• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.10-19
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• 2020

BACKGROUND: This study was to carry out risk assessment of contamination of cadmium (Cd), lead (Pb), and inorganic arsenic (I-As) in agricultural products of 25 crops from the abandoned mine areas. The 36 typical investigation sites located in Gyeongbuk provincial area were selected by considering the heavy metal levels, that had been known that the amount of the heavy metals exceeded the contamination level based on the previous survey. METHODS AND RESULTS: Cadmium, lead, and total arsenic (T-As) concentrations were determined using microwave device and ICP-MS. Inorganic arsenic was determined by HPLC-ICP-MS. The limits of quantification for heavy metals were 0.59 ㎍/kg for Cd, 0.42 ㎍/kg for Pb, 0.55 ㎍/kg for T-As, and sum of As (III) (1.74 ㎍/kg) and As (V) (2.25 ㎍/kg) for I-As, respectively. The contents of Cd, Pb, and I-As (only rice) were N.D.-0.958 mg/kg, N.D.-0.227 mg/kg, and 0.082 mg/kg, respectively, in the agricultural products. For risk assessment, dietary exposures of heavy metals through usual intake were 5.20×10^-4-7.15×10⁰ ㎍/day for Cd, 7.00×10^-5-7.75×10^-1 ㎍/day for Pb, and 1.17×10¹ ㎍/day for I-As, taking 0.01-14.37%, 0.01-2.05%, and 15.16% as risk indices, respectively. CONCLUSION: It requires to consider the critical levels of heavy metals in agricultural products due to unexpectedly high levels in a few places, while concentrations of heavy metals in the samples were relatively low in most areas.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.245-254
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• 2002

Objective : To test if the intake of $H_2$ receptor antagonists ($H_2$-RAs) increases the risk of gastric cancer in the elderly. Methods : The source population for this study was drawn from the responders to a questionnaire survey administered to the Korea Elderly Pharmacoepidemiological Cohort (KEPEC), who were beneficiaries of the Korean Medical Insurance Corporation, were at least 65 years old, and residing in Busan in 1999. The information on $H_2$-RAs exposure was obtained from a drug prescription database compiled between inn. 1993 and Dec. 1994. The cases consisted of 76 gastric cancer patients, as confirmed from the KMIC claims data, the National Cancer Registry and the Busan Cancer Registry. The follow-up period was from Jan. 1993 to Dec. 1998. Cancer free controls were randomly selected by 1:4 individual matching, which took in to consideration the year of birth and gender. Information on confounders was collected by a mail questionnaire survey. The odds ratios, and their 95% confidence intervals, were calculated using a conditional logistic regression model. Results : After adjusting for a history of gastric ulcer symptoms, medication history, and body mass index, the adjusted OR (aOR) was 4.6 (95% CI=1.72-12.49). The odds ratio of long term use (more than 7 days) was 2.3 (95% CI=1.07-4.82). The odds ratio of short term use was 4.6 (95% CI=1.26-16.50). The odds ratio of parenteral use was 4.4 195% CI=1.16-17.05) and combination use between the oral and parenteral routes (aOR, 16.8; 95% CI=1.21-233.24) had the high risk of gastric cancer. The aOR of cimetidine was 1.7 (95% CI=1.04-2.95). The aOR of ranitidine was 2.0 (95% CI=1.21-3.40). The aOR of famotidine was 1.7 (95% CI=0.98-2.80). Conclusion : The intake of $H_2$-RAs might increase the risk of gastric cancer through achlorhydria in the elderly.

• Research in Plant Disease
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• v.23 no.2
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• pp.150-158
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• 2017

