• Analytical Science and Technology
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• v.20 no.4
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• pp.323-330
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• 2007

A simple and rapid HPLC method with fluorescence detection(FLD) for quantitation of penciclovir in human plasma using a monolithic column was developed and validated. Penciclovir and ganciclovir(internal standard, I.S.) were separated on a Chromolith column RP-18e ($4.6{\times}100mm$) with a mobile phase consisting of a mixture of (A) methanol/50 mM sodium phosphate buffer containing 200 mg/L sodium dodecyl sulfate (3/97, pH 2.5) and (B) methanol/50 mM sodium phosphate buffer containing 200 mg/L sodium dodecyl sulfate (50/50, pH 2.5) at a flow gradient of $1.6{\sim}4.0mL/min$. The retention times of penciclovir and internal standard were less than 4.0 min. Calibration curve was linear ($R^2=0.9994$) over a concentration range of $0.1{\sim}5{\mu}g/mL$. Intra-day precision, accuracy and inter-day precision were 1.36~8.55 %, 92.8~100.0 % and 0.93~5.62 %, respectively with a limit of quantitation at $0.1{\mu}g/mL$. The present HPLC-FLD method is sensitive, precise and accurate. The method described herein has been successfully used for the bioequivalence study of a famciclovir formulation product after oral administration to healthy Korean volunteers.

• Analytical Science and Technology
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• v.21 no.6
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• pp.518-525
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• 2008

Mandipropamid is a new mandelamide-type fungicide to control foliar Oomycete pathogens in some vegetables. An analytical method was developed to determine mandipropamid residues in agricultural commodities using high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Mandipropamid was extracted with methanol from grape, tomato, green pepper, Chinese cabbage and potato samples. The extract was diluted with saturated sodium chloride solution and distilled water, and dichloromethane partition was followed to recover the mandipropamid from the aqueous phase. Florisil column chromatography was employed to further remove interfering co-extractives prior to HPLC analysis. Reverse-phased HPLC was successfully applied to determine mandipropamid in sample extracts with the detection at its ${\lambda}_{max}$ (223 nm). Overall recoveries of mandipropamid from fortified samples averaged $99.8{\pm}1.7$ (n=6), $89.3{\pm}5.3$ (n=6), $98.7{\pm}2.2$ (n=6), $99.7{\pm}6.8$ (n=6) and $91.1{\pm}3.1$ (n=6) for grape, tomato, green pepper, Chinese cabbage and potato, respectively. Limit of quantification of the method was 0.02~0.04 mg/kg for all samples. A LC/mass spectrometry with selected-ion monitoring was also provided to confirm the suspected residue. The proposed method was reproducible and sensitive enough to determine the terminal residue of mandipropamid in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.89-98
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• 2023

Currently, no guidelines exist regarding the maximum residues of pesticides in edible oil which is a processed food commonly consumed in Korea. This lack of guidelines hinders the evaluation of the safety of edible oil in terms of pesticide contamination. In this study, an analysis method based on heat distillation and GC-MS/MS was established by optimizing the extraction and purification procedure for 68 pesticides. Important variables in the thermal distillation procedure included heating temperature and time, and we found the nitrogen flow rate as a mobile phase and the type of dissolving solvent were not considerably affected. The determination coefficient (R²) of the residual pesticide was 0.99 or higher, and the quantitative limit (LOQ) was 0.01-0.02 mg/L. The average recovery rate (n=5) was 66.1-120.0% and the relative standard deviation was lower than ±10% when 68 pesticides were spiked at concentrations of 0.01-0.02, 0.1, and 0.5 mg/L. In addition, the within-laboratory precision was less than ±11%, meeting the Korea Food and Drug Safety Evaluation Institute's Guidelines on Standard Procedures for Preparing Food Testing Methods (2016). Therefore, the test method developed in this study can be used as a test method for managing the safety of the residual pesticide concentration in edible oil.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.535-542
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• 2010

Precise estimation of a structure's dynamic characteristics is indispensable for ensuring stable dynamic responses during lifetime especially for the structures which can experience resonance such as railway bridges. In this paper, the results of forced vibration tests of different excitation methods (vibration exciter and impact hammer) are compared to examine the differences and the cause of differences of extracted natural frequencies. Consequently a natural frequency modification method is suggested to eliminate effects of non-structural disturbance factors. Also, sequential forced vibration tests are performed before and after track construction according to the construction stage of a railway bridge, and the variation of natural frequencies are examined. Effect of added mass of vibration exciter and variation of support condition due to the level of excitation force are concluded as the major cause of natural frequency differences. Thus eliminating these effects can enhance the reliability of the extracted natural frequencies. Construction of track affects not only the mass of structure but also the stiffness of the structure. Also, the amount of increase in stiffness varies according to the level of structural deflection. Therefore, reasonable estimation of the level of structural response during operation is important for precise natural frequency calculation at design phase.

