• Journal of Chest Surgery
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• v.31 no.7
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• pp.643-649
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• 1998

Background: For the patient with chronic obstructive pulmonary disease requiring long-term oxygen therapy, oxygen concentrator machines are already widely available for use in home. In this study, we used mongrel dogs as test subjects to compare the functional efficiency and safety of the oxygen concentrator developed by our own research team with those of the imported FORLIFE(TM) machine made by AIRSEP Corp. Method and method: To test mechanical reliability, the concentrations of oxygen delivered were measured after 4 hours of continuous operation. Sixteen mongrel dogs were divided into two equal groups. Mongrel dogs in group A were given oxygen using the imported oxygen concentrator, and those in group B using the machine developed. 5 l/min of oxygen were given, after which vital signs were analyzed, arterial blood gases measured, and blood chemistry tests carried out. Results: After 4 hours of continuous operation, the imported model performed better, giving 98${\pm}$3% oxygen, compared to our model, which gave 91${\pm}$1%. In the animal experiments, oxygen concentrations were measured at the inlet of face mask 1, 2, 3, and 4 hours after continuous administration, and there was no statistically significant difference(repeated measures of analysis of variance p=0.70) between the values of 70.6${\pm}$2.5%, 67.1${\pm}$2.9%, 68.2${\pm}$2.6%, and 64.9${\pm}$3.9% that were measured from group A, and the values of 65.1${\pm}$4.8%, 65.2${\pm}$3.6%, 68.7${\pm}$4.3%, and 66.0${\pm}$5.0% measured from group B. Before oxygen administration, and at 1, 2, 3, and 4 hours after oxygen administration, arterial blood partial pressure of oxygen 87.2${\pm}$2.5 mmHg, 347.4${\pm}$29.3 mmHg, 353.4${\pm}$21.2 mmHg, 343.0${\pm}$28.8 mmHg, and 321.6${\pm}$24.4 mmHg, respectively, were read from group A, which were not statistically different (p=0.24) to the values of 102.5${\pm}$9.6 mmHg, 300.3${\pm}$17.1 mmHg, 321.6${\pm}$23.7 mmHg, 303.4${\pm}$27.4 mmHg, and 273.5${\pm}$25.9 mmHg read from group B. Nonetheless, the arterial blood partial pressure of oxygen values appear to be somewhat higher in dogs that were given oxygen using the imported oxygen concentrator. Conclusions: From these results the prototype oxygen concentrator developed appears to function relatively satisfactorily compared to the imported, established model, but may be criticized for the excessive noise generated and poor long-term endurance or consistency, which need improvement.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.351-360
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• 2000

The purpose of this study was to evaluate the microleakage of class V compomers according to acid etching treatment and treatment times. Extracted 180 sound human molar teeth were selected then prepared physiologic pulpal pressure far this experiment. In this study class V cavities were prepared on buccal surface with gingival margin located in 1mm superior to CEJ under simulate physiological conditions. These specimens were randomly divided into 6 groups of 30 each and restored following methods : A: Dyract AP + Prime&Bond 2.1 Group 1 : No acid etching, according to manufacturer's instruction. Group 2 : 15 seconds acid etching and same method with Group 1. Group 3 : 30 seconds acid etching and same method with Group 1. B: F2000 groups + Single Bond adhesive Group 1 : No acid etching, according to manufacturer's instruction. Group 2 : 15 seconds acid etching and same method with Group 1 Group 3 : 30 seconds acid etching and same method with Group 1. After 500 thermocycling between $5^{\circ}C\;and\;55^{\circ}C$, the specimens were sealed with glass ionomer and nail varnish then placed in 5% methylene blue dye for 5 hours and rinsed with tab water. The specimens were embedded in orthodontic clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimens were then observed with a stereomicroscope at $\times20$ magnification. The results of this study were statistically analyzed using the indepedent sample t-test and analysis of variance. Results were as follows, 1. In occlusal walls, microleakage were significantly reduced in acid etched group restored with Dyract AP but no statistically significance in F2000 groups. 2. In gingival walls, microleakage were significantly reduced in group 2 restored with Dyract AP, and group 2 and group 3 in F2000 groups. 3. All groups, except group 3 in Dyract AP, showed significantly less microleakage in occlusal wall than gingival wall. 4. No statistical significance were showed between group 2 and group 3 in both materials.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.231-242
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• 2008

