Improving the energy release characteristics of PTFE/Al by doping magnesium hydride

Magnesium hydride(MgH2)was doped into PTFE/Al to improve the energy release characteristics of the material system and strive for better application in military engineering.Five types of PTFE/Al/MgH2 reactive materials with different MgH2 content were prepared by molding sintering method.The dynamic mechanical properties of the materials were studied by performing split-Hopkinson pressure bar(SHPB)tests and scanning electron microscope characterizations.The thermal behavior,reaction energy,reaction process and reaction mechanism were systematically investigated by conducting thermogravimetry-differential scanning calorimetry tests,oxygen bomb calorimeter measurements,Xray diffraction and SHPB tests.The results show that MgH2 particles less than 10%content contribute to heightening the dynamic mechanical properties of PTFE/Al system.The product Mg generated by decomposition of MgH2 can not only react with gas phase C2F4þbut also undergo a Grignard-type reaction with condensed PTFE.The reaction energy and ignition threshold of PTFE/Al/MgH2 reactive materials enhance monotonously as MgH2 content rose.With the increase of MgH2 content from 0%to 20%,the reaction time is prolonged as well as the reaction intensity is enhanced dramatically arising from the massive water vapour produced by the reaction between O2 and H2.The gaseous products generated can form a high pressure shortly after the reaction,which helps to elevate the damage effect of the PTFE/Al system.

Mechanism of SCD1 in promoting proliferation,migration and invasion of human papillary thyroid cancer cells

Objective:To investigate the effects of SCD1 on the proliferation,migration and invasion of human papillary thyroid cancer cell line TPC1.Methods:The expression of SCD1 in human thyroid follicular epithelial normal cells Nthy-ori 3-1 and thyroid papillary carcer cell lines TPC1,BCPAP and K1 was detected by Western blot.The negative control and SCD1 siRNA were transfected respectively into human thyroid papillary carcer cell line TPC1,then the expressions of SCD1 mRNA and protein in each group were tested by real-time fluorescence quantitative PCR(qRT-PCR)and Western blot.The effects of interfering SCD1 on the proliferation,migration and invasion of TPC1 cells were detected by CCK-8 method and Transwell chamber assay respectively.Meanwhile,the expression levels of epithelial-mesenchymal transition(EMT)related proteins(N-cadherin,Snail,vimentin and E-cadherin)were detected by qRT-PCR and Western blot.Results:The expression level of SCD1 in TPC1 was significantly higher than that in Nthy-ori 3-1,BCPAP and K1(P<0.05).Compared with the blank control group(Control)and the control interference group(si-NC),the expression of SCD1 mRNA and protein in the interference SCD1 group(si-SCD1)was significantly decreased(P<0.05).The proliferation,migration and invasion of TPC1 cells were significantly inhibited after interfering with SCD1(P<0.05).It was also found that interfering SCD1 could increase the expression of E-cadherin protein while the expression of vimentin,Snail and N-cadherin protein were inhibited significantly(P<0.05).Conclusion:Interfering SCD1 was able to inhibit the proliferation,migration and invasion of thyroid papillary cancer cell TPC1 with the potential mechanism by inhibition of the EMT procedure.

Application of Autologous Costal Cartilage Scaffold in Reconstruction of Microtia Ear

Objective To investigate the application effect and manufacturing skills of autologous costal cartilage scaffold in ear reconstruction for microtia.Methods From January 2016 to January 2019,41 patients with microtia reconstruction in our hospital were selected,all of whom were type II or type III pediatric deformities.All patients underwent auricle reconstruction and retroauricular skin expansion and autologous costal cartilage stent.The first stage of the operation is to insert a skin dilator behind the residual ear and inject water to expand.The second stage of the operation is to carve and repair the soft ribs(usually 6 or 7 ribs)from the body,make a three-dimensional auricle support for auricle reconstruction,place a negative pressure drainage tube,and follow up for 3 to 6 months to observe the three-dimensional shape of the reconstructed auricle and the formation of cranioauricular angle.Results 41 patients with microtia had good three-dimensional shape of auricle reconstruction,normal auricle position,moderate cranioauricular angle,good helix and triangular fossa structure,and good bilateral symmetry.Patients and their families were satisfied with the effect of auricle reconstruction.Conclusion Autologous costal cartilage is a good scaffold for auricle reconstruction.It is through efficient and elaborate carving and splicing that a good three-dimensional auricle structure can be formed.Combined with early flap expansion,a good postoperative appearance effect can be obtained,which is the appropriate method for auricle reconstruction at present.