• Analytical Science and Technology
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• v.34 no.5
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• pp.193-201
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• 2021

We have demonstrated a sensitive analytical method of measuring oleracone D in mouse plasma using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Oleracone D and oleracone F (internal standard) in mouse plasma samples were processed using a liquid-liquid extraction method with methyl tertbutyl ether, resulting in high and reproducible extraction recovery (80.19-82.49 %). No interfering peaks around the peak elution time of oleracone D and oleracone F were observed. The standard calibration curves for oleracone D ranged from 0.5 to 100 ng/mL and were linear with r² of 0.992. The inter- and intra-day accuracy and precision and the stability fell within the acceptance criteria. The pharmacokinetics of oleracone D following intravenous and oral administration of oleracone D at doses of 5 mg/kg and 30 mg/kg, respectively, were investigated. When oleracone D was intravenously injected, it had first-order elimination kinetics with high clearance and volume of distribution values. The absolute oral bioavailability of this compound was calculated as 0.95 %, with multi-exponential kinetics. The low aqueous solubility and a high oral dose of oleracone D may explain the different elimination kinetics of oleracone D between intravenous and oral administration. Collectively, this newly developed sensitive LC-MS/MS method of oleracone D could be successfully utilized for investigating the pharmacokinetic properties of this compound and could be used in future studies for the lead optimization and biopharmaceutic investigation of oleracone D.

• The Journal of Information Systems
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• v.28 no.2
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• pp.153-179
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• 2019

Purpose This study collects the issues about work-life balance in Korea and United States and suggests the specific plans for work-life balance by the comparison and analysis. The objective of this study is to contribute to the improvement of people's life quality by understanding the concept of work-life balance that has become the issue recently and offering the detailed plans to be considered in respect of individual, corporate and governmental level for society of work-life balance. Design/methodology/approach This study collects work-life balance related issues through recruit sites in Korea and United States, compares and analyzes the collected data from the results of three text mining techniques such as LDA topic modeling, term frequency analysis and keyword extraction analysis. Findings According to the text mining results, this study shows that it is important to build corporate culture that support work-life balance in free organizational atmosphere especially in Korea. It also appears that there are the differences against whether work-life balance can be achieved and recognition and satisfaction about work-life balance along type of company or sort of working. In case of United States, it shows that it is important for them to work more efficiently by raising teamwork level among team members who work together as well as the role of the leaders who lead the teams in the organization. It is also significant for the company to provide their employees with the opportunity of education and training that enables them to improve their individual capability or skill. Furthermore, it suggests the roles of individuals, company and government and specific plans based on the analysis of text mining results in both countries.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.83-92
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• 2021

There are continuous and tremendous attempts to apply various sensor systems and ICTs into the dairy science for data accumulation and improvement of dairy productivity. However, these only concerns the fields which directly affect to the dairy productivity such as the number of individuals and the milk production amount, while researches on the physiology aspects of dairy cows are not enough which are fundamentally involved in the dairy productivity. This paper proposes the basic approach for extraction of daily behavior pattern from hourly behavioral data of dairy cows to identify the health status and stress. Total four clusters were grouped by k-means clustering and the reasonability was proved by visualization of the data in each groups and the representatives of each groups. We hope that provided results should lead to the further researches on catching abnormalities and disease signs of dairy cows.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.197-207
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• 2023

Concrete is a widely used material due to its excellent compressive strength and durability. However, depending on the surrounding environment and the characteristics of the materials used in the construction, various defects may occur, such as cracks on the surface and subsidence of the structure. The detects on the surface of the concrete structure occur after completion or over time. Neglecting these cracks may lead to severe structural damage, necessitating regular safety inspections. Traditional visual inspections of concrete walls are labor-intensive and expensive. This research presents a deep learning-based semantic segmentation model designed to detect cracks in concrete walls. The model addresses surface defects that arise from aging, and an image augmentation technique is employed to enhance feature extraction and generalization performance. A dataset for semantic segmentation was created by combining publicly available and self-generated datasets, and notable semantic segmentation models were evaluated and tested. The model, specifically trained for concrete wall fracture detection, achieved an extraction performance of 81.4%. Moreover, a 3% performance improvement was observed when applying the developed augmentation technique.

• Analytical Science and Technology
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• v.13 no.3
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• pp.297-303
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• 2000

Isotope-dilution inductively coupled plasma mass spectrometry was used to determine trace amounts of Cd, Cu, Pb, Ni and Zn in sediment. Sediment samples were dissolved by microwave digestion with addition of mixed acid ($HNO_3$, HF and $HClO_4$). Lead was determined after separation of alkaline and alkaline earth metals by an ammonium pyrrolidenedithiocarbarmate (APDC) solvent extraction. The other elements were determined after separation of iron, tin and titanium by hydroxide precipitation. Recovery efficiency of the analyte elements was not satisfactory, but most of matrix elements causing the isobaric interference could be effectively eliminated by the separation. Good agreement was achieved with the certified values in the analysis of the two sediment reference materials.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.694-698
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• 2004