Purpose: The purpose of this study was to investigate the bond strength of the core-veneer interface in all ceramic systems. Material and Methods: The all ceramic systems tested with their respective veneer were IPS Empress 2 with IPS Eris, IPS e.max Press with IPS e.max Ceram and IPS-e.max ZirCAD with IPS e.max Ceram. Cores (N=36, N=12/group, diameter: 10mm, thickness: 3mm) were fabricated according to the manufacturer's instruction and cleaned with ultrasonic cleaner. The veneer(diameter: 3mm, thickness: 2mm) were condensed in stainless steel mold and fired on to the core materials. After firing, they were again ultrasonically cleaned and embedded in acrylic resin. The specimens were stored in distilled water at $37^{\circ}C$ for 1 week. The specimens were placed in a mounting jig and subjected to shear force in a universal testing machine(Z020, Zwick, Germany). Load was applied at close to the core-veneer interface as possible with crosshead speed of 1.00mm/min until failure. Average shear bond strengths(MPa) were analyzed with a one-way analysis of variance and the Tukey test(${\alpha}=.05$). The failed specimens were examinated by scanning electron microscopy(JSM-6360, JEOL, Japan). The pattern of failure was classified as cohesive in core, cohesive in veneer, mixed or adhesive. Results: The mean shear bond strength($MPa{\pm}SD$) were IPS e.max Press $32.85{\pm}6.75MPa$, IPS Empress 2 $29.30{\pm}6.51MPa$, IPS e.max ZirCAD $28.10{\pm}4.28MPa$. IPS Empress 2, IPS e.max Press, IPS e.max ZirCAD were not significantly different from each others. Scanning electron microscopy examination revealed that adhesive failure did not occur in any all ceramic systems. IPS Empress 2 and IPS e.max Press exhibited cohesive failure in both the core and the veneer. IPS e.max ZirCAD exhibited cohesive failure in veneer and mixed failure.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.163-175
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• 1974

Effects on yields, yield components and nutrient content of potassium depression for two or three weeks at various growth stages were investigated in rice (var. Jinheung) under sand culture system.(K 40 ppm 1973) 1. Analysis of variance showed significant difference among treatments of both two-week (at p=0.01) and three-week depression (at p=0.05) in yield. 2. Most sensitive stage to potassium depression on yield appeared two weeks until heading (42% yield decrease) and sensitivity decreased the growth stage is apart from heading either before or after. During 30 days after transplanting two-week potassium depression increased yield, but three-week depression decreased yield. Until about 30 days after heading depression caused poor yield. 3. Root potassium involves in harvest index, filled grain ratio and grain weight with significant correlation and considerably in spikelet per panicle while potassium in leaf sheath+culm involves considerably in spikelet per panicle and panicle per hill. Relative total dry matter weight was significantly correlated with panicle per hill, spikelet per panicle and K or K/Ca+Mg only in leaf sheath+culm. The indications are that root potassium contributes for building sink and efficiency of structure while potassium in leaf sheat+culm primarily for building source, productive structure. 4. Relative yield was significantly correlated with potassium content in root and leaf sheath+culm and with K/Ca+Mg and its ratio before and after depression in root indicating that potassium depression occurs greatly in root and that K/Ca+Mg might have more important role than K content alone under depression. 5. Optimum level of $K_2O$ appears around 3% in leaf blade. 4% in leaf sheath+culm and 1% in root under the assumption that below these level the same content has the same role in relation to yield during growth. The K/Ca+Mg appeares to be 2.5 in root and should not decrease throughout the growth stages. 6. The increase of sodium content in plant by K depression was highest, especially in leaf sheath during the most insensitive period to K depression suggesting that insensitivity may be attributed to partial replacement of Na for K. Partial replacement seems very little in sensitive stage (later stage) and sensitive organ (root).

• Horticultural Science & Technology
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• v.34 no.6
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• pp.818-829
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• 2016

