• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.422-431
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• 2019

Severe droughts in spring have occurred frequently in Korea in recent years, exerting a critical impact on corn yield. Therefore, it is necessary to find physiological and/or molecular indicators of the response to drought stress in maize plants. In this study, we investigated the effects of water-deficit stress on two Korean elite F₁ maize hybrids, Ilmichal and Gwangpyeongok, by withholding water for 10 days at tassel initiation. The water deficit drastically reduced the relative leaf water content, leaf number, leaf area, and stem length, leading to dry matter reduction. Moreover, it reduced the SPAD values and stomatal conductance of leaves in drought-stressed plants of both hybrids. Importantly, the number of leaves and SPAD value were non-destructive and easy to investigate in response to water-deficit stress, suggesting that they may be useful indicators for screening drought-tolerant genetic resources. We detected more than 100 spots that were differentially accumulated under drought stress. Of these spots, a total of 21 protein spots (≥1.5-fold) from drought-exposed maize leaves were successfully analyzed by MALDI-TOF-TOF mass spectrometry. Functional annotation using Gene Ontology analysis revealed that most of the identified proteins were involved in carbohydrate metabolism, stress response fatty acid catabolism, photosynthesis, energy metabolism, and transport. The protein expression levels were increased in both Ilmichal and Gwangpyeongok, except for triosephosphate isomerase, fructose-bisphosphate aldolase, and an uncharacterized protein. The lactoylglutathione lyase delta (3,5)-delta (2,4)-dienoyl-CoA isomerase was overexpressed in Gwangpyeongok only. The results obtained from this study suggest that the drought-specific genes may be useful as molecular markers for screening drought-tolerant maize genotypes.

• Journal of Life Science
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• v.23 no.11
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• pp.1325-1335
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• 2013

Working dogs, such as rescue dogs, military watch dogs, guide dogs, and search dogs, are selected by in-training examination of desired traits, including concentration, possessiveness, and boldness. In recent years, genetic information has been considered to be an important factor for the outstanding abilities of working dogs. To characterize the molecular features of the canine genes related to phenotypes for working dogs, we investigated the 24 previously reported genes (AR, BDNF, DAT, DBH, DGCR2, DRD4, MAOA, MAOB, SLC6A4, TH, TPH2, IFT88, KCNA3, TBR2, TRKB, ACE, GNB1, MSTN, PLCL1, SLC25A22, WFIKKN2, APOE, GRIN2B, and PIK3CG) that were categorized to personality, olfactory sense, and athletic/learning ability. We analyzed the chromosomal location, gene-gene interactions, Gene Ontology, and expression patterns of these genes using bioinformatic tools. In addition, variable numbers of tandem repeat (VNTR) or microsatellite (MS) polymorphism in the AR, MAOA, MAOB, TH, DAT, DBH, and DRD4 genes were reviewed. Taken together, we suggest that the genetic background of the canine genes associated with various working dog behaviors and skill performance attributes could be used for proper selection of superior working dogs.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.191-198
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• 2019

This study investigated the residual characteristics of bifenthrin and chlorothalonil in crown daisy and suggested pre-harvest residue limits (PHRLs) based on their dissipation patterns and biological half-lives. The samples for residue analysis were harvested at 0 (3 hr), 1, 3, 5, 7, 9, 11, 13, 15, 18, 22 and 26 days after treatment, and analyzed by $GC/{\mu}-ECD$ and TOF/MS. The limit of quantitation (LOQs) of bifenthrin and chlorothalonil were 0.0046 mg/kg and 0.0007 mg/kg, respectively. Recoveries ranged from $88.67{\pm}7.97%$ and $99.90{\pm}16.03%$, showing that this method is appropriate for the analysis of the pesticide residues in crown daisy. Being well within first order kinetics, the biological half-lives of the pesticide residues in crown daisy were 9.63 days for bifenthrin and 6.54 days for chlorothalonil. The PHRLs of bifenthrin and chlorothalonil were recommended as 11.70 mg/kg and 24.10 mg/kg for 26 days before harvest, respectively.

