• Journal of Life Science
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• v.21 no.6
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• pp.819-828
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• 2011

To inspect norovirus contamination of groundwater in south eastern areas of Korea, a systematic survey of groundwater in Busan, Ulsan, and Gyeongsangnam-do was performed for two years from 2009 to 2010. For this purpose, we first optimized the nested reverse transcription-PCR condition by designing two sets of primers for the detection of norovirus genogroups, GI and GII. Of 145 samples, 21 (25.9%) and 15 (23.4%) were norovirus positive in the dry season (April to June) and wet season (July to August), respectively. The detection frequencies of norovirus in Busan, Ulsan, and Gyeongsangnam-do were 15%, 7%, and 32%, respectively, reflecting a geographical difference in their distribution. The GI and GII isolates were 5 and 31, respectively, indicating the prevalence of GII in the tested areas. According to phylogenetic analysis of their nucleotide sequences, all of the GI isolates were identified to genotype GI.5 whilst the GII isolates were divided into two genotypes, GII.3 and GII.4. Neither physical-chemical parameters such as pH, temperature, oxidation-reduction potential, and dissolved oxygen, nor microbial indicators of water quality such as total bacteria, total coliforms, and Escherichia coli were statistically correlated with contamination of norovirus in the groundwater. Interestingly, however, the presence of norovirus was closely correlated with low turbidity (<0.50 NTU). The present study suggests that periodical monitoring of norovirus in groundwater is necessary to prevent epidemic waterborne diseases and to secure better sanitary conditions for public health.

• Journal of Preventive Medicine and Public Health
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• v.43 no.5
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• pp.369-376
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• 2010

Objectives: The purpose of this study was to examine the associations of current body weight and body mass index (BMI) at age three and birth weight in developing chronic respiratory illness in childhood and identify possible interaction underlying its mechanism. Methods: The study was carried out with 422 children who were enrolled in a hospital-based birth cohort. Birth related anthropometric data were collected at birth. At age 3 years, the presence of respiratory symptoms was evaluated by using the Korean version of core questionnaire for wheezing and asthma from the International Study of Asthma and Allergies in Childhood (ISAAC). Physical examination was carried out to measure the child's weight and height. Results: Children in the lowest birth weight tertile (aOR = 3.97, 95% CI = 0.94-16.68) or highest BMI tertile (aOR = 3.68, 95% CI = 1.24-10.95) at three years of age were at an increased risk of chronic respiratory illness. Children who were initially in the lowest birth weight tertile but now belong in the highest weight tertile had higher risk of chronic respiratory illness compared to those who had remained in the middle tertile (OR=16.35, 95% CI=1.66-160.57). Conclusions: Children with lower birth weight or higher BMI were at an increased risk of chronic respiratory illness. In addition, children who were initially in the lowest birth weight tertile but are now in the highest weight tertile had higher risk of chronic respiratory illness compared to those who remained in the middle tertile.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.361-368
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• 2016

As the tertiary industry is being developed, many problems are introduced in an industrial area in Korea. This study aims to investigate the residents' health conditions, such as the prevalence of metabolic syndrome and fatty liver diagnosed by ultrasonography, comparing the urban with the industrial areas. The subjects were 378 adults in the urban area and 376 adults in the industrial area. Subject variables accounted for were gender, age, drinking habits, smoking habits, physical activities, waist circumferences and BMI. In blood tests, fasting blood glucose, triglyceride, HDL, blood pressures, total cholesterol, AST, ALT and GGT were examined. Also, the presence and absence of fatty liver, diagnosed using ultrasonography, was investigated. As a result, the prevalence of metabolic syndrome were 43.7% in the urban area and 51.6% in the industrial area, hence it was significantly higher in the industrial area than in the urban area. Fasting blood glucose, triglyceride and waist circumference in the distribution of the individual components were 47.4, 53.7, and 16.1% in the urban area and 54.5, 61.5, and 22.9% in the industrial area respectively, so it was substantially higher in the industrial area than in the urban area. On the other hand, HDL, diastolic blood pressure, and fatty liver were 25.7, 43.4, and 44.7% in the urban area and 21.3, 19.9, and 36.7% in the industrial area respectively and thus it was much higher in the urban area than in the industrial area. In conclusion, this study shows that there were significant differences between the residents' health condition, comparing the urban area to the industrial area. Therefore, the precaution and aggressive management of metabolic syndrome may be necessary, in accordance with the characteristics of the industrial zone.