A new method for the simultaneous determination of seven transition metal ions in water and food by microcolumn high-performance liquid chromatography has been developed. The lead, cadmium, mercury, nickel, cobalt, silver and tin ions were pre-column derivatized with tetra-(4-aminophenyl)-porphyrin ($T_4$-APP) to form the colored chelates which were then enriched by solid phase extraction with $C_{18}$ cartridge. The enrichment factor of 50 was achieved by eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The chelates were separated on a ZORBAX Stable Bound microcolumn ($2.0{\times}50\;mm,\;1.8\;{\mu}m$)with methanol-tetrahydrofuran (95 : 5, v/v, containing 0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0) as mobile phase at a flow rate of 0.5 mL/min and detected with a photodiode array detector from 350-600 nm. The seven chelates were separated completely within 2.0 min. The detection limits of lead, cadmium, mercury, nickel, cobalt, silver and tin are 4 ng/L, 3 ng/L, 6 ng/L, 5 ng/L, 5 ng/L, 6 ng/L, 4 ng/L respectively in the original samples. This method was applied to the determination of the seven transition metal in water and food samples with good results.

• Journal of The Korean Association of Information Education
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• v.17 no.1
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• pp.43-52
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• 2013

As a tool of programming education, a robot is effective in creative problem solving abilities and logical thinking skills. It also provides practical, operational learning experience to learners, when using as a tool of learning, it can help learners' specific understanding for the contents of education and lead to an active participation in learning. This research focuses on the robot's instrumental use in the mathematics class. So the lesson activities with relation to the fourth grade math curriculum were developed after the functional analysis of the robot and the extraction of educational utilization with function. The result shows that there wasn't a significant difference in achievement test but there was a positive response in the most of the survey items. It shows that robots lead to an active participation in class, to be interested in math class and were helpful to understand math concepts. There was also a positive response in the result of learner interviews such as dynamic, collaborative communication, experiential, practical lessons that are rare sights in normal math class.

• Journal of the Korean Society of Food Science and Nutrition
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• v.6 no.1
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• pp.73-79
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• 1977

Heavy metals in the rice and rice paddy soil of Kyung Nam district were surveyed by use of MIBK extraction and atomic absorption spectrophotomter. Mercury was analyzed by nom-flame mercury vapor method. Rice paddy soil showed that cupper amounted to the level of $13.8{\sim}8.4ppm$, average value of 11.5ppm. Lead: $2.6{\sim}0.6ppm$, average 0.02ppm. The conentration of heavy metal $0.04{\sim}0.01ppm$, average 1.5 ppm, Zinc ; $16.1{\sim}7.2ppm$, average 11.3 ppm. Cadmium in rice were containted $2.59{\sim}0.16ppm$ of cupper, average value of 1.80 ppm. Lead: $0.2{\sim}N.D$, Zinc ; $0.11{\sim}0.60ppm$. Cadmium was shown trace at 4 places and mercury was shown trace at 6 places. Cupper showed the highest ratio of heavy metal. Levels in rice and soil whereas zinc showed the highest transmission from soil to rice.

• Resources Recycling
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• v.15 no.6 s.74
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• pp.41-47
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• 2006

A study for recovering of copper and lead from electronic scraps has been carried out using a combination of bioleaching and solvent extraction. It was found that the citric acid generated by Aspergillus niger could be an imporant leaching agent acting in the solubilization of copper, iron, lead and tin from the electronic scrap. Copper could be selectively extracted by 10% LIX84 from the leaching solution and it recoved 99.9% of metallic copper by electrowinning process. Tin and iron were extracted from the remaining solution by 10% Alamine336 and stripped by NaCl solution. Finally, tin could be recovered as a metallic precipitates from the mixed solution of tin and iron by cementation with iron powder.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.449-458
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• 1996

Most of the conventional electrocardiowaphs foil to detect signals other than P-QRS-T due to the limited SNR and bandwidth. High-resolution electrocardiography(HRECG) provides better SNR and wider bandwidth for the detection of micro-potentials with higher frequency components such as vontricular late potentials(LP). We have developed a HRECG using uncorrected XYZ lead for the detection of LPs. The overall gain of the amplifier is 4000 and the bandwidth is 0.5-300Hz without using 60Hz notch filter. Three 16-bit A/D converters sample X, Y, and Z signals simultaneously with a sampling frequency of 2000Hz. Sampled data are transmitted to a PC via a DMA-controlled, optically-coupled serial communication channel. In order to further reduce the noise, we implemented a signal averaging algorithm that averaged many instances of aligned beats. The beat alignment was carried out through the use of a template matching technique that finds a location maximizing cross-correlation with a given beat tem- plate. Beat alignment error was reduced to $\pm$0.25ms. FIR high-pass filter with cut-off frequency of 40Hz was applied to remove the low frequency components of the averaged X, Y, and Z signals. QRS onset and end point were determined from the vector magnitude of the sigrlaIL and some parameters needed to detect the existence of LP were estimated. The entire system was designed for the easy application of the future research topics including the optimal lead system, filter design, new parameter extraction, etc. In the developed HRECG, without signal averaging, the noise level was less than 5$\mu$V$_rms RTI$. With signal averaging of at least 100 beats, the noise level was reduced to 0.5$\mu$V$_rms RTI$, which is low enough to detect LPs. The developed HRECG will provide a new advanced functionality to interpretive ECG analyzers.