• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.6 s.165
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• pp.955-965
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• 2007

Safety helmets are used widely in various industries by workers since they are legally required to wear them. However, thermal discomfort is one of the major complaints from helmet users. To relieve this problem, frozen gelled packs can be considered for use inside the helmets. In this paper, tests were performed on humans to evaluate the physiological strains of wearing safety helmets and to investigate the effects of using frozen gelled packs inside the helmets. Experiments were conducted in a climatic chamber of WBGT $33{\pm}1^{\circ}C$ under four differed experimental conditions: 1) not wearing a safety helmet(NH); 2) wearing a safety helmet with frozen gelled pack A(HA); 3) wearing a safety helmet with frozen gelled pack B(HB); and 4) wearing only a safety helmet(OH). The results were as follows. First, when comparing NH with OH, physiological responses such as $\bar{T}_{sk},\;T_r$, HR and sweat rate were significantly higher in OH and subjective sensations were reported as less hot and more comfortable than NH(p<.05). Second, in regard to the frozen gelled packs inserted inside the safety helmets, some physiological responses in HA were different from those in HB, according to the two different types of packs. HA was hotter, more uncomfortable and less exhausted than HB. However, result from both HA and HB were lower than those from OH in terms of temperature and humidity inside safety helmet, sweat rate, $T_r$ increase, heat storage(p<.05). When wearing safety helmets with frozen gelled packs, it was shown that heat strain can be alleviated. These results are expected to help millions of workers who complain that wearing safety helmets is uncomfortable and messy.

• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.35-48
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• 2014

In order to estimate the effect of additional nutrients on phytoplankton growth and horizontal phytoplankton community distribution during the autumn season in 2010 and 2011, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas in Gwangyang Bay, Korea. Also, nutrient additional experiments were conducted to assess additional nutrient effects on phytoplankton assemblage using the surface water. In both years, the total nutrients were high at the enclosed inner bay and the mouth of Seomjin River, whereas it was low at the St.15~20 where in influenced by the surface warm water current from offshore of the bay. On the other hand, nano- and pico-sized Chl. a were gradually increased towards the outer bay and their trends were significant in 2011 than in 2010. The cryptophyta species occupied more than 85% of total phytoplankton assembleges in 2010, whereas their abundance in 2011 remainds to be 1/10 levels of 2010. Following the cryptophata species, the diatom Chaetoceros spp. and Skeletonema-like spp. were found to be dominant species. Further the biosaasy experimental results shows that the phytoplankton biomass in the +N and +NP treatments was higher compared to control and +P treatments and its trend was significant at St.8 and St.20 where nutrient concentration were low. Based on the bioassay and field survey, providing the high nutrients may have stimulated to phytoplankton growth such as S. costatum-like spp.. In particular, opportunistic micro-algae such as Cryptomonas spp. were able to achieve the high biomass under the relatively mid nutrient condition from bottom after break down of seasonal stratification in the Gwangyang Bay.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.799-810
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• 2004

This study was conducted to determine effects of spent composts of Se-enriched mushrooms (Se-SMC) as the dietary selenium source on carcass characteristics, plasma glutathione peroxidase(GSH-Px) activity and Se deposition in finishing Hanwoo steers. In combination with both Se-SMC and normal SMC, experimental treatment diets were formulated to contain 0.1, 0.3, 0.6 and 0.9 ppm of Se on a dry matter basis. A total of 20 finishing Hanwoo steers (average BW = 613 kg, average age = 20 to 24 mo) were allotted to treatments in four groups of five steers per pen for 12 wk preceding slaughter. While the experiment is employed, blood samples were taken to analyze Se concentration and GSH-Px activity, and muscle and liver samples were collected for analyses of Se contents in their tissues after slaughter. DMl and BW gain were not affected by dietary Se level and any toxic symptoms in treatments with a higher level of Se were not observed. No differences were noted for carcass characteristics. Se concentration in whole blood and plasma GSH-Px activity were linearly increased with the increasing level of dietary Se (P < 0.01). Se content in the hind leg for Se-SMC supplemented groups significantly increased (P < 0.05) upon dietary Se level, with 0.27, 0.37, 0.40 and 0.46 !1g1g dry, respectively. However, Se content in the loin was not affected by dietary Se levels. Se content in the liver was significantly increased(P < 0.05) as dietary Se increased, with 0.79, 1.40, 2.39 and 3.10 !1g1g dry, respectively. These results suggested that Se in the Se-SMC was highly bioavailable, and Se-SMC might be used not only as an inexpensive way of providing Se for ruminants but also as another way of producing Se-fortified beef.