• Journal of Mushroom
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• v.17 no.4
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• pp.191-196
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• 2019

The edible ectomycorrhizal mushroom Amanita javanica is a valuable species protected by forest law in Korea. However, basic characterization data on its use as an important forest resource has been limited. This study was performed to determine mycelia growth characteristics of the domestically isolated Amanita javanica strain NIFoS 1267 on potato dextrose agar media under diverse culture conditions. Physical factors temperature, pH, and light, as well as chemical factors salts, heavy metals, and pesticides were examined for their effects on the growth of the mushroom strain. The mycelia of A. javanica strain exhibited optimal growth when cultured in dark at 30℃ in media with a pH of 5-6. Normal levels of growth were observed in media containing up to 2% saline. At a heavy metal ion content of 50 ppm, mycelial growth was not affected by arsenic ion but was affected by cadmium and lead ions. In the tests performed with two pesticides used in Korean forests, the growth of the mushroom strain was not affected by the presence of abamectin, but was inhibited in media containing acetamiprid, emamectin benzoate, or thiacloprid. These results are expected to facilitate artificial cultivation of A. javanica as a new commercial product.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.312-312
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• 2012

Magnesium oxide has become focus for research activities due to its use in magnetic tunnel junctions and for understanding of do ferromagnetism. Theoretical investigations on such type of system indicate that the presence of defects greater than a threshold value is responsible for the magnetic behaviour. It has also been shown experimentally that by decreasing the film thickness and size of nanoparticles, enhancement/increase in magnetization can be achieved. Apart from the change in dimension, swift heavy ions (SHI) are well known for creating defects and modifying the properties of the materials. In the present work, we have studied the irradiation induced effects in magnesium oxide thin film deposited on quartz substrate via X-ray absorption spectroscopy (XAS). Magnesium oxide thin films of thickness 50nm were deposited on quartz substrate by using e-beam evaporation method. These films were irradiated by 200 MeV Ag15+ ion beam at fluence of $1{\times}10^{11}$, $5{\times}10^{11}$, $1{\times}10^{12}$, $3{\times}10^{12}$ and $5{\times}10^{12}ions/cm^2$ at Nuclear Science Centre, IUAC, New Delhi (India). The grain size was observed (as studied by AFM) to be decreased from 37 nm (pristine film) to 23 nm ($1{\times}10^{12}ions/cm^2$) and thereafter it increases upto a fluence of $5{\times}10^{12}ions/cm^2$. The electronic structure of the system has been investigated by X-ray absorption spectroscopy (XAS) measurements performed at the high energy spherical grating monochromator 20A1 XAS (HSGM) beamline in the National Synchrotron Radiation Research Center (NSRRC), Taiwan. Oxides of light elements like MgO/ZnO possess many unique physical properties with potentials for novel application in various fields. These irradiated thin films are also studied with different polarization (left and right circularly polarized) of incident x-ray beam at 05B3 EPU- Soft x-ray scattering beamline of NSRRC. The detailed analysis of observed results in the wake of existing theories is discussed.

• Membrane Journal
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• v.28 no.3
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• pp.187-195
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• 2018

In this work, the morphology of polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) membranes were systemically investigated using phase inversion technique, to target membrane contactor applications. As the presence of macrovoids degrade the mechanical integrity of the membranes and jeopardize the long-term stability of membrane contactor processes (e.g. wetting), a wide range of dope compositions and casting conditions was studied to eliminate the undesired macrovoids. The type of solvent had significant effect on the membrane morphology, and the observed morphology were correlated to the physical properties of the solvent and solvent-polymer interactions. In addition, to fabricate macrovoid-free structure, the effects of different coagulation temperatures, inclusion of additives, and addition of nonsolvents were investigated. Due to the slow crystallization rate of P(VDF-co-HFP) polymer, it was found that obtaining porous membrane without macrovoids is difficult using only nonsolvent-induced phase separation method (NIPS). However, combined other phase inversion methods such as evaporation-induced phase separation (EIPS) and vapor-induced phase separation (VIPS), the desired membrane morphology can be obtained without any macrovoids.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.547-551
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• 1994

A series of samples in the $Nd_{1-x}Ba_xFeO_{3-y}$ system has been prepared by heating the reactants to$1200^{\circ}C$ under an ambient atmosphere, and the solid solutions were identified by X-ray power diffraction analysis. The crystal systems of samples with x = 0.00 and 0.25 were found to be orthorhombic whose local symmetry is similiar to the distorted octahedral with orthoferrite type one, whereas those with x = 0.50 and 0.75 to be the cubic system. Since Fe ions in the solid solutions are a mixed valence state between $Fe^{3+}\;and\;Fe^{4+}$ ions, the nonstoichiometric chemical formulas could be determined from the mole ratio of $Fe^{4+}$ ion and oxygen vacacies. According to the Mossbauer spectroscopic analysis, the presence of 5-coordinated $FeO_5$ was evidenced only in the barium compounds along with $FeO_6,\;and\;FeO_4$, but not in the strontium and calcium compounds. The samples with x = 0.25 and 0.50 show a spectrum of superparamagnetism, which might be due to the formation of a domain of the ferromagnetic interaction between the $Fe^{3+}\;and\;Fe^{4+}$ ions. The electrical conductivities of all samples are within semiconducting range. Since the $Fe^{4+}$ ion acts as an electron acceptor level during the electron transfer between the Fe through intermediate $O^{2-}$ ions, the activation energy of the compounds decreases with the increment of $Fe^{4+}$ content.

