• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.507-517
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• 2008

There are considerable in vitro and in vivo evidences for remineralization and demineralization occurring simultaneously in incipient enamel caries. In order to "heal" the incipient dental caries, many experiments have been carried out to determine the optimal conditions for remineralization. It was shown that remineralization is affected by different pH, lactic acid concentrations, chemical composition of the enamel, fluoride concentrations, etc. Eighty specimens from sound permanent teeth without demineralization or cracks, 0.15 mm in thickness, were immersed in lactic acid buffered demineralization solutions for 3 days. Dental caries with a surface zone and subsurface lesion were artificially produced. Groups of 10 specimens were immersed for 10 or 12 days in lactic acid buffered remineralization solutions consisting of pH 4.3 or pH 6.0, and 100, 50, 25, or 10 mM lactic acid. After demineralization and remineralization, images were taken by polarizing microscopy (${\times}100$) and micro-computed tomography. The results were obtained by observing images of the specimens and the density of the caries lesions was determined. 1.As the lactic acid concentration of the remineralization solutions with pH 4.3 was higher, the surface zone of the carious enamel increased and an isotropic zone of the subsurface lesion was found. However, the total decalcification depth increased at the same time. 2.In the remineralization solutions with pH 6.0, only the surface zone increased slightly but there was no significant change in the total decalcification depth and subsurface zone. In the lactic acid buffer solutions with the lower pH and higher lactic acid concentration, there were dynamic changes at the deep area of the dental carious lesion.

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.98-106
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• 2008

The purpose of this study was to evaluate whether intracanal irrigation method could affect the adhesion between intracanal dentin and root canal filling materials (Gutta-percha/AH 26 sealer and Resilon/Epiphany sealer). Thirty extracted human incisor teeth were prepared. Canals were irrigated with three different irrigation methods as a final rinse and obturated with two different canal filling materials (G groups: Gutta-percha/AH 26 sealer, R groups: Resilon/Epiphany sealer) respectively. Group G1, R1-irrigated with 5.25% NaOCl Group G2, R2-irrigated with 5.25% NaOCl, sterile saline Group G3, R3-irrigated with 5.25% NaOCl, 17% EDTA, sterile saline Thirty obturated roots were horizontally sliced and push-out bond strength test was performed in the universal testing machine. After test, the failure patterns of the specimens were observed using Image-analyzing microscope. The results were as follows. 1. Gutta-percha/AH 26 sealer groups had significantly higher push-out bond strength compared with the Resilon/Epiphany sealer groups (p < 0.05). 2. Push-out bond strength was higher when using 17% EDTA followed by sterile saline than using NaOCl as a final irrigation solution in the Resilon/Epiphany sealer groups (p < 0.05). 3. In the failure pattern analysis, there was no cohesive failure in Group G1, G2, and R1. Gutta-percha/AH 26 sealer groups appeared to exhibit predominantly adhesive and mixed failure patterns, whereas Resilon/Epiphany sealer groups exhibited mixed failures with the cohesive failure occurred within the Resilon substrate.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.233-240
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• 1988

A simple and selective isocratic HPLC method for the analysis of tissue polyamine contents is described and applied on the study of the changes of the hepatic polyamine contents after partial hepatectomy in male rats. The hepatic polyamines are extracted with 0.4 M perchloric acid containing 2 mM disodium EDTA, and then the extract is redissolved in 100 ul of 1 M sodium carbonate and incubated with 300 ul of FNBT-dimethylsulfoxide (1: 100) mixture. The N-2'-nitro-4'-trifluoromethylphenyl drivatives of polyamines are separated through a ERC-ODS column in an isocratic mode with an acetonitrile-water (80:20) mobile phase within 20 min. per a sample, while monitoring the effluent at 242 nm. This improved method which could detect subnanogram of each polyamines is highly specific and reproducible as evidenced by the application of it on the study of the changes of polyamine contents in the regenerating rat liver after partial hepatectomy.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.213-223
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• 1993

To investigate the endothelium dependent vascular reactivity of the systemic arterial and the pulmonary arterial system in acute renal hypertensive rats of 2-kidney, 1-ligation type (RHRs), acetylcholine (ACh)-induced vasodilation and depressor effects were evaluated in isolated arteries and in vivo, respectively, in the presence and absence of functional endothelium. ACh $(10^{-5}\;M)$ relaxed the intact thoracic aortas from RHRs and normotensive rats (NRs), but the effect was significantly smaller for those from RHRs (34 and 86%, respectively, p<0.01). ACh-induced vasodilation was completely abolished after removal of endothelial cell or pretreatment with EDRF inhibitors, L-NAME and MB, indicative of its dependence on intact endothelial or EDRF function. ACh also induced vasorelaxation of the intact pulmonary arteries from RHRs and NRs; however, unlike the effects on the thorcic aorta, no significant difference in amplitude was noted between two groups. ACh $(0.1{\sim}10\;{\mu}g/kg,\;i.v.)$ reduced mean systemic arterial pressure in anesthetized RHRs and in NRs to the similar magnitude (% change: 39 and 46% at $10\;{\mu}g/kg$, respectively) and these hypotensive effects were significantly decreased after pretreatment with L-NAME (30 mg/kg, i.v.). Deprssor effects of ACh on mean pulmonary arterial pressure were similar in RHRs and NRs with and without pretreatment of L-NAME. However, in both NRs and RHRs, the depressor effects of ACh on mean pulmonary arterial pressure were significantly reduced compared with those for mean systemic arterial pressure, and the increment of mean pulmonary arterial pressure noted after L-NAME $(0.1{\mu}100\;mg/kg,\;i.v.)$ was significantly smaller than that for mean systemic arterial pressure. These results indicate that in RHRs the endothelial cell function was impaired, at least in part, in systemic arterial system, but not in pulmonary arterial system, and both ACh-evoked and basal release of EDRF was less in the pulmonary arterial system than in systemic arterial system of both NRs and RHRs.

