• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.62-69
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• 2014

In the results of monitoring nitrate concentration in more than 8,000 groundwater wells around agro-livestock, the average and maximum nitrate concentration was 9.4 mg/L and 101.2 mg/L, respectively. Since about 31% of the monitoring wells was exceed the quality standard for drinking water, nitrate control such as remediation or source regulation is required to conserve safe-groundwater in South Korea. Typical nitrate-treatment technologies include ion exchange, reverse osmosis, and biological denitrification. Among the treatment methods, biological denitrification by indigenous microorganism has environmental and economic advantages for the complete elimination of nitrate because of lower operating costs compared to other methods. Major mechanism of the process is microbial reduction of nitrate to nitrite and nitrogen gas. Three functional genes (nosZ, nirK, nirS) that encode for the enzyme involved in the pathway. In this work, we tried to develop simple process to determine possibility of natural denitrification reaction by monitoring the functional gene. For the work, the functional genes in nitrate-contaminated groundwater were monitored by using PCR with specific target primers. In the result, functional genes (nosZ and nirK) encoding denitrification enzymes were detected in the groundwater samples. This method can help to determine the possibility of natural-nitrate degradation in target groundwater wells without multiplex experimental process. In addition, for field-remediation application we selected nitrate-contaminated site where 200~600 mg/L of nitrate is continuously detected. To determine the possibility of nitrate-degradation by stimulated-natural attenuation, groundwater was sampled in two different wells of the site and nitrate concentration of the samples was 300 mg/L and 616 mg/L, respectively. Fumarate for different C/N ratio was added into microcosm bottles containing the groundwater to examine denitrification rate depending on carbon concentration. In the result, once 1.5 times more than amount of fumarate stoichiometry required was added, the 616 mg/L of nitrate and 300 mg/L of nitrate were completely degraded in 8 days and 30 days. The nitrite, byproduct of denitrification process, was also completely degraded during the experimental period.

• Tuberculosis and Respiratory Diseases
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• v.84 no.4
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• pp.291-298
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• 2021

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard diagnostic method for mediastinal and hilar lymphadenopathy. Although rare, fatal infectious complications can occur following EBUS-TBNA. However, to date, there is a lack of effective preventive strategies to reduce these complications. We started a trial to investigate the effect of chlorhexidine mouthrinse on the prevention of microbial contamination during EBUS-TBNA. Methods: This study is a single-center, parallel-group, assessor-blinded randomized controlled trial (RCT). We will enroll 112 adult participants undergoing EBUS-TBNA using a convex probe, and randomly assign them to two groups at a 1:1 ratio. The intervention group will gargle for 1 minute with 100 mL of 0.12% chlorhexidine gluconate before EBUS-TBNA, while the control group will have no mouthrinse before the procedure. Immediately after completion of EBUS-TBNA on all targeted lesions with an aspiration needle, a needle wash sample will be taken by instilling 5 mL of sterile saline into the used needle. The primary outcome is colony forming unit (CFU) counts in aerobic cultures of the needle wash samples. Secondary outcomes are CFU counts in anaerobic cultures, fever within 24 hours after EBUS-TBNA, and infectious complications within 4 weeks after EBUS-TBNA. Conclusion: This trial was designed as the first RCT to investigate the effect of chlorhexidine mouthrinse on the prevention of microbial contamination during EBUS-TBNA. Results from this trial can provide clinical evidence for a simple, safe, and cost-effective strategy to prevent infectious complications following EBUS-TBNA (ClinicalTrials.gov ID: NCT04718922, registered on 22 January 2021).

• Journal of the Korean Geotechnical Society
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• v.35 no.6
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• pp.39-48
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• 2019

This study investigated the lateral behavior of monopile embedded in the dry sand through cyclic lateral loading test using a centrifuge test. The sand sample for the experiment was the dry Jumunjin standard sand at 80% relative density and the friction angle of $38^{\circ}$. In the experimental procedure, firstly, it was determined the static lateral bearing capacity by performing the static lateral loading test to decide the cyclic load. This derived static lateral bearing capacity values of 30%, 50%, 80%, 120% were determined as the cyclic lateral load, and the number of cycle was performed 100 times. Through the results, the experiment cyclic p-y curve was calculated, and the cyclic p-y backbone curve by depth was derived using the derived maximum soil resistance point by the load. The initial slope at the same depth was underestimated than API (1987) p-y curves, and the ultimate soil resistance was overestimated than API (1987) p-y curves. In addition, the result of the comparison with the suggested dynamic p-y curve was that the suggested dynamic p-y curve was overestimated than the cyclic p-y backbone curve on the initial slope and soil resistance at the same depth. It is considered that the p-y curve should be applied differently depending on the loading conditions of the pile.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.334-339
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• 2019

