• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.125-125
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• 2001

Peroxynitrite (ONOO), a potent cytotoxic oxidant formed by the reaction of nitric oxide (ㆍNO) and superoxide radical (ㆍO$_2$), reacts rapidly to cause of oxidization and nitration process. The importance of the regulation of ONOO$^{-}$ has been recently recognized because of the lack of specific endogenous enzymes against ONOO$^{-}$. Coffee that is a complex mixture containing a variety of components has been reported to have both beneficial and hazardous effects.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.140-144
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• 2014

• YAKHAK HOEJI
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• v.41 no.4
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• pp.480-483
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• 1997

The efficient synthesis of p-(acetylamino)phenylacetic acid(7), a antirheumatic agent, is reported. Methyl phenylacetate(3) was prepared from Friedel- Crafts reaction of benzene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate(1) followed by reductive desulfurization with zinc dust in acetic acid. Compound(7) was obtained from 3 by a sequence of nitration, reduction, N-acylation, and hydrolysis.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.317.2-317.2
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• 2002

Peroxynitrite, formed from the reaction of .O2- and .NO, is a cytotoxic species that can oxidize several cellular components such as proteins. lipids and DNA. Oxidative stress is considered to be the major cause of aging and many age-related diseases including Alzheimer's disease. rheumatoid arthritis. cancer. and atherosclerosis. ONO-, a powerful oxidant, can cause damage of proteins, lipid and DNA through nitration and oxidation. (omitted)

• Environmental Analysis Health and Toxicology
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• v.11 no.3_4
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• pp.33-44
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• 1996

Photolysis of TCBs in aqueous solutions of sodium nitrite and triethylamine (TEA) at neutral pH has been investigated. TCBs yielded trichloronitrobenzenes(TCNBs) as primary photoproducts, and their corresponding trichlorophenols (TCPs) via two types of reaction, one, nitration, and the other, by direct hydroxylation with OH radical. Isomerized products and TCBs were also identified. Photosensitization with TEA resulted in the formation of small yields of dichlorobenzenes(DCBs) by reductive dechlorination of TCBs.

• The Journal of Internal Korean Medicine
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• v.25 no.2
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• pp.268-276
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• 2004

Objective : Peroxynitrite $(ONOO^-)$, formed from the reaction of $O_2^-$ and NO, is a cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA. It has been implicated in the aging process and age-related disease such as Alzheimer's disease, rheumatoid arthritis, cancer and atherosclerosis. The aim of this study was to investigate scavenging activities of $ONOO^-$ and its precursors. NO and $O_2^-$ and its scavenging mechanism using fluorescent probes, DCFDA, DAF-2 and DHR 123.. Methods : Psoralea corylifolia was crushed. The crushed Psoralea corylifolia was extracted 3 times, each time with 3 volumes of methyl alcohol at $60^{\circ}C$ for 24 h. The extract was filtered and evaporated under reduced pressured using a rotary evaporator to yield 16g. This was done to investigate scavenging activities of $ONOO^-$, NO, $O_2^-$ and its scavenging mechanism using fluorescent probes, DCFDA, DAF-2 and DHR 123. Results : After Psoralea corylifolia was added authentic $ONOO^-,\;{\cdot}\;O_2^-$ and NO was markedly scavenged. Also, $ONOO^-$ induced by $O_2^-$ and NO (these derived from SIN-1) was inhibited. The data showed a decrease in $ONOO^-$ mediated nitration of tyrosine through electron donation after Psoralea corylifolia was added. Data showed a dose-dependent correlation with inhibition of nitration of bovine serum albumin induced by $ONOO^-$, Furtheremore, LPS-induced ROS and RNS generation was blocked. Conclusions: These results suggest potential for use of Psoralea corylifolia as an effective $ONOO^-$ scavenger to counter the aging process and age-related diseases.