• Journal of Apiculture
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• v.32 no.3
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• pp.139-146
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• 2017

Floral scent emitted from many plants is the critical factors for pollinator attraction and defense for adaptation in environments. The fragrance components of flowers are different in composition by geographical origins, climate factors and the development stages of flowers. In the present study, we investigated the volatile-floral compounds in flowers of Robinia pseudoacacia L. and defined the chemical contribution for flowering periods. The volatile compounds analysis was performed by gas chromatography with mass selective detector after solid phase microextraction (SPME). We reported different compositional features of fragrance compounds according to flowering periods. The abundant compounds identified in stage 1 were ${\alpha}$-pinene (66.80%) and ${\beta}$-pinene (26.53%). Those of the stage 2 were (Z)-${\beta}$-ocimene (37.57%), ${\alpha}$-pinene (15.16%), benzaldehyde (16.63%), linalool (12.13%). The volatiles of stage 3 comprised an abundance of (Z)-${\beta}$-ocimene (64.94%), ${\alpha}$-pinene (9.84%), linalool (8.92%), benzaldehyde (1.71%). Leaf volatiles were distinct from those in the reproductive plant parts by their high relative amount of (E)-${\beta}$-ocimene (23.50%) and (Z)-3-Hexenyl acetate (27.87%). Differences in flower scents of the different stages and leaves are discussed in light of biochemical constraints on volatile chemical synthesis and of the role of flower scent in evolutionary ecology of R. pseudoacacia.

• Journal of the Korean Society of School Health
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• v.13 no.2
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• pp.295-317
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• 2000

This study was conducted to prevent oral disease of primary school, middle school, and high school students, providing basic data for the development of oral health education programs. Data were collected from 898 primary school, middle school, and high school students from March 2, 1999 to May 31, 1999. The results of this study are summarized as follows; 1) The subjects of this study were primary school students(32.6%), middle school students(33.0%), and high school students(34.4%). Boy students were slightly more prevalent than girl students. That is, primary school boys were 56.3%, middle school boys were 53.2%, and high school boys were 52.6%. 2) According to the self-judgement of oral health, primary school students were better than middle/high school students and boy students were better than girl students, 63.5% of primary school students and 57.8% of middle/high school students brushed their teeth once or twice a day. 3) 76.3% of middle/high school students and 63.5% of primary school students experienced dental caries. Girl students were higher than boy students in experiencing dental caries, 35.9% of primary school students and 27.6% of middle/high school students experienced periodontal disease. 4) 22.9% of primary school students and 7.9% of middle/high school students received oral examinations periodically. Girl students showed a higher rate than boy students in primary school, while boy students showed a higher rate than girl students in middle/high school. 5) Explaining to the reasons for reluctant visits to dental hospitals and clinics, 'no time to go' was highest(22.9% of primary school students; 27.4% of middle/high school students) and the rate of 'feeling scared' was second highest. Middle/high school students were more reluctant to visit dental hospitals and clinics than primary school students. In case of problematic symptoms in the mouth, the rate of 'feeling painful or cold in teeth when eating cold or hot foods' was highest, 71.3% of primary school students was concerned about oral health, while 68.6% of middle/high school students was concerned about it. 6) In gathering to the sources of information on oral health, the rate of medical institutions was highest(30.0%) in primary school students, while the rate of family members or persons around them was highest in middle/high school students. 7) 54.9% of primary school students received oral health education, while 13.1% of middle/high school students received it. Only 4.7% of middle school and high school girls received it. In relation to dental health education, the rate of 'possibility of prevention of oral caries or disease of the gum' was highest. 79.5% of primary school students and 80.3% of middle school students answered that they would attend oral health education. 8) 60.4% of primary school students and 60.2% of middle/high school students think the purpose of oral health is to prevent dental caries and disease of the gums. In preventing dental caries, 78.8% of primary school students and 71.8% of middle school students thought that periodical oral examination was effective, 88.4% of primary school students and 88.8% of middle/high school thought that brushing one's teeth was effective and 64.1% of primary school students and 50.7% of middle school students thought that the use of toothpaste containing fluoride was effective. In preventing periodontal disease, 91.1% of primary school students and 90.2% of middle/high school students thought that brushing one's teeth was effective, while 72.4% of primary school students and 70.3% of middle/high school students thought that teeth cleaning was effective. 9) 16.0% of middle school students and 12.7% of high school students thought that their oral health condition was healthy. According to individual experiences in dental treatment, the rate of experience of middle school students was higher than that of high school students, 12.7% of middle school students received oral examinations periodically, while only 3.3% of high school students did so. 10) In cases of 'having no problematic symptoms in the mouth' and 'concerns about oral health', the rate of middle school students was higher than that of high school students. In gathering obtaining information on oral health, the rate of obtaining it through broadcast media including TV, Radio, etc. was highest in middle school students, while the rate of obtaining it through family members or persons around them was highest in high school students. 11) 81.7% of middle school students have not received oral health education. In case of girl students, 97.3% have not received it in high school students. 85.6% of middle school students and 151.2% of high school students think that oral health education is necessary. 12) According to the knowledge level of oral health, the point of high school students($26.33{\pm}2.33$) was similar to the point of high school students($26.23{\pm}2.30$). It appeared that the point of primary school students was highest($26.35{\pm}2.50$) The more concerned about oral health the students were the higher the knowledge level of oral health was. In conclusion, the middle/high school students' knowledge level of oral health was lower than primary school students. The rate of middle/high School students' experience in oral health education was too low. Therefore, it is necessary to intensify oral health education for middle/high school students. Especially, the necessity of oral health education to girl students is strongly recommended. Developing an oral health education program for primary school, middle school, and high school students, related public authority and organizations, teachers; and dentists must actively make efforts together in order to maintain healthy teeth through having students prevent dental caries and periodontal disease.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.11-19
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• 1999

