Bifunctional nickel oxide-based nanosheets for highly efficient overall urea splitting.

Porous and hollow Ni0.9Fe0.1Ox microspheres assembled from 2D nanosheets exhibit excellent bifunctional activity for both urea oxidation reaction and hydrogen evolution reaction, in which the potential for overall urea splitting is 1.455 V at 10 mA cm-2.

Ascorbic acid secretion in the human stomach and the effect of gastrin.

AIM:To investigate the changes of gastric mucosal ascorbic acid secretion in patients with nonulcer dyspepsia and the effect of gastrin on it, and to relate any observed changes to H.pylori infection and mucosal histology.METHODS:Ascorbic acid secretions in patients were examined by collecting continuously gastric juice for one hour after having aspirated and discarded fasting gastric juice. Using the clearance rate (mL/min) of ascorbic acid from blood to gastric juice represented ascorbic acid secretion in the gastric mucosa.Ascorbic acid concentrations in plasma and juice were measured by ferric reduced method.RESULTS:Gastric ascorbic acid secretions in H.pylori-positive patients (1.46mL/min,range 0.27-3.78) did not significantly differ from those in H.pylori-negative patients(1.25mL/min, 0.47-3.14)(P>0.05). There were no significant differences in ascorbic acid secretions between patients with mild (1.56mL/min, 0.50-3.30), moderate (1.34mL/min, 0.27-2.93) and severe (1.36mL/min, 0.47-3.78) inflammation (P >0.05). There were no significant differences in ascorbic acid secretions between patients without activity (1.45mL/min, 0.27-3.14) and with mild (1.32mL/min, 0.61-2.93), moderate (1.49mL/min, 0.50-3.78) and severe (1.43mL/min, 0.51-3.26) activity of chronic gastritis either (P>0.05). Ascorbic acid secretions in patients with severe atrophy (0.56mL/min, 0.27-1.20) were markedly lower than those in patients without atrophy (1.51mL/min, 0.59-3.30) and with mild (1.43mL/min, 0.53-3.78) and moderate (1.31mL/min,0.47-3.16)atrophy(P<0.005). There was a significant negative correlation between ascorbic acid secretion and severity of atrophy (correlation coefficient =-0.43, P<0.005). After administration of pentagastrin, ascorbic acid secretions were markedly elevated (from 1.39mL/min, 0.36-2.96 to 3.53mL/min, 0.84-5.91) (P <0.001).CONCLUSION:Ascorbic acid secretion in gastric mucosa is not affected by H.pylori infection. Gastric ascorbic acid secretion is markedly related to the severity of atrophy, whereas not related to the severity of inflammation and activity. Gastrin may stimulate gastric ascorbic acid secretion. A decreased ascorbic acid secretion may be an important factor in the link between atrophic gastritis and gastric carcinogenesis.