• Journal of dental hygiene science
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• v.17 no.6
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• pp.487-494
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• 2017

There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.

• The Journal of the Petrological Society of Korea
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• v.6 no.2
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• pp.77-85
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• 1997

The Early Proterozoic reworked rock association occurs within the Preacmbrian high grade metamorphic rocks in the area of Daqingshan, Inner Molgolia. In this association, the various large scale ductile deformation belts, form a nappe structure where the foliation steeply dips to north and the lineation ($340^{circ}-30^{\circ}$) plunges at $45^{\circ}55^{\circ}$. This result indicates the subduction/extension with northern part thrusting over the southern part at high angle. The southern subducted microlithon has the characteristics of prograde metamorphism. The northern thrusted microlithon shows the evidence of retrograde metamorphism with decreasing pressure and increasing temperature. The main rock types of Early Proterozoic Moyites are biotite adamellite and syenogranites occurring in the form of small batholiths or stocks and alkali-feldspar granites in veins. The biotite adamellites are progressively contacted with the Archean and Early Proterozoic rocks and contain a great deal of enclaves of metamorphosed rocks, suggesting an anatexis origin. The geochemical characteristics of moyites show the typical features of anatexis granite. At middle to late Early Proterozoic time, the continent-continent collision formed the large scale thrusting and imbrication of Archean basement rocks. According to the mineral assemblage and thermobarometer of Paria et al. (1988) give the following P-T condition : up-faulted block; $700-710^{\circ}C$, 0.72-0.78 Gpa (early stage) and $600^{\circ}C$, 0.44 Gpa (late stage), footwall block; $620^{\circ}C$, 0.8 Gpa (early stage), $620-840^{\circ}C$, 0.64-0.45 Gpa (peak) and $620-630^{\circ}C$, 0.35Gpa (late stage). These results suggest a clockwise P-T-t path (jin et al., 1991, 1994). According to the depth-temperature model in the comperature subduction zone and the experimental data of Wyllie et al. (1983), we propose a tectonic-magmatic-thermal model to account for metamorphism-anatexis of moyite occurring in subduction-shear zone.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.186-189
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• 2005

For the assessment of the clinical application of histogram on internal parenchymal organs, ultrasonography with a multi-frequency transducer was taken. We scanned in the region of right cranial abdomen for both liver and right kidney, and left cranial abdomen for liver, spleen and left kidney in 9 normal Beagle dogs. The data from histogram examined in a region of interest centered on each picture element of B-mode images at the same depth were compared among liver, renal cortex, spleen, cortex and medulla of each kidney. The right renal cortex showed significantly lower echogenicity than parenchyma of liver by $15{\%}$. Spleen was more echogenic than the cortex of the left kidney by $23{\%}$, and liver was more echogenic than the left renal cortex by $30{\%}$. Renal cortex was more echogenic than medulla by $47{\%}$ and $65{\%}$ on the right and left side, respectively (p<0.05). The mean (${\pm}SD$) values calculated echogenicity were $46.2{\pm}12.3\;(95\%$ confidential interval (CI), 41.0 to 55.0) and $53.4{\pm}12.1\;(95\%$ CI, 47.0 to 55.1) in in the right renal cortex and liver parenchyma, $65.0{\pm}11.8\;(95\%$ CI, 57.9 to 71.0) and $51.0{\pm}16.9\;(95\%$ CI, 42.8 to 54.1) in splenic parenchyma and renal cortex. And the mean values calculated echogenicity were $65.0{\pm}10.15\;(95\%$ CI, 60.1 to 71.5) and $52.0{\pm}9.4\;(95\$ CI, 43.8 to 60.3) in liver parenchyma and the left renal cortex, $54.5{\pm}18.3\;(95\%$ CI, 40.1 to 62.8) and $35.0{\pm}16.2\;(95\%$ CI, 24.2 to 43.6) in the left renal cortex and medulla. And the mean values calculated echogenicity were $55.0{\pm}14.4\;(95\%$ CI, 47.3 to 61.7) and $40.0{\pm}13.2\;(95\%$ CI, 34.3 to 46.7) in the right renal cortex and medulla, respectively. In addition, the echogenicity ratios were $0.86{\pm}0.11$ between the right renal cortex and liver parenchyma, $1.37{\pm}0.47$ between spleenic parenchyma and the left renal cortex, $1.30{\pm}0.19$ between liver parenchyma and the left renal cortex. All the values measured showed significant different (p<0.05). Ultrasound histogram is simple, useful and feasible to evaluate the sonographic architecture of the internal organs such as liver, spleen and kidney, quantitatively.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.431-440
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• 2014