• The Transactions of the Korea Information Processing Society
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• v.5 no.10
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• pp.2575-2583
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• 1998

The productionof the highly relible softwae systems and theirs performance evaluation hae become important interests in the software industry. The software evaluation has been mainly carried out in ternns of both reliability and performance of software system. Software reliability is the probability that no software error occurs for a fixed time interval during software testing phase. These theoretical software reliability models are sometimes unsuitable for the practical testing phase in which a software error at a certain testing stage occurs by causes of the imperfect debugging, abnornal software correction, and so on. Such a certatin software testing stage needs to be considered as an outlying stage. And we can assume that the software reliability does not improve by means of muisance factor in this outlying testing stage. In this paper, we discuss Bavesian software reliability growth modeling and estimation procedure in the presence of an imidentitied outlying software testing stage by the modification of Jehnski Moranda. Also we derive the Bayes estimaters of the software reliability panmeters by the assumption of prior information under the squared error los function. In addition, we evaluate the proposed software reliability growth model with an unidentified outlying stage in an exchangeable model according to the values of nuisance paramether using the accuracy, bias, trend, noise metries as the quantilative evaluation criteria through the compater simulation.

• Korean Journal of Plant Taxonomy
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• v.36 no.3
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• pp.163-187
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• 2006

Taxonomic studies were conducted to evaluate the interspecific relationships in Viola albida var. albida and its related taxa using seven populations for morphology, palynology and anatomy. Molecular phylogenetic studies were also examined in 28 populations including 19 Korean, four Chinese, two Japanese, one American population and two outgroups using nrITS, and 27 populations except V pinnata for trnL-F region of chloroplast DNA. Morphological differences was observed among seven populations of three species in leaf shape, but characters such as serrate number of leaf margins, petal size, pistil shape were showed overlap between populations. Pollen shape of seven populations was monad and grain shape on the polar axis was semi-angular. Morphology of aperture was tri-colporate, and the surface sculpturing was scabrate in rugulate. The grain shape of equatorial view of five populations was prolate whereas V albida var. taknhashii type 1 and V albida var. chaerophylloides type 3 were subprolate. The anatomical characters of rnidvein of leaf, petiole, peduncle, root were also described for the species. The stomatal apparatus of the leaves was observed only in abaxial surface, and the number of stoma per unit ($mm^2$) were abundant in incised than lobate or cleft margin of the leaves. The nrITS analysis shows that V. pinnata and V. dissecta was monophyletic and occupied a basal position in the V. albida var. albida and its related taxa. The other clade including infraspecific populations of V. albida, and V. eizanensis was paraphyletic. The trnL-F noncoding region analysis was similar to the ITS tree. According to the above observations in morphology, palynology, anatomy, and molecular phylogenetic analysis, the significant differences were not found except for leaf shape in Viola albida var. albida and its related taxa, therefore V. albida var. takanhashii and V. albida var. chaerophylloides were considered to be an infraspecific taxa of V. albida var. albida rather than an independent species, subvariety or variety of V. pinnata and V. dissecta.

• The Korean Journal of Mycology
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• v.17 no.3
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• pp.124-131
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• 1989

Some factors effecting on mycelial growth and cultural substrates using pine sawdust were investigated to develop an artificial cultivation technique. The optimal temperature and media pH for the mycelial growth were at $25^{\circ}C$ and 4.0, respectively. The mycelial growth was not different among three isolates tested. Among them ASI 19003 isolate showed the highest mycelial density and fruitbody yield. Among supplements added into pine sawdust, wheat bran was the best and its appropriate percentage was 20 for the mycelial growth. The mycelial densities were uprisen according to the amounts of the supplement. The highest yield, 107g/bottle of the sporophores of the mushroom was obtained from the substrates supplemented by 30% of wheat bran, but no fruitbody was formed on non supplemented one. Optimal moisture contents of the substrates was different for the mycelial growth, pinheading and fruitbody yields. Sixty five, 60 and 75% of moisture contents of the substrates were optimal for the mycelial growth, pinheading and fruitbody yields, respectively.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.670-676
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• 1997

