Base editing-mediated targeted evolution of ACCase for herbicide-resistant rice mutants

Base editing technologies enable precise base alterations in a target gene without inducing double-stranded breaks,and thus are powerful for targeted gene evolution in vivo(Zhan et al.,2021).The newly evolved cytosine deaminases such as evoAPOBEC1,evoFERNY and evoCDA1,adenine deaminase TadA8e,and a near-protospacer adjacent motif(PAM)less SpRYCas9 variant,have greatly increased base editing efficiency and expanded the editing window in plants(Zhang et al.,2021;Xu et al.,2021c;Tan et al.,2022).Dual cytosine and adenine editors enable concurrent C-to-T and A-to-G conversions and thus enrich the editing outcome.Although plant dual editors have been developed(Li et al.,2020;Xu et al.,2021a),they are rarely applied in evolving plant genes due to low efficiencies.

Kinetic Monte Carlo code development and application on the formation of hydrogen-vacancy clusters in tungsten

We have developed an object kinetic Monte Carlo(OKMC)code and simulated hydrogen-vacancy clustering behavior and dependence on temperature and hydrogen-vacancy ratio in tungsten.For each of the temperatures we simulated from 300 K to1000 K,H_nV clusters with smaller n form before those with larger n.The elevating temperature leads to a decrease in hydrogen vacancies:H_(10)V and H_9V clusters dominate at 300 K and 600 K,whereas H_5V,H_6V,and H_7V clusters dominate when the temperature reaches 1000 K.Furthermore,only H_nV clusters with smaller n formed when a lower hydrogen-vacancy ratio was used due to insufficient availability of hydrogen atoms to occupy vacancies.The results suggest hydrogen emission occurs very rarely at lower temperatures,while higher temperatures facilitate the dissociation of hydrogen from H_nV clusters.

The effect of hydrogen on the recombination of Frenkel pair in tungsten： A theoretical insight

Tungsten (W), with its primary advantages, is considered as the most promising candidate for plasma facing materials (PFMs) for the next generation of fusion devices such as ITER. However, continuous bombardment with 14.1 MeV neutron introduces Frenkel defects as the primary damage in W [1]. The Frenkel defects, composed of self-interstitial atoms (SIAs) and vacancies, can develop to extended defects such as voids and interstitial clusters, resulting in hardening, swelling and embrittlement of W, thus degrading the properties of W [2]. The recombination of SIAs and vacancies is an effective way to reduce the Frenkel defects in bulk W, which enhances the radiation resistance of W based on recent theoretical calculations [3,4]. The moving of the SIA to the vacancy could finish the recombination process through instantaneous or thermally activated way [3]. The instantaneous recombination region is an ellipse with the semi-minor axis of 5.4 ? and semi-major axis of 18 ? according to the molecular dynamics calculation [4].