• Applied Biological Chemistry
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• v.11
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• pp.173-184
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• 1969

To elucidate the effect of Amo-1618(4-hydroxyl-5-isopropyl-2-methlphenyl trimethyl ammonium chloride, 1-piperidine carboxylate) known as a kind of growth retardant, on the growth, grain yield, increasing the efficiency of nitrogen fertilizer, behavior of mineral nutritions and the rate of phosphorus utilization, this experiment was conducted pot culture method in a vinyl house. Two nitrogen level, namely, practical nitrogen level(1 N) and three times nitrogen level(3 N) was made and labelled double-calcium-superphosphate $Ca(H_2P^{32}O_4)_2.\;2H_2O)$ as a source of radioactive phosphorus(P-32) was employed $80\;{\mu}c/pot$, respectively. Rice seedlings, variety 'Suwon No. 82', was transplanted to a 1/50,000 a china pot on June 13 in 1968. For treatment, at early stage of tillering, 10,000 ppm solution of Amo-1618 was foliar sprayed only one time. The Duncan's new mutiple-range test was adopted for statistical analysis evaluating experimental data at 5% level significance. The results obtained may be summarized as follows; 1) No significant difference was found among the treatments in plant height, but in plot of Amo-1618 treatment and 3 N level, number of tillers was significantly increased than that of others. 2) Weight of 10,000 kernels and seed-setting rate was also remarkably increased in same treatment above. 3) Grain yield per pot was significantly increased in Amo-1618 and 3 N level application. This results seemed to be due to the increased the factors on the yield. 4) Contents of nitrogen and phosphorus per cent in the grain was likewise increased in Amo-1618 and 3 N application. There is, however, no difference among treatments in the content of nitrogen and phosphorus in the leaves and culms of rice plants. 5) On the other hand, the contents of potassium and magnesium, no distinctly tendeny showed among treatments. 6) The rate of phosphorus utilization was significantly increased in the plot of Amo-1618 and 3 N application.

• Journal of Korea Water Resources Association
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• v.50 no.11
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• pp.715-723
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• 2017

Extracellular Polymeric Substances (EPS) in the water environment assemble fine, colloidal particles, such as clays, microorganisms and biomass, in large flocs, which are eventually subject to sedimentation and deposition and determine water/sediment quality and quantity. This study hence aimed to investigate the way that water and colloidal chemistry affects EPS-mediated flocculation of colloidal particles, using a jar-test experiment. Especially, ionic strength, divalent cation and humic substances concentrations were selected as experimental variables in the jar-test experiments, to elucidate their effects on EPS-mediated flocculation. A higher ionic strength increased flocculation capability, reducing electrostatic repulsion between EPS-attached colloidal particles and enhancing particle aggregation. 0.1 M NaCl ionic strength had higher flocculation capability, with 3 times larger floc size and 2.5 times lower suspended solid concentration, than 0.001 M NaCl. Divalent cations, such as $Ca^{2+}$, built divalent cationic bridges between colloidal particles and EPS (i.e., $colloid-Ca^{2+}-EPS$ or $EPS-Ca^{2+}-EPS$) and hence made colloidal particles to build into large, settelable flocs. A small $Ca^{2+}$ concentration enhanced flocculation capability, reducing suspended solid concentration 20 times lower than the initial dosed concentration. However, humic substances, adsorbed on colloidal particles, reduced flocculation, because they blocked EPS adsorption on colloidal particles and increased negative charges and electrostatic repulsion of colloidal particles. Suspended solid concentration in the tests with humic substances remained as high as the initial dosed concentration, indicating stabilization rather than flocculation. Findings about EPS-mediated flocculation in this research will be used for better understanding the fate and transport of colloidal particles in the water environment and for developing the best management practices for water/sediment quality.

