• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.1
• /
• pp.27-35
• /
• 1998

This study describes the influence of combustion parameters on the nitric oxide emission, such as injection timing, air flow rate, injected amount of fuel, and compression ratio of engine. In order to determine the influence factors on the nitric oxide emission, the experiment were investigated with various parameters of engine cycle. According to the results of this study, the retardation of injection timing and the increases of airflow rate, and the decreases of fuel injection amount reduce the nitric oxide concentration in the exhaust emissions. Also, the increases of compression ration of engine increase in the concentration of nitric oxide formation in the combustion chamber. The results of this study give a guideline to decrease the nitric oxide formation by using the simulation program.

• Journal of Life Science
• /
• v.16 no.2 s.75
• /
• pp.192-198
• /
• 2006

Epidemiological studies have demonstrated an association between exposure to diesel exhaust particles (DEP) and adverse cardiopulmonary effects. Despite the epidemiological proof, the pathogenesis of DEP-related pulmonary diseases remain poorly understood. So, comprehensive in vivo and in vitro researches are required to know the effects of DEP on diverse lung diseases. Alveolar macrophages (AM) and airway epithelial cells are known as important cellular targets in DEP-induced lung diseases. Other studies have shown that nitric oxide (NO) is involved in particle matter induced lung injury. The present study was undertaken to determine whether DEP has an synergistic effects on lipopolysaccharide (LPS)-induced NO formation and inducible nitric oxide synthase (iNOS) with nitrotyrosilated-protein formation in cultured primary alveolar macrophages. The formation of NO was determined through the Griess reaction in the cultured medium and iNOS with nitrotyrosilated-proteins are analyzed by immunohistochemical staining and Western analysis. The results indicate that DEP exposure does not induce NO formation by itself, however DEP showed significant synergistic effects on LPS-induced NO formation. So, our results suggest that DEP inhalation could aggravate inflammatory lung disease through NO formation.

• Journal of the korean Society of Automotive Engineers
• /
• v.7 no.3
• /
• pp.83-93
• /
• 1985

The prediction of emission concentrations in a 4cycle spark ignition engine was made by considering nonuniform model with thermodynamics, chemical equilibrium and kinetic mechanism of nitric oxide. Calculation of this model shows that a temperature difference of the order of 500K can be established across he cylinder. Results of the kinetic calculation of nitric oxide show that the temperature gradient across the cylinder has a profound effect on the nitric oxide formation. The predicted values for nitric oxide, carbon dioxide and carbon monoxide agree with measured ones for a variety of equivalence ratio.

• Corrosion Science and Technology
• /
• v.9 no.1
• /
• pp.20-28
• /
• 2010

According to the bipolar model, ion selectivity of some species in the passive film is important factor to control the passivation. An increase of cation selectivity of outer layer of the passive film can stabilize the film and improves the corrosion resistance. Therefore, the formation and roles of ionic species in the passive film should be elucidated. In this work, two types of solution (hydrochloric or sulfuric acid) were used to test high N and Mo-bearing stainless steels. The objective of this work was to investigate the formation of oxyanions in the passive film and the roles of oxyanions in passivation of stainless steel. Nitrogen exists as atomic nitrogen, nitric oxide, nitro-oxyanions (${NO_x}^-$), and N-H species, not nitride in the passive film. Because of its high mobility, the enriched atomic nitrogen can act as a reservoir. The formation of N-H species buffers the film pH and facilitates the formation of oxyanions in the film. ${NO_x}^-$ species improve the cation selectivity of the film, increasing the oxide content and film density. ${NO_x}^-$ acts similar to a strong inhibitor both in the passive film and at active sites. This facilitates the formation of chromium oxide. Also, ${NO_x}^-$ can make more molybdate and nitric oxide by reacting with Mo. The role of Mo addition on the passivation characteristics of stainless steel may differ with the test environment. Mo exists as metallic molybdenum, molybdenum oxide, and molybdate and the latter facilitates the oxide formation. When nitrogen and molybdenum coexist in stainless steel, corrosion resistance in chloride solutions is drastically increased. This synergistic effect of N and Mo in a chloride solution is mainly due to the formation of nitro-oxyanions and molybdate ion. Oxyanions can be formed by a 'solid state reaction' in the passive film, resulting in the formation of more molybdate and nitric oxide. These oxyanions improve the cation selectivity of the outer layer and form more oxide and increase the amount of chromium oxide and the ratio of $Cr_2O_3/Cr(OH)_3$ and make the film stable and dense.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.2
• /
• pp.333-337
• /
• 1998

