• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.435-448
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• 2022

Objectives: As the time spent wearing masks has increased with spread of COVID-19, various research related to masks have been reported. However, there are still few experiments on the physiological response of the body to wearing industrial dust masks in South Korea. Considering the actual working hours at the work site, it is necessary to investigate the comfort of industrial dust masks. Therefore, this study aims to confirm the change in subjective discomfort level according to the wearing time for industrial dust masks in South Korea that have been certified for safety by KCS. Methods: This study evaluated subjective discomfort level over four hours. The experimental conditions were five types: not worn (control group), special grade, first grade, second grade (with valve), and second grade (without valve). The subjective discomfort levels were classified for breathing, warmth (body and face) and wetness (body and face). Subjects recorded their discomfort level on a checklist every one hour. Results: In special grade and second grade (without valve), the discomfort level in terms of breathing, warmth (face), and wetness (face) was significantly higher than that of the control group. However, the effects of all kinds of industrial dust masks on the discomfort level in the body were low. Conclusions: Since this study was conducted on subjects working in an office with a comfortable working environment, it is difficult to apply it to workers at actual industrial sites. However, it is considered meaningful as the first clinical study to evaluate the subjective level of discomfort over a long time for domestic industrial dust masks that have been certified for safety by KCS.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.933-942
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• 2006

This experiment was carried out to investigate effects of honeybee venom treatment on the humoral immune response in pigs. Corresponding author : S. K. Cho, Dept. of Animal Sci. Chung-Buk National University, Kaesin-dong, Cheongju, 361-763, Korea. phone : 043-261-2551. E-mail : deercho@chungbuk.ac.kr To investigate effects of natural honeybee venom on the concentration of immunoglobulin G, A, and M, 20 piglets(LY×D) from 3 sows were allocated into two groups bee venom-treated group(10 piglets) and non-treated control(10 piglets). Natural honeybee venom was treated at 0, 3, 6 days after birth and the acupoints were Hai-men(ST-25), Du-kou(CV-8) and Jiao-chao(GV-1) points at 0, 3 days after birth and the regions of castration and tail amputation point at 6 days. Control group was injected 1㎖ of saline to the same site. Concentrations of IgG, A, and M were measured with immunoturbidimetric method at 0, 3, 7, 14, and 21 days after treatment. To investigate the effect of bee venom on the production of antibodies against hog cholera and atrophic rhinitis vaccines that were used as indicator antigens, 40 piglets(LYxD) from 5 sows were grouped as bee venom-treated group (20 piglets) and control group(20 piglets). Natural honeybee venom was treated at 0, 3days(castration, tail amputation) and 21days after birth. The acupoints were Hai-men(ST-25), Du-kou(CV-8) and Jiao-chao (GV-1) points at 0 day, the regions of castration and tail ampution at 3 days and Jiao-chao(GV-1) and Bai-hui(GV-20) points at 21days after birth(weaning). Control group was injected 1ml of saline to the same site. Atrophic rhinitis vaccine was injected twice at 24 and 44 days after birth and hog cholera vaccine was also injected twice at 44 and 64 days after birth. Antibody titers against Bordetella bronchiseptica and hog cholera virus were measured by using tube agglutination and ELISA tests at 24, 34, 44, 54 and 74 days after birth. Concentrations of IgG of treated group were 339.52, 366.48, 296.52, 242.06 and 219.06mg/dl at 0, 3, 7, 14 and 21 days after birth, respectively. In contrast, concentrations of IgG in control group were respectively 347.10, 334.14, 243.28, 205.18 and 191.58mg/dl during same periods with treated group. Concentrations of IgG at 0 day was not significantly different between the treated group and control group but treated group were significantly increased by 10.28% at 3 days after birth (P<0.02), 21.88% at 7 days after birth(P<0.01), 18.0% at 14 days after birth(P<0.07) and 14.3% at 21 days after birth(P<0.01). Concentrations of IgA and Ig M were not significantly different. Antibody titers against hog cholera virus were significantly increased by 57.0% at 24 days after birth(P<0.03), 74.6% at 34 days after birth (P<0.006), 48.6% at 44 days after birth(P<0.017), 45.0% at 54 days after birth(P<0.16) and 44.4% at 74 days after birth (P<0.006) in bee venom treated group in comparison with control group. Antibody titers against the Bordetella bronchiseptica was significantly increased in Beevenom treated group as 9.1% (P<0.32) at 24days, 39.7% (P<0.002) at 34days, 31.9% (P<0.02) at 44days, 33.4% (P<0.01) at 54days and 57.3% (P<0.007) at 74 days after birth when compared with those of control group pigs. Collecting together, the results in this study showed that immune responses were increased by treatment of natural honeybee venom to pigs. These results suggested that the treatment of bee venom could be used effectively for the increase of productivity in livestock industry.