• Journal of Korea Water Resources Association
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• v.53 no.8
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• pp.627-636
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• 2020

Debris flow disasters primarily occur in mountainous terrains far from cities. As such, they have been underestimated to cause relatively less damage compared with other natural disasters. However, owing to urbanization, several residential areas and major facilities have been built in mountainous regions, and the frequency of debris flow disasters is steadily increasing owing to the increase in rainfall with environmental and climate changes. Thus, the risk of debris flow is on the rise. However, only a few studies have explored the characteristics of flooding and reduction measures for debris flow in areas designated as steep slopes. In this regard, it is necessary to conduct research on securing independent disaster prevention technology, suitable for the environment in South Korea and reflective of the topographical characteristics thereof, and update and improve disaster prevention information. Accordingly, this study aimed to calculate the amount of debris flow, depending on disaster prevention performance targets for regions designated as steep slopes in South Korea, and develop an independent model to not only evaluate the impact of debris flow but also identify debris barriers that are optimal for mitigating damage. To validate the reliability of the two-dimensional debris flow model developed for the evaluation of debris barriers, the model's performance was compared with that of the hydraulic model. Furthermore, a 2-D debris model was constructed in consideration of the regional characteristics around the steep slopes to analyze the flow characteristics of the debris that directly reaches the damaged area. The flow characteristics of the debris delivered downstream were further analyzed, depending on the specifications (height) and installation locations of the debris barriers employed to reduce the damage. The experimental results showed that the reliability of the developed model is satisfactory; further, this study confirmed significant performance degradation of debris barriers in areas where the barriers were installed at a slope of 20° or more, which is the slope at which debris flows occur.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.517-529
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• 1998

Purpose : Although many studies have investigated the dosimetric aspects of stereotactic radiosurgery in terms of target volume, the absorbed doses at extracranial sites: especially the lens or thyroid - which are sensitive to radiation for deterministic or stochastic effect -have infrequently been reported. The aim of this study is to evaluate what effects the parameters of radiosurgery have on the absorbed doses of the lens and thyroid in patients treated by stereotactic radiosurgery, using a systematic plan in a humanoid phantom. Materials and Methods : Six isocenters were selected and radiosurgery was planned using the stereotactic radiosurgery system which the Department of Therapeutic Radiology at Seoul National University College of Medicine developed. The experimental radiosurgery plan consisted of 6 arc planes per one isocenter, 100 degrees for each arc range and an accessory collimator diameter size of 2 cm. After 250 cGy of irradiation from each arc, the doses absorbed at the lens and thyroid were measured by thermoluminescence dosimetry. Results : The lens dose was 0.23$\pm$0.08$\%$ of the maximum dose for each isocenter when the exit beam did not pass through the lens and was 0.76$\pm$0.12$\%$ of the maximum dose for each isocenter when the exit beam passed through the lens. The thyroid dose was 0.18$\pm$0.05$\%$ of the maximum dose for each isocenter when the exit beam did not pass through the thyroid and was 0.41$\pm$0.04$\%$ of the maximum dose for each isocenter when the exit beam Passed through the thyroid. The passing of the exit beam is the most significant factor of organ dose and the absorbed dose by an arc crossing organ decides 80$\%$ of the total dose. The absorbed doses of the lens and thyroid were larger as the isocenter sites and arc planes were closer to each organ. There were no differences in the doses at the surface and 5 mm depth from the surface in the eyelid and thyroid areas. Conclusion : As the isocenter and arc plane were placed closer to the lens and thyroid, the doses increased. Whether the exit beams passed through the lens or thyroid greatly influenced the lens and thyroid dose. The surface dose of the lens and thyroid consistently represent the tissue dose. Even when the exit beam passes through the lens and thyroid, the doses are less than 1$\%$ of the maximum dose and therefore, are too low to evoke late complications, but nevertheless, we should try to minimize the thyroid dose in children, whenever possible.

