• Journal of Oral Medicine and Pain
• /
• v.21 no.1
• /
• pp.89-101
• /
• 1996

This study was performed to investigate influence of the changes of head posture on resting electromyographic (EMG) activity in anterior temporalis, masseter, sternocleidomastoid muscle and trapezius, and on status of occlusal contacts. For this study twenty-nine patients with temporomandibular disorders(TMD) and thirty dental students without any masticatory symptoms were selected as patients group and control group, respectively. EMG activity($\mu$V) at rest was observed in four kind of head postures such as natural or normal head posture(NHP), forward head posture(FHP), upward head posture(UHP), downward head posture(DHP), and in NHP and FHP, EMG activity with flat occlusal splint was also checked. BioEMG$^\textregistered$(Bioelectromyograph, Bioresearch Inc., USA) was used to record EMG activity in the above four muscles with eight locations on both sides. The author used T-Scan$^\textregistered$(Tekscan Co., USA) system to investigate the changes of oclusal contats on clenching in the four head postures about number, force, time(duration) and total left-right statistis(TLR, occlusal stability crossing left-right dental arch on clenching). For taking in upward or downward head posture, head was inclined $10^{\circ}$ upward or downward and CROM$^\textregistered$ (cervical-range-of motion, Performance attainment Inc., USA) was used to maintain same posture during the procedure. The results obtained were as follows : 1. For resting EMG activity, anterior temporalis did not show any difference by change of head posture, but masseter and sternocleidomastoid muscle showed higher value of EMG activity in FHP and UHP, and trapezius showed higher value of EMG activity in FHP and DHP. 2. EMG activity of trapezius was higher than that of any other muscles in NHP, FHP, and DHP, but in UHP, the activity was the lowest reversely. 3. Patients group showed higher EMG activity than control group did in all the muscles in NHP. And significant difference between the two groups were also observed in anterior temporalis in FHP, in sternocleidomastoid muscle in UHP, and in sterno-cleidomastoid muscle and trapezius in DHP with higher activity in patients group. 4. There was no change of EMG activity in NHp with splint, but EMG activity in anterior temporalis and masseter was decreased in FHP with splint. 5. In general, status of occlusal contacts was not changed with head posture in all subjects, and difference between patients group and control group was only noted for number and force of tooth contact in UHP and DHP with more value in control group. 6. Correlationship between EMG activity and number ad force of tooth contacts was shown negatively with regard to masseter in NHP, and trapezius in UHP and DHP.

• Polymer(Korea)
• /
• v.34 no.2
• /
• pp.178-183
• /
• 2010

Medical metal stents inserted to patients with a cardiovascular disease associated with coronary artery system have relatively increased the survival rate. The development of new stents is, however, urgently required due to restenosis and late thrombosis generated in metal stents. To solve these problems, the biodegradable polymers such as poly(lactide-co-glycolide) (PLGA), poly(L-lactide)(PLLA), and poly ($\varepsilon$-caprolactone)(PCL) were mixed with alpha lipoic acid (ALA), which is well known to inhibit the proliferation of neointimal hyperplasia. Subsequently, the ALA-loaded polymers were coated on stainless steel by electrospray. The drug-eluting behaviors from the coated polymers were investigated according to kinds and concentrations of polymers, spray rates, and kinds of solvents. The drug-eluting rate from PCL with the lowest glass transition temperature was the fastest among three polymers and followed by PLGA and PLLA. The surface roughness increased as the spray rate was increased and also the drug-eluting rate was affected by kinds of solvents with different boiling point. It is expected that drug-eluting stent (DES) coated with ALA-loaded polymers can be applied practically for clinical applications by controlling the behavior of drug release.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.2
• /
• pp.142-145
• /
• 2009

The cytotoxic activity against human cancer cells and anti-tumor effect in Balb/c mice of a 70% ethanol extract from masou salmon (MSE) was investigated. The cancer cell lines including human breast adenocarcinoma (MCF-7), human lung carcinoma (A549), human hepatoblastoma (HepG2), human gastric carcinoma (AGS), human cervical adenocarcinoma (HeLa) and transformed primary human embryonal kidney (293) exposed to MSE decreased cell viability as indicated by the MTT assay. The MSE shows significant cytotoxicity on MCF-7, A549, HepG2, AGS and HeLa cells, and are more active than 293 cells. The treatment with 1 mg/mL MSE resulted in 9.2%, 12.7%, 16.6%, and 16.9% cell survival against A549, MCF-7, HepG2, and AGS cells, respectively. Moreover, anticancer effect in vivo of MSE was tested in the animal system using Balb/c mice transplanted sarcoma-180 cells. MSE showed inhibition of tumor growth and the rate of inhibition was 44.7% and 55.7% at the 25 mg/kg body weight and 250 mg/kg body weight, respectively. Thus, we suggest that MSE could be a beneficial material for human cancer prevention.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.3
• /
• pp.24-30
• /
• 2016