The structural failure of the glutaraldehyde-treated xenograft valves has been the primary concern about the limited durability as predicted from the begimling of clinical use, and long-term follow-up has shown a significant incidence of primary tissue failure(PTF) from both biological and mechanical reasons. Twenty-seven patients with the low-profile lonescu-Shiley valves explanted from mitral position for PTF(Group III) were studied on the patient characteristics and valve pathology, and the results were compared with the matched observations of the Haycock(Group I) and of the standard-profile lonesiu-Shiley valves(Group II). Patients were aged 16 to 56 years(mean, 38.0$\pm$ 11.0 years), and the size of the failed mitral bioprosthesis was 30.8$\pm$ 1.3 mm. The hemodynamic consequences were stenosis in 29.6%, insufficiency in 44.4%, mixed steno-insufficiency in 14.8%, together with normal function for the rest of patients of prophylactic re-replacement. Pathology revealed calcification with or without tissue damage in 63.0% and tissue damage with or without calcification in 58.l%, in contrast with the observations of predominant tissue damage(76.8%) over calcification in Group I and of calcification(76.1%) over tissue damage in group II. Although dystrophic calcification has long and repeatedly dealt with patient's young age as a determinant of valve durability, such a characteristic evidence was not reached even in patients with calcified valves. Moreover, the prolonged explantation p riods from the studied on the previous report suggested strongly yet possibly evolving destructive processes among the valves in the remaining patients, and awaits further follow-up. In conclusion, PTF of the xenograft valves seems to result from more complicated biologic and metabolic reasons as well as more complex mecharical factors than the reported, and newer generation prostheses, with tissue preservation with glutaraldehyde, do not likely to provide decisive improvement in the occurrence of structural failurebioprostheses is generally limited to the highly aged.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.736-741
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• 2008

Background: Pneumonia continues to be the most common major infection in trauma patients. Despite the advances in prevention, diagnosis, and treatment for pneumonia, it remains a major cause of morbidity and mortality. The aim of this retrospective study is to identify the risk factors and clinical features of ventilator-associated pneumonia among chest trauma patients. Material and Method: The study population consisted of 78 mechanically ventilated patients admitted to the ICU of Chonnam National University Hospital between January, 2001, and December, 2006. The patients were divided into two groups: those with pneumonia (Group I) and without pneumonia (Group II). Clinical predictors of the occurrence and mortality for ventilator associated pneumonia were analyzed. Result: There were 57 men and 21 women, with a mean age of $48.3{\pm}19.9$ years. Almost half of the patients, 48.7% (38 of 78), had pneumonia. The mortality rate was 21.0% (8 of 38) in Group I and 2.5% (1 of 40) in Group II. The predictors of ventilator-associated pneumonia were the duration of mechanical ventilation (17.4 days vs 6.5 days, p<0.001), the mean stay in the ICU (21.7 days vs 9.7 days, p<0.001), the use of inotropics due to hemodynamic instability (63.1% vs 25.0%, p=0.001), and the serum level of CRP ($11.3{\pm}7.8$ vs $6.4{\pm}7.3$, p=0.006). Conclusion: Posttraumatic ventilator-associated pneumonia was significantly related with the duration of mechanical ventilation, the mean stay in ICU, and the use of inotropics due to hemodynamic instability. The serum level of CRP at admission was higher in the pneumonia group. Morbidity and mortality can be reduced by early identification of predictive factors for developing pneumonia in chest trauma patients.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.848-852
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• 2012

Vegetation can make not only to lower the urban ambient air temperature (UAAT) by crop evapotranspiration (ET) and increasing solar radiation albedo, but also to reduce the urban air pollution by $CO_2$ uptake and $O_2$ emission in addition to the reducing ozone concentrations by aid of lower the UAAT. To evaluate the effect of vegetation on urban heat island mitigation (UHIM), the climate change of 6 cities during 30 years are analysed, and the amount of ET, $CO_2$ uptake, $O_2$ emission and ozone concentrations are estimated in Korea. The most hot season is the last part of July and the first part of August, and the highest average UAAT of a period of ten days was $35.03^{\circ}C$ during 30 years (1979 - 2008). The mean values of maximum ET of rice and soybean in urban area during urban heat island phenomena were 6.86 and $6.00mm\;day^{-1}$, respectively. The effect of rice and soybean cultivation on lowering the UAAT was assessed to be 10.5 and $3.0^{\circ}C$ in Suwon, respectively, whereas the differences between the UAAT and canopy temperature at urban paddy and upland in Ansung were 2.6 and $2.2^{\circ}C$. On the other hand, the urban-garden in Suwon city had resulted in lowering the UAAT and the surface temperature of buildings to 2.0 and $14.5^{\circ}C$, respectively. Furthermore, the amounts of $CO_2$ uptake by rice and soybean were estimated to be 20.27 and $15.54kg\;CO_2\;10a^{-1}day^{-1}$, respectively. The amounts of $O_2$ emission by rice and soybean were also assessed to be 14.74 and $11.30kg\;O_2\;10a^{-1}day^{-1}$, respectively. As other cleaning effect of air pollution, the ozone concentrations could be also estimated to reduce 21.0, 8.8, and 4.0 ppb through rice-, soybean cultivation, and urban gardening during most highest temperature period in summer, respectively.