To propose the improvement and management plans to strengthen the pollutant removal efficiency of dam reservoir's constructed wetlands(CWs), the operation status and configuration of CWs (including water depth, operational flow, water flow distribution, residence time, and pollutant removal efficiency, aspect ratio, open water/vegetation ratio etc.) were analyzed in 10 major wetlands constructed in dam reservoirs. The pollutant concentrations in the inflows of the studied CWs were lower than those of American and European constructed wetlands. Especially, organic matter concentrations in all of inflows were below 3 mg/L(as BOD) due to advanced treatment of sewage disposal plant and an intake of low concentration water during dry and normal seasons. The average removal efficiency of total nitrogen(TN) and total phosphorus(TP) for 10 CWs ranged from 7.6~67.6%(mean 24.9%) and -4.9~74.5%(mean 23.7%), respectively, showing high in wetlands treating municipal wastewater. On the other hand, the removal efficiency of BOD was generally low or negative with ranging from -133.3 to 41.7%. From the analysis of the operation status and configuration of CWs, it is suggested that the low removal efficiency of dam reservoir's CWs were caused by both structural (inappropriate aspect ratio, excessive open water area) and operational (neglecting water-level management, lack of facilities and operation for first flush treatment, lake of monitoring during rainy events) problems. Therefore, to enable to play a role as a reduction facility of non-point source(NPS) pollutants, an appropriate design and operation manuals for dam reservoir's CW is urgently needed. In addition, the monitoring during rainy events, when NPS runoff occur, must be included in operation manual of CW, and then the data obtained from the monitoring is considered in estimation of the pollutant removal efficiency by dam reservoir's CW.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.177-184
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• 1991

We have investigated geographical distribution and physico-chemical properties of water masses or water types at mid-bottom depth in the neighbouring sea of Cheju Island in August 1986. In 50m layer the Yellow Sea Bottom Cold Water(YSBCW) below $12^{\circ}C$ was observed in the northwestern area of Cheju Island, while the Tsushima Warm Water(TWW) with relatively high temperature$(>16^{\circ}C)$ and salinity more than 34.0 in its southeastern area extended as far as the coast of about 15km. Also, 50m layer at the outside stations of its southwestern area indicated relatively cold water temperature$(11-30^{\circ}C)$, probably due to southward transport of the Yellow Sea Bottom Cold Water(YSBCW . The Yellow Sea Warm Water(YSWW), the mixed water of the YSBCW and the TWW, ranged $13^{\circ}C$ to $16^{\circ}C$ in water temperature and was appeared mainly in the coastal and intermediate area of Cheju Island. And the relatively cold water in the southwestern area and the Tsushima Warm Water were more extensively distributed in 50m layer than the deeper layer. Horizontal distributions of nitrate and phosphate showed a pattern similar to that of water temperature. As it were, the Yellow Sea Bottom Cold Water had the highest concentration of nutrients, while southwestern outside stations had the lowest nutrient contents. Especially, the concentration of nitrate in the latter was remarkably low compared with the value at the other stations. It may be attributed to intensive vertical mixing by collision of the northward driven Tn with the southward driven YSBCW. Also, it was particular that the Tsushima Warm Water indicated relatively high silicate content corresponding to that of the Yellow Sea Bottom Cold Water. Based on the data of $\Delta Si/\Delta P$ ratio, it seems that the mid-bottom waters in this study area are younger than the surface or intermediate water in the Korean East Sea.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel, undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesiodistally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference in fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even if that portion consists of mainly enamel and a little dentin structure.

