Objective:To investigate the corrosion fatigue strength of laser-welded specimens fabricated from commercially pure titanium (TA2) and titanium alloy(TC4). Methods:TA2 and TC4 were mechanically processed into a certain size and joined by laser welding. A fatigue testing machine was used to test tensile load and fatigue strength after soaked in synthetic saliva. The fatigue fracture surface was examined by scanning electron microscopy (SEM). Results: The fatigue strengths of the laser-welded test specimens showed no significant differences compared to specimens in air. SEM examination showed that there were no defects such as corrosion pits. Conclusion: There are no significant differences between either laser-welded metal in the corrosion fatigue strength for dry specimens and specimens in synthetic saliva.

Objective To study the hemoprotective effects of a rotary magnetic field (RMF) to radiation-injured mice. Methods 132 male BALB/c mice were randomly divided into four groups: a normal group (N), a magnetic treatment group (M), an irradiation group(R) and an irradiation combining magnetic treatment group (R + M). Mice in the N group received no treatment. Mice in the R and R + M groups received total body irradiation with 6.0 Gy 60Co γ/rays. Mice in the M and R + M groups were treated with a RMF for one and half an hour at a time, twice a day, totally for 30 days. The survival rate was observed for 30 days. On days 0, 5, 9, 15, 21, 30, the subjects' peripheral blood cells were counted. On day 9, 23 and 30, the number of bone marrow nucleated cells (BMNCs), colony forming unit-spleen (CFU-S), spleen-body ratio, the cell cycle and apoptosis of bone marrow cells were measured. The pathological sectioning of the femur was performed and the expression level of bone morphogenetic proteins (BMP2/4) in the bone marrow was evaluated. Results ①No mice died in the N and M group. The RMF treatment increased the survival rate and survival days among the irradiated mice (P < 0.01). ②The RMF treatment increased the number of blood cells in their peripheral blood of the R + M group. ③The number of BMNCs, CFU-S and the proportation of G2 + M stage in the R + M were markedly higher than that of the R group, but the proportation of the apoptosis was lower than that of the R group on the 9th day (P < 0.05). Furthermore, the spleen index in the R + M group was also higher than that of the R group on the 23rd day (P < 0.05). ④RMF could improve the expression level of BMP2/4 in the radiation-injued mice. Conclusion The RMF treatment had an obvious protective effect against the effects of irradiation and it accelerated the recovery of hematopeiesis and the hematopoietic microenvironment in mouse bone marrow.

Objective:To investigate the relationship between the expression of serum exsomal miRNA-155-5p (miR-155-5p) and prognosis in patients with esophageal squamous cell carcinoma (ESCC).Methods:A total of 336 samples from ESCC patients in Fujian Provincial Cancer Hospital from October 2014 to December 2015 were collected. The relative expression levels of serum exsomal miR-155-5p were detected by using real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). Cut-off value of the expression levels of serum exsomal miR-155-5p was determined by using X-tile software. Based on the optimal cut-off value, patients were divided into miR-155-5p low expression group and miR-155-5p high expression group. The survival curve was drawn by using Kaplan-Meier method and Cox proportional hazards regression model was used to make survival analysis.Results:The cut-off value of serum exsomal miR-155-5p expression level was 2.340. According to the cut-off value, patients were divided into miR-155-5p low expression group (<2.340) of 51 cases and miR-155-5p high expression group (≥2.340) of 285 cases. There were no statistical differences in age ( χ2 = 0.020, P = 0.887), gender ( χ2 = 0.283, P = 0.595), tumor location ( χ2 = 0.063, P = 0.977), differentiation grade ( P = 0.474), clinical staging ( χ2 = 3.996, P = 0.136) and surgery treatment ( χ2 = 0.941, P = 0.332) of patients in both groups. ESCC patients in serum exsomal miR-155-5p high expression had a higher risk of death compared with patients in miR-155-5p low expression group ( HR = 1.763, 95% CI 1.049-2.961, P = 0.032). Conclusion:The high expression level of serum exsomal miR-155-5p is associated with poor prognosis in ESCC patients and it could be used as a prognostic new marker in ESCC patients.