• The Korean Journal of Physiology
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• v.28 no.1
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• pp.27-35
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• 1994

We investigated the alterations in basal tone of aortic strips by changing the Ca concentration, basal $^{45}Ca$ uptake and $^3H-nitrendipine$ binding of the single cells of aortic smooth muscles in the spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. While the basal tone of the aortic strips in WKY rats was not affected by alteration of Ca concentration, that in SHR was decreased by the removal of Ca from the bath solution and was recovered by the restoration of Ca to normal levels. This contraction increased in a Ca concentration-dependent manner and reached a maximum at 2 mM Ca. The basal tone of aorta in SHR was suppressed by verapamil $(10^{-6}M)$. The basal tone of aorta in SHR increased about 50% in the strips of endothelial rubbing, compared with that of intact endothelium. Basal $^{45}Ca$ uptake in the aortic single smooth muscle cells of SHR was greater than that of WKY (p<0.01), Specific bindings of $[^3H]nitrendipine$ in the aortic single smooth muscles of SHR and WKY were saturable. The dissociation constant $(K_d)\;was\;0.71{\pm}0.15\;and\;1.18{\pm}0.08nM$ SHR, respectively, and the difference in $K_d$ between two strains was statistically significant (p<0.03). The maximal binding capacity $(B_{max})\;was\;34.6{\pm}3.2\;and\;47.4{\pm}4.3\;fmol/10^6$ SHR respectively, and the difference of $(B_{max})$ between two strains was statistically significant (p<0.05). from the above results, it is suggested that the increase of Ca influx via potential-operated Ca channels and the increase of the number of dihydropyridine-sensitive Ca channels contribute to high basal tone of the aortic strips in SHR.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.55-62
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• 2006

Orthodontic mini-implants, despite its usefulness as anchorage, have some limits such as loosening. Therefore, various shapes and lengths have been studied. The aim of this study is to analyze the shape and length of mini-implants mechanically. The shapes of mini-implants (1.6 mm, Dual Top, Jeil Medical Co., Seoul, Korea) were cylindrical and taper. The lengths of mini-implants were 6 mm and 8 mm. The tested groups were 5 groups (cylindrical 6 mm, cylindrical 8 mm, taper 6 mm, taper 8 mm and taper 8 mm modified whose thread is reduced from the middle to upper part). All were inserted and removed on the polyurethane foam with the torque measured. During insertion and removal, the taper shape needed higher torque than the cylindrical shape, and the 8 mm length than the 6 mm length (p<0.001). The taper 6mm group showed superior insertion torque (p<0.001) and similar removal torque to the cylindrical 8 mm group. The taper 8 mm modified group with gradually reduced threads, showed continuous high removal torque after the peak. The initial mechanical stability can be provided by the tapered shape and also, affected by length and thread design.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.185-193
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• 2008

This study has been carried out to examine the feasibility of soil washing process for reducing arsenic contamination level of soil around $Dalch\hat{e}n$ Mine. The results of physicochemical tests of the target soil showed that pH was weak alkalic ($pH{\simeq}7.8$), soil texture was coarse sand, and organic contents (5.7%) and CEC (Cation exchange capacity; 21.5 meq/100 g) were similar with those of soils generally found in Korea. Contamination levels of arsenic were found to over 201 mg/kg which exceed the Korea standard levels of countermeasure and concern. To investigate chemical partitioning of heavy metals, sequential extraction procedures were adopted and it was found that arsenic was predominantly associated with the residual fraction among five fractional forms as much as over 85%, which is demonstrating that only less than 15% of all might be vulnerable to a selected washing agents. Among 6 kinds of washing agents applied on the screening for arsenic-contaminated soil, HCl and $H_3PO_4$ solution were selected as promising washing agents. In comparison with HCl and $H_3PO_4$ solutions for arsenic washing by kinetic experiment in the change of pH, soil-solution ratio, temperature, and washing solution concentration, $H_3PO_4$ solution was determined to best one of agents tested, which showed faster washing rate than HCl to accomplish regulatory goal.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.15-20
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• 2012

