• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1114-1119
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• 2002

Purpose : The purposes of this study were to determine short- and long-term fractal correlation behavior of heart rates during daily activity in patients with neurocardiogenic syncope. Methods : Twenty five patients with histories of neurocardiogenic syncope episodes were included. Their analogue 24h ambulatory Holter electrocardiograms were analyzed. The tape was digitized and the digitized electrocardiograms were partioned into sections of one hour. Then their RR intervals were measured and 20,000 points of RRI were used. To quantify the fractal correlation behavior, we employed the detrended fluctuation analysis, and short-term($n{\leq}16$, ${\alpha}_1$) and long-term(n>16, ${\alpha}_2$) fractal scaling exponents were calculated. Results : When compared to control, 24-hour average values of ${\alpha}_1$ and all ${\alpha}_1$ values at quarters of each day were significantly higher in patients with syncope. On the contrary, their 24-hour average value of ${\alpha}_2$ and all ${\alpha}_2$ values at quarters of each day were lower in patients with syncope. However, statistical significances were found in 24-hour average value of ${\alpha}_2$ and in ${\alpha}_2$ value at MN-6AM. Conclusion : In the syncope patients with neurocardiogenic syncope, short-term fractal scaling exponents of RR interval was significantly high throughout the day. Therefore, their RR intervals were smoother in the short term scale and had a tendency to continue in the same direction of increase or decrease, which may contribute to persistent decrease in heart rate during a syncopal attack.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.37-43
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• 1981

This pot experiment was conducted to find out the optimal fertilization ratio of the cations(K: Ca: Mg) in various soil conditions. Soil samples were collected from uncultivated mountains and hills where development for grass lands is under consideration. The optimum ratios were computed by the Homes systematic variation technique. The results were summarized as follows : 1. The optimum fertilization ratios of the cations (K : Ca : Mg) for the high yields of grass-clover mixed sward at various areas were obtained (Table 4) 2. The relatively high optimum fertilization ratios of K in Daegu and Taegwalryong, Ca in Unbong, and Mg in Cheju district gave the high yields of clover in mixed sward. They were positively related to the low contents of the above cations in the soils or the relatively low content ratio comparing with other cations. 3. The yields of clover in mixed sward were seriously affected by the changes in both the fertilization ratio and total concentration of cations comparing to those of the grass yields. As a consequence, total yields, quality, and botanical composition of the mixed sward were also affected. 4. The antagonis among the cations K, Ca, and Mg was known from the point of mineral contents of grass and clover. 5. The equivalent ratio K/(Ca+Mg) or grass was greatly increased by the range of 2.4 and 3.3 in the K-group treatment, which was higher than the critical level 2.2 of grass tetany, otherwise that. of clover by the range of 0.9 and 1.2. Therfore, it may be concluded that if the botanical composition of grass/legume sward is optimum, the incidence of grass tetany can be eliminated.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.493-502
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• 2012

Objectives: The purpose of this study is to investigate the mass concentration of nanoparticles and understand the characteristics of elements of heavy metal concentrations within nanoparticles in the air using Micro-Orifice Uniform Deposit Impactor Model-110 (MOUDI-110), based on indoor and outdoor air. Methods: This Study sampled nanoparticles using MOUDI-110 indoors (office) and outdoors at S University in Asan, Korea in order to reveal the concentration of nanoparticles in the air. Sampling continued for nine months (10 times indoors and 14 times outdoors) from March to November 2010. Mass concentrations of nanoparticle and concentrations of heavy metals (Al, Mn, Zn, Ni, Cu, Cr, Pb) were analyzed. Results: Indoors, geometric mean concentration of nanoparticles ranged in size from 0.056 ${\mu}m$ to 0.10 ${\mu}m$ and those of 0.056 ${\mu}m$ or less recorded 0.929 ${\mu}g/m^3$ and 1.002 ${\mu}g/m^3$, respectively. On the other hand, the levels were lower outdoors with 0.819 ${\mu}g/m^3$ and 0.597 ${\mu}g/m^3$. Mann-Whitney U tests showed that the difference between the indoors and the outdoors was statistically meaningful in terms of particles of 0.056 ${\mu}m$ or less (p<0.05) in size. These results are possibly influenced by the use of printers and duplicators as the factor that increased the concentration of nanoparticles. In seasonal concentration distribution, the level was higher during the summer compared to in the autumn. Those of 0.056 ${\mu}m$ or less in size presented a statistically meaningful difference during the summer (p<0.05). These results may be influenced by photochemical event as the factor that makes the levels high. Regarding zinc, among the other heavy metals, the fine particles ranged in size from 0.056 ${\mu}m$ to 0.10 ${\mu}m$ and those of 0.056 ${\mu}m$ or less recorded 1.699 $ng/m^3$ and 1.189 $ng/m^3$ in the outdoors. In the indoors, the levels were lower, with 0.745 $ng/m^3$ and 0.617 $ng/m^3$. Cr and Ni at the size of 0.056 ${\mu}m$ or less, both of which have been known to pose severe health effects, recorded higher concentrations indoors with 0.736 $ng/m^3$ and 0.177 $ng/m^3$, compared to 0.444 $ng/m^3$ and 0.091 $ng/m^3$ outdoors. By season, Zn, Ni, Cu and Pb posted a high level of indoor concentration during the fall. As for Cr, the level of concentration indoors was higher than outdoors both during the summer and the autumn. Conclusion: This study indicates the result of an examination of nano-sized particles and heavy metal concentrations. It will provide useful data for the determination of basic nanoparticle standards in the future.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.115-122
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• 2017