A procedure based on high-performance liquid chromatography (HPLC) is described to determine ${\beta}-carotene$ in infant formulas. The method for ${\beta}-carotene$ analysis was performed on a C18 reversed-phase column using acetonitrile/methanol/dichloromethane (6:1:3, v/v/v) as a mobile phase. ${\beta}-Carotene$ was determined in HPLC with photo diode array (PDA) detector. The parameters of validation were specificity, linearity, LOD, LOQ, accuracy, precision and repeatability. The specificity was confirmed by the retention time and the linearity ($R^2$), which was over 0.999 in the range of 0.125~2 mg/L. The detection and quantification limits were 0.064 and 0.193 mg/L, respectively. The accuracy and precision of this method using an STD spiked sample were 80~119% and 1.02~2.05% respectively. The method was applied to the analysis of various infant formula and follow-up formulas products containing ${\beta}-carotene$, and all the products contained acceptable levels of ${\beta}-carotene$ for nutrition labeling.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.89-100
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• 2019

Sleep apnea, a medical condition associated with a variety of complications, is generally monitored by standard sleep polysomnography, which is expensive and uncomfortable. To overcome these limitations, this study proposes an unconstrained wearable monitoring system with stretch-fiber sensors that integrate with the wearer's clothing. The system allows patients to undergo examinations in a familiar environment while minimizing the occurrence of skin allergies caused by adhesive tools. As smart clothing for adult males with sleep apnea, long-sleeved T-shirts embedding fibrous sensors were developed, enabling real-time monitoring of the patients' breathing rate, oxygen saturation, and airflow as sleep apnea diagnostic indicators. The gauge factor was measured as 20.3 in sample 4. The maximum breathing intake, measured during three large breaths, was 2048 ml. the oxygen saturation was measured before and during breath-holding. The oxygen saturation change was 69.45%, showing a minimum measurable oxygen saturation of 70%. After washing the garment, the gauge factor reduced only to 18.0, confirming the durability of the proposed system. The wearable sleep apnea monitoring smart clothes are readily available in the home and can measure three indicators of sleep apnea: respiration rate, breathing flow and oxygen saturation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.227-236
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• 2018

This study was conducted to define hippocampal volume differences between a stress-laid group and normal individual group via meta-analysis. This investigation included studies that contained hippocampal volume measurements in association with stress from 1990 to 2016. Magnetic resonance imaging (MRI) measurements of hippocampal volumes were used to determine the mean size, standard deviation and sample size. The pooled effect size was measured by the standardized mean difference (SMD) with a 95% confidence interval. This meta-analysis included 13 studies comprising 374 stress subjects and 439 normal subjects. Eight studies targeted war-related veterans and holocaust survivors, while five targeted personal trauma associated with childhood abuse, rape, accident or financial hardship. The overall mean effect size (Hedges' g) was -0.70 (-1.04; -0.37). Overall, the SMD value was -0.70, with a moderate effect size, but high heterogeneity. Depending on the characteristics of the stressor, studies were divided by subgroups of war-related veterans and subjects with personal trauma and then analyzed again. In the war-related subgroup, the Hedges' g was -0.47 (-0.78; -0.16), while in the personal stressor-related subgroup it was -0.91 (-1.57; -0.26). These results indicate that there was a significant negative correlation between psychological stress and hippocampal volume.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.2
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• pp.106-115
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• 2021