Purpose: MCNS is found in approximately $85\%$ of the idiopathic nephrotic syndrome in children and shows good prognosis with initial steroid therapy. MCNS most commonly appears between the ages of 2 and 10 yr. But the incidence and prognosis in adolescent MCNS are different from those found in young children; the prognosis and the response to therapy is unfavorable with increasing ages. So we compared the prevalence and the clinical manifestations of adolescent MCNS with that of childhood MCNS for management of adolescent MCNS. Methods: We conducted a retrospective study with a review of histopathologic findings and clinical manifestations of the 216 cases with MCNS which were divided into children group and adolescent group by their age of onset; under 12 years(childhood) and between 12-18 years(adolescent). Results: 1) The number of childhood idiopathic nephrotic syndrome was 245 cases, and that of adolescent idiopathic nephrotic syndrome was 55 cases. 188 cases($77\%$) showed MCNS, 30 cases($12\%$) FSGS, 4 cases($1.6\%$) MSPCN in childhood idiopathic nephrotic syndrome; 28 cases($51\%$) showed MCNS, 12 cases($22\%$) FSGS in adolescent idiopathic nephrotic syndrome. 2) The mean onset age was $7.53{\pm}5.5$ years, and the male to female ratio was 3.8:1 in childhood onset and 2.5:1 in adolescent onset with male predominance. 3) Hematuria was associated with $17\%$ of childhood onset and $39.3\%$ of adolescent onset disease(P=0.005). Hypertension appeared in $0.5\%\;and\;7\%$ in each group without significant difference between the groups. 4) 24 hour urine protein, SPI, albumin, BUN, cholesterol level showed no significant difference. 5) The response of childhood onset and adolescent onset MCNS to steroid therapy showed complete remission in $11.7\%\;&\;14.7\%$, infrequent relapsing in $29.2\%\;&\;28.5\%$, frequent relapsing in $23.9\%\;&\;14.7\%$, steroid dependent in $21.8\%\;&\;28.6\%$ each. Steroid resistant showed $13.3\%\;&\;14.7\%$ with no significance. 6) Immunosuppresant therapy was performed $57\%$ in childhood onset and $65\%$ in adolescent onset. 7) Mean number of relapse and duration from onset to first relapse showed no significance between two groups. Conclusion : Our results indicate that the incidence of hematuria, the rate of steroid dependent and frequent relapsing, and the recurrence rate were higher in adolescent MCNS; showed poorer steroid responsiveness and prognosis. Our data also point to the need for a more aggressive therapy to treat and make recommendations for the adolescent population as a whole.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.388-394
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• 2014

BACKGROUND: Aclonifen is used as a systemic and selective herbicide to control a wide spectrum broad-leaf weeds by inhibition carotenoid biosynthesis, and then its MRLs(Maximum Residue Limits) will be determined in onion and garlic. In this study, a new official method was developed for aclonifen determination in agricultural products to routinely inspect the violation of MRL as well as to evaluate the terminal residue level. METHODS AND RESULTS: Aclonifen was extracted from crop samples with acetone and the extract was partitioned with dichloromethane and then purified by silica solid phase extraction(SPE) cartridge. The purified samples were detected GC using an ECD detector. Limits of detection(LOD) was 0.001 mg/kg and quantification(LOQ) was 0.005 mg/kg, respectively. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, $10{\times}LOQ$, $50{\times}LOQ$, n=5). The recoveries were ranged from 74.3 to 95.0% with relative standard deviations(RSDs) of less than 8%. All values were consistent with the criteria ranges requested in the Codex guidelines(CAC/GL 40). CONCLUSION: The proposed analytical method was accurate, effective and sensitive for aclonifen determination and it will be used to as an official method in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.360-364
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• 1990

