• The Korean Journal of Pharmacology
• /
• v.28 no.2
• /
• pp.201-212
• /
• 1992

Effect of exogenous taurine on HOCl, $NH_2Cl$ and other oxidants-induced degradation of hyaluronic acid was investigated. The scavenging action of taurine on HOCl, $NH_2Cl$ and other oxidants was examined. The antioxidant action of taurine was also compared with that of thiol compounds. Viscosity of hyaluronic acid was markedly decreased by HOCl and $NH_2Cl$ on a dose dependent fashion. The degradative effect of HOCl on hyaluronic acid was greater than that of $NH_2Cl$. Taurine effectively inhibited HOCl-and $NH_2Cl-induced$ degradation of hyaluronic acid in a dose dependent fashion. The degradative effect of HOCl was markedly inhibited by DMSO. $Fe^{2+}$ plus $H_2O_2-induced$ degradation of hyaluronic acid was inhibited by catalase and DMSO but not affected by taurine. The desradative action of xanthine and xanthine oxidase was effectively inhibited by SOD and catalase but not affected by taurine. HOCl was significantly decomposed by taurine, DMSO, GSH and MPG. Both absorbance of HOCl at 250 nm and absorbance of $NH_2Cl$ at 242 nm were significantly increased by the addition of taurine. Interaction of $NH_2Cl$ with GSH or MPG showed an initial peak absorbance, but these absorbances were gradually decreased with time. OH production in the presence of $Fe^{2+}$ and $H_2O_2$ was inhibited by catalase and DMSO but not affected by taurine. Taurine did not affect $^1O_2$ production by U.V. irradiation which is responsible for DABCO and DABA. GSH and MPG markedly inhibited the degradative action of HOCl. These results suggest that the protective action of taurine on oxidants-induced damages of tissue components, including degradation of hyaluronic acid may be attributable to both its scavenging action on HOCl and $NH_2Cl$ and the complex formation of taurine with HOCl or $NH_2Cl$ without scavenging action on oxygen free radicals. Sulfhydryl group of taurine appears to show partially a protective action on HOCl-and $NH_2Cl-induced$ degradation.

• The Korean Journal of Pharmacology
• /
• v.28 no.2
• /
• pp.129-136
• /
• 1992

As it has been reported that the depolarization-induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus and various lines of evidence indicate the involvement of adenylate cyclase system in $A_1-adenosine$ post-receptor mechanism in hippocampus, it was attempted to delineate the role of adenylate cyclase system in the $A_1-receptor-mediated$ control of ACh release in this study. Slices from rat hippocampus were incubated with $[^3H]-choline$ and the release of the labelled products was evoked by electrical stimulation $(3\;Hz,\;5\;Vcm^{-1},\;2\;ms,\;rectangular\;pulses)$, and the influence of various agents on the evoked tritium-outflow was investigated. $N^6-cyclopentyladenosine$ (CPA), a specific $A_1-adenosine$ receptor agonist, in concentrations ranging from 0.1 to $10\;{\mu}M$, decreased the $[^3H]-ACh$ release in a dose-dependent manner without the changes of basal rate of release. 8-cyclopentyl-1,3-dipropylxanthine $(DPCPX,\;1{\sim}10\;{\mu}M)$, a selective $A_1-receptor$ antagonist, increased the $[^3H]-ACh$ release in a dose-related fashion with slight increase of basal tritium-release. And the CPA effects were significantly inhibited by DPCPX $(2\;{\mu}M)$ pretreatment and the dose-response curve produced by CPA was shifted to the right. The responses to N-ethylmaleimide $(NEM,\;10\;&\;30\;{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked ACh-release and the basal release, and the CPA effect were completely abolished by NEM pretreatment. Forskolin, a specific adenylate cyclase activator, in concentrations ranging from 0.3 to $10\;{\mu}M$, increased the evoked ACh-release in a dose-dependent manner and the CPA effects were inhibited by forskolin. These results indicate that the $A_1-adenosine$ heteroreceptor plays an important role in ACh-release via nucleotide-binding protein Gi in the rat hippocampus and that the adenylate cyclase system might be participated in this process.