• The Journal of Fisheries Business Administration
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• v.16 no.1
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• pp.91-124
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• 1985

Mariculture is contrasted with inland aqua-culturing fisheries. It is defind as the Industry of rearing Aquaorganism in limited coastal area relatively shallow in depth. Then, It's coming into being realization of Mariculture in it is long in history that Mariculture was realized in Korea. But it is from the early part of 1960s, that this industry has normally developed. Owing to 200 miles economy-zone problems of coastal countries, the development of deep sea fishing was limited, so the Korean Government has now appreciated the importance of cultured industries in the field of coastal fisheries. And the Korean Mariculture the output of which was only 18, 000 M/T in '60s attained 540, 000M/T in 1980s, has now occupied its relative importance in Korean Fisheries Industry. So the purpose of this report is to suggest the prospect of technical development of mariculture in the future of Korea, through the analysis of the various problems that affect upon the individual management '||'&'||' fishing ground utilization, along with the appreciation of "how to extend of those technical innovation" and "how the fishermen's technique level is extended at this stage. According to this study, the result is summarized as follows. First, Maricultural technique is classified into 8 sub-techniques as follows, as shown in fig. 1.Fig. 1. The Formation structure of mariculture technique Second, the change of technical method of mariculture in coastal area of Korea has made as 5 stages; 1) Scattering of culturing organism 2) Culturing by putting stone and installing bamboo 3) Culturing by installing rope and seeding 4) Culturing of putting objectives in cages 5) Culturing fish by feed Third, the maricultural fisheries of Korea has about 70 years long in history. It began from 1910s. But at that time there was no special technique in aquaculture and its technique was confined in searching out the object of species. The species was laver, oyster ect.Forth, although realization of mariculture in Korea has been long time, it is of late from 1960s that this has been industrial with normal development, and its technique of mariculture has mainly has developed from 1970s. Its result not only contributed to the high growth in Korean ecconomy along with the well balanced development between industires, but also it played a great role for the resolution of nation's food problem. Especially maricultural production has shown its sustained annual increase of 13.8% during the last 20 years. So the portion of mariculture among total fisheries stucture was extended from 4.1% in the early 1960s to 22.4% in 1980s.Fifth, it could be safely said that such development in maricultural field is resulted from the activity of aquacultural institutes such as Fisheries Reseach '||'&'||' Development production of major kinds such as Oyster, Sea-mustard, and Laver etc. As well as in the innovation of aquaculturing method with synthetic fiber utilization. FRDA has played important role in the efficient propargation of new aquacultural technique.Sixth, as for the change in aquaculture structure and its during period between 1970s and 1980s, the private management participation shown 25% increase from household number of 45, 173 to 56, 268 in total number. And in the respect of the management scale, of their management decreased, while it showed an increase in relative large scale management, the increase over 3 employees compared with other fisheries field between '70s and 80s. This must be an major trait to be recorded, Now the data above mentioned are shown as in table 1 and 2.Table 1. The maricultural fishing ground development situation in 982.Table 2. The mariculture management as seen in the employmnet size in high seasion.Owing to the technical innovation, of the mariculture in coastal area new income of fishermen increased and it also is true that the number of fishermen participating in its industrialization increased. But the problem being from now on is the self-discharge of the destruction fishing ground considered resulted from rapid expansion in aquaculture industry and the preventive system of sentility of fishing ground. sentility of fishing ground.

• Journal of The Korean Association For Science Education
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• v.36 no.5
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• pp.739-756
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• 2016

