Glutathione transferases (GSTs) form a family of detoxication enzymes instrumental in the inactivation and elimination of electrophilic mutagenic and carcinogenic compounds. The Pi class GST P1-1 is present in most tissues and is commonly overexpressed in neoplastic cells. GST P1-1 in the dog, Canis lupus familiaris, has merits as a marker for tumors and as a target for enzyme-activated prodrugs. We produced the canine enzyme CluGST P1-1 by heterologous bacterial expression and verified its cross-reactivity with antihuman-GST P1-1 antibodies. The catalytic activity with alternative substrates of biological significance was determined, and the most active substrate found was benzyl isothiocyanate. Among established GST inhibitors, Cibacron Blue showed positive cooperativity with an IC50 value of 43 nM. Dog GST P1-1 catalyzes activation of the prodrug Telcyta, but the activity is significantly lower than that of the human homolog. 相似文献
In-air epitaxy of nanostructures (Aerotaxy) has recently emerged as a viable route for fast, large-scale production. In this study, we use small-angle X-ray scattering to perform direct in-flight characterizations of the first step of this process, i.e., the engineered formation of Au and Pt aerosol nanoparticles by spark generation in a flow of N2 gas. This represents a particular challenge for characterization because the particle density can be extremely low in controlled production. The particles produced are examined during production at operational pressures close to atmospheric conditions and exhibit a lognormal size distribution ranging from 5–100 nm. The Au and Pt particle production and detection are compared. We observe and characterize the nanoparticles at different stages of synthesis and extract the corresponding dominant physical properties, including the average particle diameter and sphericity, as influenced by particle sintering and the presence of aggregates. We observe highly sorted and sintered spherical Au nanoparticles at ultra-dilute concentrations (< 5 × 105 particles/cm3) corresponding to a volume fraction below 3 × 10–10, which is orders of magnitude below that of previously measured aerosols. We independently confirm an average particle radius of 25 nm via Guinier and Kratky plot analysis. Our study indicates that with high-intensity synchrotron beams and careful consideration of background removal, size and shape information can be obtained for extremely low particle concentrations with industrially relevant narrow size distributions.
To explore the effect of the operating pressure on the flow and thermal characteristics in a vertical tube with supercritical n‐decane, the inner wall temperature along the streamwise direction, the applicability of empirical correlations and buoyancy criteria are studied firstly. The mechanisms in views of density distribution, velocity field, turbulence intensity, the thickness of the thermal boundary layer, and secondary flow are then analyzed. It is observed that the buoyancy is helpful for the phenomenon of heat transfer deterioration at lower operating pressures but higher operating pressures can diminish this tendency. According to this reason, the empirical correlation proposed by Bae and Kim is suitable for the higher operating pressures but cannot well predict the occurrence of heat transfer deterioration. However, it can be evaluated by the buoyancy criterion Gr/Re2 = 0.01 qualitatively. The decrease of turbulence intensity, the thickened thermal boundary layer, and secondary flow generation make contributions to the heat transfer deterioration in particular. Similarly, this situation can be diminished and even removed by the higher operating pressures. 相似文献
Novel oxygen-deficient double-perovskite type oxide Ba2NixCo2−xO6 was applied to produce O2/CO2 mixed stream gas for oxyfuel combustion application. A series of different Co concentration substituted Ba2NixCo2−xO6 was synthesized by an EDTA-citrate sol-gel combustion method. The oxygen carriers, Ba2Ni0.25Co1.75O6, Ba2Ni0.45Co1.55O6, Ba2Ni0.65Co1.35O6 and Ba2Ni0.85Co1.15O6 were c\characterized by scanning electron microscopy and cyclic oxygen adsorption/desorption experiments. The results showed that the capacity of provided O2 was improved by the partial substitution of Ni by Co. In addition, the synthesized perovskites exhibit good regeneration ability. The optimal degree of Co substitution was x = 0.25 for Ba2NixCo2−xO6 with consideration of oxygen desorption ability. Therefore, Ba2Ni0.25Co1.75O6 was selected to examine the influence of the operating parameters on the oxygen release performance. It was found that the desorption temperature and CO2 partial pressure are the two main operating parameters for the oxygen desorption performance. Further, the proposed novel double perovskite Ba2Ni0.25Co1.75O6 provided excellent performance, the O2 production of Ba2Ni0.25Co1.75O6 can still reach 120 mg/g after 10 cycles. 相似文献