Pear scab caused by Venturia nashicola has been reported as an important disease of pear resulting in lowering the quality of pear fruits. In this study, it was conducted to investigate the relationship between resistance of V. nashicola and mutation of ${\beta}$-tubulin gene and the fungicide resistance in field isolate group in benzimidazole fungicides. Responce of V. nashicola to carbendazim could be classified into 3 groups as sensitive that does not grow at all on PDA amended with $0.16{\mu}g/ml$ of carbendazim, low resistance that could not grow in $4.0{\mu}g/ml$ medium, and high resistance that can grow even at $100{\mu}g/ml$. Thirty isolates of V. nashicola collected from 3 regions as Wonju, Naju, and Okcheon were highly resistant to carbendazim. Analysis of the nucleotide sequence of ${\beta}$-tubulin gene of V. nashicola showed that there was no difference in the nucleotide sequence between the sensitive and the low-resistant isolate, but GAG at codon 198 (glutamic acid) was replaced with GCG (alanine) in the high-resistant isolate. Among 10 isolates obtained from the Okcheon, 5 isolates showed the substitution of glycine for glutamic acid, which were resistant to carbendazim, but more sensitive to the mixture of carbendazim and diethofencarb than others. Through these results, all isolates of V. nashicola isolated in pear orchard were found to be resistant to benzimidazoles. Also, mutants E198A and E198G at ${\beta}$-tubulin were found to be important mechanisms of V. nashicola resistance against benzimidazole fungicides.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.539-546
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• 2009

The effect of hemorrhage on the electroencephalogram(EEG) was investigated in fifteen mixed-breed dogs anesthetized with ketamine, propofol and isoflurane. Animals were randomly allocated to three groups (n = 5) by anesthetic agents; group 1 (ketamine 5 mg/kg, IV), group 2 (propofol $156\;{\mu}g$/kg/min, IV) and group 3 (isoflurane 2.0% end-tidal concentration). Medetomidine ($40\;{\mu}g$/kg, IM) was used in all dogs as a preanesthetic agent. Recording electrode for EEG was positioned at CZ. EEG, heart rate, systolic/diastolic blood pressure, $pCO_2$, $pO_2$ and blood pH were measured before anesthesia, after anesthesia and after every bleedings. Three bleedings were accomplished by drawing blood through the femoral artery catheter at a rate of 7 ml/kg (10% of total blood volume) for 10 minutes. In the course of hemorrhage, a systolic/diastolic pressure continuously decreased in all groups. The $pCO_2$ values and heart rates were increased in all groups. The $pO_2$ values were most significantly increased in group 1 compared with those in other groups. The pH values were not significantly changed. On statistical analysis of EEG, there was no significant changes in group 1 and 3. But in group 2, band 3, 4 and 7 were significantly altered after 2nd and 3rd bleeding. Power alterations of band 3, 4 and 7 were thought to be related with hemorrhage over 20% of total blood volume in group 2. In conclusion, the regulation of infusion rate would be considered when a dog, anesthetized with propofol, bleed over 20% of total blood volume.

• Korean Journal of Organic Agriculture
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• v.16 no.4
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• pp.435-453
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• 2008

The crop rotation is very important in the organic agriculture and the soybean crop should be included in the rotation. Even though the inoculation of the root can be performed by the soil inoculation in the soybean crop, the effect of the soil inoculation should be proved in the organic soil. For the research of the effects in the formation of the nodule of soybeans, the growth and the quantity through the inoculation into the soil, the field experiment was conducted in 2006 at Ipjang Experimental Farm of Dankook University. The number of nodule in the testing varieties of the inoculated soil plot was $1.4{\sim}2$ times larger than those in the non-inoculated soil plot. The number of nodule was decreased in the non-inoculated soil plot after R2 stage, but it was increased in the inoculated before R4 stage and it was decreased after then. The periodical change of weight of the nodule was shown as same as the number of nodule. The dry weight of inoculated was increased than non-inoculated in Daewonkong, but it was decreased than non-inoculated in Shinpaldalkong2 and SS2-2. The amount of chlorophyll of the inoculated soil plot was more than the non-inoculated soil plot by 9% in Daewonkong, but the inoculated soil plot was less than the non-inoculated soil plot by 13%, 33% each in Shinpaldalkong2 and SS2-2. The number of pods, the number of grains and the weight of grains in the yield characteristics of the inoculated soil plot were more than in the non-inoculated soil plot in Daewonkong, but the number of pods, grains and the weight of grains in the yield result in the inoculated soil plot was less than in the non-inoculated soil plot in Shinpaldalkong2 and SS2-2. The mean yield(per 10a) of Daewonkong was increased 11% in the inoculated soil plot, but the mean yeil(per 10a) of Shinpaldalkong2 was decreased 4% and SS2-2 was also decreased 23%.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.117-126
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• 1999