• Journal of Astronomy and Space Sciences
• /
• v.26 no.4
• /
• pp.451-466
• /
• 2009

While substorms are known to generally occur under southward IMF conditions, they can sometimes occur even under northward IMF conditions. In this paper, we studied the substorms that occurred in May, 2000 to 2002 to examine some statistical characteristics of the IMF and solar wind associated with northward IMF substorms. We focused on the cases where two or more substorms occurred successively under northward IMF conditions. Also, by checking Sym-H index associated with each of the substorms we determined whether or not there is any association of such northward IMF substorm occurrence with storm times. We also examined statistical properties at geosynchronous altitude in terms of magnetic field dipolarization and energetic particle injection. The following results were obtained. (i) Most of the northward IMF substorms occurred under average solar wind conditions. The majority of them occurred within 2 hrs duration of northward IMF Bz state, but there are also a nonnegligible number of substorms that occurred after a longer duraiton of northward IMF Bz state. (ii) While most of the substorms occurred as isolated from a magnetic storm time, those that occurred in a magnetic storm time show a higher average value of IMF and solar wind than that for the isolated substorms. (iii) About 55% of the substorms were associated with the IMF clock angle that can possibly allow dayside reconnection, and the other 45% were associated with more or less pure northward IMF conditions. Therefore, for the latter cases, the energy input from the solar wind into the magnetosphere should be made by other way than the dayside reconnection. (iv) For most of the substorms, the magnetic field dipolarizations and energetic particle injections at geosynchronous altitude were identified to be generally weak. But, several events indicated strong magnetic field dipolarizations and energetic particle injections.

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.394-403
• /
• 2016

$H_2$ production by chemical looping is an efficient method to convert hydrocarbon fuel into hydrogen with the simultaneous capture of concentrated $CO_2$. This process involves the use of an iron based oxygen carrier that transfers pure oxygen from oxidizing gases to fuels by alternating reduction and oxidation (redox) reactions. The enhanced reactivities of copper oxide doped iron-based oxygen carrier were reported, however, the fundamental understandings on the interaction between $Fe_2O_3$ and CuO are still lacking. In this study, we studied the effect of dopant of CuO to $Fe_2O_3/ZrO_2$ particle on the morphological changes and the associated reactivity using various methods such as SEM/EDX, XRD, BET, TPR, XPS, and TGA. It was found that copper oxide acted as a chemical promoter that change chemical environment in the iron based oxygen carrier as well as a structural promoter which inhibit the agglomeration. The enhanced reduction reactivity was mainly ascribed to the increase in concentration of $Fe^{2+}$ on the surface, resulting in formation of charge imbalance and oxygen vacancies. The CuO doped $Fe_2O_3/ZrO_2$ particle also showed the improved reactivity in the steam oxidation compared to $Fe_2O_3/ZrO_2$ particle probably due to acting as a structural promoter inhibiting the agglomeration of iron species.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.9 no.1
• /
• pp.13-25
• /
• 1998

Aim：We think that the most important etiology in parent abuse is the psychodynamic and psychopathology in the family. So, we investigated the adolescents being admitted in SNMH, whose chief complaints were parent abuse. We were trying to explore families psychodynamic and psychopathology, especially mother-child interaction and to differentiate them in according to developmental psychopathology. Method：Our objects were the adolescent patients admitted in SNMH from 1987 to 1997 because they attacked parents verbally and physically. We examined 21 adolescents except those with psychosis, organic mental disorder, autism and mental retardation by means of interview or chart review. Result and Conclusion：The number of male patients was 14 and the number of female patients was 7. The most common diagnosis was conduct disorder and borderline personality disorder. The mean age was in the mid-teens. We observed 4 subgroups that were divided developmentally in object relation. 1) Symbiotic group with mother：(1) They did not separate and remain in symbiotic relationships with their mothers based on insecure attachment. Fathers were abscent emotionally and physically, and their mothers were prominent in close relationships with the patients in their family , where as the patients were the only man in the family. Adolescents entered the second separation-individuation. They expressed anger and internal tension involved with the close attachment with their mothers and also attempted separation from their mothers through physically attacking them. (2) These patients had suffered from physical illness and developmental delay since birth. Therefore the parents overprotected their children. The children had persistent infantile omnipotence and fantasies of power, so they could not deal with unrealistic states, adapt to reality, and depended on their parents overtly. They easily acted out unless their demands were fulfilled. 2) Borderline personality disorder：We observed deficiencies in care taking. Their parents had personality problems and immaturity. They coulden’t help their children to be separated in the rapproachment phase. Their conflict about dependence-independence was revived in the second separation-individuation adolescent period. We understand parent abuse as an attempt to overcome the conflict. 3) Conduct disorder：They did not build up basic attachment with their parents. They think of their parents as only a means of fulfilling their needs. When patients’ need were not fulfilled and remained in a conflicted state, they attacked their parents, unable to control their aggressions and impulses.