Sperm cryopreservation is an important method of assisted reproductive techniques and storing genetic resources. It plays a vital role in genetic improvement, livestock industrial preservation of endangered species, and clinical practice. Consequently, the cryopreservation technique is well organized through various studies, especially on Korean native cattle (Hanwoo). However, the cryopreservation technique of Korean native brindled cattle, which is one of the native cattle species in Korea, is not well organized. Therefore, it is necessary to develop a Supplementary Table technique for the cryopreservation of Korean native brindled cattle. For this purpose, it is important to first evaluate the quality of the currently produced cryopreserved sperm of Korean native brindled cattle. In this study, we randomly selected 72 individual Korean native brindled cattle semen samples collected from 8 different region research centers and used them to evaluate sperm functions. We focused on the quality evaluation of cryopreserved Korean native brindled cattle semen following the measurement of motion kinematics, capacitation status, intracellular ATP level, sperm motility, and cell viability. Then, the values of each of the eight groups were derived from various sperm parameters of nine individual samples, including sperm motility, kinematics, cellular motility, and intracellular ATP levels, which were used to compare and evaluate sperm function. Overall, differences in various sperm parameters were observed between most of the research centers. Particularly, the deviations of motility and motion kinematics were high according to the sample. Therefore, we suggest that it is necessary to develop a standard method for the cryopreservation of Korean native brindled cattle semen. We also suggest the need for sperm quality evaluation of the cryopreserved semen of Korean native brindled cattle before using artificial insemination to attain a high fertility rate.

• Journal of Korea Foundry Society
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• v.41 no.1
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• pp.26-38
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• 2021

The status of Ppuri industry, including foundry industry was analyzed through statistical surveys over the past 10 years from 2009 to 2018, and summarized for each six Ppuri industries' points of view. Various statistics of Ppuri industry defined by the KSIC (Korean Standard Industry Classification) was obtained, and the status of Ppuri industry was identified through a sample survey of 5,000 companies from more than 30,000 target business companies of Ppuri industry. Throughout the analyzing process, we presented a variety of indicators, such as the number of the Ppuri companies and its ratio, regional distribution through Korean provinces, number of workers, characteristics by age group, sales, profit rates, etc. By devising a comparative method to measure the relative strength of Ppuri industry in Korea, Germany, and Japan, we have presented the competitiveness index change over the 10 years of time. The competitiveness index can be effectively and meaningfully used during various activities of the development of Ppuri industry in the forth coming future. With the current obtained data, we figured out the status of each 6 Ppuri industries, regional distribution, status of workers, sales and profit rates. We also suggested various proposals for strategy and policy making for each sector with urging voluntary response from Ppuri industry.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.655-666
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• 2020

This study evaluated the characteristics of arsenic production in groundwater through microbial community analysis of groundwater contaminated with high arsenic in Haman area. Groundwater in Haman area is contaminated with arsenic in the range of 0-757.2 ㎍/L, which represents the highest arsenic contamination concentration reported in Korea as natural groundwater pollution source. Of the total 200 samples, 29 samples (14.5%) showed higher arsenic concentration than that of 10 ㎍/L, which is the standard for drinking water quality, and 8 samples (4%) found in wells with 80-100 m depth were above 50 ㎍/L. In addition, seven wells with arsenic concentration more than 100 ㎍/L located in the northern part of Haman. As a result of microbial community analysis for high arsenic-contaminated groundwater, the microbial community compositions were significantly different between each sample, and Proteobacteria was the most dominant phyla with an average of 61.5%. At the genus level, the Gallinonella genus was predominant with about 12.8% proportion, followed by the Acinetobacter and Methermicoccus genus with about 7.8 and 7.3%, respectively. It is expected that high arsenic groundwater in the study area was caused by a complex reaction of geochemical characteristics and biogeochemical processes. Therefore, it is expected that the constructed information on geochemical characteristics and microbial communities through this study could be used to identify the origin of high arsenic groundwater and the development of its controlling technology.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.455-465
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• 2011

In order to assess and mitigate climate change, the role of forest biomass as carbon sink has to be understood spatially and quantitatively. Since existing forest statistics can not provide spatial information about forest resources, it is needed to predict spatial distribution of forest biomass under an alternative scheme. This study focuses on developing an upscaling method that expands forest variables from plot to landscape scale to estimate spatially explicit aboveground biomass(AGB). For this, forest stand variables were extracted from National Forest Inventory(NFI) data and used to develop AGB regression models by tree species. Dominant/codominant height and crown density were used as explanatory variables of AGB regression models. Spatial distribution of AGB could be estimated using AGB models, forest type map and the stand height map that was developed by forest type map and height regression models. Finally, it was estimated that total amount of forest AGB in Danyang was 6,606,324 ton. This estimate was within standard error of AGB statistics calculated by sample-based estimator, which was 6,518,178 ton. This AGB upscaling method can provide the means that can easily estimate biomass in large area. But because forest type map used as base map was produced using categorical data, this method has limits to improve a precision of AGB map.