Vertical and standing column well ground heat exchangers have mostly been installed for ground source heat pump systems (GSHP) and thermal response tests (TRT) have been applied to evaluate the thermal characteristics for these heat exchangers. In this paper, the TRT coupled with a line source method was applied to evaluate the thermal characteristics of the horizontal ground heat exchanger (HGHX). Load tests of a HGHX were also performed to examine the daily variations of the ground and fluid temperatures associated with the daily intermittent operation of GSHP. For this test, the straight HGHX (depth 2 m, length 50 m, 8 line) was installed in Ansan city. The results showed that the variations of ground thermal conductivity of HGHX during one year were relatively small with the range of $1.43{\sim}1.64W/m{\cdot}K$, and the maximum and minimum values appeared in December and May, respectively. Load tests with heat injection rate of 6.0 kW for 10 hours per day to HGHX during twelve days were performed in June, September and December, and resulted in a ground initial temperature rise of $4.31^{\circ}C$, $3.14^{\circ}C$, and $1.21^{\circ}C$ during these days, respectively.

• Journal of Korean Society of Rural Planning
• /
• v.22 no.4
• /
• pp.1-11
• /
• 2016

Public transportation is public service that is contributed to the convenience of the public. However, opportunity for public services in rural areas is weaker than the chance in urban areas. The purpose of this study is to evaluate accessibility of various public facilities using public transportation. To evaluate the accessibility, we calculate the various time from community center to the nearest bus stop, walking time, riding time in bus, and waiting time for transfer. The results of this study ares as follows; (1) Villages occupy 19.8% in rural areas that walking time from community center to the nearest bus stop takes over 10 minutes in integrated Chungju-si; (2) The average speed is 21.9 km/hr estimated to departure and arrival time of bus route; (3) The accessibility time from community center using the average bus speed takes 15.43 minutes to public facilities, 35.15 minutes to emergency center, 8.70 minutes to medical center, 9.70 minutes to elementary school, 16.26 minutes to middle school, and 22.61 minutes high school; (4) The transfer time of public transportation takes 13.46, 21.96, 10.48, 7.78, 11.11, 16.10 minutes to public facilities, emergency center, medical center, elementary school, middle school, and high school, respectively; (4) Traffic accessibility using bus vehicles in the East and South Chungju-si is lower than areas in the West and North Chungju-si. Some villages surrounding public offices (eup-myeon office) which have a high density of population, indicate a high traffic accessibility.

• Korean Journal of Soil Science and Fertilizer
• /
• v.50 no.4
• /
• pp.259-274
• /
• 2017

To get some informations for sustainable paddy use, the productivities of soils with two years of cropping systems were estimated through pot experiment using two pretreated groups of not autoclaved 'natural'- and 'autoclaved'-soils without any fertilization. And then the relationship between the productivities, called yield potentials, and the characteristics of soils as affected by cropping systems, such as rice-rice (R-R), ricebarley-rice-barley (R-B-R-B), rice-barley-rice-wheat (R-B-R-W), soybean-barley-soybean-barley (S-B-S-B), of which barley and wheat were composted at a level of $10MT\;ha^{-1}$, and S-B-S-B without compost, was analyzed. These treatments were established in mid-mountainous loam paddy, which contained exchangeable Ca of $11.8cmol_c\;kg^{-1}$, located at the altitude of 285 m above sea level in Sangju of Korea. Crops for the estimation of soil productivity were rice cv. 'Seolemi' and soybean cv. 'Chamol'. As a result, under the natural soils condition, rice grain and straw were highly produced in composted S-B-S-B soils (p < 0.05) and lowly in R-R soils (p < 0.05). While soybean grain and stem were higher in R-R soils (p < 0.05) than other soils which not significantly different each other. In case of autoclaved soils, the yield potentials of rice and soybean were high together in either composted R-B-R-B/W or S-B-S-B soils compared to R-R and uncomposted S-B-S-B soils (p < 0.05). In especial, these yield potentials under the natural soils condition were commonly influenced by soil porosity showing negative correlation for rice (p < 0.01); positive for soybean (p < 0.05). And the porosity possibly reversed even the symbiotic contribution of indigenous Bradyrhizobium japonicum for soybean. Under autoclaved soils condition the potentials of rice and soybean showed negative correlations with soil C:N ratio (p < 0.05) similarly to the case of rice in the natural soils.

