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.

Mucosal bacterial dysbiosis in patients with nodular lymphoid hyperplasia in the terminal ileum

BACKGROUND Nodular lymphoid hyperplasia(NLH)in the small intestine is a rare benign lesion characterized by multiple small nodules on the intestinal surface.Patients with terminal ileal NLH may experience long-term abdominal pain,diarrhea,and abdominal distension,among other symptoms.Supplementation with probiotics could mitigate these symptoms.NLH is linked to the immune system,and it may result from accumulation of plasma-cell precursors due to a maturational defect during the development of B lymphocytes.The intestinal microbiome plays an essential role in the immune system.Thus,we speculate that the gut flora plays a key role in terminal ileal NLH.AIM To explore the correlation between intestinal flora and terminal ileal NLH.METHODS We collected mucosal biopsy samples that were obtained via colonoscopy from 15 patients with terminal ileal NLH(the test group)and 15 normal subjects(the control group).We subsequently performed 16 S-r RNA gene amplicon sequencing of these samples,and the results were evaluated using alpha diversity,beta diversity and microbial composition analyses.The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to predict the metabolic pathways and orthologous groups according to the Kyoto Encyclopedia of Genes and Genomes database.RESULTS Compared with the control group,the terminal ileal NLH group showed an increased alpha diversity(P<0.05).The overall intestinal microbiota in the NLH group was significantly different from that of the control group(P<0.05),implying that there was the dysbiosis in the terminal ileal NLH patients.The relative abundance of phylum Bacteroidetes was significantly lower in the NLH group,while that of Patescibacteria and Campilobacterota was significantly higher.The genus Bacteroides was the dominant gut microbiota in both groups,but its abundance was significantly lower in the test group than it was in the control group.Conversely,the relative abundances of Haemophilus,Streptococcus,Pseudomonas,Actinomyces,TM7 X,Fusobacterium nucleatum,Parvimonas,Granulicatella,Helicobacter,and the[Eubacterium]nodatum group were significantly higher in the test group than they were in the control group.In addition,several altered metabolic pathways,orthologous groups,and modules were found.For example,the Peptidoglycan biosynthesis and Aminoacyl t RNA biosynthesis were both increased in the test group.CONCLUSION Maintaining the microbial balance and supplementing targeted protective bacteria could improve symptoms and potentially reduce the risk of lymphoma transformation in patients with terminal ileal NLH.