• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.667-676
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• 2006

The reduction of $Hg^{2+}$ in the aqueous phase results in the production of dissolved gaseous mercury(DGM), and the volatilization of DGM has been identified as an important mechanism for the loss of Hg from waterbodies to the atmosphere. Although mercury emission in the world is known to be mostly from Asia, there have been few studies of measuring DGM concentrations in lakes in Asia. In this study, DGM concentrations were measured at Juam reservoir($35^{\cir}00'N,\;127^{\circ}14'E$), Korea. The results showed that the average concentrations of DGM at the upper and down stream of the lake during summer time were $95{\pm}8\;and\;130{\pm}15$ pg/L, respectively and the concentration of total mercury(TM) at the upper and down stream was $2.1{\pm}0.7,\;1.7{\pm}0.3$ ng/L respectively. Average DGM concentration during summer time($101{\pm}14pg/L$) was approximately 5.5 times higher than that during fall($18{\pm}0.1pg/L$). The DGM concentrations ai the midstream decreased from 32 to 13.7 pg/L during rain event, while the TM concentrations increased from 2.2 ng/L to 2.7 ng/L indicating the deposition of mercury from the atmosphere. Also, the diurnal patterns between DGM concentrations and UV intensities were observed. Water temperatures and DOC concentrations were significantly related to DGM concentrations, while TM concentrations were negatively related to DGM concentrations(p<0.0001). Comparing with the study of Dill et al.,(2006) the average concentrations of DGM $(109{\pm}15pg/L)\;and\;TM(2.2{\pm} 0.4ng/L)$ at Juam reservoir were approximately 3 and 2.2 times higher than those measured in other lakes(DGM: $38{\pm}16pg/L$, TM: $1.0{\pm}1.2ng/L$).

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• The Korean Journal of Mycology
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• v.12 no.3
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• pp.105-110
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• 1984

Seven seed samples of corn obtained from Kangweon Provincial Office of Rural Development, Kerea were tested for seed-borne fungi, and found that all the samples tested were infected with Fusarium moniliforme to an extent of $6.0{\sim}79.5%$. Severely infected seed samples showed poor germination on blotter. Seed component plating showed that the fungus present not only in tip caps, pericarps and endosperms, but also in embryos. Heavy infection of the fungus caused severe seed rot and seedling blight in soil, but the damage was not severe and many plants grew without any symptoms when the seeds with light infection were sown in soil. However the fungus was frequently detected from inside of the stems of healthy looking seedlings. The results indicate that the fungus transmit from seed to plant systemically. In inoculation experiments, the fungus produced stem rots on corn plants of 110 days old. The cultivar of Hwangok 3 was revealed more susceptible to the fungus than that of Suweon 19.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.1
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• pp.51-70
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• 2001

Characteristics of handwriting were investigated and compared between the patients with writing disabilities and normal elementary school pupils. Generally, the heights of the letters of the patients were significantly larger than those of normal children, and letters of the patients were more sparsely distributed than those of controls. The distance between the words were significantly reduced in the patients’ writings, which indicated that patients had much more problems of space-leaving than normal pupils. Letter heights differences were significant across all grades in the patients and normal controls. The heights of the letters decreased as they grew older, and the slope of the decrements were more steeper in normal girls(r=-0.45) than girls with writing disabilities(r=-0.16). Sex differences were found in the letter spacings in low grades(grades 1, 2), that is, the distances between the letters were significantly narrower in the male patients than normal boys in these grades, and the differences were almost indiscriminating in grades 3 through 5, and finally, in sixth grade, letter spacings were signifycantly broader in normal boys than male dysgraphics. In girls, letter spacings were significantly broader in the patients across all grades. These findings supports the hypothesis that male and female writings were qualitatively different and that distinct mechanisms served in boys and girls dysgraphics. Across all grades and sexes, spaces between the words of the patients were significantly broader than normal pupils, which suggested that space-leaving between the words was important in Korean writings. There was trend that letter spacings and word spacings decreased across grades, but in girls, no correlations between the letter spacings and grades were found. Correlation analyses revealed that letter heights and letter spacings had mild correlation(r=0.11-0.15), and that letter spacings and word spacings had robust correlation(r=0.99). Phonological errors were mostly found in last phoneme(Jong-seong), especially double-phoneme(ㄳ, ㄵ, ㄶ, ㄺ, ㄻ, ㄼ, ㄾ, ㄿ, ㅀ, ㅄ), and in the case the sound values changed due to assimilations of phonemes. Semantic errors were rare in both groups. Space-leaving errors were correlated with phonological errors, and more frequent in boys than girls. In conclusion, significant differences existed in the letter heights, letter spacings, word spacings, and frequencies of phonological errors and spaceleaving errors between the patients with writing disabilities and normal pupils. The characteristics of writings changed across grades and the developmental profiles were somewhat quantitatively different between the groups. The differences became obvious from the second-third grades.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.274-281
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• 2020

