Kinetic analysis of γ-glutamyltransferase reaction process for measuring activity via an integration strategy at low concentrations of γ-glutamyl p-nitroaniline

At 0.12 mmol/L γ-glutamyl p-nitroaniline(GGPNA),an improved integrated method was developed for kinetic analysis of γ-glutamyltransferase(GGT) reaction process and the integration with the classical initial rate method to measure serum GGT.For the improved integrated method,an integrated rate equation,which used the predictor variable of reaction time and considered inhibitions by both GGPNA and products,was nonlinearly fit to GGT reaction processes.For the integration strategy,classical initial rates were estimated when GGPNA consumption percentages were below 50%;otherwise,maximal reaction rates of GGT were estimated by the improved integrated method and converted into initial rates according to the differential rate equation at 0.11 mmol/L GGPNA.The inte-gration strategy was validated using optimized GGT kinetic parameters and 10-s intervals to record reaction curves within 8.0 min.By the integration strategy,there was a linear response from 0.9 to 32.0 U/L GGT,coefficients of variation were below 3.5%for GGT from 8.0 to 32.0 U/L(n=5) ,and GGT activities in clinical sera responded linearly to their classical initial rates at 2.00 mmol/L GGPNA with an expected slope.Therefore,the integration strategy was successful in measuring GGT at 0.12 mmol/L GGPNA.

Properties and structure of a new non-reactive mold flux for high-Al steel

During the conventional continuous casting process of high-aluminum steels(w([Al])>0.5 wt.%),some components of slag,such as SiO_(2),B_(2)O_(3),and TiO_(2),could be reduced by aluminum in molten steel.Therefore,the CaO-BaO-Al_(2)O_(3)-CaF2-Li2O non-reactive mold fluxes were designed using the simplex grid method and molecular dynamics to mitigate the slag-metal interface reaction and stabilize the performance of mold fluxes.The results show that the components of nonreactive quinary system are 20-40 wt.% CaO,14-34 wt.% BaO,14-34 wt.% Al_(2)O_(3),4-12 wt.% F,and 4-8 wt.% Li_(2)O.Molecular dynamics simulation results show that[AlO_(4)]-tetrahedron acts as network formers and melt network structure is mainly chain and lamellar in the low-viscosity area.The cross sections of w(F)=8 wt.%,w(Li_(2)O)=8 wt.%and w(F)=12 wt.%,w(Li2O)=8 wt.% are important reference sections for the design of mold flux,with the compositions of 22-40 wt.%CaO,14-34 wt.% BaO,20-34 wt.%Al_(2)O_(3) and 23-40 wt.%CaO,14-34 wt.%BaO,20-28 wt.% Al_(2)O_(3),respectively.