N2/NO Ratio (no + ratio)

Distribution by Scientific Domains


Selected Abstracts


Temperature-Programmed Oxidation of Soot in a Hybrid Catalysis-Plasma System

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2008
H. Lin
Abstract Non-thermal plasma (NTP) technology was applied to promote the temperature-programmed oxidation (TPO) of soot over a perovskites type of La0.8K0.2MnO3 catalyst. The O radicals originating from the decomposition of O2, as well as NO dissociation if nitrogen oxide were involved, reduce the ignition temperatures of soot. In NO-O2 -He, for example, the ignition temperature decreased to 240,C from 290,C as the voltage increased from 0,kV to 15,kV. The higher voltage also benefited the adsorption of NO molecules onto the catalyst surface (NOad). As a result, the maximum N2/NO ratio (conversion ratio of NO into N2) rose from 23,% to 53,%. Some of the NO molecules were dissociated into N and O radicals in plasma, and hence, the N2/NO ratio was further enhanced due to the combination of N atoms. In any case, the redox process between NOx and soot proved to be important in soot oxidation. [source]


REGULATION OF FIBROGENESIS DURING THE EARLY PHASE OF COMMON BILE DUCT OBSTRUCTION

ANZ JOURNAL OF SURGERY, Issue 7 2006
Atilla Engin
Background: Both nitric oxide (NO) and prostaglandins have been proposed as inhibitor substances involved in collagen deposition in the hepatic parenchyma. The possible reciprocal connections between NO and eicosanoids in the development of liver fibrosis were investigated during the initial phase of common bile duct obstructions. Methods: A total of 30 male albino guinea pigs were randomly and equally assigned to three groups. Group 1 underwent sham laparotomy. Group 2 and group 3 were subjected to permanent common bile duct ligature for 24 and 72 h , respectively. Changes in the liver prostaglandin E2 (PGE2), leukotriene C4, malondialdehyde contents and plasma nitrite plus nitrate concentrations were measured. To evaluate the extent of hepatic fibrosis, histological assessment of liver was confirmed with the equivalent hydroxyproline contents of liver. Results: Twenty-four hours after ligature, the amount of malondialdehyde and PGE2 and plasma nitrite plus nitrate concentrations increased significantly, whereas liver hydroxyproline contents did not change. However, 72 h after ligature (Group 3), lipid peroxidation and collagen deposition were significantly higher than that of the group 2 animals. The PGE2 : leukotriene C4 ratio peaked at 24 h and later decreased, whereas PGE2 : NO ratio remained unchanged in both group 2 and group 3 animals. Conclusions: The initiation of collagen synthesis occurred in portal tract as early as within the first 72 h of bile duct obstruction. The optimum function of reactive oxygen species on the stellate cell activation might be determined by the interaction between NO and PGE2. [source]


Ginkgo biloba extract improves coronary artery circulation in patients with coronary artery disease: contribution of plasma nitric oxide and endothelin-1

PHYTOTHERAPY RESEARCH, Issue 6 2008
Yu-Zhou Wu
Abstract In patients with coronary artery disease (CAD), coronary blood flow is usually impaired due to imbalanced vasoactive substances such as nitric oxide (NO) and endothelin-1 (ET-1). The study was designed to test the effects of Ginkgo biloba extract (GBE) on the distal left anterior descending coronary artery (LAD) blood flow and plasma NO and ET-1 levels. Eighty CAD patients were randomly assigned to GBE (n = 42) and control (n = 38) groups. The LAD blood flow was assessed non-invasively using Doppler echocardiography at baseline and after 2 weeks. GBE treatment demonstrated a significant improvement in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with controls (14.61 4.51% vs 0.67 2.66%, 9.03 4.81% vs 0.34 2.67% and 14.69 5.08% vs 0.68 3.00%, respectively, p < 0.01). NO was increased by 12.42% (p < 0.01), whereas ET-1 was decreased by 5.82% (p < 0.01). The NO/ET-1 ratio was increased by 19.47% (p < 0.01). A linear correlation was confirmed between the percentage change in LAD blood flow and in NO, ET-1 or NO/ET-1 ratio following GBE treatment. The results suggest that GBE treatment in CAD patients led to an increase of LAD blood flow, which might at least be related partly to the restoration of the delicate equilibrium between NO and ET-1. Copyright 2008 John Wiley & Sons, Ltd. [source]