A new method for preparing a rat intracerebral hemorrhage model by combining focused ultrasound and microbubbles

Background:We aimed to prepare a non-invasive,reproducible,and controllable rat model of intracerebral hemorrhage with focused ultrasound(FUS).Methods:A rat intracerebral hemorrhage(ICH)model was established by combining FUS and microbubbles(μBs),and edaravone was used to verify whether the free radical scavenger had a protective effect on the model.The brain tissue of each group was sectioned to observe the gross histology,blood-brain barrier(BBB)permeability,cerebral infarction volume,and histopathological changes.Results:Compared with the FUS group,the BBB permeability was significantly increased in the FUS+μBs(F&B)group(p=0.0021).The second coronal slice in the F&B group had an obvious hemorrhage lesion,and the FUS+μBs+edaravone(F&B&E)group had smaller hemorrhage areas;however,ICH did not occur in the FUS group.The cerebral infarction volume in the F&B group was significantly larger than that in the FUS group(p=0.0030)and F&B&E group(p=0.0208).HE staining results showed that nerve fibrinolysis,neuronal necrosis,microglia production,and erythrocytes were found in both the F&B group and the F&B&E group,but the areas of the nerve fibrinolysis and neuronal necrosis in the F&B group were larger than the F&B&E group.Conclusions:A rat ICH model was successfully prepared using theμBs assisted FUS treatment,and edaravone had a therapeutic effect on this model.This model can be used to study the pathophysiological mechanism of ICH-related diseases and in preclinical research on related new drugs.

Preparation of a novel cross-linked polyetherimide with enhanced breakdown strength and high-temperature energy storage performance

Polymer dielectrics with excellent energy storage performance at high temperature are urgently needed in advanced applications,such as hybrid electric vehicles,smart grid and pulsed power sources.Polyetherimide(PEI),which is supposed to be the most promising candidate among polymer dielectric materials,displays a limitation for high-temperature polymer dielectrics owing to the rapidly decreasing discharged energy density(U_(d))and charge-discharge efficiency(η).Herein,a novel PEI with cross-linked networks was firstly prepared by utilising 2,4,6-Triaminopyrimidine(TAP)as a cross-linker.The results showed that the breakdown strength of the cross-linked PEI(c-PEI)with 2 wt%TAP increased to 399.4 MV/m,showing an increment of 23.3%in comparison with noncross-linked PEI.Additionally,owing to the restrained polarisation loss and relaxation loss by cross-linked networks,the dielectric loss of c-PEI dielectric gradually decreased with the increasing content of TAP.Of particular significance was the c-PEI dielectrics exhibiting improved U_(d)andηat high temperature.The maximum U_(d)of c-PEI with 2 wt%TAP was 2.53 J/cm3 at 150℃,which was 24.8%higher than non-cross-linked PEI(2.11 J/cm^(3)at 150℃).This research provides an innovative strategy to achieve novel PEI dielectrics with improved U_(d)andηat high temperature.