Hampyong Bay is a semienclosed and macrotidal bay which opens to the eastern Yellow Sea through a narrow inlet in the southwestern coast of Korea. In order to understand the tidal-flat sedimentation in the semienclosed setting, morphology, sediments, accumulation rate and sea cliff erosion were investigated in the tidal flat of Hampyong Bay. The tidal flat of Hampyong Bay lacks intertidal drainage systems, and generally shows the concave-upward profile whose relief is designated by marked morphological features such as high-tide beaches, intertidal sand shoals and tidal creeks. Surfacial sediments of the tidal flat mainly consist of mud, sandy mud, gravelly mud, gravelly sand and muddy gravel, thus showing the textural characteristics of multimodal grain-size distribution, poorly sorting and positive skewness. The sediments generally coarsen landward due to the increase in coarse fraction content. Sedimentary structures are deeply bioturbated, but parallel lamination and lenticular bedding are locally found in the mudflat near mean low water line. Annual accumulation rates across the tidal flat (along Line SM) average -5.2 cm/yr with a range of -45.8~+4.2 cm/yr, indicating that the tidal flat is erosional. In general, erosion rates of upper and lower tidal flat are higher than those of middle tidal flat. Seasonally, the erosion rates are much higher during spring and winter when dominant wind direction corresponds to the long axis of Hampyong Bay. Sea cliffs are eroded at a rate of 1.4 m/yr. The biggest sea cliff erosion generally occurs 1~2 months later after tidal flats were extensively eroded. Such erosions of tidal Oats and sea cliffs in the semienclosed bay setting are interpreted to be due to wind waves coupled with local sea-level rise.

• Korean Journal of Microbiology
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• v.48 no.3
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• pp.180-186
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• 2012

Pseudomonas aeruginosa, a Gram-negative bacterium, is an ubiquitous and opportunistic human pathogen, which expresses many virulence factors through quorum sensing (QS) regulation. QscR, one of the QS signal receptors of P. aeruginosa, has unique features that make it possible to distinguish QscR from other QS receptors. In the present study, we focused on amino acid residues responsible for such a broad signal specificity of QscR. Thus we constructed mutant QscRs: $QscR_{T72I}$, $QscR_{R132M}$, and $QscR_{T140I}$ by substituting $72^{nd}$ threonine, $132^{nd}$ arginine, and $140^{th}$ threonine residues with isoleucine, methionine, and isoleucine, respectively by site-directed mutagenesis. When we examined the activity of these mutant QscRs, $QscR_{R132M}$ failed to respond to N-3-oxododecanoyl homoserine lactone (3OC12-HSL), but $QscR_{T72I}$ and $QscR_{T140I}$ remained the ability to respond to 3OC12-HSL despite much reduction of the sensitivity. When we treated a variety of acyl-HSLs with different structure, $QscR_{T72I}$ and $QscR_{T140I}$ showed better responsiveness to N-decanoyl HSL (C10-HSL) or N-dodecanoyl HSL (C12-HSL) that has no oxo-moiety at $3^{rd}$ carbon of acyl group than to 3OC12-HSL, and $QscR_{R132M}$ showed no responsiveness to any acyl-HSLs tested here. In addition, $QscR_{T72I}$ and $QscR_{T140I}$ were inhibited by 5f, a QscR inhibitor as similarly as wild type QscR was. These results suggest that while the $130^{th}$ arginine is crucial in both activity and acyl-HSL binding of QscR, the $72^{nd}$ and $140^{th}$ threonines are important in the activity, but they are little responsible for the discrimination of acyl-HSLs or competitive inhibitor.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.585-592
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• 2004

