氮元素对CrFeMnVTi6高熵合金显微组织和力学性能的影响

为了评估氮元素的间隙固溶强化机制对高熵合金性能的影响,采用机械冶金化和放电等离子体烧结工艺制备N掺杂Cr Fe Mn VTi6高熵合金,并利用XRD、SEM、TEM和FIB检测手段对合金的相组成及显微组织进行表征。实验结果显示,CrMnFeVTi6合金组织由Ti Nx、BCC、Laves相和B2有序相组成。因此,合金在低温区域(<380℃)具有极高的强度(>2729 MPa)和硬度。针对该高熵合金的BBC基体进行不同强化机制的定量计算,结果表明,氮元素引起的间隙固溶强化效果为-634 MPa/at.%,远好于其他合金中的碳或硼元素,这表明,在高熵合金里添加氮元素能够有效提高合金强度。

Effect comparison of knee-chest elastic bandage fixation and Pavlik harness fixation on the treatment of femoral shaft fractures in newborns

Objective:To study and analyze the clinical efficacy of fixation of the elastic bandage of immobilization of knee-chest position and Pavlik harness fixation in the treatment of neonatal femoral shaft fractures.Methods:A retrospective analysis was conducted from May 2010 to March 2017 with a total of 37 cases of femoral shaft fracture of the newborn.Among them,17 newborns with femur shaft fracture were treated using this fixation of the elastic bandage of immobilization of knee-chest position,and 20 newborns were treated utilizing Pavlik harness fixation.All patients were followed up for 24 months.It was compared between the two groups in length of hospitalization,hospitalization cost,the incidence of complications,fracture healing rate and post-operation angulation,rotation and shortening indexes.Results:Compared with the Pavlik harness fixation group,the hospitalization cost of knee-chest elastic bandage fixation group was lower(P<0.05),the difference was statistically significant.There is no significant difference between the two groups in terms of length of hospitalization,complications and fracture healing.The two groups of treatment methods compared in angle formation,rotation and shortness(P>0.05),with no statistical difference.Conclusions:Both knee-chest elastic bandage fixation and Pavlik harness fixation are effective methods for the treatment of neonatal femoral shaft fractures.But the former has lower cost and simpler operation,which is worthy of clinical application.

Luteolin affects the EMT transformation and cell biological behavior of osteosarcoma U2OS cells via the PI3K/AKT/NF-κB signaling pathway

Objective:To investigate the effect of luteolin on the Epithelial-mesenchymal transition(EMT)of osteosarcoma cell line U2OS and its molecular mechanism by regulating phosphoinositide 3-kinase/protein kinase B/nuclear factor-kappa B(PI3K/AKT/NF-κB)signaling pathway.Methods:U2OS cells were treated in different concentrations(10,20 and 40μmol/L)of luteolin.MTT was used to detect the effect of luteolin on the proliferation of osteosarcoma U2OS cells.Transwell chamber assay was used to detect the influence of luteolin on migration of U2OS cells.qPCR was used to detect the influence of luteolin on the mRNA expression of Bax,Bcl-2 and Caspase-2 in U2OS cells.Western blot was used to observe the change of p-PI3K,p-AKT,p-IKK and NF-κB proteins.Immunofluorescence was used to detect the influence of luteolin on the protein expression of E-cadherin and vimentim.Results:Luteolin inhibited significantly the proliferation of U2OS cells(P<0.05)in a time-concentration-dependent manner.Luteolin inhibited significantly the migration of U2OS cells(P<0.05).After treatment with luteolin,the mRNA expression of Bax and Caspase-2 was increased significantly(P<0.05),but Bcl-2 was reduced significantly(P<0.05)in U2OS cells.The protein expression of p-PI3K,p-AKT,p-IKK,NF-κB,E-cadherin and vimentin was decreased significantly(P<0.05).Conclusions:Luteolin inhibits the proliferation,migration and EMT transformation of osteosarcoma U2OS cells,which may be related to the inhibition of PI3K/AKT/NF-κB signaling pathway.