• The Korean Journal of Pharmacology
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• v.20 no.1 s.34
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• pp.55-65
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• 1984

Comparative effects of $PGF_{2{\alpha}}$ and ouabain on the isolated rat(Sprague-Dowley) atria were studied. The isolated rat atria were prepared for isometric myography in the isolated organ bath containing Feigen's solution perfused with 95% $O_2$ and 5% $CO_2$, and the pH of the medium was maintained at 7.4. The cumulative concentration-response relationship revealed the positive inotropic effects of both drugs with the higher potency of $PGF_{2{\alpha}}$ and the higher efficacy of ouabain. $PGF_{2{\alpha}}$ showed a positive chronotropic effect, but ouabain showed a tendency of increasing the contraction rate. In low-Ca(1.4 mM) medium, the positive inotropic and chronotropic effect of $PGF_{2{\alpha}}$(by $3{\times}10^{-8}M$) were preponderant $(p<0.05{\sim}p<0.005)$ over those of ouabain(by $3{\times}10^{-3}M$). $Ca^{++}$-addition(cumulative, to 2.8, 4.2, 5.6, and 7.0 mM) into the medium evoked the more sensitive response in the $PGF_{2{\alpha}}$ group than in the ouabain group. In low-K(2.8 mM) medium, the $PGF_{2{\alpha}}a(3{\times}10^{-8}M)$ group and the ouabain$(3{\times}10^{-3}M)$ group showed similar tensions(DT and RT) and contraction rates. And both group showed significantly(p<0.05p<0.01) higher tensions and contraction rates than those of the control group. By the cumulative addition of the $K^+$(to 4.2, 5.6, 7.0 and 8.4 mM), only the DT of the $PGF_{2{\alpha}}$ group was sustained at signifcantly$(p<0.05{\sim}p<0.01)$ higher level than the DT of the control group. The $K^+$-addition inhibited the positive inotropic effect of ouabain significantly (p<0.05). The cumulative addition of lidocaine in high concentrations $(1{\times}10^{-5}\;to\;1{\times}10^{-3}M)$ evoked no significant influence on the intropic activities of $PGF_{2{\alpha}}$ and ouabain, but significant ${\beta}$-blockade with propranolol could not inhibit the positive intropic and chronotropic effect of $PGF_{2{\alpha}}$. In conclusion, it is presumed that $PGF_{2{\alpha}}$ may have some more active mechanism of accelerating the influx of $Ca^{++}$ across the cell membrane of the isolated rat atria as compared with ouabain, and the action site may be located at the cell membrane. As a supposition which needs further investigations, it is presumed that $PGF_{2{\alpha}}$ may have its specific membrane receptors on the atrial muscle or sinus node cells.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.153-165
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• 2023