• 한국노년학
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• v.39 no.2
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• pp.325-345
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• 2019

The purpose of this study is a exploratory study for understanding the process of the social isolation of the socially isolated elderly through the approach to their life history. The research was analyzed by one of the methods of qualitative research on life history, the conceptual framework of 'Dimensions, turning, and adaptation' of Mandelbaum(1973). According to the results of this study, the socially isolated elderly people were found to be socially isolated by experiencing complex difficulties such as family disconnection, poverty, poor job and health deterioration. Specifically, in the area of life, there was experience of poor relationship with parent, absence of family, poverty of family and unfavorable relationship with surrounding people in life with original family before isolation. They had bad jobs in the labor market, such as hard labor, delivery, business, and chores. In the area of turning point, we experienced family break due to the separation of the original family and the spouse due to various reasons such as financial crisis, parental divorce and death, spouse affair, economic difficulty. In a transitional stage in the life, many reasons such as the financial crisis, the death of parents, the extramarital affair and economic difficulties led to the disconnection from their original family and their spouses. In an adaptive phase, participants accepted the changed life at each turning point in their lives, carrying out their roles, compromising and trying to adapt properly. He said that their current life, which has entered the social safety net system of the people's basic recipients, has led him to live a more stable life and is adapting to personal hobbies and vicarious satisfaction through networks. This result is somewhat different from previous studies in which isolated elderly people were severely exposed to the risk of depression and loneliness. However, we should also consider the characteristics of this study that interviewed elderly people with relatively low isolation. Based on the results of this research, he presented various practical policy implications.

• Korean Journal of Legislative Studies
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• v.26 no.3
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• pp.5-35
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• 2020

This article purposes to investigate opening process of the 21st National Assembly in the middle of severe conflicts between two major-parties, and predict the changes it will bring to the operation of the National Assembly. With incumbent party's taking all leadership positions of standing committees, it broke the practice since 13th National Assembly, that is, distribution of the standing committees based on the seat-ratio. It means that our National Assembly has entered a new phase in the decision-making process. While the incumbent party, with overwhelming victory in general election, emphasizes that it should dominate legislative process to support the government, the out-party claims that they should take leverage to check over government. Two opposing trends are characteristically observed in the operation of the Korean National Assembly. First of all, due to the experience under authoritarian regimes, the National Assembly has been institutionalizing decision-making processes in the direction of enforcing cooperation between parties. On the other hand, the polarization in political parties has been stronger, making it difficult to reach consensus between parties. This article claims strongly that the 21st National Assembly need to find a balance amid such two-conflicting trends. To do so, three necessary conditions are proposed: observing decision-making procedures, securing diversity within party and National Assembly, and deliberative legislative activities.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.673-687
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• 2023

Exploratory data analysis is the process of observing and understanding data collected from various sources to identify their distributions and correlations through their structures and characterization. This process can be used to identify correlations among conditioning factors and select the most effective factors for analysis. This can help the assessment of landslide susceptibility, because landslides are usually triggered by multiple factors, and the impacts of these factors vary by region. This study compared two stages of exploratory data analysis to examine the impact of the data exploration procedure on the landslide prediction model's performance with respect to factor selection. Deep-learning-based landslide susceptibility analysis used either a combinations of selected factors or all 23 factors. During the data exploration phase, we used a Pearson correlation coefficient heat map and a histogram of random forest feature importance. We then assessed the accuracy of our deep-learning-based analysis of landslide susceptibility using a confusion matrix. Finally, a landslide susceptibility map was generated using the landslide susceptibility index derived from the proposed analysis. The analysis revealed that using all 23 factors resulted in low accuracy (55.90%), but using the 13 factors selected in one step of exploration improved the accuracy to 81.25%. This was further improved to 92.80% using only the nine conditioning factors selected during both steps of the data exploration. Therefore, exploratory data analysis selected the conditioning factors most suitable for landslide susceptibility analysis and thereby improving the performance of the analysis.

