Interacting topological magnons in a checkerboard ferromagnet

This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction.Using a first-order Green function method,we analyze the influence of magnon-magnon interaction on the magnon band topology.We find that Chern numbers of two renormalized magnon bands are different above and below the critical temperature,which means that the magnon band gap-closing phenomenon is an indicator for one topological phase transition of the checkerboard ferromagnet.Our results show that the checkerboard ferromagnet possesses two topological phases,and its topological phase can be controlled either via the temperature or the applied magnetic field due to magnon-magnon interactions.Interestingly,it is found that the topological phase transition can occur twice with the increase in the temperature,which is different from the results of the honeycomb ferromagnet.

Recombinant human thrombopoietin in alleviating endothelial cell injury in sepsis

Background To evaluate the effect of recombinant human thrombopoietin(rhTPO)on clinical prognosis by exploring changes in endothelial cell injury markers and inflammatory factors in patients with sepsis after treatment with rhTPO.Methods This retrospective observational study involved patients with sepsis(diagnosed according to Sepsis 3.0)admitted to Shanghai General Hospital intensive care unit from January 1,2019 to December 31,2022.Patients were divided into two groups(control and rhTPO)according to whether they received rhTPO.Baseline information,clinical data,prognosis,and survival status of the patients,as well as inflammatory factors and immune function indicators were collected.The main monitoring indicators were endothelial cell-specific molecule(ESM-1),human heparin-binding protein(HBP),and CD31;secondary monitoring indicators were interleukin(IL)-6,tumor necrosis factor(TNF)-α,extravascular lung water index,platelet,antithrombin III,fibrinogen,and international normalized ratio.We used intraperitoneal injection of lipopolysaccharide(LPS)to establish a mouse model of sepsis.Mice were randomly divided into four groups:normal saline,LPS,LPS+rhTPO,and LPS+rhTPO+LY294002.Plasma indicators in mice were measured by enzyme-linked immunosorbent assay.Results A total of 84 patients were included in the study.After 7 days of treatment,ESM-1 decreased more significantly in the rhTPO group than in the control group compared with day 1(median=38.6[interquartile range,IQR:7.2 to 67.8]pg/mL vs.median=23.0[IQR:−15.7 to 51.5]pg/mL,P=0.008).HBP and CD31 also decreased significantly in the rhTPO group compared with the control group(median=59.6[IQR:−1.9 to 91.9]pg/mL vs.median=2.4[IQR:−23.2 to 43.2]pg/mL;median=2.4[IQR:0.4 to 3.5]pg/mL vs.median=−0.6[IQR:−2.2 to 0.8]pg/mL,P<0.001).Inflammatory markers IL-6 and TNF-αdecreased more significantly in the rhTPO group than in the control group compared with day 1(median=46.0[IQR:15.8 to 99.1]pg/mL vs.median=31.2[IQR:19.7 to 171.0]pg/mL,P<0.001;median=17.2[IQR:6.4 to 23.2]pg/mL vs.median=0.0[IQR:0.0 to 13.8]pg/mL,P=0.010).LPS+rhTPO-treated mice showed significantly lower vascular von Willebrand factor(P=0.003),vascular endothelial growth factor(P=0.002),IL-6(P<0.001),and TNF-α(P<0.001)than mice in the LPS group.Endothelial cell damage factors vascular von Willebrand factor(P=0.012),vascular endothelial growth factor(P=0.001),IL-6(P<0.001),and TNF-α(P=0.001)were significantly elevated by inhibiting the PI3K/Akt pathway.Conclusion rhTPO alleviates endothelial injury and inflammatory indices in sepsis,and may regulate septic endothelial cell injury through the PI3K/Akt pathway.