Objective of this research was to investigate the influence of lowered substrate pH on the reduction of bicarbonate injury in the vegetative growth of 'Ssanta' strawberry. The acid substrate was formulated by mixing sphagnum peat moss with pine bark (5:5, v/v) and the pH, EC, and CEC of the substrate were 4.07, $0.46dS{\cdot}m^{-1}$, and $91.3cmol^+{\cdot}kg^{-1}$, respectively. To adjust the pH of acid substrate, various amount of dolomitic lime [$CaMg(CO_3)_2$] were incorporated with the rate of 0 (untreated), 1, 2, 3, and $4g{\cdot}L^{-1}$. Then, mother plants were transplanted and grown with fertilizer solution containing $240mg{\cdot}L^{-1}$ of the $HCO_3{^-}$ and equal concentrations of essential nutrients to Hoagland solution. In growth of 'Ssanta' strawberry, fresh weight of mother plants were the highest in the treatment of $2g{\cdot}L^{-1}$ dolomitic lime such as 102.1 g followed by 94.7 g in $1g{\cdot}L^{-1}$, 91.2 g in $3g{\cdot}L^{-1}$, 75.7 g in $0g{\cdot}L^{-1}$ and 72.3 g in $4g{\cdot}L^{-1}$ treatments. The dry weight showed a similar tendency to fresh weight. At 140 days after transplanting, 5.8, 9.8, 11.8, 8.8, and 5.0 daughter plants were derived from each of the mother plants in the treatments of 0, 1, 2, 3, and $4g{\cdot}L^{-1}$ dolomitic lime, respectively. The highest occurrence of daughter plants were observed in the treatments $2g{\cdot}L^{-1}$ dolomitic lime. The substrate pH and bicarbonate concentration of 'Ssanta' strawberry seedlings in the 1 and $2g{\cdot}L^{-1}$ dolomitic lime treatments were maintained at a proper range such as 5.6 to 6.2. The micro-nutrient contents of above ground tissue in mother plants were the highest in $2g{\cdot}L^{-1}$ and the lowest in $4g{\cdot}L^{-1}$ dolomitic lime treatment. The above results indicate that incorporation rate of dolomitic lime in acid substrate with the pH of around 4 is $2g{\cdot}L^{-1}$ to raise the 'Ssanta' strawberry in propagation.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.351-358
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• 2012

BACKGROUND: Constructed wetlands for wastewater treatment are vegetated by wetland plants. Wetland plants are an important component of wetlands, and the plants have several roles in relation to the livestock wastewater treatment processes. The objectives of this study were to investigate the growth characteristics and nutrient absorption of water plants in constructed wetlands for treating livestock wastewater. METHODS AND RESULTS: In this study, livestock wastewater treatment plant by constructed wetlands consisted of $1^{st}$ water plant filtration bed, $2^{nd}$ activated sludge bed, $3^{rd}$ vertical flow(VF), $4^{th}$ horizontal flow(HF) and $5^{th}$ HF beds. Phragmites communis TRINIUS(PHRCO) was transplanted in $3^{rd}$ VF bed, Iris pseudoacorus L(IRIPS) was transplanted in $4^{th}$ HF bed and PHRCO, IRIPS and Typha orientalis PRESEL(THYOR) were transplanted in $5^{th}$ HF. Growth of water plants in constructed wetlands were the highest in October. The IRIPS growth was higher than other plant as 264 g/plant in October. The absorption of nitrogen and phosphorus by IRIS were 3.38 g/plant and 0.634 g/plant, respectively. The absorption of K, Ca, Mg, Na, Fe, Mn, Cu and Zn by water plants were higher in the order of IRIPS > THYOR > PHRCO. CONCLUSION(S): The absorption of nutrients by water plants were higher on the order of IRIPS > THYOR > PHRCO in constructed wetlands for treating livestock wastewater.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.8-15
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• 2010

