• Journal of Korean Society for Quality Management
• /
• v.47 no.1
• /
• pp.47-57
• /
• 2019

Purpose: This paper aims to investigate the concentration of fine particulate matter (PM2.5) in the Seoul area by predicting unhealthy days due to PM2.5 and comparing the regional differences. Methods: The extreme value theory is adopted to model and compare the PM2.5 concentration in each region, and each best model is selected through the goodness of fitness test. The maximum likelihood estimation technique is applied to estimate the parameters of each distribution, and the fitness of each model is measured by the mean absolute deviation. The selected model is used to estimate the number of unhealthy days (above $75{\mu}g/m^3$ PM2.5 concentrations) in each region, with which the actual number of unhealthy days are compared. In addition, the level of PM2.5 concentration in each region is analyzed by calculating the return levels for periods of 6 months, 1 year, 3 years, and 5 years. Results: The Mapo (MP) area revealed the most unhealthy days, followed by Gwanak (GW) and Yangcheon (YC). On the contrary, the number of unhealthy days was low in Seodaemun (SDM), Songpa (SP) and Gangbuk (GB) areas. The return level of PM2.5 was high in Gangnam (GN), Dongjak (DJ) and YC. It will be necessary to prepare for PM2.5 than other regions. On the contrary, Gangbuk (GB), Nowon (NW) and Seodaemun (SDM) showed relatively low return levels for PM2.5. However, in most of the regions of Seoul, PM25 is generated at a very poor level ($75{\mu}g/m^3$) every 6months period, and more than $100{\mu}g/m^3$ PM2.5 occur every 3 years period. Most areas in Seoul require more systematic management of PM2.5. Conclusion: In this paper, accurate prediction and analysis of high concentration of PM2.5 were attempted. The results of this research could provide the basis for the Seoul Metropolitan Government to establish policies for reducing PM2.5 and measuring its effects.

• Particle and aerosol research
• /
• v.6 no.4
• /
• pp.185-192
• /
• 2010

This paper reports that the installation of a carbon fiber ionizer in front of an activated carbon fiber(ACF) filter enhanced the antibacterial efficiency. In addition, the effect of the ionizer on the filtration of bioaerosols is reported. Negative air ions from the ionizer were used as antibacterial agent. The test bacteria(Escherichia coli) were aerosolized using an atomizer and were deposited on the ACF filter media for 10 minutes. E. coli deposited on the filter were exposed to negative air ions for 0, 1, 5 and 10 minutes. Then they were separated from the ACF filter by shaking incubation with nutrient broth for 4 hours. The separated E. coli were spread on nutrient agar plates and incubated at $37^{\circ}C$ for 1~3 days. The antibacterial efficiency of E. coli was measured using a colony counting method. The antibacterial efficiencies of E. coli exposed to negative air ions for 1, 5 and 10 minutes were 14%, 48% and 71%, respectively. The filtration efficiency was evaluated by measuring the number concentration of bioaerosols at the upstream and downstream of the filter media. The increase of filtration efficiency by air ions was 14%, that is similar to the 17% filtration efficiency by none air ions. The ozone concentration was below the detection limit (under 0.01ppm) when the carbon fiber ionizers were on.

• Journal of Pharmacopuncture
• /
• v.8 no.1
• /
• pp.21-30
• /
• 2005

Objectives : To observe physiological anti-body effects of anti-BV, acute toxic response, measurement of $LD_{50}$, and the effects of anti-body were evaluated. Methods : $LD_{50}$ of Anti-Bee Venom were measured, and to analyze acute toxic responses, weight, and the anti-body effects various concentrations of Anti-BV were diluted and the survival rate was measured. Cell blood count (CBC), liver, spleen, and kidney pathologies were observed from the histological aspects. Results : Experiment was conducted to observe Anti-BV as the anti-body to the bee venom and the following results were obtained : 1.anti-BV was injected intraperitoneally and no toxic responses were witnessed. All of the experiment subjects stayed alive during the experiment, making $LD_{50}$ analysis impossible. 2.Anti-BV was injected intraperitoneally in mice and no significant weight changes were measured between the control group and the experiment groups. 3. Measuring the concentration dependent survival rate, the highest survival rate was at the concentration of $1.25{\times}10^2mg/kg$(1/2.000) for Anti-BV. 4. No particular results were shown in the CBC test. 5. Observation of changes in the organ tissues, Anti-BV was found to suppress blood stasis in the liver and inhibit necrosis of the cells. Conclusion : Above results suggest that Anti-BV doesn't cause any toxic responses in the body and works as an anti-body to the bee venom. Further studies must be followed to secure the findings.