This study was carried out to get infomation on the nitric oxide production ability and its formation mechanisms of polysaccharides extracted from Ganoderma lucidum(PSG) by using murine macrophage cell line. The cultured mycelial cells of Ganoderma lucidum were extracted by alkali, and than neutralized by acid. The extract were passed through the column of DEAE cellulose for more purification. The neutral fraction was concentrated and precipitated with 95% ethanol. The precipitate was lyophilized and PSG was obtained. The immunomodulating effects of PSG on macrophage were performed by using murine macrophage cell line ATCC TIB 71 cells with PSG 0.5mg. PSG alone could not induce the production of nitrite, but it had a significant potential effect on nitrite secretion when the cells were primed and triggered with BCG and Interferon(IFN)-${\gamma}$. Also it was prominent by using calcium channel blocker(verapamil) and adenylate cyclase activator(forskolin).

• Korean Journal of Plant Resources
• /
• v.32 no.4
• /
• pp.264-269
• /
• 2019

This research was performed to identify the anti-inflammatory constituent from the herb of Lycorus lucidus (Lamiaceae). The MeOH extract of this plant material and its two fractions, the lipophilic- ($CHCl_3$ fraction) and the hydrophilic fraction (BuOH fraction), were prepared to test anti-inflammatory activity. For this purpose, the inhibition rate on inducible nitric oxide synthase (iNOS) activity was assessed by determining nitric oxide (NO) formation in lipopolysaccharide (LPS)-induced macrophage 264.7 cells. The $CHCl_3$ fraction that greatly inhibited nitric NO formation was chromatographed to lead the isolation of ursolic acid. Since ursolic acid inhibited NO formation dose dependently in this study, this compound was considered as one of the active constituent responsible for anti-inflammation. However, the activity of rosmarinic acid isolated from the BuOH fraction was weak.

• The korean journal of orthodontics
• /
• v.25 no.6 s.53
• /
• pp.715-722
• /
• 1995

Orthodontic tooth movement in response to orthodontic force results from actions of osteoclasts and osteeoblasts in the cell level. Convincing evidence has now been provided to support the view that osteoclasts are derived from mononuclear cells that originate in the bone marrow or other hematopoietic organs and they migrate to the bones via vascular routes. Nitric oxide(NO), which accounts for the biological properties of endothelium-derived relaxing factor(EDRF), is the endogenous stimulator of soluble guanylate cylase. The discovery of the formation of nitric oxide(NO) from L-arginine in mammalian tissues and its biological roles has, in the last 7 years, thrown new light onto many areas of research. Data from experiments in vitro showed that N-metyl-L-arginine(L-NMA) and L-nitro-L- arginine(L-NAME) are competitive inhibitors of nitric oxide synthase. This study suggest that the multinucleated cells in our culture have characteristics of osteoclasts and that the potential bone cell activity of nitric oxide in vitro may be mediated in part by stimulation of marrow mononuclear cells to form osteoclast-like cells. Bone marrow cells were obtaineed from tibia of 19-days old chick embryo. After sacrifice, tibia was quickly dissected and the bone were then split to expose the medullary bone. The cells were attached for 4 hours and the nonadherent cells were collected. Marrow cells weere cultured in 96-well plate in medium 199. To examine the number of TRAP-positive multinucleated cells(MNCs), $10^{-8}\;M\;Vit=D_3$ and various concentration of L-NMA and L-NAME weere added at the beginning of cultures and with each medium change. After 7 days of culture. tartrate-resistant acid phosphatase(TRAP) staining was performed for microscopic evaluation. Cells haying more than three nuclei per cell were counted as MNCs. The obsrved results were as follows;1. 1,25-dihydroxyvitamine $D_3$ stimulated the osteoclast-like multinucleated cells in cultures of chick embryo bone marrow. 2. Nitric oxide synthase inhibitors(NOSI ; N-NMA, N-NAME) stimulated the osteoclast-like cells in cultures of chick embry bone marrow. 3. 1,25-dihydroxyvitamine$D_3$ and nitric oxide synthase inhibitors did not appear to have additive effect on the generation of TRAP-positive MNCs. These results suggest that nitric oxide synthase inhibitors may stimulate the osteoclast-like multinucleated cell formation and fusion in cultures of chick bone marrow.