Purpose: The purpose of this study was to evaluate the effect of various methods of dentin bonding agent application and air abrasion pretreatment on microtensile bond strength between dentin and resin, using a self-etching adhesive system. Material and methods: Thirty freshly extracted human molars were obtained and divided into 6 groups of 5 teeth. A 2-step self etching adhesive system (Clearfil SE Bond) was used for all groups. The control specimens were prepared using a direct immediate bonding technique. The delayed dentin sealing specimens were prepared using an indirect approach without dentin prebonding. The immediate dentin sealing specimens were prepared using dentin prebonding immediately following preparation. Immediate dentin sealing teeth and delayed dentin sealing teeth had provisional restorations using Fermit for two weeks. Then all specimens of each group were divided into two groups of three, depending on air abrasion pretreatment. Composite "crowns" were incrementally built on and specimens were stored in water for 24 hours. All teeth were prepared for a microtensile bond strength test. Bond strength data were analyzed with a one-way ANOVA test, and post hoc comparison was done using the Scheffe's test. Results: The mean microtensile bond strengths of all groups were not statistically different from each other. Conclusion: When preparing teeth for indirect restorations, IDS and DDS with Clearfil SE bond, have no difference on the microtensile bond strength between dentin and resin. Air abrasion pretreatment did not affect the microtensile bond strength when using IDS and DDS with Clearfil SE bond.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.2
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• pp.130-137
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• 2012

This research evaluated the effectiveness of organic matter ratios in substrate and mulching materials under mn-irrigated condition green roofs by measuring the effects on growth of Liatris spicata. Four mulching materials were installed, i. e. nun-mulched control(CON), volcanic ash soils(VAS), non-woven black fabric mat(NBM) and pine bark(PAK). Three levels of organic maller volume percentage in an amended soil were evaluated, amended soil: organic matter=100:0($A_1O_0$), amended soil: organic matter=80:20($A_4O_1$) and amended soil: organic matter=50:50($A_1O_1$). Plant height, number of leaves, diameter of flower stalk, number of florets, chlorophyll contents, shoot fresh and dry weight were recorded from April to September, 2010, and survival rate was examined on May 2011 of the following year. In the $A_1O_0$, the number of leaves, number of florets and chlorophyll contents were higher in Liatris spicata grown on NBM than other mulching treatments. Especially, plant height, shoot fresh and dry weight were significantly higher. However, it resulted the lowest survival rate than other mulching treatments. 2. In the $A_4O_1$, the plant height, number of leaves, number of florets, shoot fresh and dry weight were higher than other mulching treatments, but there was no significant difference except for the plant height of Liatris spicata grown on NBM. The survival rate was decreased by 40~60%, compared with $A_1O_0$, after overwintering. 3. In the $A_1O_1$, the plant height, number of leaves, diameter of flower stalk, number of florets, chlorophyll contents, shoot fresh and dry weight were slightly higher than other mulching treatments, but there was no significant difference from Liatris spicata grown on NBM and VAS. The survival rate was observed by 0% over all mulching treatments after overwintering. Therefore, the non-woven black fabric mat(NBM) promoted the Liatris spicata's growth and flowering compared with other mulching treatments. However, the survival rate was decreased significantly, and the organic matter ratios were increased after overwintering under non-irrigated green roofs.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.310-315
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• 2011

BACKGROUND: Heavy-metal pollution represents an important environmental problem due to the toxic effects of metals, and their accumulation throughout the food chain leads to serious ecological and health problems. METHODS AND RESULTS: Optimum conditions in continuous-flow stirred tank reactor (CSTR) and packedbed column contactor (PBCC) using brown seaweed biosorbent were investigated. Under optimum conditions from both lab-scale biosorbent systems, removal efficiency of copper (Cu) in a large-scale PBCC system was investigated. Removal capacity of Cu using brown seaweed biosorbent in a lab-scale CSTR system was higher than that in a lab-scale PBCC system. On the other hand, over 48 L/day of flow rate in Cu solution, removal efficiency of Cu in a lab-scale PBCC system was higher than that in a lab-scale CSTR system. Optimum flow rate of Cu was 24 L/day, optimum Cu solution concentration was 100 mg/L. Removal capacity of Cu at different stages was higher in the order of double column biosorption system > single column biosorption system. Under different heavy metals, removal capacities of heavy metal were higher in the order of Pb > Cr > Ni > Mn ${\geq}$ Cu ${\geq}$ Cd ${\fallingdotseq}$ Zn ${\geq}$ Co. Removal capacity of Cu was 138 L in a large-scale PBCC system. Removal capacity of Cu a large-scale PBCC system was similar with in a lab-scale PBCC system. CONCLUSION(s): Therefore, PBCC system using brown seaweed biosorbent was suitable for treating heavy metal wastewater.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.156-163
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• 2009