This study aimed to investigate the autumn spawning by bitterling (A. rhombeus) inside mussel (Unio douglasiae) and the adaptation characteristics at the Bongseocheon Stream of Mankyeonggang River. The survey was carried out between August 2015 and July 2016. The spawning season was from September to November, and 17-75 (36.2 ± 16.44) eggs were found from mature females. During the survey period, 476 mussels were collected, 129 (27.1%) of spawned A. rhombeus. Mussels that spawned eggs, embryos, and larva of A. rhombeus (46.3 ± 4.55 mm, n = 129) were larger than than those that did not spawn (42.6 ± 8.51 mm, n = 347). The appearance frequency of A. rhombeus larva before and after the formation of lens was 99.8% (n = 597) vs. 0.2% (n = 1) from October 2015 to March 2016, 25.6% (n = 23) vs. 74.4% (n = 67) in April 2016, 0% (n = 0) vs. 100% (n = 40) on May 2016. The number of eggs, embryos, and larvae of A. rhombeus inside the mussels were 1-18 (5.6 ± 3.81). The number and appearance frequency of A. rhombeus eggs, embryos, and larvae inside the mussel according to mussel gill demibranchs position were 1 (0.01 ± 0.09, n = 1) and 0.78% in the left outer demibranch, 1-18 (2.33 ± 3.31, n = 63) and 48.84% in the left inner demibranch, 1-15 (2.97 ± 3.79, n = 76) and 58.91% in the right inner demibransh, and 1-12 (0.33 ± 1.71, n = 7) and 5.43% in the right outer demibransh. The highest frequency of the developmental position of eggs, embryos, and larvae occurred 71.8% (n = 445) in lower part 3 (L3) before formation lens and 94.4% (n = 102) in L3 after formation lens, indicating that L3 was dominating position for eggs, embryos, and larvae. More eggs, embryos, and larvae of A. rhombeus were found more often in the inner demibranshs than outer demibranchs. Since A. rhombeus is a species that spawn in the autumn and thus avoids the competition with interspecific and glochidia. However, they have to spend the winter in low water temperature. Consequently, we assume that A. rhombeus have evolved toward embryonic diapause under the low water temperature before the formation of lens and spawning inside the supracranchial cavity to save the transit energy from the water space to the suprabranchial cavity after the achieving movement ability with the formation of lens.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.229-237
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• 1987

In order to study the biological control of soil-borne disease of sesame, antagonistic isolates of Trichoderma , Bacillus sand streptomyces to Fusarium oxysporum and Rhizoctonia solani were isolated from the rhizosphere soils of sesame plants and some other habitats. Out of the isolates of microorganisms collected a strain of Trichoderma viride was selected as a biological control agent for the study and its effect on the control of damping-off and the seedling growth of sesame was investigated. The results obtained are as follows: 26 percents of Bacillus spp. isolated from the rhizosphere soil of sesame plants showed antagonism to two pathogenic fungi. Important species were B. Subtilis and B. polymyxa. Streptomyces species isolated from the rhizosphere soils of sesame lysed the cell wall of hyphae and conidia of F. oxysporum and reduced conspicuously the formation of macroconidia and chlamydospores of the fungus. 84 percents of Trichoderma spp. isolated from the rhizosphere soil of sesame plants were antagonistic to F. oxysporum and 60 percents of the isolates were antagonistic to both F. oxysporum and R. solani. Trichoderma viride TV-192 selected from antagonistic isolates of Trichoderma spp. was highly antagonistic to F. oxysporum and soil treatment with the isolate reduced notably damping-off of sesame. T. viride TV-192 showed better growth in crushed rice straw, barley straw and sawdust media than F. oxysporum. Sawdust was selective for the growth of T. viride. Supplementation of wheat bran and mixtures of wheat bran and sawdust inoculated with T. viride TV-192 in the soil reduced remarkably damping-off of sesame by F. oxysporum but high density of the fungus TV-192 caused the inhibition of seed germination and seedling growth of sesame. Inhibitory effects of Trichoderma species on seed germination and seedling growth of sesame were different according to the isolates of the fungus. Normal sesame seedlings on the bed treated with the fungus showed better growth than not treated seedlings.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.1-18
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• 1989