• Journal of the Korean Magnetics Society
• /
• v.14 no.1
• /
• pp.38-44
• /
• 2004

The iron doped colossal magnetoresistance materials with La-Ba-Mn-O perovskites structure have been synthesized by chemical reaction of sol-gel methods. Their crystallographic and magnetic properties have been studied with x-ray diffraction, VSM, RBS, Mossbauer spectroscopy, and magnetoresistance measurements. The crystal structure of the La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$ at room temperature was determined to be orthorhombic of Pnma. The lattice parameters a$\_$0/ and c$\_$0/ increased gradually, but b$\_$0/ deceased with increase of iron substitution. The magnetization and coercivity deceased, also the Curie temperature decreased from 360 K as x increased from 0.00 to 0.05. Magnetoresistence measurements were carried out, and the maximum MR ($\Delta$$\rho$/$\rho$(0)) was observed at 281 K, about 9.5 % in 10 kOe. The temperature of maximum resistance (R$\_$MAX/) decreased with increasing substitution of Fe ions and a semiconductor-metal transition temperature (T$\_$SC-M/) decreased too. This phenomena show that ferromagnetic transition temperature decreased by substituting Fe for Mn ions, it decreases double exchange interaction. This result accords with magnetic structure of neutron diffraction. Mossbauer spectra of La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$were taken at various temperatures ranging from 15 to 350 K. With lowering temperature of the sample, two magnetic phases were increased and finally it showed the two sharp sextets of spectra at 15 K. The isomer shift at all temperature range is about 0.3 mm/s relative to Fe metal, which means that both Fe ions are Fe$\^$3+/ states.Fe$\^$3+/ states.

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.560-567
• /
• 1997

A new approach to obtain stable $W_1/O/W_2$ multiple emulsions has been studied ; The basis of the interfacial interaction between a PCL-PEO-PCL triblock copolymer and a lipophilic emulsifier in the dispersed oil phase was examined. $W_1/O/W_2$ multiple emulsions were prepared by the two-step method. Arlacel P-l35 was used as a liphophilic emulsifier and Synperonic PE/F 127 as a hydrophilic one. Eutanol-G was used as an oil phase. NaCl was encapsulated within the multiple emulsion droplets as the internal marker and its release rate studies were carried out. The suability of the multiple emulsions have been assessed by measuring Separation Ratios(%) and microscopic observations. The release of NaCl was significantly reduced in $W_1/O/W_2$ multiple emulsions containing PCL-PEO-PCL triblock copolymer(2k-4k-2k or 6k-4k-6k) in the oil phase. It may be concluded that the copolymer and the emulsifier form effective interfacial complex to enhance stability and to control the release rate. The effective diffusion coefficients of the NaCl were estimated as $2.64{\times}10^{-15}s$and $3.23{\times}10^{-16}gcm^2/s$ for the $W_1/O/W_2$ multiple emulsion containing 1.2 wt % of PCL-PEO-PCL triblock copolymers with compositions of 2k-4k-2k and 6k-4k-2k, respectively. The rate of release decreased with the increase of the initial concentration of NaCl. The results were examined in view of Higuchi mechanism. A kinetic model which is similar to the model for release of dispersed drugs from a polymeric matrix was found to be suitable for the release of NaCl from $W_1/O/W_2$ multiple emulsions.

• Journal of the Korean earth science society
• /
• v.31 no.4
• /
• pp.392-402
• /
• 2010

