Application of neoadjuvant chemoradiotherapy and neoadjuvant chemotherapy in curative surgery for esophageal cancer:A metaanalysis

BACKGROUND The effectiveness of neoadjuvant therapy in esophageal cancer(EC)treatment is still a subject of debate.AIM To compare the clinical efficacy and toxic side effects between neoadjuvant chemoradiotherapy(nCRT)and neoadjuvant chemotherapy(nCT)for locally advanced EC(LAEC).METHODS A comprehensive search was conducted using multiple databases,including PubMed,EMBASE,MEDLINE,Science Direct,The Cochrane Library,China National Knowledge Infrastructure,Wanfang Database,Chinese Science and Technology Journal Database,and Chinese Biomedical Literature Database Article.Studies up to December 2022 comparing nCRT and nCT in patients with EC were selected.RESULTS The analysis revealed significant differences between nCRT and nCT in terms of disease-free survival.The results indicated that nCRT provided better outcomes in terms of the 3-year overall survival rate(OSR)[odds ratio(OR)=0.95],complete response rate(OR=3.15),and R0 clearance rate(CR)(OR=2.25).However,nCT demonstrated a better 5-year OSR(OR=1.02)than nCRT.Moreover,when compared to nCRT,nCT showed reduced risks of cardiac complications(OR=1.15)and pulmonary complications(OR=1.30).CONCLUSION Overall,both nCRT and nCT were effective in terms of survival outcomes for LAEC.However,nCT exhibited better performance in terms of postoperative complications.

Thermal fatigue crack growth behavior of ZCuAlFeMn alloy strengthened by laser shock processing

The effect of laser shock processing(LSP) on the hardness, surface morphology, residual stress, and thermal fatigue properties of a ZCuAl10Fe3Mn2 alloy was investigated to improve the thermal fatigue performance and decrease the surface crack of high-temperature components. The microstructure and crack morphology were analyzed by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The results showed that laser shock could significantly improve the thermal fatigue performance of the alloy at a pulse energy of 4 J. Under the effect of thermal stress and alternating stress, microstructure around the specimen notch was oxidized and became porous, leading to the formation of multiple micro-cracks. The micro-cracks in the vertical direction became the main cracks, which mainly expanded with the conjoining of contiguous voids at the crack tip front. Micro-cracks in other directions grew along the grain boundaries and led to material shedding.

Effects of laser shock processing,solid solution and aging,and cryogenic treatments on microstructure and thermal fatigue performance of ZCuAl_(10)Fe_(3)Mn_(2)alloy

The materials used in variable temperature conditions are required to have excellent thermal fatigue performance.The effects of laser shock processing(LSP),solid solution and aging treatment(T6),and cryogenic treatment(CT)on both microstructure and thermal fatigue performance of ZCuAl_(10)Fe_(3)Mn_(2) alloys were studied.Microstructure and crack morphology were then examined by scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).The result showed that,after being subjected to the combination treatment of T6+CT+LSP,the optimal mechanical properties and thermal fatigue performance were obtained for the ZCuAl_(10)Fe_(3)Mn_(2) alloy with the tensile strength,hardness,and elongation of 720 MPa,300.16 HB,and 16%,respectively,and the thermal fatigue life could reach 7,100 cycles when the crack length was 0.1 mm.Moreover,the ZCuAl_(10)Fe_(3)Mn_(2) after combination treatment shows high resistance to oxidation,good adhesion between the matrix and grain boundaries,and dramatically reduced growth rate of crack.During thermal fatigue testing,under the combined action of thermal and alternating stresses,the microstructure around the sample notch oxidized and became loose and porous,which then converted to micro-cracks.Fatigue crack expanded along the grain boundary in the early stage.In the later stage,under the cyclic stress accumulation,the oxidized microstructure separated from the matrix,and the fatigue crack expanded in both intergranular and transgranular ways.The main crack was thick,and the path was meandering.

Mechanism and threshold fluence of nanosecond pulsed laser paint removal

In this paper, the nanosecond pulse laser surface treatment of the waterborne anti-rust paint on HT250 gray cast iron was carried out. The area and depth of the per-pulse laser ablation paint layer were measured. The threshold of laser energy density was determined through the relations with ablation area and depth. The paint removal mechanism was discussed by analyzing the ablation features of the paint layer on laser cleaning. The features of the paint removal under various laser energy densities were characterized, and the process parameters in the experiments were investigated.The results showed that there were four thresholds and three kinds of mechanisms in the paint removal process with nanosecond pulsed laser. The ablation threshold of substrate was deepened on the laser parameters. The ablation processes were included thermal ablation, thermal vibration and paint ionization concurrently, respectively. The surface cracks and paint debris were observed at the edge of the cleaning path, which were ascribed to the vibration effect by laser. In addition, the vibration effect could significantly increase the width of paint removal. Paint ionization has also a significant influence on the substrate morphology. Paint ionization would have an obvious impact on the formation of the substrate morphology. It is desirable to fabricate approach to remove the paint layer without damaging the substrate under optimized laser parameters by nanosecond pulse laser.