• Korean Journal of Veterinary Research
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• v.11 no.1
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• pp.1-39
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• 1971

The purpose of present study was to investigate the possibility to immunize guineapigs and swine against Metastrongylus apri infection by the administration of irradiated infective larvae. Four main experiments were undertaken. Firstly, three groups of infective larvae irradiated at $3{\times}10^4r$, $4{\times}10^4r$, and $5{\times}10^4r$ respectively were inoculated to guineapigs and their immunogenic effects were examined from the clinical, anatomical, and serological viewpoints to decide the optimal dose of X-ray for the atenuation of them. Secondly, the migratory behavior of the larvae irradiated at the optimal dose was compared with that of normal infective larvae. Thirdly, pigs were inoculated with each 5,000 infective larvae irradiated at the optimal dose and the clinical, anatomical and serological responses of them before and after challenge were examined. Fourthly, the heated extract of adult M. apri which had been used as an antigen in the serological examinations was analyzed and compared with that of adult Ascaris suis and of adult Trichuris suis by immunoelectrophoretic method. The results obtained are summerized as follows: 1) The optimal dose of X-ray for the atenuation of the infective larvae which can minimize the pathogenecity but keep the antigenecity of the infective larvae was $5{\times}10^4r$. 2) Guineapigs could become completely resistant to subsequent challenge infection by the administration of 1,000 infective larvae irradiated at $5{\times}10^4r$, without showing any symptom of disease before and after the challenge. 3) There were some indication that guineapigs could acquire complete immunity after they overcome the infection with normal infective larvae. 4) It was shown that, in guineapigs, the $5{\times}10^4r$-irradiated larvae can migrate to the large intestine and mesenteric lymph node within a day, where they stay for as long as 16 days to stimulate the host's immunity. 5) It also was shown that, in guineapigs, the normal infective larvae challenged to resistant guineapigs can migrate to the large intestine and mesenteric lymph node, where they are affected by the immune mechanism of host within 10 days without further migration. 6) Pigs could become partially resistant to subsequant challenge by the administration of 5,000 infective larve irradiated at $5{\times}10^4r$; no clinical symptom occurred after the administration, but milder symptoms of parasitic bronchitis were observable after the challenge infection and fewer number of worms were detected from the lungs at autopsy compared with severe symptoms and much number of worms in control pigs. 7) It was shown that, in pigs, a few of the $5{\times}10^4r$-irradiated larvae can migrate to the lungs, where they stay for as long as 104 days in stunted and sterile states; their body-lengths were short and their uteri developted no eggs. 8) There was evidence that the male larvae were more susceptible to X-ray than the female larvae. 9) Antibodies relating to the administration with $5{\times}10^4r$-irradiated or normal larvae were detected from the sera of both guineapigs and pigs by means of indirect haemagglutination and agar diffusion precipitin tests. Relatively higher antibody titers were recorded by the former test, but precipitin bands were demonstrable only when the positive sera were concentrated in one tenth of original volume in the later one. 10) The antibody titers of pig sera began to rose on 14 days, kept their peak during the period from 14 th day to 21st day, and fell to a low level on 28 days after the administration of $5{\times}10^4r$ or normal infective larvae. 11) A slight increase in gamma globublin of the pig sera occurred following the administration. The gamma globulin level showed a tendency to fluctuate in acordance with the antibody level. 12) A marked eosionophilia occurred in pigs on 7 or 14 days following the administration. The eosinophil count showed the same tendency to fluctuate as the gamma globulin did. 13) It was shown that the serum antibodies detected by the heated extract of adult Metastrongylus apri react crossly with the heated extract of adult Ascaris suis but not with that of adult Trichuris suis in indirect haemagglutination and agar diffusion preciption reactions. 14) The heated extract of adult Metastrongylus apri could he divided into 9 antigenic components by immunoelectrophoresis, one (arc 4) of which was shown to be common to both extracts of adult Ascaris suis and adult Trichuris suis, and the other one (arc 9) to only the extract of adult Ascaris suis.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.795-807
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• 1996