The purpose of this study is to propose effective scenarios for green areas in apartment complexes that can improve the connection between green spaces considering wind flow, thermal comfort, and mitigation of the urban heat island effect. The study site was an apartment complex in Godeok-dong, Gangdong-gu, Seoul, Korea. The site selection was based on comparing temperatures and discomfort index data collected from June to August 2020. Initially, the thermal and wind environment of the current site was analyzed. Based on the findings, three scenarios were proposed, taking into account both green patches and corridor elements: Scenario 1 (green patch), Scenario 2 (green corridor), and Scenario 3 (green patch & corridor). Subsequently, each scenario's wind speed, wind flow, and thermal comfort were analyzed using ENVI-met to compare their effectiveness in mitigating the urban heat island effect. The study results demonstrated that green patches contributed to increased wind speed and improved wind flow, leading to a reduction of 31..20% in the predicted mean vote (PMV) and 68.59% in the predicted percentage of dissatisfied (PET). On the other hand, green corridors facilitated the connection of wind paths and further increased wind speed compared to green patches. They proved to be more effective than green patches in mitigating the urban heat island, resulting in a reduction of 92.47% in PMV and 90.14% in PET. The combination of green patches and green corridors demonstrated the greatest increase in wind speed and strong connectivity within the apartment complex, resulting in a reduction of 95.75% in PMV and 95.35% in PET. However, patches in narrow areas were found to be more effective in improving thermal comfort than green corridors. Therefore, to effectively mitigate the urban heat island effect, enhancing green areas by incorporating green corridors in conjunction with green patches is recommended. This study can serve as fundamental data for planning green areas to mitigate future urban heat island effects in apartment complexes. Additionally, it can be considered a method to improve urban resilience in response to the challenges posed by the urban heat island effect.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.206-216
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• 2018

We analyzed the effects of spatio-temporal variation in the leaf production of oaks on the density and species richness of herbivores, as well as the consumption by herbivores in the east coastal region of Korea, which is an area that has been damaged by forest fires. The main herbivore that feeds on oak leaves was moth larvae. In mid-August the insect larvae showed the highest density and species richness. Approximately 60.5% of total plant-eating insect larvae were present from August to September 2011. Oak leaf production was at its peak from July to August, and the peak damage caused by herbivores was from August to September. Depending on the investigation timing and site of the survey, oak leaf production, larval densities, and species richness showed large variations. The average production of oak leaves between July and August was estimated to be $0.96ton\;ha^{-1}$. The production of oak leaves during this period also showed spatial variations ranging from 0.34 to $1.89ton\;ha^{-1}$. In August, the consumption of oak leaves by the herbivores showed spatial variations ranging from 0.15 to $1.51ton\;ha^{-1}$. Where oak leaves had a higher yield, they tended to increase in density and species richness of the herbivores. As the production of oak leaves increased, so did the overall consumption and consumption rate by the herbivores. This means that the production of oak leaves is highly related to time and space, and there is a concentration response in which the new individuals gather. Research into the spatio-temporal heterogeneity of the food sources and their effects on the higher levels of the food web can help us quantitatively understand and evaluate the structure and functions of the burnt ecosystem that is caused by forest fires.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.15-24
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• 2015

$CH_4$ is a trace gas and one of the key greenhouse gases, which requires continuous and systematic monitoring. The application of eddy covariance technique for $CH_4$ flux measurement requires a fast-response, laser-based spectroscopy. The eddy covariance measurements have been used to monitor $CO_2$ fluxes and their data processing procedures have been standardized and well documented. However, such processes for $CH_4$ fluxes are still lacking. In this note, we report the first measurement of $CH_4$ flux in a rice paddy by employing the eddy covariance technique with a recently commercialized wavelength modulation spectroscopy. $CH_4$ fluxes were measured for five consecutive days before and after the rice transplanting at the Gimje flux monitoring site in 2012. The commercially available $EddyPro^{TM}$ program was used to process these data, following the KoFlux protocol for data-processing. In this process, we quantified and documented the effects of three key corrections: (1) frequency response correction, (2) air density correction, and (3) spectroscopic correction. The effects of these corrections were different between daytime and nighttime, and their magnitudes were greater with larger $CH_4$ fluxes. Overall, the magnitude of $CH_4$ flux increased on average by 20-25% after the corrections. The National Center for AgroMeteorology (www.ncam.kr) will soon release an updated KoFlux program to public users, which includes the spectroscopic correction and the gap-filling of $CH_4$ flux.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.633-641
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• 2012

