• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.234-241
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• 1997

The effects of bulk densities(${\rho}_b$) on saturated hydraulic conductivity (Ksat) and solute elution patterns were investigated from five different bulk densities ranging from $1.1Mg/m^3$ to $1.5Mg/m^3$ with each increment of $0.1Mg/m^3$. The hydraulic conductivities observed were divided into two stages: (1) a linearly decrease with increase in bulk density up to $1.4Mg/m^3$, (2) a steady state where the bulk density is greater than $1.4Mg/m^3$. Using the saturated hydraulic conductivity at the steady state, we figured out the equation describing the correlation between bulk densities(${\rho}_b$) and saturated hydraulic conductivity(Ksat) as follows: $Ksat=-19.2({\rho}_b{^2})+6{\rho}_b+15.5$, (r=0.985). Electrical conductivity(EC) measured from the leachate of the soil column showed that EC at the same pore volume were decreased with an increase in the bulk density from $1.2g/cm^3$, $1.5g/cm^3$, as shown in the time taken to collect the same pore volume at each respective bulk density. The maximum relative concentrations (C/Co=1) from the breakthrough curves for the anions of $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$, which are weakly adsorbed on the soil particles, moved to the right of the graph, while a distinctive retardation occurs at the bulk density between $1.3Mg/m^3$ and $1.4Mg/m^3$. The time taken to recover about 90% of indigenous sulphate was approximately twice as those of chloride and nitrate, resulting in slightly stronger adsorption characteristics for sorption sites on the soil surface. Thus, we can conclude that the salt accumulation in green house soil might be significantly influenced by it's bulk density at the soil depth, as well as the adsorption capacity of ions for the sorption sites in soils.

• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.47-57
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• 1989

T. verrucosum infection has been reported for the first time in 1986 in Korea and has been increasing progressively. To evaluate the progress of clinical and histopathological change of dermatophytosis caused by T. verrucosum, inoculation study, using T. verrucosum isolated from infected human(human strain) and from infected cattle(cattle strain), was done in 24 male albino Hartley guinea pig. Their clinical and histopathological changes were evaluated. In addition, comparison for the growth rate between human strain and cattle strain on Sabouraud's glucose agar was made. The results were as follows: 1. Growth rate on Sabouraud's glucose agar : Cattle strain showed significantly more rapid growth rate than human strain on Sabouraud's glucose rate at $25^{\circ}C$ and $37^{\circ}C$. And cattle strain showed more rapid growth rate at $37^{\circ}C$ than $25^{\circ}C$. But human strain showed no significant difference of growth rate at both temperature. 2. Clinical findings: Initial erythema, scale and crust were developed about 8th after inoculation. All three findings reached maximum severity about 12th to 16th day and disappeared about 30th to 34th day after inoculation. There was no significant difference in progress of erythema, scale and crust between cattle strain and human strain. 3. Histopathological findings: Although mild acanthosis was noticed on the 3rd day after inoculation, the other findings including parakeratosis, intraepidermal abscess, spongiosis and vascular change, cellular infiltration were found on 9th day after inoculation. They reached maximum severity on the 12th day and lasted to the 25th day after inoculation. After that, all three findings were decreased gradually between 29th day and 33th day. On the PAS stainings, hyphae and spores were found on the 6th day and disappeared on the 21th day after inoculation. 4. In trichophytin skin test, all of the 24 guinea pigs became positive within average $9.83{\pm}1.17$ lays. These findings suggested that dermatophytosis caused by T. verrucosum induced rapid cell mediated immunity and contributed to rapid resolution of the lesion.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.352-362
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• 2023

Harvest time is one of the most important determining factors of seed quality, especially for species that produce seeds over irregular and long-term periods, such as Larix kaempferi. A cone collection plan must be established to increase seed production efficiency and stable mass production. We investigated seed qualities such as seed efficiency, germination rate, and T₅₀ (germination speed), with 7 or 8 cone collection times at a clonal seed orchard of L. kaempferi in Chungju between 2021 and 2022. A multivariate analysis was then performed for the collected data. In early August, decreases in the moisture contents and browning of cones were observed. These were followed by a decrease in germination rate, with a peak at the end of September, but no clear trend was observed. The later the cones were harvested, the better the seed vigor (T₅₀). However, the seed yield and efficiency decreased owing to increases in seed scattering and the number of insect-damaged seeds. As a result, the optimal time of seed harvest for the seed orchard was in early August. To produce uniform seedlings, insect damage must be reduced through timely control and harvest cones in early September. This shows that the degree of browning and moisture content of cones can be used as indicators of the timing of cone collection in L. kaempferi seed orchards.

• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1151-1163
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• 2020

Purpose This study aimed to evaluate changes of subprosthetic pannus on cardiac CT and determine its relationship to echocardiographic findings in patients with mechanical aortic valve replacement (AVR). Materials and Methods Between April 2011 and November 2017, 17 AVR patients (56.8 ± 8.9 years, 12% male) who showed pannus formation on CT and had undergone both follow-up CT and echocardiography were included. The mean interval from AVR to the date of pannus detection was 10.5 ± 7.1 years. In the initial and follow-up CT and echocardiography, the pannus extent and echocardiographic parameters were compared using paired t-tests. The relationship between the opening angle of the prosthetic valve and the pannus extent was evaluated using Pearson correlation analysis. Results The pannus extent was significantly increased on CT (p < 0.05). The peak velocity (3.9 ± 0.8 m/s vs. 4.2 ± 0.8 m/s, p = 0.03) and mean pressure gradient (36.4 ± 15.5 mm Hg vs. 42.1 ± 15.8 mm Hg, p = 0.03) were significantly increased. The mean opening angles of the mechanical aortic leaflets were slightly decreased, but there was no statistical significance (73.1 ± 8.3° vs. 69.4 ± 12.1°, p = 0.12). The opening angle of the prosthetic leaflets was inversely correlated with the pannus extent (r = -0.57, p < 0.001). Conclusion The pannus extent increases over time, increasing transvalvular peak velocity and the pressure gradient. CT can be used to evaluate the pannus extent associated with hemodynamic changes that need to be managed by surgical intervention.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.321-337
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• 1994

The garbage from the dwelling houses was composted in two kinds of small composter in laboratory to investigate the possibility of garbage composting. They were general small composters. One (type 1) was insullated but the other (type 2) was not. Because it was found that type 2 was not available for composting under our meteorological conditions through winter experiment, only type 1 was tested in spring and summer. The experiment was performed for 8 weeks in each season. The seasonal variation of several compounds in compost was evaluated and discussed. The result summarized belows are those taken at the end of the experiment, if the time was not specified. 1) The maximum temperature was $58^{\circ}C$ in spring, $57^{\circ}C$ in summer and $41^{\circ}C$ in winter. This temperature was enough to destroy the pathogen except for winter. 2) The mass was reduced to average 62.5% and the volume reduction was avergae 74%. 3) The density was estimated as 0.7kg/l in spring, 0.8kg/l in summer and 1.1kg/l in winter. 4) The water content was not much changed for composting periods. It had 75.6% in spring and 76.6% in summer and winter. 5) There was a great seasonal difference in pH value. It was reached to pH 6.13 in spring, pH 8.62 in summer and pH 4.75 in winter. 6) The faster organic matter was decomposed, the greater ash content was increased. Cellulose and lignin content were increased, but hemicellulose content was reduced during composting period. 7) Nitrogen contents were in the range of 3.1-5.6% and especially high in summer. After ammonium nitrogen contents were increased at the early stage of composting period, they were decreased. The maximum ammonium nitrogen content was 3,243mg/kg after 2 weeks in winter, 6,053mg/kg after 3 weeks in spring and 30,828mg/kg after 6 weeks in summer. C/N-ratios were not much changed. Nitrification occurred actively in spring and summer. 8) The contents of volatile and higher fatty acids were increased in early stage of composting and reduced after that. The maximum content of total fatty acid was 10.1% after 2 weeks in winter, 5.8% after 2 weeks in spring and 15.7% after 4 weeks in summer. 9) The contents of inorganic compounds were not accumulated as composting was proceeded. They were in the range of 0.9-4.4% $P_2O_5$, 1.6-2.9% $K_2O$, 2.4-4.6% CaO and 0.30-0.80% MgO. 10) CN and heavy metal contents did not show any tendency. They were in the range of 0.11-28.99mg/kg CN, 24-166mg/kg Zn, 5-129mg/kg Cu, 0.8-14.3mg/kg Cd, 7-42mg/kg Pb, ND-30mg/kg Cr and $ND-132.16\;{\mu}g/kg$ Hg.