• Journal of Conservation Science
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• v.32 no.4
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• pp.549-560
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• 2016

The purpose of this study is to identify the material characteristics of blackwares excavated from the Bonggok kiln site in Jinan-gun, Jeollabuk-do Province, South Korea, by scientific analyses and a reproduction experiment. Scientific analyses were conducted to determine the physical properties, chemical composition and for microscopic observation of blackwares. A reproduction experiment was also conducted by producing ceramic samples with black glaze, red ocher and limestone, and then cross sections of the samples were observed. The analysis results showed that all the excavated blackwares have similar properties such as chromaticity, specific gravity, absorption factor and porosity, but there is a difference depending on the crystallization of the ceramics. Thermal analysis showed that the exothermic peak was observed at about $1200^{\circ}C$, and crystal structure analysis indicated the presence of mullite. Hence, it can be concluded that the firing temperature of the excavated blackwares was around $1100-1200^{\circ}C$. Moreover, the glaze present on these blackwares has about 22% higher $Fe_2O_3$ content than those excavated from other places; however, the former has lower CaO content. For the reproduction experiment, samples were made using limestone as a flux and red ocher as a glaze. The results show that the cross section of the glaze layer of the reproduced sample have iron crystals with dendritic structures, similar to those present in the excavated black-wares. It is assumed that such iron crystals were formed during the process of melting and solidification of the iron oxide present in the blackwares.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.1
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• pp.13-17
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• 2009

Purpose: The purpose of this study was to know the cause of the tenderness at pes anserinus. Materials and Methods: Out of 24 patients with tenderness at pes anserinus, 23 patients were female and 1 patient was male, and their average age was 65.9 years old. We checked the tenderness at pes anserinus by history taking & physical examniation and then, checked the pes anserinus for the presence of bursitis by US in outpatient clinic. With no evidence of bursitis by US, we injected steroid-lidocaine mixture intraarticularly and checked whether the tenderness disappeared after 2~3 minutes. Results: There was no case with bursitis at pes anserinus by US. The tenderness at pes anserinus diminished in 2-3 minutes after the intraarticular injection of the steroid-lidocaine mixture. After 6 weeks follow up, 16 patients(66.7%) had little or no tenderness at pes anserinus. 8 cases had the recurrence of tenderness recurred, 4 cases underwent arthroscopic operation on the meniscal tear, and 1 case underwent total knee arthroplasty. All cases underwent any operations had the tenderness at pes anserinus disappeared. The others 3 cases did not undergo total knee arthroplasty despite of radiologic obliteration of knee joint adequate for Kellgren-Lawrence grade IV. Conclusion: Without the bursitis at Pes Anserinus, patients the osteoarthritis may have the tenderness due to the referred pain.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.415-427
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• 1996

As a part of host factors of dental caries, saliva has been well known for its important role in relation to dental caries. The studies on its physical and chemical characteristics on development and progress of dental caries has been conducted. Recently, various comparisons between saliva of caries-susceptable individuals and caries-free individuals has been done and the efforts to understand the mechanisms of salivary intervention of development and progress of dental caries is actively in progress. In this study, 15 children with rampant dental caries and 15 caries free children without any systemic diseases from the ages of 2 to 5 were chosen for the experiment and the whole saliva and parotid saliva from each individuals were collected and protein compositions were compared using polyacrylamide gel electrophoresis (PAGE). As results of this study, in parotid saliva, there was no difference in protein compositions between the rampant dental caries and the caries free children. While electrophoresis was done with the whole saliva, protein with 120 KDa was found in children with rampant dental caries. However, this protein was not found or unclear, if any for the caries free group. (Exceptionally, clear protein band was present for one person.) Protein compositions of whole saliva of rampant dental caries group was compared before and after the caries control and thick and clear protein bands of about 120 KDa were found in both cases. Protein compostions of caries free children and adults were identical. Quantitative analysis of protein was done for the rampant dental caries group and the control group and no significant difference was found. Taken all together, protein with molecular weight of 120 KDa, found in rampant dental caries group, was still present when the treatment for the dental caries was done so it can be assumed that this protein has no interrelation with the presence of active carious lesions during saliva collecting. It can also be presumed that this specific salivary protein with the molecular weight of 120 KDa found in rampant dental caries group has effect on development and progress of dental caries. Identification on this protein with the molecular-weight of 120 KDa and the role of this protein against dental caries remain to be solved.