This study evaluated the responses of 18 potato cultivars to three levels of salinity stress (electrical conductivity, EC: 1.0, 4.0, and $8.0dS{\cdot}m^{-1}$). Stem, leaf, root, chlorophyll, tuber yield, and proline content were investigated and statistically analyzed using analysis of variance (ANOVA) and correlations. Stem number and stem diameter were not affected by salinity, but stem length and aerial weight showed highly significant responses to salinity. Aerial weight decreased with increasing salinity levels in most cultivars, while it increased in some the cultivars 'Daejima', 'Goun', 'Haryeong', and 'LT-8'. Leaf number, leaf area index, and leaf weight were most significantly affected by salinity and the cultivar ${\times}$ salinity interaction. Root length, root weight, total chlorophyll and chlorophyll a were affected by salinity, but not by the cultivar ${\times}$ salinity interaction. The opposite trend was shown in chlorophyll b. Although there was great variability among cultivars, tuber yield decreased in all cultivars, and was most significantly influenced by salinity and the cultivar ${\times}$ salinity interaction. 'Superior', 'Kroda', 'Romana', and 'Duback' gave better tuber yields under salinity at EC 4.0 and $8.0dS{\cdot}m^{-1}$ than the cultivars with better aerial weights. Proline content was increased by salinity in all cultivars, and was more remarkable in the cultivars with better aerial weights than in cultivars such as 'Superior' and 'Kroda' with better tuber yields. Leaf number, leaf area index, leaf weight, and root length parameters were considered to be useful criteria in the evaluation of salt tolerance because of their high positive correlation with tuber yield; however, given its negative correlation with tuber yield under high salinity, proline content was not. Salinity tolerances varied greatly among potato cultivars. The low correlation between growth and yields of aerial parts under high salinity suggests that, in commercial agriculture, it might be more practical to compare relative yields to controls. Additionally, 'Superior', 'Kroda', 'Romana', and 'Duback' might be very useful cultivars to use in breeding programs to develop salinity-tolerant potatoes, as well as for sustainable potato production in saline areas.

• Food Science and Preservation
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• v.22 no.3
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• pp.303-313
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• 2015

This study investigates the physicochemical, microbiological and sensory characteristics of seasonal salted-Kimchi cabbages to provide basic data on its uniform quality. Generally, seasonal salted-Kimchi samples had different pH values at initial storage periods, but there was no difference in pH between the seasonal samples when stored for longer periods. The samples from the fall and winter seasons were relatively low in acid and high in solid soluble content compared to samples from other seasons. Salted-Kimchi cabbages in the summer showed the highest microbiological number compared to samples from other seasons. In the sensory evaluation, there were differences in the appearance, aroma, and taste, depending on seasonal samples at different storage periods. The correlation coefficient between the quality characteristics in the seasonal samples showed a positive or negative correlation between the quality characteristics at 1% significant level. In the principal component analysis, F1 and F2 were shown the 51.81% and 14.23% of the total variance (66.21%), respectively. In the PCA pattern of seasonal salted-Kimchi cabbages during storage periods, winter samples were distributed on the top of F2, spring samples were in the middle of F2, while the rest of the samples were distributed on the bottom of F2. According to increasing storage periods, initial storage samples were distributed at the left of F1, while other samples were located at the right of F2.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.331-337
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• 1988

To investigate the effects of forest stand and stony characteristics on interception loss from canopy trees, throughfall and stemflow under the canopy of a pine stand and a hardwood stand were measured during 4-month periods July to October, 1986 at the Kwanak Arboretum near Anyang, and the data were analysed by correlation and regression methods. The man results obtained from this study are summerized as follows : 1. The overall throughfall collected during measurement period were 593.5mm(76.7%) in the pine stand and 663.1mm(81.8%) in the hardwood stand oui of total percipitation of 773.8mm. Combined regression analysis describes the relation between total precipitation(P) and throughfall(T) in the pine stand as T=-1.8675+0.8320 P. in the hardwood stand as T=-8179+0.8805P. 2. And the sum of stemflow from measurement of total precipitation in the pine stand and the hardwood stand were 37.4mm(4.8%) and 15.5mm(2%), respectively. In total precipitation less than 2.5mm, stemflow were not measured in both the pine stand and the hardwood stand. Regression equations for the pine stand and the hardwood stand are S=-0.6155+0.0698P, S=-0.0497+0.0183P. The mean slope and intercept of the individual regression of stemflow on rainfall for each fewest stand indicate the proportion of the rain diverted to the trunks and trunk water capacity, respectively. 3. Interception loss accounted for 142.9mm(18.5%) in the pine stand and 125.2mm(16.2%), in the hardwood stand. 4. By quadratic predictive model of relation between interception loss and total incident rainfall, the extent of variance in interception loss explained was about 72% and 61% in the pine stand and the hardwood stand respectively.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.197-207
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• 2011