• Journal of Life Science
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• v.33 no.10
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• pp.767-775
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• 2023

Sulfasalazine is a disease-modifying antirheumatic abiotic agent. It is a derivative of aminosalicylic acid and has been used for the treatment of various inflammatory diseases, such as rheumatoid arthritis, ulcerative colitis, and Crohn's disease, since it was first synthesized in 1941 and approved as a medicine in the United States in 1950. However, its mechanism of action has not yet been clearly identified. In this study, the effects of sulfasalazine on cell survival, apoptosis, and cell cycle progression in macrophages, which are major immune cells that regulate inflammatory responses, were investigated using mouse macrophage RAW 264.7 cells. Sulfasalazine inhibited the viability of RAW 264.7 cells in a dose-dependent manner, starting at a concentration of 0.25 mM. Annexin-V staining was used to confirm that the decrease in cell viability was due to apoptosis, and the number of Annexin-V-positive cells increased significantly at a concentration of 0.25 mM or higher. The effect of sulfasalazine on the expression of key proteins that regulate the G0/G1 phase of the cell cycle was also investigated. Sulfasalazine treatment significantly increased the expression of the cyclin-dependent kinase inhibitors p21 and p27 in RAW 264.7 cells. Although sulfasalazine is frequently used as a control drug in studies on inflammatory diseases, such as inflammatory colitis and rheumatoid arthritis, studies on its effect on macrophages are very limited. Therefore, the results of this study are expected to provide vital information on the use of sulfasalazine as a disease treatment.

• Journal of the Daesoon Academy of Sciences
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• v.46
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• pp.33-68
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• 2023

Simwudo (尋牛圖), known as Ox Seeking Pictures, originated in the 11th-12th century and have consistently played a guiding role in the teachings of various religions in East Asia. Some Korean religions that emerged during modern times conveyed their teachings through depictions of ox seeking or herding. Among them, Daesoon Jinrihoe stands out as a representative religion. The belief system of this particular religion elucidates its distinct doctrine and worldview by reimagining Simwudo, into a new set of six panels (seven or nine panels in some variations). The Simwudo of Daesoon Jinrihoe differs from that of Buddhism, particularly in its treatment of meditation (禪), both in terms of context and significance. While they share similarities in the aspect of ox-seeking, the Buddhist Simwudo symbolizes human nature, whereas the Simwudo of Daesoon Jinrihoe represents the great Dao of Heaven and Earth propagated by Kang Jeungsan and brought into completion by Jo Jeongsan. In the Buddhist context, the subject of the search is the Ox, signifying the restoration of a deluded human's pure nature in order to achieve personal salvation and in some version of Simwudo, reenter society to perform salvific actions for others. On the other hand, in the Simwudo of Daesoon Jinrihoe depicts the process of a human attaining immortality and following the teachings of Jeungsan and Jeongsan. This culminates in the final image which is the redemption of the world. The final phase of the Buddhist Simwudo, depending on the version, is either enlightenment (personal salvation) or reentering society to perform salvific actions (as a bodhisattva), whereas the Simwudo of Daesoon Jinrihoe show the simultaneous achievement of the perfection of humanity and the redemption of the world. This distinction highlights the fundamental differences between the Simwudo of these two distinctly different religious traditions. These differences arise from the contrasting purposes pursued by Buddhism and Daesoon Jinrihoe.

• Animal Bioscience
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• v.37 no.6
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• pp.1096-1109
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• 2024

Objective: This research aims to explore the nutritional and bioactive peptide properties of goat meat taken from various primal cuts, including the breast, shoulder, rib, loin, and leg, to produce these bioactive peptides during in vitro gastrointestinal (GI) digestion and absorption. Methods: The goat meat from various primal cuts was obtained from Boer goats with an average carcass weight of 30±2 kg. The meat was collected within 3 h after slaughter and was stored at -80℃ until analysis. A comprehensive assessment encompassed various aspects, including the chemical composition, cooking properties, in vitro GI digestion, bioactive characteristics, and the bioavailability of the resulting peptides. Results: The findings indicate that the loin muscles contain the highest protein and essential amino acid composition. When the meats were cooked at 70℃ for 30 min, they exhibited distinct protein compositions and quantities in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, suggesting they served as different protein substrates during GI digestion. Subsequent in vitro simulated GI digestion revealed that the cooked shoulder and loin underwent the most significant hydrolysis during the intestinal phase, resulting in the strongest angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition. Following in vitro GI peptide absorption using a Caco-2 cell monolayer, the GI peptide derived from the cooked loin demonstrated greater bioavailability and a higher degree of ACE and DPP-IV inhibition than the shoulder peptide. Conclusion: This study highlights the potential of goat meat, particularly cooked loin, as a functional meat source for protein, essential amino acids, and bioactive peptides during GI digestion and absorption. These peptides promise to play a role in preventing and treating metabolic diseases due to their dual inhibitory effects on ACE and DPP-IV.