• Korean Journal of Environmental Agriculture
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• v.14 no.2
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• pp.232-245
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• 1995

The garbage from the dwelling house was composted in two kinds of small composter in the laboratory, and the possibility of garbage composting was examined. The composters were general small. One (type 3) was constructed with the double layer walls and the other (type 4) was the same as the first except for being insulated. Because it was found that type 3 was not available for composting under our meteorological conditions through the winter experiment, only type 4 was tested in spring and summer. The experiment was performed for 8 weeks in each season. The seasonal variation of several components in the compost was evaluated and discussed. The results summarized below were those obtained at the end of the experiment, if the time was not specified. 1) The maximum temperature was $43^{\circ}C$ in winter, $55^{\circ}C$ in spring and $56^{\circ}C$ in summer. 2) The mass was reduced to an average of 63% and the volume reduction was an average of 78%. 3) The density was estimated as 1.5 kg/l in winter and 0.8 kg/l in spring and summer. 4) The water content was not much changed during the composting periods. It was 79.3% in winter, 75.0% in spring and 70.0% in summer. 5) After pH value increased during the first week, it decreased until the second week and increased again continuously thereafter. It reached pH 6.19 in winter, pH 7.59 in spring and pH 8.69 in summer. 6) The faster the organic matter was decomposed, the greater the ash content increased. The contents of cellulose and lignin increased, but that of hemicellulose decreased during the composting period. 7) Nitrogen contents were in the range of 3.3-6.8% and especially high in summer. After ammonium contents increased at the early stage of the composting period, they decreased. The maximum ammonium-nitrogen content was 2,404mg/kg after 8 weeks in winter, 12,400mg/kg after 3 weeks in spring and 20,718mg/kg after 3 weeks in summer. C/N-ratios decreased with the lapse of composting time, but they were not much changed. Nitrification occurred actively in summer. 8) The contents of volatile and higher fatty acids increased at the early stage of composting and reduced after that. The maximum content of total fatty acid was 9.7% after 6 weeks in winter, 14.8% after 6 weeks in spring and 15.8% after 2 weeks in summer. 9) The contents of inorganic components were not accumulated as composting proceeded. They were in the range of 0.9-4.4% $P_2O_5$, 1.6-2.4% $K_2O$, 2.2-5.4% CaO and 0.30-0.61% MgO. 10) CN and heavy metal contents did not show any tendency. They were in the range of 0.21-14.55mg/kg CN, 11-166mg/kg Zn, 5-65mg/kg Cu, 0.5-10.8mg/kg Cd, 6- 35mg/kg Pb, ND-33 mg/kg Cr and ND-302.04 g/kg Hg.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.65-74
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• 1972

A local rice variety, Jinheung and newly bred IR667-Suwon 214 were grown in $5m^2$ concret pot with two spacings and two nitrogen levels and their ripening structure and its function were comparatively investigated to elucidate the causes of unusually low ripened grain ratio of IR667 lines. The following differences between two varieties were found. 1. Though IR667 had much lower ripened grain ratio (64%) than Jinheung (85%) grain yield(790 kg/10a) of IR667 was higher than that (760 kg/10a) of Jinheung. 2. Number of ripined grain per net assimiration rate (NAR) at 10 days after heading was a little higher in IR667 (6,490) than in Jinheung (6,360) consiting to lower grain weight ($29.9{\times}10^{-3}g$) in IR667 than $31.2{\times}10^{-3}g$ of Jinheung. But number of total grain per NAR was much higher (10,530) in IR667 than 7,290 of Jinheung indicating that it was the probable cause of low ripened grain ratio of IR667. 3. Extinction coeificient (K) was 0.115 in IR667 and 0.200 in Jinheung, thus IR667 could construct greater ripening structure per unit area. 4. Number of grain per LAI was decreased with increasing LAI at heading and the decreasing rate was similar for both IR667 and Jinheung. 5. Critical leaf area index at which crop growth rata (CGR) is maximum was 6.5 for IR667 and 5.2 for Jinheung. Below 5.2 of LAI net assimilation rate was always higher an Jinheung throughout the growing season. 6. The estimated optimum leaf area index having maximum grain yield was 7.4 for IR667 and 6.2 for Jinheung at 10 days after heading. However, actual leaf area index was 6.2 for IR-667 and 4.7 for Jinheung and these were even below critical leaf area index. 7. The decrease of LAI during ripening period was great in IR667 but photosynthesis per $m^2$ was decreased more rapidly in Jinheung. 8. Net assimilation rate (NAR) decreased with the increase of LAI at any time of ripening period. The decreasing rate of NAR with the increase of LAI was greater in IR667 with ripening. The greater decreasing rate of NAR in IR667 seemed to be attributed to low photosynthetic activity and high respiratory loss due to the requirement of higher optimum temperature of ripening. 9. Grain yield-ripened grain ratio curve showed less contribution of dry matter yield after heading to grain yield in IR667 than in Jinheung due to unfavorable ripening environment(specialy air temperature) indicating that yield of IR667 could most effectively increased through the improvement of ripening environment.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.5-6
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• 1972

