Incomplete radiofrequency ablation provokes colorectal cancer liver metastases through heat shock response by PKCα/Fra-1 pathway

Objective: Incomplete radiofrequency ablation(ICR) has been proposed as a major cause of recurrence in the treatment of hepatic metastatic tumors.We tried to determine the mechanisms of this progression in colorectal cancer(CRC) liver metastasis(CRLMs)Methods: We have established a mouse model of radiofrequency ablation(RFA) therapy to demonstrate increased risk of recurrence of CRLMs with ICR.Here we focused on heat shock-induced CRC malignancy.Sub-lethal heat shock(HS) in CRC cell lines provoked cell growth, invasion, and tumor initiation in vitro and in vivo.Results: We found that Fra-1, which lies downstream of PKCα-ERK1/2 signaling, was significantly increased by HS compared with the untreated CRC cells.Silencing Fra-1 reversed the tumor promoting effects of HS.Furthermore, proliferation and tumor initiation inducer c-Myc, together with tumor invasion inducer matrix-metalloprotase 1(MMP-1) expression were up-regulated by AP-1/Fra-1 induced genes transcription.Conclusions: Our study demonstrated that ICR generated HS induces CRC malignancy by targeting Fra-1, which could be a potential prognostic marker and a promising therapeutic strategy to prevent disease recurrence after radiofrequency ablation treatment.

Pressure Driven Structural Evolutions of 0.935(Na0.5Bi0.5)TiO_(3)-0.065BaTiO_(3)Lead-Free Ferroelectric Single Crystal through Raman Spectroscopy

Pressure evolution of local structure and vibrational dynamics of the perovskite-type relaxor ferroelectric single crystal of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3(NBT-6.5BT)is systematically investigated via in situ Raman spectroscopy.The pressure dependence of phonon modes up to 30GPa reveals two characteristic pressures:one is at around 4.6GPa which corresponds to the rhombohedral-to-tetragonal phase transition,showing that the pressure strongly suppresses the coupling between the off-centered A-and B-site cations;the other structural transition involving the oxygen octahedral tilt and vibration occurs at pressure∼13–15GPa with certain degree of order-disorder transition,evidenced by the abnormal changes of intensity and FWHM in Raman spectrum.

Investigation of flow unsteadiness in a highly-loaded compressor cascade using a dynamic mode decomposition method

Unsteady flow in the hub endwall region has long been a hot topic in the turbomachinery community.However important it is to the performance of the whole engine,the coherent unsteady flow phenomena are still not well understood.In this paper,the complex flow field in the hub endwall of a cantilevered compressor cascade has been investigated through numerical approach.The predicted results were validated by experimental data.To highlight the dominant flow structures among irregular and chaotic motions of various vortices,a Dynamic Mode Decomposition(DMD)method was utilized.The results show that there exist three dominant periodic flow structures:the oscillation of the leakage vortex,a circumferential migration of a Breakdown Induced Vortex(BIV)and the fluctuation of the passage vortex.These three coherent structures all together form a self-sustained closed loop which accounts for the flow unsteadiness of the studied cascade.During this process,the BIV plays a key role in inducing the flow unsteadiness.Only if the BIV is strong enough to affect the passage vortex,the flow unsteadiness occurs.This study expands current knowledge base of flow unsteadiness in a compressor environment,and shows the efficacy of the DMD method for revealing the origin of flow unsteadiness.