The study aimed at examining how different reline resins affect flexural strength and flexural modulus of denture base. A total of 80 specimens ($64{\times}10{\times}3.3$ mm, according to ISO 1567:1999) of heat-polymerized resin, 40 specimens for (Lucitone199(Dentsply Int., NewYork, USA), SR Ivocap(Ivoclar AG, Schaan, Liechtenstein)) respectively, were polymerized according to the manufacturer's instructions and divided into eight groups(n = 10). Control group specimens remained intact. Specimens in the other groups were abraded on both sides to 2 mm thickness, and were relined in 1.3 mm thickness with 3 types of resins (Lucitone199(Dentsply), SR Ivocap(Ivoclar), and Rebase II(Tokuyama Co., Ltd, Tokyo, Japan)). All specimens were preserved in distilled water at $37^{\circ}C$ for 50 hours, and then were subjected to flexural strength testing in a universal testing machine using 3-point loading. A crosshead speed of 5 mm/min was used, and the distance between the supports was 50 mm. Data analyses included one-way analysis of variance(ANOVA) and the Tukey Honestly Significant Difference test (p=.05). Both heat-polymerized resin groups and auto-polymerized resin groups showed statistically low flexural strength and flexural modulus than control groups. Specimens relined with Lucitone 199 showed significantly higher flexural strength and flexural modulus than those relined with SR-Ivocap. Specimens relined with auto-polymerized resin showed significantly lower flexural strength and flexural modulus than those relined with heat-polymerized resin. Relining with heat-polymerized resins showed superior mechanical properties to relining with an auto-polymerized resin. Relining with the same heat-polymerized resin as the denture base does not affect mechanical properties of a denture. Lucitone199 using a compression-mould technique resulted in the highest flexural strength.

• Journal of Naturopathy
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• v.7 no.1
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• pp.10-19
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• 2018

The purpose of this study was to investigate the distribution and variation of the anion and cation number in the aerosols at 16 sites in the Jeju area. The average value of anion counts was raged from 449.35 ions/cm³ at Jeju city to 3471.25 ions/cm³ in the Chunjiyeon falls. In order, the lowest Jeju-si < hamdeok < 1100 m < farm < gyorae A < saryoni < jeolmul < gyorae B < geomunoreum < halla forest < hallasan garden < seongpanak < dongbaeksan < jeongbang < wonyang, respectively. There was statistically significant difference between the anion counts of the measured values in the order of elevation. The mean value of cation measurements was from 90 ions/cm³ for Cheonjiyeon, to 729.8 ions/cm³ for Halla forest garden, which showed the highest value. In order, the lowest 729.8 ions/cm³ of Cheonjiyeon < 1100 m < dongbaeksan < Jeju-si < saryoni < wonyang < seongpanak < hamdeok < jeongbang < gyorae B < jeolmul < Farm < gyorae A < halla forest < geomun and < halla garden, respectively. The geographically low area and the high area were measured low and difference in the two ions. The differences between the content of the anion, cation and/or altitude were significant each other in the variance analysis. The correlation between the anion and cation content and/or altitude was statistically significant (r=.396, p<.001). In conclusion, the result of showing the temporal distribution and variation of the anion and cation content in the aerosols in Jeju island forests provides important information for healthcare.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.11 no.1
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• pp.79-90
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• 2000

Objective：This study was performed in order to develop a measuring instrument for assessing and predicting delinquent behavior of the adolescents in Korea. Methods：This study was methodological research for developing a questionnaire for measuring delinquent behavior. Through the relevant literature review and personal interview using open-ended question with 12 adolescents in schools, outpatient basis and the juvenile corrective institutions, the author developed a pre-questionnaire with 31 items for assessing delinquent behavior among delinquentprone adolescents. Statistical method employed were test-retest reliability and Cronbach's alpha coefficient for testing reliability and factor analysis for testing validity of this questionnaire, and t-test for mean difference between student adolescents and delinquent adolescents, using SAS program. Subject served for this study consisted of 2,177 adolescents including 1,206 students and 971 delinquent adolescents by proportional stratified random sampling method. Results：1) Three stable factors were emerged and these contributed 52.2% of the variance in the total score. All 31 items loaded above .40 on each factor. 2) Factor I was named as antisocial delinquent behavior(17 items), factor II was named as aggressive delinquent behavior(8 items), and factor III was named as psychopathic delinquent behavior(6 items). 3) Comparison of these 3 factors between student adolescents and delinquent adolescents showed that there was a significant difference in factor Ⅰ(t=-42.91(student), -41.71(delinquent), p=.0001), factor II(t=-34.10(student), -35.72(delinquent), p=.0001), factor III(t=-14.24(student), -14.26 (delinquent), p=.0000), and total score(t=37.02(student), -36.38(delinquent), p=.0001). 4) Internal consistency reliability was tested by Cronbach's ${\alpha}$. Cronbach's ${\alpha}$ was .952 for total 31 items and .950, .866 and .721 for each 3 factors related to delinquent behavior. Conclusions：The author confirmed that this scale can use for measuring delinquent behavior, and hope to make a contribution to screening test and prevention of juvenile delinquency in Korea.