Processing of organic waste is converted to anaerobic digestion for environmental friendly and sustainable energy recovery and reduction of sludge. In this study, ECOPAD (ECOdays' Plug-flow Anaerobic Digster)design for a high solids content and high organic matter content were used to investigate an applicability and efficiency of food waste treatment and poultry wastewater treatment. Case-by-case analysis of treatment efficiency of ECOPAD using food waste of city "P" and city "S". Volatile Solids basis organic removal efficiency of city "P" and city "S" was 84% and 88% respectively. And, the content of methane (P City: 70%, S City: 71%) was measured similarly. In the case of poultry waste bio-gas production was measured to $1.6Nm^3/kg$-VSrem, and methane content was measured to 69%.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.505-511
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• 2012

While the existing sewage treatment facilities are mainly being operated by biological processes, winter-time efficiency improvement and additional phosphorus treatment equipment using chemicals have been required to follow the effluent criteria of TP (0.2, 0.3 and 0.5 mg/L for the zone of I, II and III respectively) and $BOD_5$ (5.0 mg/L) which is intensified from 2012 in Republic of Korea. We made an investigation into actual condition of biological treatment process and calculated the optimal chemical input amount by jar test of supernatant of secondary sedimentation tank to evaluate the process improvement for the intensified criteria. Ejector BAF system for removing TP, $BOD_5$ of sewage effluent was suggested. The concentration of TP from biological process is 0.3-0.8 mg/L, and the input amount of optimal chemical coagulant was above Al/P ratio of 3(1.9 mg/L as Al) to meet the criteria of TP for secondary treatment effluent. From the results of this experiment, the best Al/P ratio for Ejector BAF system was about Al/P ratio of 1, and LV of BAF process for intensified criteria of $BOD_5$ and TP was below 1.97m/hr.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.6
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• pp.649-655
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• 2018

Objective: This paper reports the possibility of using of a locking horizontal mattress suture technique in repairing lacerations that are difficult to suture with staples. Methods: Data were collected retrospectively over a 6-month period regarding the routine repair of scalp lacerations: those in areas injured by a high energy blunt mechanism, continued to bleed after pressure, nonlinear or damaged skin repaired with a locking horizontal mattress technique, and simple interrupted technique. The effects of the two techniques used to repair scalp lacerations on wound healing, complication rate, and patient satisfaction were examined. The categorical variables are expressed as the number and percent. A Mann-Whitney-Wilcoxon test was used for statistical analysis. A P-value less than 0.05 was considered significant. Results: Thirty-seven consecutive patients with scalp lacerations presented for care. Wound closure was accomplished with the locking horizontal mattress sutures in 40.5% (n=15) (median length, 5.0 cm; interquartile range [IQR], 4.0-7.0 cm). Simple interrupted sutures (median length, 4 cm; IQR, 3.0-5.0 cm) were used in 59.5% (n=22) (P=0.015). The frequency of additional bandage compression (P=0.008), frequency of exudative hemorrhage (P=0.018), and suture mark frequency at suture removal (P=0.047) were significantly lower in the locking horizontal mattress group. Conclusion: The locking horizontal mattress suture, which has the advantage of a horizontal mattress suture, may be one of the ways that can be used alternatively to treat scalp lacerations that difficult to suture with staples.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.76-85
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• 2004

Anaerobic decomposition of municipal solid waste (MSW) had potential adverse impacts such as the production of methane and long-term post closure on human health and the environment. It was demonstrated that aerobic degradation of MSW resulted in the reduction of a methane yield and the enhancement of stabilization of MSW. Excavated solid wastes were both aerobically and anaerobically treated in order to evaluate the effects of air injection on the stabilization of landfill site. The municipal solid waste (MSW) samples were excavated from a 10-year old landfill (operation period: 1991. 11~1994. 11), Jeonju, Korea. Excavated municipal solid wastes are primarily composed of soils and vinyl/plastics. For the two aerobic simulated lysimeters, the levels of $O_2$ ranged 1.6~23.1% and the levels of $CO_2$ ranged 1.5~15.1%, which confirmed the aerobic decomposition. Aeration did prevent methane formation. For the anaerobic simulated lysimeter, the $CO_2$ rose as $O_2$ was consumed and low levels of CH4 were produced. The pH levels ranged from 7.7 to 8.9 for anaerobic lysimeter and from 7.3 to 8.5 for aerobic lysimeters. As expected, aerobic treatment proved to enhance the removal of biodegradable materials in the excavated solid wastes when monitoring the concentration of BOD, COD, $NH_4-N$, and $NO_3-N$ in the leachate.

