar fractal structures of aggregates have been clearly demonstrated by the statistical analysis of gyration radius distribution and the existence of a scaling distribution of the reduced cluster size.The fractal dimension determined from the relationship between mass and gyration radius of aggregates was 1.80 or so.The fractal dimension of the aggregates drawn from the radial distribution function and structure factor of a single aggregate is about 1.90-2.10.It was also showed that,along with the increasing of particle volume fraction,the fractal dimension will increase in a nearly square root manner,and the spatial range of the fractal structure appearing becomes narrower.Also,the gelation transition can only occur in a particle suspension system where the particle volume fraction is greater than a critical value.