To testy time division scheme, we performed some experiments in a circular water tank(13m in diameter and 1m deep). A result of that is shown in figure 4. The 2-dimensional position of the pinger was calculated by the method of hyperbolic line of position calculation. The resolution of the time difference on the base line is 2.5cm. In experiments, the multiple pingers of a single frequency were distinguished and tracked successfully. When the experiment is carried out in the water tank, some multi-path pulses always occur. To delete it, several 10 ms of time delay is inserted onto the program after a group of the normal signals are received. Some normal pulses are not received by the time delay, however there is no problem, practically, for the distinction and the tracking of the pulse. In 2-dimensional positioning, the pinger position can be calculated with three hydrophones. However, if four hydrophones are available, the positioning accuracy will be higher than three hydrophones only by some techniques. Another good feature of the use of four hydrophones is that the positioning of the pinger is capable if a hydrophone fails in receiving them. We also tested this distinguishing method in the field using another type pingers(APPENDIXA).

• Journal of Korea Foresty Energy
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• v.19 no.2
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• pp.93-101
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• 2000

Wood of Robinia pseudoacacia and bark of Populus alba$\times$P. glandulosa, Fraxinus rhynchophylla and Ulmus davidiana var. japonica were collected and extracted with acetone-water(7:3, v/v) in glass jar to examine whether its bioactive compounds exist. The concentrated extracts were fractionated with hexane, chloroform, ethylacetate and water, and then freeze-dried for column chromatography and bioactive tests. The isolated compounds were sakuranetin-5-O-$\beta$-D-glucopyranoside from Populus alba $\times$Pl glandulosa, 4--ethyoxy-(+)-leucorobinetinidin frm R. pseudoacacia and fraxetion from F. rhynchophylla and were characterized by $^1H$ and$^{13}C $ NMR and positive FAB-MS. Decay-resistant activity was expressed by weight loss ratio and hyphae growth inhibition in the wood dust agar medium inoculated wood rot fungi. R. pseudoacacia showed best anti-decaying property in both test and its methanol untreated samples, indicating higher activity than methanol treated samples in hyphae grwoth test. In antioxidative test, $\alpha$-tocopherol, one of natural antioxidants, and BHT, one of synthetic antioxidants, were used as references to cmpare with the antioxidant activities of the extacted fractions. Ethylacetate fraction of F. rhynchophylla bark indicated the hightest activity in this test and all fractions of R. pseudiacacia extractives also indicated higher activities compared with the other fractions. In the isolated compounds, aesculetin isolated from F. rhynchophylla bark showed best activity and followed by robonetinidin from R. pseudoacaica.

• Korean Journal of Environmental Biology
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• v.22
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• pp.1-10
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• 2004

We conducted three experiments to estimate the toxicity of POPs (persistent organic pollutants) on two copepod species (Acartia erythraea and A. omorii) and Artemia sp.; (1) 48 h-LC$_{50}$ of A. omorii with the five PAHs [polycyelic aromatic hydrocarbons anthracene, benzo〔a〕pyrene, fluoranthene, phenanthrene, pyrene〕 which were often detected in the Gwangyang Bay, (2) toxicity of benzo〔a〕pyrene and TBT on Artemia in different temperatures (1$0^{\circ}C$, 15$^{\circ}C$, 2$0^{\circ}C$), (3) effects of benzo〔a〕pyrene and TBT on egg Production rate, hatching rate and fecal Pellet Production of two copepod species (A. erythraea and A. omorii) fed on Heterocapsa triquetra (dinoflagellate) exposed in benzo〔a〕pyrene. Toxic chemicals which were most effective to A. omorii were flueranthene (48 h-LC$_{50}$ 19.20 $\mu\textrm{g}$ L$^{-1}$ ) and benzo〔a〕pyrene (48 h-LC$_{50}$ 29.89 $\mu\textrm{g}$ L$^{-1}$ ). The toxi- city of chemicals to Artemia increased when temperature increased. The toxicity of TBT was about 100 times higher than that of benzo〔a〕pyrene at 15$^{\circ}C$. Food materials (Heterocapsa triquetra) exposed in benzo〔a〕pyrene, affected negatively the rate of egg production, hatching rate and the fecal pellet production of the copepods at the high concentration. It is suggested that an increase in the concentration of benzo〔a〕pyrene might offset the production of copepods in marine ecosystems. This study suggests that copepods may be used as n indicator for early warning of the risk of POPs in marine ecosystems.