This study was conducted to identify the effects of caffeine on the lipid and protein components or blood chemistry levels of the serum as well as the total homogenate, mitochondrial and microsomal fraction of the rat(Sprague-Dawley, female) liver. Acute test were conducted to determine those effects. The acute test was conducted by dividing rats into 7 groups according to the time lapsed after a single oral administration of 100mg/kg caffeine(that is control, 2hrs, 4hrs, 8hrs, 24hrs, 48hrs and 72hrs lapsed group). The concentrations of glucose, urea nitrogen, uric acid, creatinine, total protein, albumin, A/G ratio, triglyceride, total cholesterol, HDL-cholesterol, free fatty acid, phospholipid as well as the activities of alanine aminotransferase(ALT), aspartate aminotransferase(AST) and alkaline phosphatase(ALP) were measured in the serum of each experimental groups. The concentrations of the carbonyl group, malondialdehyde(MDA) and the patterns of the SDS-PAGE(Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis) were analyzed to determine the oxidative damages and metabolic changes on the lipid and protein components in the serum, and total homogenate, mitochondrial and microsomal fractions of the rat liver. The results obtained from this study were summarized as follows; 1. The concentrations of serum glucose were significantly higher(p<0.01) between 4(143.0mg/dl) and 8hrs(138.0mg/dl) in comparison to that of the control(101.1mg/dl) after a single oral administration of caffeine(100mg/kg). While on the other, there were no significant differences in the concentrations of urea nitrogen, uric acid, creatinine, total protein, albumin and albumin/globulin(A/G) ratio in comparison to those of the control. 2. The concentrations of total cholesterol and HDL-cholesterol in serum were significantly higher(p<0.01) between 4(77.4mg/dl, total cholesterol) and 8hrs(64.7mg/dl, HDL-cholesterol) in comparison to those of the control(62.8, 46.7mg/dl) after a single oral administration of caffeine(100mg/kg). On the other hand, the concentrations of triglyceride in serum were significantly lower(p<0.01) after 8hrs(38.8mg/dl) in comparison to that of the control(66.5mg/dl). 3. The activities of AST in serum was significantly higher(p<0.05) from 2hrs(149U/L) to 8hrs(178U/L) in comparison to the control(112U/L) after a single oral administration of caffeine(100mg/kg). The activities of ALT in serum were significantly higher(p<0.01) at 4(45.5U/L), 24(49.3U/L), 48(46.8U/L) and 72 hrs(42.3U/L) in comparison to that of the control(39.7U/L) after a single oral administration of caffeine(100mg/kg). On the other hand, there were no significant differences in the activities of ALP in comparison to that of the control. 4. The concentrations of free fatty acid in serum were significantly higher(p<0.01) at 8hrs(65.0mg/dl) in comparison to that of the control(37.6mg/dl) after a single oral administration of caffeine(100mg/kg). However, there were no significant differences in the concentrations of carbonyl group and malondialdehyde within serum, and liver homogenate, mitochondrial and microsomal fractions in comparison to that of the control. 5. The patterns of SDS-PAGE in serum, mitochondrial and microsomal fraction of the liver showed no significant differences.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1348-1353
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• 2005

Purpose : Influenza is a respiratory disease which prevails widely every year and shows high morbidity and mortality among not only chronic invalids and the old, but also among infants and young children. To prevent community-acquired influenza infection, to facilitate prompt antiviral therapy and to avoid unnecessary use of antibiotics, an easy, rapid diagnostic method for the influenza virus is needed. We evaluated a lateral-flow immunoassay(QuickVue Influenza Test), compared to viral culture. Methods : During two consecutive years from Jan. 2004 to June 2004 and from Feb. 2005 to Jan. 2005, 408 patients who were suffering from fever, cough and/or sore throat and myalgia were enrolled in our study. A total of 408 patients were tested with $QuickVue^{(R)}$(Quidel Co., San Diego, USA) influenza rapid antigen test and virus cultures at the same time. Results : Of the 408 patients tested, children who showed positive results at the virus culture numbered 77; among them, 55(71.4 percent) were type A/H3N2 and 22(28.5 percent) were type B. QuickVue influenza test had a sensitivity of 71.4 percent and a specificity of 95.8 percent. The positive and negative predictive values were 79.7 percent and 93.5 percent, respectively. Conclusion : In our study, this test had comparable high sensitivity and high specificity and many advantages, such as being easy to perform and simple to interpret, and showing rapid results. If rapid influenza antigen tests are widely applied in the clinic, we can begin treatment more rapidly and reduce influenza complications and the abuse of antibiotics.