Noise and air pollution, which accompany the development of industry and the increase of population, contribute to the deterioration of urban environment. The air pollution level of Seoul has gradually increased and the city residents are suffering from a high pollution of noise. If no measures were taken against pollution, the amount of emission of pollutant into air would be 36.7 thousand tons per year per square kilometer in 1975, three times more than that of 1970, and it would be the same level as that of United States in 1968. The main sources of air pollution in Seoul are the exhaust has from vehicles and the combustion of bunker-C oil for heating purpose. Thus, it is urgent that an exhaust gas cleaner should be instaled to every car and the fuel substituted by less sulfur-contained-oil to prevent the pollution. Transportation noise (vehicular noise and train noise) is the main component of urban noise problem. The average noise level in downtown area is about 75㏈ with maximum of 85㏈ and the vehicular homing was checked 100㏈ up and down. Therefore, the reduction of the number of bus-stop the strict regulation of homing in downtown area and a better maintenance of car should be an effective measures against noise pollution in urban areas. Within the distance of 200 metres from railroad, the train noise exceeds the limit specified by the pollution control law in Korea. Especially, the level of noise and steam-whistle of train as measured by the ISO evaluation can adversely affect the community activities of residents. To prevent environmental destruction, many developed countries have taken more positive action against worsening pollution and such an action is now urgently required in this country.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.413-419
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• 2011

Nanoscale zero-valent iron (NZVI) particles were tested as remediation media for groundwater contaminated by organic pollutants (e.g., TCE, trichloroethylene). The contaminated groundwater contained anions ($NO_3^-$, $Cl^-$, $SO_4^{2-}$, and $HCO_3^-$) and natural organic matter (NOM). Treatability of commercial NZVI particles (NANOFER 25, Nanoiron, Czech) was tested by using a synthetic groundwater and the field groundwater samples. More than 95% of 1.8 mM TCE was removed within 20 hours with a NZVI dosage of 25 g/L ($k=0.15hr^{-1}$). Repetitive degradation experiments revealed that the removal capacity of NANOFER 25 was 0.19 mmole TCE/g NZVI. TCE degradation reactions were not substantially affected by the presence of each anion with concentrations as high as 100 times the average field concentrations. However, when the four anions ($NO_3^-$, $Cl^-$, $SO_4^{2-}$, $HCO_3^-$) were present simultaneously. the degradation reactivity and removal capacity were decreased by 60% ($k=0.069hr^{-1}$) and 10%, respectively. The k value of TCE degradation in the presence of NZVI (25 g/L) with dissovled organic carbon of 2.5 mg/L was also decreased by 84% ($k=0.025hr^{-1}$). In the experiments with the field groundwater, more than 90% of $1.8{\mu}M$ TCE, which is the concentration of TCE at the source zone, was removed within 10 hours with a NANOFER 25 dosage of 25 g/L. The results imply that the contaminated groundwater can effectively be treated by NANOFER 25 with more information on the hydrogeology of the site.

• Tuberculosis and Respiratory Diseases
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• v.59 no.2
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• pp.170-178
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• 2005

Background : Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are rare but significantly imperative in inducing chronic pulmonary hypertension. Clinically, it is difficult to distinguish between IPAH and CTEPH. However, the treatment of pulmonary hypertension is different depending on the disease. The present study was performed to analyze the similarities and differences in clinical features between IPAH and CTEPH. Methods : During a nine-year period, thirty-three patients with IPAH and twenty-two patients with CTEPH were enrolled. Symptoms, physical findings, chest radiograph, electrocardiograph, pulmonary function test, echocardiograph, perfusion lung scan, right heart catheterization results were analyzed between both the groups. Results : The median age of IPAH group was 33 (6~70) years that was lower than that (52(27~80) years) of CTEPH group. Amongst the IPAH patients, there was female predominance (76 %) and there was no sex difference between the patients with CTEPH. Both the groups exhibited similarity in the results of chest radiograph, electrocardiograph, pulmonary function test, and echocardiograph. In the perfusion lung scan, all IPAH patients exhibited findings with normal (28%) or low probability (72%) of pulmonary embolism and all CTEPH patients exhibited findings with high probability of pulmonary embolism. Conclusion : Although IPAH and CTEPH bear similarities in terms of symptoms, physical signs and general investigation results, there were differences in age distribution, sex predominance and results of perfusion lung scan.