• Korean Journal of Veterinary Research
• /
• v.37 no.4
• /
• pp.925-934
• /
• 1997

This study was directed at inducing the production of antibodies by immunizing heifers with bovine sperm antigen and on measuring the serum antibodies using indirect immunofluorescence assay(IFA) and agglutination test. The effect of antisperm antibodies on fertilizing capacity of bovine spermatozoa was evaluated. 1. Three heifers between 12- and 15- month old were immunized with bovine spermatozoa or phosphate-buffered saline. In heifers immunized with bovine spermatozoa serum IgG level was highest between 3 weeks and 5 weeks postimmunization detected by IFA. The antibody levels persisted through week 7 and slowly declined until week 20 and then antisperm antibodies were localized on spermatozoa. The fluorescent antisperm antibodies were detected at 2~20 weeks and at 6~9 weeks postinoculation on acrosome and tail, respectively. Among 21 sera from repeat breeder cows, only one cow has shown positive antisperm antibody response detected by IFA. 2. In spite of vital rate of bovine sperm after swim-up was not significantly affected by different concentration of antisperm antibodies in sera, the numbers of bovine sperm after swim-up were significantly reduced in proportion to the increased concentration of antibodies. Above 1/512 dilution of antibody neither influence on vital rate and numbers of bovine sperm nor sperm agglutination after swim-up. The study has also shown that the vital rate and number of sperm after swim-up and capacitation were also significantly reduced by the addition of antisperm antibodies. Although antisperm antibodies did not influence on the acrosome reaction rate of sperm during swim-up, did significantly reduce the sperm acrosome reaction rate after capacitation. The studies have resulted that the bovine antisperm antibodies can prevent the sperm motility by agglutination and block the capacitation and acrosome reaction of bovine sperm.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.4
• /
• pp.312-317
• /
• 2005

The objectives of this paper are to study the absorption characteristics of $NH_3$ bubbles in the binary nanofluids and to quantify the effects of surfactants and nano-particles on the bubble absorption performance. 2-Ethyl-1-Hexanol, n-Octanol, and 2-Octanol are used as the surfactants and nano-sized $Al_{2}O_3$ and Cu particles are added to make the binary nanofluids into $NH_3/H_{2}O$ solution. The concentration of $NH_3$ solution ($x_s$), the concentration of surfactants ($x_{SA}$), and the mass fraction of nano-particles ($w_{np}$) are considered as key parameters. The experimented ranges of $x_s,\;x_{SA},\;and\;w_{np}$ are $0{\sim}17.92\%,\;0{\sim}1,500\;ppm\;and\;0{\sim}0.2\%$, respectively. The absorption rates are calculated by measuring initial and final weights of test section and exposed time. In addition, the bubble absorption processes are visualized using the shadow graphic method. The results show that the absorption performance is significantly enhanced up to 4 times by adding the surfactants and up to 3 times in the binary nanofluids.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.5
• /
• pp.814-821
• /
• 2000

In order to investigate the possible use of omija extract as natural preservatives for nabak kimchi omija extract was tested for antioxidation and electron-donating ability and further more antimicrobial activites against lactic acid bacteria of nabak kimchi. The concentration of the test sample used were 0.5, 1.0, 1.5, 2.0%. Antioxidative activity measured the TBA value, when omija extract concentration % is higher the antioxidation effect were more evident with the increased omija extract concentrations, and showed a high electron donating activity more than 1.0%. As the result of isolated lactic acid bacteria from nabak kimchi the primary separation tool 117 strains, of these 4 strains which had excellent growth and a strong acid formation capability was selected the second time and Lactobacillus brevis, Lactococcus faecalis, Leuconostoc mesenteriodes, Lactobacillus palantarum were identified. After measuring the antimicrobial activity of the four lactid acid bacteris, except Lactobacillus brevis the other three bacteria showed strong antimicrobial activities. The results suggest the possible use of the omija extract as natural preservative for nabak kimchi.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.323-325
• /
• 2022

In this paper, after administration of Chlorin e6 to kill cervical cancer cells, PDT (photodynamic therapy) using laser or LED was studied for Ce6 concentration and apoptosis by administration time. After photostimulation was applied to cervical cancer cells, qualitative and quantitative evaluation through imaging and quantitative evaluation using CCK-8 were performed. As a result of the experiment, as the concentration of Ce6 increased, a large amount of cells were killed, and it was confirmed that the Ce6+PDT test group killed more. When comparing the LED and the laser, the laser was able to kill cells only at a local location, and the LED showed the result that it was possible to kill the cells in a wide range. In addition, when irradiating a local location, such as a laser, when measuring the cell viability, it is judged to be accurate to image processing the location.