Our previous studies demonstrated that relaxin in concert with estrogen promotes development of the mammary parenchyma during the last third of gestation in gilts, and the specific relaxin-binding sites were present in the mammary gland. This study was conducted to determine if relaxin-binding sites in the mammary gland were functional relaxin receptors. Three cycling cross-bred gilts were bilaterally ovariectomized on day 0 of the experiment. Beginning on day 15 and continuing through day 29 post-surgery, the gilt received an im. injection of estradiol benzoate at 12-hr intervals. Beginning on day 22 post-surgery, highly purified porcine relaxin was administered(lug/hr) into the left fourth mammary gland from the anterior end via miniature osmotic pump. Physiological saline was administered to the right fourth mammary gland. The gilt was sacrificed on day 29 post-surgery and histological characteristics of the mammary parenchyma were examined. The mammary glands treated locally with saline showed little, if any, lobulo-alveolar development, whereas the mammary glands treated with relaxin showed not only marked lobulo-alveolar development but also prominent secretions in the alveoli. The saline-treated glands were characterized by relatively dense and highly organized collagen fiber bundles. Whereas, in the relaxin-treated mammary glands, collagen fiber bundles were dispersed and loosely organized. In conclusion, relaxin-binding sites in the mammary gland are functional relaxin receptors and relaxin acts directly on the pig mammary gland to promote development of the alveoli and remodeling of the extracellular matrix.

• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.219-231
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• 1996

The aim here is to analyse the system of description of GIS in all of the high school textbooks passed with the official approval, to find the degree to which teachers understand about GIS, and to consider the present condition of GIS instruction. Most of the authors of textbooks generally underestimate importance of GIS, and there is difference among their awareness. In the system of description of GIS, there are only a few kinds of textbooks in which explanation of GIS is made coherently from the purpose of instruction aim through the chapter summary and to overall test in both of the Korean Geography and the World Geography. This trend is due to the degree of distribution of the GIS specialists in writing a textbook while the other texts books shows just a brief introduction of GIS concept. Although there is the limit for teachers to study how to teach GIS due to its very technological aspect as well as few previous training and teacher's guide. Thus it is evident that about a half of teachers who responded taught high school students without a knowledge on GIS, and a few of them even never referred to that concept. These facts may negatively affect the status of a geography in the society of information. For the solution of these issues, it is considered how to repair the description system and its contents. Besides, the variation among textbooks is reduced at the further revision of the 7th curriculum. And the printed matters of GIS are sufficiently provided for the teachers to use as their teaching aids. It is desirable that the GIS instruction models should be further developed for college education, and the programs for the on-the-job teachers training should be arranged. Besides, the previous training for the on-the-job teachers should be achieved more practically with enough time before the revision of curriculum.

• Development and Reproduction
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• v.11 no.3
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• pp.245-251
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• 2007

Vinclozolin(VCZ), a systemic dicarboximide fungicide, has been used in the control of diseases caused by microorganism of some species in fruits, vegatables and ornamental plants. Although VCZ itself is a very weak antagonist for androgen receptor binding, both melabolites M1 and M2 are effective antagonists. The present study was undertaken to examine whether prepubertal exposure to VCZ affects on the onset of puberty and the associated reproductive parameters such as hormone receptor expressions in female rats. VCZ(10 mg/kg/day) was administered daily from postnatal day 21(PND 21) through the day when the first vaginal opening(V.O.) was observed. Gross anatomy and weight of reproductive tissues were compared to test the VCZ's effects on the cell proliferation. Furthermore, histological studies were performed to assess the structural alterations in the tissues. To determine the transcriptional changes in progesterone receptor(PR), total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction(RT-PCR). As a result, delayed V.O. was shown in the VCZ group(PND $34.00{\pm}1.22$) compared to the control group(PND $38.20{\pm}1.92$; p<0.01). VCZ treatment significantly decreased the wet weight of ovaries and uteri compared to the control group(p<0.01). Graafian follicles and corpora lutea were observed only in the ovaries from the control animals, while numerous primary, secondary follicles and small atretic follicles were observed in the ovaries from VCZ group. Similarly, hypotrophy of luminal and glandular uterine epithelium was found in the VCZ group. In the semi-quantitative RT-PCR studies, the transcriptional activity of PR in ovary(p<0.01) from VCZ group were significantly lower than those from the control group while in uterus were similar compared with the control group. The present studies demonstrated that the acute exposure to VCZ during the critical period of prepubertal stage could inactivate the reproductive system resulting delayed puberty in female rats.