Statement of problem: Recently, there have been increased esthetic needs for posterior dental restorations. The failure of posterior dental ceramic restoration are possible not only by the characters of the component materials but also by the type of food. Purpose: The research aim was to compare the in vitro fracture resistance of simulated first molar crowns fabricated using 4 dental ceramic systems, full-porcelain-occlusal-surfaced PFG, half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon and selected Korean foods. Material and methods: Eighty axisymmetric crowns of each system were fabricated to fit a preparation with 1.5- to 2.0-mm occlusal reduction. The center of the occlusal surface on each of 15 specimens per ceramic system was axially loaded to fracture in a Instron 4465, and the maximum load(N) was recorded. Afterwards, selected Korean foods specimens(boiled crab, boiled chicken with bone, boiled beef rib, dried squid, dried anchovy, round candy, walnut shell) were prepared. 15 specimens per each food were placed under the Instron and the maximum fracture loads for them were recorded. The 95% confidence intervals of the characteristic failure load were compared between dental ceramic systems and Korean foods. Afterwards, on the basis of previous results, 14Hz cyclic load was applied on the 4 systems of dental ceramic restorations in MTS. The reults were analyzed by analysis of variance and Post Hoc tests. Results: 95% confidence intervals for mean of fracture load 1. full porcelain occlusal surfaced PFG Crown: 2599.3 to 2809.1 N 2. half porcelain occlusal surfaced PFG Crown: 3689.4 to 3819.8 N 3. Ice Zirkon Crown: 1501.2 to 1867.9 N 4. Empress 2 Crown: 803.2 to 1188.5 N 5. boiled crab: 294.1 to 367.9 N 6. boiled chicken with bone: 357.1 to 408.6 N 7. boiled beef rib: 4077.7 to 4356.0 N 8. dried squid: 147.5 to 190.5 N 9. dried anchovy: 35.6 to 46.5 N 10. round candy: 1900.5 to 2615.8 N 11. walnut shell: 85.7 to 373.1 N under cyclic load(14Hz) in MTS, fracture load and masticatory cycles are: 1. full porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 4796.8-9321.2 cycles under 2224.8 N(round candy)load, no fracture under smaller loads. 2. half porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 881705.1-1143565.7 cycles under 2224.8 N(round candy). no fracture under smaller loads. 3. Ice Zirkon Crown fractured at 95% confidence intervlas of 979993.0-1145773.4 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. 4. Empress 2 Crown fractured at 95% confidence intervals of 564.1-954.7 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. Conclusion: There was a significant difference in fracture resistance between experimental groups. Under single load, Korean foods than can cause fracture to the dental ceramic restorations are boiled beef rib and round candy. Even if there is no fracture under single load, cyclic dynamic load can fracture dental posterior ceramic crowns. Experimental data with 14 Hz dynamic cyclic load are obtained as follows. 1. PFG crown(full porcelain occlusion) was failed after mean 0.03 years under fracture load for round candy(2224.8 N). 2. PFG crown(half porcelain occlusion) was failed after mean 4.1 years under fracture load for round candy(2224.8 N). 3. Ice Zirkon crown was failed after mean 4.3 years under fracture load for boiled chicken with bone(382.9 N). 4. Empress 2 crown was failed after mean 0.003 years under fracture load for boiled chicken with bone(382.9 N).

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.418-428
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• 2007

Physical and chemical properties of the aggregate by-products including sludge and crushed dust samples collected from the 21 private companies throughout the country were analyzed to evaluate possible usage of the by-products as artificial soil materials for plantation. The pH of the materials ranged from 8.0 to 11.0. The organic matter content was $2.85g\;kg^{-1}$, and the total nitrogen content and available phosphate content were low as 0.7 percents and $12.98mg\;kg^{-1}$, respectively. Exchangeable $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $Na^+$ were 2.29, 0.47, 0.02 and $0.05cmol\;kg^{-1}$, respectively. Heavy metal contents were lower than the limits regulated by environmental law of Korea. Textural analysis showed that most of the materials were silt loam with low water holding capacity ranged from 0.67 to 7.41 percents, and with low hydraulic conductivity ranged from 0.4 to $2.8m\;s^{-1}$. Mineralogical analysis showed that the aggregate by product materials were mostly composed of silicate, alumina and ferric oxides except calcium oxide dominant materials derived from limestones. The primary minerals were quartz, feldspars and dolomites derived from granite and granitic gneiss materials. Some samples derived from limestone material showed calcite and graphite together with the above minerals. According to the result, it can be concluded that the materials could be used as the artificial soil material for plantation after proper improvement of the physico-chemical properties and fertility.