Influence of heat treatments on incipient melting structures of DD5 nickel-based single crystal superalloy

The evolution of microstructure and formation mechanism of incipient melting microstructure of DD5 single crystal superalloy during solution heat treatment were studied by scanning electron microscopy(SEM),electron probe microanalysis(EPMA),and energy dispersive spectroscopy(EDS).The solidus and liquidus of single crystal alloy were obtained by differential scanning calorimetry(DSC).Results show that the mosaic-like eutectic and fan-like eutectic are dissolved at first,and the coarseγ'phase is dissolved later during the solution heat treatment of 1,390°C/2 h+1,310°C/4 h+1,320°C/10 h+air cooling(AC).The composition segregations of Al,Ta,W and Re are 0.99,0.96,1.04 and 1.16,respectively,which close to 1.The incipient melting is caused by the low local temperature of the alloy,and the micropore region with a lower melting point is the preferred position for incipient melting.

Effect of complete revascularization in acute coronary syndrome after 75 years old:insights from the BleeMACS registry

BACKGROUND The prognostic benefit of complete revascularization in elderly patients(aged over 75 years)with multi-vessel disease and acute coronary syndrome(ACS)is currently unclear.This study aimed to determine the long-term prognostic impact of complete revascularization in this population.METHODS We conducted this study using data obtained from the BleeMACS(Bleeding complications in a Multicenter registry of patients discharged after an Acute Coronary Syndrome)registry,which was carried out from 2003 to 2014.The objective was to categorize older patients diagnosed with ACS into two groups:those who underwent complete revascularization and those who did not.Propensity score matching and the Kaplan-Meier analysis were employed to examine differences in one-year clinical outcomes.The primary endpoint was major adverse cardiovascular event(MACE),which encompassed a combination of all-cause mortality and myocardial infarction.RESULTS Out of 1263 patients evaluated,445 patients(35.2%)received complete revascularization.Patients who underwent complete revascularization had a higher prevalence of hypertension and prior percutaneous coronary intervention compared to those who did not.During the one-year follow-up period,complete revascularization was associated with a significantly decreased risk of MACE[13.7%vs.20.5%,hazard ratio(HR)=0.63,95%CI:0.45–0.88,P=0.007]and a lower risk of myocardial infarction(5.9%vs.9.9%,HR=0.55,95%CI:0.33–0.92,P=0.02).However,it was not linked to a lower risk of all-cause death(9.5%vs.13.5%,HR=0.68,95%CI:0.45–1.02,P=0.06).Similar results were observed in the subgroup analysis.CONCLUSIONS Long-term clinical improvements were observed in ACS patients aged over 75 years with multi-vessel disease who achieved complete revascularization.Therefore,adhering to guidelines for complete revascularization should be recommended for elderly patients.

Mild haemoglobin drop and clinical outcomes in acute coronary syndrome patients:finding from the BleeMACS registry

BACKGROUND Haemoglobin drop is common in acute coronary syndrome(ACS)patients and correlates with poor prognosis.However,the association between mild haemoglobin drop and adverse clinical outcome remains insufficiently investigated.This study aimed to examine the association between in-hospital haemoglobin drop and risk for adverse clinical outcomes in ACS patients,especially those with mild drop.METHODS Included patients from the BleeMACS(Bleeding complications in a Multicenter registry of patients discharged after an Acute Coronary Syndrome)registry were categorized into three groups by the presence and amount of in-hospital haemoglobin drop(non-drop,mild drop and severe drop).The cut-off point between mild drop and severe drop is≥3 g/dL.Multivariate Cox regression was used to assess the association between haemoglobin drop and major adverse cardiac endpoints(MACE).Patients taking potent P2Y_(12) inhibitors were selected for the additional analysis.Propensity score matching was used to avoid selective bias in the additional analysis.RESULTS Of 6911 patients,4949 patients(71.6%)experienced in-hospital haemoglobin drop.Compare with non-drop group,patients with haemoglobin drop had higher risk of MACE[adjusted hazard ratio(HR)=1.36,95%CI:1.03–1.80 for mild drop group;adjusted HR=1.70,95%CI:1.07–2.68 for severe drop group].Patients in mild drop group were less likely to receive potent P2Y_(12) inhibitors at discharge(mild drop group vs.severe drop group vs.non-drop group:10.9%vs.10.7%vs.23.8%).After propensity score matching adjustment among patients with potent P2Y_(12) inhibitors,patients in mild drop group were not associated with an increased risk of MACE than those in non-drop group(adjusted HR=1.52,95%CI:0.49–4.72).CONCLUSIONS In-hospital haemoglobin drop was common in ACS patients and associated with a higher risk for adverse events.Reduced prescription for potent P2Y_(12) inhibitors may be responsible for poor prognoses among patients with mild haemoglobin drop.