In this study, the effects of the inelastic shear behavior of beam-column joint on the response of RC OMRF are evaluated in the inelastic time history analysis. For an example, a 5-story structure for site class SB and seismic design category C was designed in accordance with KBC2009. Bending moment-curvature relationship for beam and column was evaluated using fiber model and bending moment-rotation relationship for beam-column joint was calculated using simple and unified joint shear behavior model and moment equilibrium relationship. The hysteretic behavior was simulated using three-parameter model suggested in IDARC program. The inelastic time history analysis with PGA for return period of 2400 years showed that the model with inelastic beam-column joint yielded smaller maximum base shear force but nearly equivalent maximum roof displacement and maximum story drift as those obtained from analysis using rigid joint. The maximum story drift satisfied the criteria of KBC2009. Therefore, the inelastic shear behavior of beam-column joint could be neglected in the structural design.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.67-80
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• 2014

The thickness of permafrost in Eastern Siberia is from 200 to 500 meters. The seasonally frozen layer can vary from 0 to 4m depending on ground temperature and its location. The shear wave velocity varies from 80m/s in summer to 1500m/s in winter depending on soil type. When melted, large impedence will occur due to the difference between the shear wave velocity of seasonally frozen soil and that of permafrost layer. Large displacement may occur at the boundary of the melted and the frozen layer, and this phenomenon should be considered in a seismic design. In this research, one-dimensional equivalent linear analyses were performed to investigate the effects of the seasonally frozen layer on ground amplification characteristics. Soil profiles of Yakutsk and Chara in Eastern Siberia were selected from geotechnical reports. 20 recorded ground motions were used to evaluate the effect of input motions. As the thickness of seasonally frozen layer and the difference in the shear wave velocity increases, the amplification is shown to increase. Peat, very soft organic soil widely distributed throughout Eastern Siberia, is shown to cause significant ground motion amplification. It is therefore recommended to account for its influence on propagated motion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.73-82
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• 1989

When the flood occurs in the alluvial rivers, the rivers adjust to the flood by means of the mechanism of the river bed variations and its morphological changes to pass that safely, the numerical model was developed to simulate the process of the alluvial river bed variation due to flood wave and carried out by the flood routing for flood wave and the sediment routing for river bed variation. The flood wave, river bed variation, and bed material size distribution may be analysed and predicted by this model. The ability of this model to predict the process of river bed response was proved by the application to the reach from Paldang dam to Indogyo site. In view of the flood analysis considering the sediment process, the effects of river bed variation for the flood routing may be negligible because the river bed variation is smaller than the unsteady flow variation during the same period. By the application of this model, it is shown that, in occurring of sequential flood events, the variation of the river bed and bed material size distribution due to flood wave is more dependent on the first flood event than the latter flood events, and that the river bed variation in this reach of the downstream Han river is dependent on the degradation and the coarsening of bed materials.

• Earthquakes and Structures
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• v.2 no.3
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• pp.207-232
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• 2011

The development of reliable earthquake mitigation plans and seismic risk management procedures can only be based on the establishment of comprehensive earthquake hazard and loss scenarios. Two cities, Grevena (Greece) and D$\ddot{u}$zce (Turkey), were used as case studies in order to apply a comprehensive methodology for the vulnerability and loss assessment of lifelines. The methodology has the following distinctive phases: detailed inventory, identification of the typology of each component and system, evaluation of the probabilistic seismic hazard, geotechnical zonation, ground response analysis and estimation of the spatial distribution of seismic motion for different seismic scenarios, vulnerability analysis of the exposed elements at risk. Estimating adequate earthquake scenarios for different mean return periods, and selecting appropriate vulnerability functions, expected damages of the water and waste water systems in D$\ddot{u}$zce and of the roadway network and waste water system of Grevena are estimated and discussed; comparisons with observed earthquake damages are also made in the case of D$\ddot{u}$zce, proving the reliability and the efficiency of the proposed methodology. The results of the present study constitute a sound basis for the development of efficient loss scenarios for lifelines and infrastructure facilities in seismic prone areas. The first part of this paper, concerning the estimation of the seismic ground motions, has been utilized in the companion paper by Kappos et al. (2010) in the same journal.