The purpose of this study is to analyze and evaluate the self-directed learning contents of Earth science area in the basic course of the 7th grade. For this purpose, we applied the 'Cyber Home Study Content Quality Control Tool' presented in 'Elementary Secondary Education e-Learning Quality Management Guidelines (Ver.2.0)' of Korea Education & Research Information Service (2008). The results of contents analysis are as follow: First, it was presented that the study guide introduced the contents which should be studied for one class, properly. And it was not analyzed that the diagnosis assesment was not completed in the initiative study; Second, it was possible to study choosing the contents fitting the learner's level of learning in the main study, it was comprised of about 15 minutes. Third, it was performed without feedback for incorrect answers in the learning assessment, just the number of wrong questions. And the learning arrangement present the important contents learned in that class, summarizing and arranging again. The results of content evaluation are as follows: First, a big difference was not showed against the needs analysis, instructional design, interaction in each class. And the evaluation of the ethics was not included a word or sentence not suitable. The evaluation of copyright, it was analyzed that Work within the content display in compliance with international copyright Second, the evaluation of instructional design presented mainly the description of a simple picture based, the visible resources like flash card were poor. And in the evaluation of Supporting System, it was presented that the contents were installed so that it was freely available for learners. But it was analyzed that there was no memo-function learners were able to jot down something during the studying contents. And in the evaluation for evaluation, the clear valuation basis about the described content was not presented. So there were slightly differences for each class. Third, in the evaluation and analysis for learning content, it was presented that there were some big differences for each class because it was not composed of the latest information, not corrected and complementary.

• Journal of The Korean Association For Science Education
• /
• v.37 no.6
• /
• pp.937-949
• /
• 2017

In this study, we investigated how science teachers perceive the changes in school systems, including infrastructure and curriculum, in the context of preparing for future education. And the changes in their perception of the educational environment, the challenges, and changes of science teachers' classroom practices were also explored. In-depth interviews and analysis were conducted with two science teachers in a middle school that is trying to innovative on changes compared with general schools. The results of the study are as follows: First, teachers perceived that their schools had factors that could change the science class in terms of school size and infrastructure, peer teacher culture, and students' abilities. Second, the enthusiasm of teachers who are trying various ways of teaching and the students' ability to adapt in a smart learning environment formed a synergistic circle that lowered entry barriers to trying changes. Third, science classes changed to activity-centered classes, and teachers realized that these changes promoted students' self-directed learning. Fourth, teachers perceived themselves as playing an independent role in curriculum management, and this perception promoted more varied attempts in improving their classes. Through the changes of the learning environment and systems of the school and the formation of a culture that shares their challenges and innovations with the voluntary learning community, teachers constantly try to change their classes and schools. The changes of school need to be understood in the context of the interaction of teachers, students, and infrastructure.

• Tuberculosis and Respiratory Diseases
• /
• v.58 no.5
• /
• pp.490-497
• /
• 2005

Background : The paraoxonase enzyme plays a significant role in the detoxification of various organophosphorous compounds in mammals, and paraoxonase (PON) 1 is one of the endogenous free-radical scavenging systems in the human body. In this study, we investigated the interaction between cigarette smoking and the genetic polymorphism of PON1 with lung cancer in Korean males. Methods : Three hundred thirty five patients with lung cancer and an equal number of age-matched controls were enrolled in this study. Every subject was asked to complete a questionnaire concerning their smoking habits and alcohol drinking habits. A 5' exonuclease assay (TaqMan) was used to genotype the PON1 Q192R polymorphism. The effects of smoking habits and drinking habits, the PON1 Q192R polymorphism and their interactions were statistically analyzed. Results : Cigarette smoking and the Q/Q genotype of PON1 were significant risk factors for lung cancer. Individuals carrying the Q/Q genotype of PON1 were at a higher risk for lung cancer as compared with those individuals carrying the Q/R or R/R genotype (odds ratio, 2.84; 95% confidence interval, 1.69 - 4.79). When the groups were further stratified by the smoking status, the Q/Q PON1 was associated with lung cancer among the current or ex-smokers (odds ratio, 2.56; 95% confidence interval, 1.52 - 4.31). Current smokers or ex-smokers who had the Q/Q genotype showed an elevated risk for lung cancer (odds ratio: 15.50, 95% confidence interval: 6.76 - 35.54) as compared with the group of subjects who never smoked, and had the Q/R or R/R genotype. The odds ratios (95% confidence interval) of smokers with the PON1 Q/Q type compared to the nonsmokers with the PON1 Q/R or R/R type were 53.77 (6.55 - 441.14) for squamous cell carcinoma, 6.25 (1.38 - 28.32) for adenocarcinoma, and 59.94 (4.66 - 770.39) for small cell carcinoma, and these results were statistically significant. Conclusion : These results suggest that cigarette smoking and the PON1 Q/Q genotype are risk factors for lung cancer. The combination of cigarette smoking and the PON1 Q/Q genotype significantly increased the lung cancer risk irrespective of the histologic type of cancer.