• YAKHAK HOEJI
• /
• v.57 no.6
• /
• pp.388-393
• /
• 2013

Previously, we have reported that lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, increased melanin synthesis through intracellular $Ca^{2+}$ release in B16 cells. In this study we investigated the possible involvement of nitric oxide (NO) in the mechanism of lovastatin-induced melanogenesis. Lovastatin elevated NO formation in a dose-dependent manner. Treatment with mevalonate, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), precursors of cholesterol, did not significantly alter the lovastatin-induced NO production, suggesting that inhibition of cholesterol metabolism may not be involved in the mechanism of this action of lovastatin. Both NO formation and melanogenesis induced by lovastatin was significantly suppressed by treatment with $N^G$-nitro-L-arginine methyl ester (L-NAME) and 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide (cPTIO), an inhibitor of NO synthase and a NO scavenger, respectively. The lovastatin-induced NO production was significantly affected not by EGTA, an extracellular $Ca^{2+}$ chelator, but by an intracellular $Ca^{2+}$ chelator (BAPTA/AM) and intracellular $Ca^{2+}$ release blockers (dantrolene and TMB-8). Taken together, these results suggest that lovastatin may induce melanogenesis through NO formation mediated by intracellular $Ca^{2+}$ release in B16 cells. These results further suggest that lovastatin may be a good candidate for the therapeutic application of various hypopigmentation disorders.

• Korean Journal of Pharmacognosy
• /
• v.36 no.2 s.141
• /
• pp.116-120
• /
• 2005

Paeonol (2-hydroxy-5-methoxyacetophenone) obtained by silica gel column chromatography of the essential oil extracted from Paeonia moutan (Paeoniaceae) was methylated by dimethylsulfate to yield methylpaeonol (2,5-di-O-methylacetophenone). Both compounds inhibited nitric oxide (NO) foundation in lipopolysaccharide-induced macrophage RAW 264.7 cells in nitrite assay. In the western blotting assay, it was shown that both compounds also decreased inducible nitric oxide synthase (iNOS)-and cyclooxygenase-2(COX-2) formation. Methylpaeonol produced more potently inhibited NO-, iNOS and COX-2 formation in the assays than paeonol. These results suggest that paeonol is in part responsible for anti-inflammatory activity of Paeonia moutan, and that synthesis of paeonol derivatives may produce a promising candidate for andtiifnalmmatory agent.

• Natural Product Sciences
• /
• v.25 no.1
• /
• pp.34-37
• /
• 2019

Phytochemical studies were performed to identify the active principles of Phryma leptostachya var. asiatica (Phyrymaceae) for anti-inflammation. The anti-inflammatory activity was assessed by measuring the inhibition rate on nitric oxide (NO) formation in lipopolysaccharide (LPS)-activated macrophage 264.7 cells. Of the five compounds including ursolic acid, phrymarolin I, harpagide, haedoxancoside A, and acteoside isolated from this plant, ursolic acid showed the most prominent inhibition of NO formation. Therefore, ursolic acid may be the anti-inflammatory principle of Phryma leptostachya var. asiatica.