This experiment was undertaken to clarify derivation of resistance of Japonica type of rice varieties to rice blast in Korea and to classify Japonica type of rice varieties on the basis of their rice blast reaction in the blast nuisery test. 1. The resistance of Iljin, Kwancheok 9, Koshi, Baedal and Paldal, Jaekeon, Sinpung, Jinheung, Hokwang and Palkeum, and Gwangmyungbyeo and Yeongdeogbyeo to rice blast was derived from Kyudai Taicho Asahi 3, Futaba and 2067, respectively. 2. The resistance of Kwanok, Mankyeong and Nongbaek to the rice blast was derived from Kanto 55, Hokwang and Kusabue, and Ishigarisiroge, respectively. 3. The resistance of Seomjinbyeo, Sinseonchalbyeo, Donghaebyeo and Tamjinbyeo to the rice blast was derived from Milyang 20 and the source of resistance to the rice blast in Jinjubyeo and Daecheongbyeo was HR 769 or HR 1590. 4. The resistance of Dobongbyeo, Gwanagbyeo and Chiagbyeo to the rice blast was derived from Tjina, Kongo and Kuik 90, respectively. 5. The resistance of Seolagbyeo, Seonambyeo, Kihobyeo, Namyangbyeo, Samnambyeo, Seohaebyeo, Whaseongbyeo, Daegwanbyeo and Taeseongbyeo, and Sobaegbyeo, Odaebyeo and Unbongbyeo to the rice blast was derived from Fuji 280 and Fuji 269, respectively. 6. The source of resistance to the rice blast in Cheonmabyeo and Baegambyeo was BL 7 and Nongbaek, the resistance of Dongjinbyeo and Sangpungbyeo to the rice blast was derived from Satominori and Simokita, respectively. 7. Japonica type of rice varieties was classified into eleven varietal groups according to their reaction to the blast as follows. Eight varieties of Jinheung group, two varieties of Dongjinbyeo group, two varieties of Jinjubyeo group, three varieties of Gwanagbyeo group, four varieties of Sobaegbyeo group, one variety of Nongbaek group, two varieties of Baegambyeo group, five varieties of Sinseonchalbyeo group, five varieties of Seonambyeo group, two varieties of Taeseongbyeo group and some variety of Nagdongbyeo group.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.720-729
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• 2000

Background : Histological analysis of tuberculosis shows a spectrum of findings, from well formed granulomatous inflammation with few bacilli in patient with normal immune response to M. tuberculosis to poorly formed granulomatous inflammation with many bacilli in patient with defective immune response. To evaluate the degree of immune response to M. tuberculosis, we studied the histologic features, including the presence of acid fast bacilli(AFB) in lymph node of patients with cervical tuberculous lymphadenitis, and compared them with clinical characteristics. Methods : We reviewed the histologic features of 33 cases of cervical tuberculous lymphadenitis and processed the excised nodes for auramine-rhodamine staining to detect AFB. The AFB positivity in tissue was compared with the histologic features(degree of granuloma formation, presence of caseation necrosis, presence of neutrophilic infiltration) and clinical characteristics(lymph node size, duration of symptom, presence of local symptom or radiologic evidence of pulmonary tuberculosis). Results : 1) The mean age at diagnosis was 42.4 years, and male to female ratio was 1:4.5. 2) Histologically, all cases showed well formed granuloma and variable degrees of caseation necrosis, and 39% of the cases showed neutrophilic infiltration in the granulomatous inflammation. 3) AFB were confirmed in 52% of the cases, and they were found extracellularly and at the periphery of caseation necrosis. 4) There was no association between AFB positivity and histological features or clinical characteristics. Conclusion : Cervical tuberculous lymphadenitis showed well formed granulomatous inflammation with caseation necrosis, and there was no association between AFB positivity in the tissue and histological or clinical characteristics.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.123-131
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• 1988