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.139-153
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• 2010

Nitrosative stress is defined as pathophysiological conditions that are related to covalent modifications of proteins by nitration/nitrosylation by forms of nitrogen oxide ($NO_x$), leading to DNA damage, ultimately, cell death. This type of stress condition appears to be associated with a number of disease states, including diabetes, inflammation and neurodegenerative diseases. Since these pathological conditions are frequently chronic in nature and, thus, require long-term treatment, changes in pharmacokinetics are likely to affect the therapy. Transporters are membrane proteins that facilitate the movement of substrates, including drugs, across plasma membranes of epithelial / endothelial cells. Since it is now increasingly evident that transporters are pharmacokinetically significant, functional alteration of transporters by this stress condition may have therapeutic relevance. In this review, experimental techniques that are used to study both in vivo and in vitro nitrosative stress are summarized and discussed, along with available literature information on the functional implication of transporters under conditions of nitrosative stress conditions. In the literature, both functional induction and impa irment were apparently present for both drug transporter families [i.e., ATP-binding cassette (ABC) and solute carrier families (SLC)]. Furthermore, a change in the function of a certain transporter appears to have temporal dependency by impairment in the early phase of nitrosative stress and induction thereafter, suggesting that the role of nitrosative stress is complex in terms of functional implications of the transporters. Although the underlying mechanisms for these alterations are not fully understood, protein nitration/nitrosylation appears to be involved in the functional impairment whereas transcript factor(s) activated by nitrosative stress may play a role, at least in part, in functional induction. Interestingly, functional induction under conditions of nitrosative stress has not been observed for SLC transporters while such impairment has been documented for both ABC and SLC transporters. Further investigations appear to be necessary to fully delineate the underlying reasons for these differences on the impact and importance of nitrosative stress conditions.

• Journal of Ocean Engineering and Technology
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• v.24 no.6
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• pp.76-80
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• 2010

Oil hydraulic piston pumps are being extensively used around the world, because of their simple design, light weight, effective cost, etc. An oil hydraulic pump is likely to have the serious problems of high leakage, friction, and low energy efficiency after a long period of use. In an oil hydraulic piston pump, the clearance between the valve block and piston plays an important role for volumetric and overall efficiency. In this study, the wear property of the SACM645 material with DLC coating used for a hydraulic piston pump was determined by experimentation with variable heat treatment. To investigate the effect according to the piston surface condition, five different types of specimens were prepared. The maximum tensile strengths of the QT and QT Nitration specimens had similar values of about 800 MPa, but the strains indicated a big difference. In a wear test, the wear characteristic of the DLC coating specimen was shown to be excellent. The QT, QT + IH, QT + Nitration, and matirx specimen showed similar wear characteristics. In the case of a dry condition without oil, the DLC coating specimen had good wear resistance, with no wear shown.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.50-57
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• 2016

We studied the Lab-scale process for the development of DNAM in aspect of safety and overall efficiency. Melamine is used for starting material of process, DNAM was synthesized by oxidation and nitration reaction. In order to optimize the process parameters with the product in higher yield and purity, a systematic study with variation of different parameters like molar ratio of nitrating mixture, conditioning time and order of reactant was carried out. The optimized reaction conditions for the synthesis of DNAM were : conditioning time of $3{\pm}3.5$ hour and nitrating mixture in 1:1.4 molar ratio. In order to proceed a stable reaction, melamine was added with enough time to relieve reaction heat. From these reaction condition, DNAM could be obtained in a yield of more than 60%.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1389-1397
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• 2005

Since blast-induced vibration may cause serious problem to the rock mass as well as the nearby structures, the prediction of blast-induced nitration and the stability evaluation must be performed before blasting activities. Dynamic analysis has been increased recently in order to analyze the effect of the blast-Induced vibration. Most of the previous studies, however, were based on the continuum analysis unable to consider rock joints which significantly affect the wave propagation and attenuation characteristics. They also adopted pressure corves estimated tv theoretical or empirical equations as input detonation load, thus there were very difficult to reflect the characteristics of propagating media. In this study, therefore, we suggested a dynamic distinct element analysis technique which uses velocity waveform obtained from a test blast as an input detonation load. A distinct element program, UDEC was used to consider the effect of rock joints. In order to verify the validity of proposed method, the test blast was simulated. The predicted results from the proposed method showed a good agreement with the measured vibration data from the test blast. Through the dynamic numerical modelling on the planned road tunnel and slope, we evaluated the effect of blast-induced nitration and the stability of rock slope.