ABSTRACT
Yttrium vanadate:europium nanoprobes (YVO4∶Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method.Due to the overlapping of the excitation spectrum of YVO4∶Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4∶Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4∶Eu NPs was quenched.Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4∶Eu as nanoprobes based on IFE.Some experimental parameters, such as the adding amount of YVO4∶Eu NPs, pH value of the reacting solution, and reacting time, were investigated.Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×104 mol/L and the detection limit was 1.0×10-6 mol/L (3σ).The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%.This method is simple, rapid, sensitive and accurate.
ABSTRACT
Objective To evaluate the efficacy and safety of distal embolic protection device(DPD) on acute myocardial infarction(AMI) with ST-segment elevation.Methods Two hundred and sixty-seven patients with ST-segment elevation AMI treated in emergency with percutaneous coronary intervention(PCI) from Jan.1,2004 to Dec.31,2005 in the Department of Cardiology,Xijing Hospital were studied retrospectively.169 patients were included in control group and 98 in DPD group.Patients in control group were treated with emergency PCI,while those in DPD group were treated with DPD during emergency PCI.The incidence of "no-reflow" phenomenon,thrombolysis in myocardial infarction(TIMI) 3 flow,and ST segment resolution were observed,and mortality in-hospital and left ventricular ejection fraction(LVEF) at 1 week after PCI were compared between the two groups.Results The incidence of "no-reflow" was 3.06%(3/98) in DPD group and 13.61%(23/169) in control group(P