• Environmental Analysis Health and Toxicology
• /
• v.24 no.3
• /
• pp.241-249
• /
• 2009

Heavy metal contaminants on the aquatic environment are of interest because they can have severe effects on economy and public health. Recently, the studies for monitoring of heavy metals try to do on aquatic system to assess safety and health of ecosystem by heavy metals. Thus, biological responses were investigated on Korean fairy shrimp Branchinella kugenumaensis exposed to cadmium (Cd) or copper (Cu) for long-periods (30 days). The survival rate decreased significantly (p<0.05) on B. kugenumaensis exposed to Cd and Cu at all concentrations. Especially, the highest decrease was observed at the relatively high concentration of Cd and Cu (p<0.01) and the response by Cd exposure was at dose-dependent. The growth rates were also decreased significantly (p<0.05) on B. kugenumaensis exposed to Cd and Cu for at all concentrations. Then, the reproduction rate, numbering cyst, was decreased significantly (p<0.01) on B. kugenumaensis after Cd or Cu exposures. Long exposure of the relatively high concentration Cd and Cu can have severe effects on the reproduction, while exposures of Cd and Cu can not have effects on sex ratios of B. kugenumaensis. Additionally, asymmetric telson deformity was only observed after Cd exposure. Therefore, these results suggest that B. kugenumaensis is a sensitive bio-indicator of heavy metal exposure and these biological responses of B. kugenumaensis give important information for long-term monitoring on aquatic ecosystem.

• Korean Journal of Environmental Biology
• /
• v.36 no.1
• /
• pp.90-97
• /
• 2018

This study assessed the effect of ozone to control pathogenic bacteria in inlet water flowing to flounder farms, establishing operational parameters of ozonation at seawater conditions. Hydraulic retention time in a reaction pipeline after ozonation was fixed at 3 minutes in a flow through system. Concentrations of total residual oxidant (TRO) by ozonation were measured according to different ozonation intensities. The oxidant reduction potential (ORP), which is indirect but enables real-time measurement, was measured in relation to TRO values. TRO values were $0.01{\pm}0.01mg\;L^{-1}$ at an ORP range of 320-410 mV, $0.07{\pm}0.02mg\;L^{-1}$ at 600 mV, and $0.16{\pm}0.03mg\;L^{-1}$ at 700 mV. A heterotrophic marine bacteria colony was reduced by 80.6-97.9%, showing the suppression effect of ozonation on total bacteria in inlet water. At an ORP range of 400-500 mV, colonies of heterotrophic marine bacteria, Vibrio spp., and gram negative bacteria were significantly reduced in outlet water from a culture tank with ongrowing flounder (230 g) at a stocking density of $8kg\;m^{-2}$. Especially, Vibrio spp. and gram negative bacteria were seldom found at 400-500 mV. The daily feeding rate was from over 0.7% to total body weight at 300-500 mV, showing better performance than that in the control. The pathogenic bacteria entering the flounder farm were effectively removed when the ORP range to 400 mV or less.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.2
• /
• pp.131-138
• /
• 2013

The precision aerial application of small farms, such as paddy, upland and orchard fields using agricultural unmanned helicopters became a new paradigm. The objective of this study was to evaluate the performance of a GPS module and algorithm, controlling drift of agricultural helicopter by the crosswind and maintaining the position for emergency landing. Purpose of the drift control, of which an algorithm works while hovering is related with the emergency sequence that coping with abnormal conditions of rotorcraft system. However, the inertial attitude control cannot detect a drifting motion of fuselage moving at the constant velocity, thus the crosswind takes the helicopter away from the landing position. Performance of the drift control module, based on the GPS that a hovering position did not deviate within 5m in diameter, were tested and evaluated. Initially, the reaction against a disturbing gust wind was sensitive, soon the helicopter maintained its locking position and azimuth within 5m in diameter. It was, however, difficult for the helicopter to recognize the swaying and nodding, the some deviation was expected due to the discrepancy characteristics of the GPS signal. The performance of the drift control proved the effectiveness of the module to maintain the position against an unintended drift during the emergency landing or hovering.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.3
• /
• pp.565-573
• /
• 2000

Sewer pipe in Korea is generally constructed with concrete pipes. Moreover, the sewer system is susceptible to the corrosion problem due to the regulation employing anaerobic treatment processes, such as domestic sewage treatment facilities, nightsoil septic tanks and so on. The objective of this study is investigated to experimental test of $H_2S$ production rate affecting corrosion of sewer pipe in Korea. In this study, tube-type and sealed-type reactor were used to examine the reactions in the microorganism suspended growth and biofilm. Furthermore. concentration changes were investigated with COD and sulfate reduction in each reactor. Sulfide production rate was $50.4mg-H_2S/g-VSS{\cdot}d$ in the sealed-type reactor and in the tube-type biofilm reactor was $2.8{\sim}18.8g-H_2S/m^2{\cdot}d$.