Variational first hyperpolarizabilities of 2,3-naphtho-15-crown-5 ether derivatives with cation-complexing: a potential and selective cation detector.

Crown ethers, as a kind of heterocycle, have been the subject of great interest over recent decades due to their selective capability to bind to metal cations. The use of a constant crown ether, such as naphtho-15-crown-5 (N15C5), and varied metal cations (Li+, Na+, K+, Be2+, Mg2+, Ca2+, Co2+, Ni2+, Cu2+) makes it possible to determine the contributions of the metal cations to nonlinear optical (NLO) responses and to design an appropriate NLO-based cation detector. N15C5 and its metal cation derivatives have been systematically investigated by density functional theory. It is found that the dependency of the first hyperpolarizability relies on the metal cation, especially for transition metals. The decrease of the first hyperpolarizabilities for alkali metal cation derivatives is due to their relatively low oscillator strengths, whereas the significant increase of the first hyperpolarizabilities for transition metal cation derivatives can be further illustrated by their low transition energies, large amplitudes and separate distributions of first hyperpolarizability density. Thus, the alkali metal and transition metal cations are distinguishable and the transition metal cations are easier to detect by utilizing the variations in NLO responses.

Protective effect of omeprazole on gastric mucosal of cirrhotic portal hypertension rats.

OBJECTIVE: To observe the protective effect of omeprazole on gastric mucosal of cirrhotic portal hypertension rats. METHODS: All rats were randomly divided into normal control group, cirrhosis and treatment group. Thioacetamide was used to establish rat model of cirrhotic portal hypertension. The necrotic tissue of gastric mucosa ulcer focus, degree of neutrophils infiltration at the ulcer margin, portal pressure, portal venous flow, abdominal aortic pressure, abdominal aortic blood flow at front end, gastric mucosal blood flow (GMBF), glycoprotein (GP) of gastric mucosa, basal acid secretion, H(+)back -diffusion, gastric mucosal damage index, NO, prostaglandin E2(PGE2) and tumor necrosis factor-α (TNF-α) were determined respectively, and the pathological changes of gastric mucosa were also observed by microscope. RESULTS: Compared with cirrhosis group and the control group, the ulcer bottom necrotic material, gastric neutrophil infiltration and UI of the treatment group were all decreased significantly (P<0.01), GMBF value, GP values, serum NO, PGE2, TNF-α were all significantly increased. CONCLUSIONS: Omeprazole has an important protective effect on gastric mucosal and it can increase gastric mucosal blood flow and related to many factors.