Hard/soft permanent magnets have attracted a lot of attention because of their rich magnetic properties and their potential for realizing giant energy products. However, energy products obtained by scientists in exper...Hard/soft permanent magnets have attracted a lot of attention because of their rich magnetic properties and their potential for realizing giant energy products. However, energy products obtained by scientists in experiments are much smaller than the theoretical values, which has been studied by various analytical and numerical methods. The famous Stoner-Wohlfarth model(S-W model) is too simple to give the hysteresis loops whereas the intensively used variational method is too complicated to reveal the underlying mechanism in a simple form. The analytical model proposed in this paper maintains a balance between simplicity and precision, where the spins in the soft layer rotate fast and coherently with the applied field while those in the hard layer response to the applied field much slower but also coherent. An exchange coupling is provided to maintain the exchange spring which drags the spins in the hard layer to follow those in the soft layer. Similar to the more sophisticated model, the calculated hysteresis loops display three typical magnetic phases, i.e., the rigid composite magnet, the exchange spring and decoupled magnet, whereas the simple SW model can only give one single phase, i.e., the rigid composite one. In addition to the hysteresis loop, the energy product and the nucleation fields have been calculated and compared with those calculated by other methods, which justifies our model.Careful comparisons show that our calculations are in good agreement with the experimental results and other theoretical results, especially for the important coercivity value and the related mechanism.展开更多
Mammalian individuals differ in their somatic cell cloning efficiency,but the mechanisms leading to this variation is poorly understood.Here we found that high cloning efficiency buffalo fetal fibroblasts(BFFs)display...Mammalian individuals differ in their somatic cell cloning efficiency,but the mechanisms leading to this variation is poorly understood.Here we found that high cloning efficiency buffalo fetal fibroblasts(BFFs)displayed robust energy metabolism,looser chromatin structure,high H3 K9 acetylation and low heterochromatin protein 1α(HP1α)expression.High cloning efficiency BFFs had more H3 K9 ac regions near to the upstream of glycolysis genes by Ch IP-seq,and involved more openness loci related to glycolysis genes through ATAC-seq.The expression of these glycolysis genes was also found to be higher in high cloning efficiency BFFs by q RT-PCR.Two key enzymes of glycolysis,PDKs and LDH,were confirmed to be associated with histone acetylation and chromatin openness of BFFs.Treatment of low cloning efficiency BFFs with PS48(activator of PDK1)resulted in an increase in the intracellular lactate production and H3 K9 acetylation,decrease in histone deacetylase activity and HP1αexpression,less condensed chromatin structure and more cloning embryos developing to blastocysts.These results indicate that the cloning efficiency of buffalo somatic cells is associated with their glycolytic metabolism and chromatin structure,and can be improved by increasing glycolytic metabolism.展开更多
基金Project supported by National Natural Science Foundation of China(11074179,51771127,51571126,51772004)the Scientific Research Fund of Sichuan Provincial Education Department(18TD0010,16CZ0006)
文摘Hard/soft permanent magnets have attracted a lot of attention because of their rich magnetic properties and their potential for realizing giant energy products. However, energy products obtained by scientists in experiments are much smaller than the theoretical values, which has been studied by various analytical and numerical methods. The famous Stoner-Wohlfarth model(S-W model) is too simple to give the hysteresis loops whereas the intensively used variational method is too complicated to reveal the underlying mechanism in a simple form. The analytical model proposed in this paper maintains a balance between simplicity and precision, where the spins in the soft layer rotate fast and coherently with the applied field while those in the hard layer response to the applied field much slower but also coherent. An exchange coupling is provided to maintain the exchange spring which drags the spins in the hard layer to follow those in the soft layer. Similar to the more sophisticated model, the calculated hysteresis loops display three typical magnetic phases, i.e., the rigid composite magnet, the exchange spring and decoupled magnet, whereas the simple SW model can only give one single phase, i.e., the rigid composite one. In addition to the hysteresis loop, the energy product and the nucleation fields have been calculated and compared with those calculated by other methods, which justifies our model.Careful comparisons show that our calculations are in good agreement with the experimental results and other theoretical results, especially for the important coercivity value and the related mechanism.
基金supported by the National Natural Science Foundation of China(31772597,31972996,31902125)Guangxi Natural Science Foundation(2017GXNSFAA198311)。
文摘Mammalian individuals differ in their somatic cell cloning efficiency,but the mechanisms leading to this variation is poorly understood.Here we found that high cloning efficiency buffalo fetal fibroblasts(BFFs)displayed robust energy metabolism,looser chromatin structure,high H3 K9 acetylation and low heterochromatin protein 1α(HP1α)expression.High cloning efficiency BFFs had more H3 K9 ac regions near to the upstream of glycolysis genes by Ch IP-seq,and involved more openness loci related to glycolysis genes through ATAC-seq.The expression of these glycolysis genes was also found to be higher in high cloning efficiency BFFs by q RT-PCR.Two key enzymes of glycolysis,PDKs and LDH,were confirmed to be associated with histone acetylation and chromatin openness of BFFs.Treatment of low cloning efficiency BFFs with PS48(activator of PDK1)resulted in an increase in the intracellular lactate production and H3 K9 acetylation,decrease in histone deacetylase activity and HP1αexpression,less condensed chromatin structure and more cloning embryos developing to blastocysts.These results indicate that the cloning efficiency of buffalo somatic cells is associated with their glycolytic metabolism and chromatin structure,and can be improved by increasing glycolytic metabolism.