• Journal of Korean Neurosurgical Society
• /
• v.63 no.1
• /
• pp.45-55
• /
• 2020

Objective : Fibrin sealants have been used for hemostasis, sealant for cerebrospinal fluid leakage, and adhesive barrier in neurosurgery. Further, as its clinical use and role of an effective drug delivery vehicle have been proposed. This study was performed to measure antibacterial activity and continuous local antibiotic release from different concentrations of vancomycin-impregnated fibrin sealant in vitro. Methods : Antibacterial activity was investigated by disk diffusion test by measuring the diameter of the growth inhibition zone of bacteria (methicillin-resistant Staphylococcus aureus, ATCC29213) from vancomycin-embedded fibrin sealant disc diluted at five different concentrations (C1-C5; 8.33, 4.167, 0.83, 0.083, and 0.0083 mg/disc, respectively). Continuous and conditioned release of vancomycin concentration (for 2 weeks and for 5 days, respectively) were also measured using high-performance liquid chromatography (HPLC) method. To mimic the physiologic wound conditions with in vitro, conditioned vancomycin release in phosphate buffer solution (PBS) was measured and replaced PBS for five consecutive days, half a day or completely daily. Results : In the disk diffusion test, the mean diameters of bacterial inhibition zone were 2.54±0.07 cm, 2.61±0.12 cm, and 2.13±0.15 cm (C1, C2, and C3 respectively) but 1.67±0.06 cm and 1.23±0.15 cm in C4 and C5, respectively. Continuous elution test elicited the peak release of vancomycin from the fibrin sealant at 48 hours, with continued release until 2 weeks. However, conditioned vancomycin release decreased to half or more on day 2, however, the sustainable release was measured over the therapeutic dose (10-20 ㎍/mL) for 5 days and 4 days in assays of half and total exchange of PBS. Conclusion : This study suggests that fibrin sealant can provide an efficient vehicle for antibiotic drug release in a wide range of neurosurgical procedures and the safe and effective therapeutic dose will be at the concentration embedded of 4.167 mg/disc or more of vancomycin.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.12 no.3
• /
• pp.239-245
• /
• 2024

PS(Prestressed) tendons are under high tensile stress and have a smaller concrete cover than RC(Reinforced Concrete) member, so that the more conservative specifications on corrosion have been proposed for PS member. In this study, three levels of chloride concentrations(0.0 mol/l, 0.125 mol/l, and 0.25 mol/l) were prepared for evaluating the corrosion behavior in different position of 7 strand wires. For accelerating corrosion and measuring the corrosion amount in tendon, the tendon was embedded in partially saturated soil, and HCP(Half Cell Potential) was measured from the soil surface. During the test period of 28 weeks, HCP was measured every two weeks and the corrosion weight in the tendon was measured at 16 and 28 weeks of test period. Through the test, HCP result in tendon increased as the wires were located toward bottom due to high saturation. HCP in the lowest wire position showed an increase by 5.92 % compared to that in top position in 0.25 mol/l condition. The lower the position of the wire contained more saturation, which yielded increasing corrosion amount and HCP in tendon. In addition, the relation between corrosion weight and chloride concentration was quantitatively obtained through regression analysis.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.4
• /
• pp.117-124
• /
• 2016

Stress is resistance to stimuli to destroy a balance of mind and body in order to maintain an original steady state : A type of response and avoidance. Mild stress, which happens in tension, has a positive effect to improve concentration, but most of stress is likely to be a main factor to damage health. This is because it causes physical ailments and psychological diseases (e.g., depression, anger, frustration, loneliness, and anxiety). The purpose of this study is to analyze the difference between two groups, daytime and night university students, on ego-state, stressors, and stress coping types to improve their academic achievement by reducing their stress. There were 266 university students, who participated in a survey from November 30, 2015 until September 30, 2016. The study employed three measuring instruments : Ego-gram, stressor scale, and stress coping type scale. All the collected data were analyzed through regression analysis and t-test. The results of the regression analysis showed no significant differences in ego-state, stressors, and stress coping types between two groups. However, the results of t-test showed significant difference between the two groups : In terms of ego-state, a CP (Critical Parent) average of the night university students was significantly higher than the daytime university students'. Also, there is a significant difference in employment, future issues, and economic issues : the daytime university students considered employment and future issues more serious, while the night university students had more mental burdens of economic issues. When it comes to coping stress types, there was no significant difference between the two groups.