• Environmental Engineering Research
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• v.19 no.2
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• pp.157-163
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• 2014

The adsorption of Cr(VI) from aqueous solutions to activated carbon fiber (ACF) was investigated using both batch and flow-through column experiments. The batch experiments (adsorbent dose, 10 g/L; initial Cr(VI) concentration, 5-500 mg/L) showed that the maximum adsorption capacity of Cr(VI) to ACF was determined to 20.54 mg/g. The adsorption of Cr(VI) to ACF was sensitive to solution pH, decreasing from 9.09 to 0.66 mg/g with increasing pH from 2.6 to 9.9; the adsorption capacity was the highest at the highly acidic solution pHs. Kinetic model analysis showed that the Elovich model was the most suitable for describing the kinetic data among three (pseudo-first-order, pseudo-second-order, and Elovich) models. From the nonlinear regression analysis, the Elovich model parameter values were determined to be ${\alpha}$ = 162.65 mg/g/h and ${\beta}$ = 2.10 g/mg. Equilibrium isotherm model analysis demonstrated that among three (Langmuir, Freundlich, Redlich-Peterson) models, both Freundlich and Redlich-Peterson models were suitable for describing the equilibrium data. In the model analysis, the Redlich-Peterson model fit was superimposed on the Freundlich fit. The Freundlich model parameter values were determined to be $K_F$ = 0.52 L/g and 1/n = 0.56. The flow-through column experiments showed that the adsorption capacities of ACF in the given experimental conditions (column length, 10 cm; inner diameter, 1.5 cm; flow rate, 0.5 and 1.0 mL/min; influent Cr(VI) concentration, 10 mg/L) were in the range of 2.35-4.20 mg/g. This study demonstrated that activated carbon fiber was effective for the removal of Cr(VI) from aqueous solutions.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.217-224
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• 2009

The pig slurry is one of important fertilizer source for production of crops in recent years, but it has many controversial points of utilization such as offensive odor, lack of spread equipment and farmland possession, respectively. This study was carried out in order to remove water pollutants and malodor of pig slurry using biofiltration system. The biofiltration system consists of pig slurry separator, mixing shift and attached blade for sawdust or ricehull, air injection nozzle and outlet for pig slurry and sawdust or ricehull. The characteristics pH, $BOD_5$ (Biochemical Oxygen Demand), $COD_{Mn}$ (Chemical Oxygen Demand), SS (Suspended Solid), T-N (Total Nitrogen), T-P (Total Phosphorus) of the untreated pig slurry used in this study were 7.2, 34,450, 24,604, 71,000, 4,194, $1,631\;ml/{\ell}$, respectively. The $NH_3$ (Ammonia) and $H_2S$(Hydrogen Sulfide) concentration were 70.0, 9.6 ppm, respectively. The initial total microorganisms of pig slurry were $5.0{\times}10^3\;cfu/ml$, and Salmonella, Bacillus were $5.8{\times}10^2$, $1.1{\times}10^3\;cfu/ml$, respectively. The filtration system was very effective on removal of water pollutants of pig slurry. The removal efficiency of the offensive odor of ammonia and hydrogen sulfide in sawdust was higher than those of ricehull. The total microorganisms and bacillus of pig slurry are on the increase by sawdust and ricehull, but Salmonella showed a tendency to decrease in number after that time. Accordingly, the filtration system was very effective to produce a good quality pig slurry.

• Resources Recycling
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• v.8 no.5
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• pp.51-58
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• 1999

The sbdy iwestlgaled ihc propa-ties of Lhe dust\ulcorner rrom fe~~oallomya ~~ufacturTeh. e chemical composition, cornpasitlon material, p d c l e sire md shapes of the bulk dust, sired dust and magnetically separated durl were mvesligaled. As the re\ulcornerulL, we suppose that the dust from &gh Carbon Fenama~~gunesMc anuiact~vingP rocess is not sufiicient as solulce material of Mn because of ale low Mn canlenl (13.5%) and complicaled composition mate~ial. The dust from Bug F!lter or AOD Proccss is mi~inlym ade up of 0.2-2 pm Mn30, (Hausmam~iu)p iutlde in spherical shape and thc Mn content is 63.190.The dust from Cooler of AOD Process is inninly made up of coarse Ca(O1-Or)zM. n,FeyO,, SiO, and fine Mn30d.