The purpose of the study is to reflect on 'myself' as a teacher educator of college of education in depth and to improve my instruction through self-study with three critical collaborators. 17 pre-service science teachers and I have participated in this study of a teacher educator's course since March 2016 after the preliminary practice in 2015. The video recorded the course for 11 weeks with about 40 hours of lessons. The data source also included teacher educator's reflective journals, lecture evaluations, online boards and so on. Questionnaires were distributed and answered both at the beginning and at the end of the course and pre-service teachers wrote their reflective journals. Four of them were in the focus group interviews. During the course, the weekly group meeting of critical collaborators analyzed the emerging issues based on the lesson clips and teacher educator's reflective journals with discussion for the course innovation. Four phases were revealed in the process and for the purpose of the course such as exploration, conflicts, challenges, and changes. The results showed that first, we identified tensions among the teacher educator's multiple identities as a lecturer, a faculty member, and a researcher. Second, there were differences between goals of teacher educator and pre-service teachers in the course, and this obstructed the success of the course sometimes. Third, these practices led to explore balanced alternative views and interpretations of the problem by critical views and to expand and improve our teaching practice and thinking. In addition, the self-study with critical collaborators helped to bring conflicts and issues below my practice to light for collaborative reflection and it gave a chance to understand ourselves as teacher educators in different ways.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.576-584
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• 2000

Background : With the increase of cigarette consumption by women and the young, the incidence of lung cancer is expected to increase during the next three or four decades in Korea. The purpose of this study was to analyze the smoking habits in patients with lung cancer and to identify the gender differences in terms of their susceptibility to cigarette related carcinogens. Method : This investigation was a hospital-based case control study, which included the data of 178 case subjects (72 females, 106 males) with lung cancer and 218 control subjects (97 females, 121 males) with diseases unrelated to smoking. The information was obtained through a direct personal interview and a questionnaire related to personal smoking history. Results : The relative frequency of the squamous cell carcinoma was substantially higher in males than in females (61.3% in males, and 29.2% in females), while adenocarcinoma including bronchoalveolar cell carcinoma was higher in females(31.9% in females, 18.9% in males). Kreyberg I lung cancer was of relatively higher frequencies in males and smokers, while Kreyberg II lung cancer was higher in females and never smokers. The odds ratios (ORs) at each exposure level were consistently higher in females than males. For all cell types, the risk of lung cancer was increased with the quantity of smoked cigarettes, duration of smoking, and depth of inhalation. Odds ratio was distinctly higher in Kreyberg I lung cancer than in total lung cancer and a steeper gradient of risk with increased smoking was observed in females. Conclusion : The relative risk for lung cancer was consistently higher in females than in males at every level of exposure to cigarette smoke. This is believed to be due to the higher susceptibility of females to tobacco carcinogens, such as gender associated differences of carcinogen activation and/or the elimination of smoking related metabolites.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.496-503
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• 2005

This study was conducted to investigate the influences of sapflow flux on soil water tensions and soil moisture content at the Abies holophylla plots in Gwangneung, Gyeonggido, from September to October 2004. The Abies holophylla had been planted in 1976 and thinning and pruning were carried out in 1996 and 2004. Sapflow flux was measured by the heat pulse method, and soil water tension was measured by tensiometer at hillslope and streamside. Time domain reflectometry probes (TDR) were positioned horizontally at the depth of 10, 30 and 50 cm to measure soil moisture content. All of data were recorded every 30 minutes with the dataloggers. The sapflow flux responded sensitively to rainfall, so little sapflow was detected in rainy days. The average daily sapflow flux of sample trees was 10.16l, a maximum was 15.09l, and a minimum was 0.0l. The sapflow flux's diurnal changes showed that sapflow flux increased from 9 am and up to 0.74 l/30 min. The highest sapflow flux maintained by 3 pm and decreased almost 0.0 l/30 mm after 7 pm. The average soil water tensions were low ($-141.3cmH_2O$, $-52.9cmH_2O$ and $-134.2cmH_2O$) at hillslope and high ($-6.1cmH_2O$, $-18.0cmH_2O$ and $-3.7cmH_2O$) at streamside. When the soil moisture content decreased after rainfall, the soil water tension at hillslope responded sensitively to the sapflow flux. The soil water tension decreased as the sapflow flux increased during the day time, whereas increased during the night time when the sapflow flux was not detected. On the other hand, there was no significant relationship between soil water tension and sapflow flux at streamside. Soil moisture content at hillslope decreased continuously after rain, and showed a negative correlation to sapflow flux like a soil water tension at hillslope. As considered results above, it was confirmed that the response of soil moisture tension to sapflow flux at hillslope and streamside were different.