This study was done to investigate the interplanting effects of corn, when a corn hybrid with tillers (IK derivaties) was interplanted with a corn hybrid without tillers(Jinjoo Ok). The interplanting ratios of two hybrids, IK and Jinjoo Ok, were 1 to 1, 1 to 2, 1 to 3, 2 to 1, and 3 to 1. The interp1anting effects were compared with monoculture for major agronomic characteristics. 1. The plant height was increased when interplanted regardless of the interplanting ratios of the two hybrids. The general growth of IK hybrid was a little hindered when the interplanting ratio of Jinjoo Ok hybrid increased. 2. The number of tillers produced by the IK hybrid increased until 40 days after emergence and appeared to increase as the interplanting ratio of IK hybrid increased. 3. When monocultured, the fresh weight of IK hybrid per 10a was 8,096kg and and 6,677kg at silking and dough stages, respectively and these were 77%, 53% over the fresh weight of Jinjoo Ok at the sarne stages. When IK and Jinjoo Ok hybrids were interplanted in 1 to 1 ratio, the fresh weight of IK was 20% higher than that of Jinjoo Ok monocultured. 4. The highest grain yield per 10a was obtained from the Jinjoo Ok hybrid monocultured and the yield was 434kg. Even the interplanting ratios between IK and Jinjoo Ok were 1 to 1 and 1 to 3, the grain yield of Jinjoo Ok was 16% and 13% over the IK, respectively. 5. Root and stalk lodging of IK hybrid was 29% when monocultured and seemed to increase as the interplanting ratio of Jinjoo Ok increased. The lowest lodging was found when the interplanting ratio of IK and Jinjoo Ok was 1 to 1. 6. Stem diameter of IK hybrid was also decreased as the interplanting ratio of Jinjoo Ok increased. The ear height of IK was lowered as the interplanting ratio of IK was increased. The two hybrids tested seemed to have tolerance to the black streaked dwarf virus(BSDV).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.251-256
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• 1981

Silage yield and nutritional values of a locally collected Korean corn line with high tillering and earing characteristics were investigated at plant densities from 2778 to 8333 plants/ l0a. This line and a non-tillering and nonprolific corn as a check were grown at four plant densities and at three planting dates. The Korean local line abbreviated as MET had the highest dry matter per l0a. The highest dry matter of the MET line compared with the check hybrid was due to the highest dry leaf weight of the MET line. The highest dry leaf weight of the MET line was due to the increased number of tillers of the MET line. Other plant parts such as ear weight, kernel weight and cob weight of the MET line were lower than those of the check hybrid. The dry husk weight per l0a of the MET line was higher than that of the check hybrid, probably due to the increased number of ears in the MET line. The total embryo production per 10 a of the MET line was significantly higher than that of the check hybrid. The increased portion of embryo of the MET line is probably responsible for the higher TON values of the MET line. No interaction between variety x planting dates or planting density was found, indicating that the MET line and check hybrid were both the same in effects of planting dates and densities. Both line and hybrid showed the highest dry matter production when the planting density was high and planting dates was early. When silage was made from either MET line or check hybrid the nutritional values in terms of crude protein, crude fat, fiber, and ash contents of the MET line were similar to those of the check hybrid. But the TON of the MET line was higher than that of the check hybrid, while the OCP of the MET line lower than that of the check hybrid. Amino acid contents of the MET line were also comparable to those of the check hybrid, while lysine content of the MET line was 10% higher than that of the check hybrid.