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.

OBJECTIVETo study the effect of glycolysis inhibitor 3-bromopyruvate (3-BrPA) in inducing apoptosis of human breast carcinoma cells SK-BR-3 and the possible mechanism.

METHODSMTT assay was used to detect the growth inhibition induced by 3-BrPA in breast cancer cells SK-BR-3. The apoptotic cells were detected by flow cytometry with propidium iodide (PI). ATP levels in the cells were detected by ATP assay kit, and DHE fluorescent probe technique was used to determine superoxide anion levels; the mitochondrial membrane potential was assessed using JC-1 staining assay.

RESULTSMTT assay showed that the proliferation of SK-BR-3 cells was inhibited by 3-BrPA in a time- and concentration-dependent manner. Exposure to 80, 160, and 320 µmol·L(-1) 3-BrPA for 24 h resulted in cell apoptosis rates of 6.7%, 22.3%, and 79.6%, respectively, and the intracellular ATP levels of SK-BR-3 cells treated with 80, 160, 320 µmol·L(-1) 3-BrPA for 5 h were 87.7%, 60.6%, and 23.7% of the control levels. 3-BrPA at 160 µmol·L(-1) increased reactive oxygen levels and lowered mitochondrial membrane potential of SK-BR-3 cells.

CONCLUSION3-BrPA can inhibit cell proliferation, reduce the mitochondrial membrane potential and induce apoptosis in SK-BR-3 cells, the mechanism of which may involve a reduced ATP level by inhibiting glycolysis and increasing the reactive oxygen level in the cells.

Apoptosis ; drug effects ; Cell Line, Tumor ; Female ; Glycolysis ; Humans ; Membrane Potential, Mitochondrial ; drug effects ; Pyruvates ; pharmacology ; Reactive Oxygen Species ; metabolism

Objective:To analyze the changes of peripheral perfusion index (PPI) with late-onset sepsis (LOS) in very low birth weight infants during hospitalization.Methods:Very low birth weight infants admitted to the neonatal intensive care unit of Children′s Hospital of Fudan University from August 1, 2021 to August 31, 2022 were consecutively included.Infants with admission age ≥three days and unstable circulation, or positive blood culture within three days after birth were excluded.From the day of admission, the PPI values of the right hand and either foot of the infants were measured with Masimo SET Radical-7 everyday while whether LOS occurred during hospitalization was observed.The mean PPI curve of very and extremely low birth weight infants without LOS was plotted.For those with LOS confirmed by blood culture, the PPI change trajectory three days before and after the occurrence of LOS was drawn, and the change trend of PPI before the occurrence of LOS was analyzed by trend chi-square test.Non-parametric test was used to analyze the effect of LOS on pre- and post-ductal PPI values.Results:A total of 107 very low birth weight infants were included in the final analysis.Among them, there were 11 infants confirmed as LOS by blood culture, 37 infants diagnosed as clinical LOS, and 59 infants without LOS.Pre-and post-ductal PPI values of very low birth weight infants without LOS were 2.06±1.30 and 1.72±0.92, respectively; those with clinical LOS were 1.90±0.94 and 1.58±0.83, respectively; those with LOS confirmed by blood culture were 1.92±1.11 and 1.62±0.82, respectively.For infants with LOS confirmed by blood culture, the pre-and post-ductal PPI values showed a continuous downward trend during three days before the onset of disease, with the lowest PPI values on the first day before the diagnosis of blood culture.The downtrend of pre-ductal PPI was statistically significant ( χtrend2=5.57, P<0.05). Conclusion:The PPI value of very low birth weight infants show a downward trend when LOS occurs.It should be observed dynamically in clinical practice, which is helpful to suspect or identify LOS as early as possible.