• 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 Life Science
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• v.33 no.12
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• pp.987-994
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• 2023

This study examined the associations between the genotypes of the galactose mutarotase (GALM) gene and carcass traits in the Hanwoo population of Jeju Island, South Korea. The GALM genotypes were determined by the 14-bp (5'-GGTCTAATGACCAG-3') insertion/deletion (InDel) polymorphisms of the 3'-untranslated region (UTR). All three genotypes (LL, LS, and SS) were found in the Hanwoo steer population. The association analysis showed significant associations between genotypes and several carcass traits, including traits related to intramuscular fat content, such as meat quality, marbling score, and backfat thickness (p<0.05). Animals harboring the SS genotype showed not only higher levels of intramuscular fat content but also lower levels of backfat thickness than animals harboring the LL and LS genotypes. On the other hand, no significant associations were found between the GALM genotypes and carcass weight, eye muscle area, meat color, or fat color (p>0.05). Deleting the 14-bp segment in the 3'-UTR resulted in the modification of the secondary structure of RNA and appeared to affect gene expression by interfering with the binding ability of GALM mRNA with RNA-binding proteins and microRNAs. These results suggest that the 14-bp InDel polymorphism in the 3'-UTR region of the GALM gene affects cattle growth traits and carcass quality through galactose metabolism-mediated fat accumulation in muscle and backfat tissues.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.30-39
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• 2023

Large dams, which are critical infrastructures for disaster prevention, are exposed to various risks such as aging, floods, and earthquakes. Better dam safety inspection and diagnosis using digital transformation technologies are needed. Traditional visual inspection methods by human inspectors have several limitations, including many inaccessible areas, danger of working at heights, and know-how based subjective inspections. In this study, drone photogrammetry was performed on two large dams to evaluate the applicability of digital data-based dam safety inspection and propose a data management methodology for continuous use. High-quality 3D digital models with GSD (ground sampling distance) within 2.5 cm/pixel were generated by flat double grid missions and manual photography methods, despite reservoir water surface and electromagnetic interferences, and severe altitude differences ranging from 42 m to 99.9 m of dam heights. Geometry profiles of the as-built conditions were easily extracted from the generated 3D mesh models, orthomosaic images, and digital surface models. The effectiveness of monitoring dam deformation by photogrammetry was confirmed. Cracks and deterioration of dam concrete structures, such as spillways and intake towers, were detected and visualized efficiently using the digital 3D models. This can be used for safe inspection of inaccessible areas and avoiding risky tasks at heights. Furthermore, a methodology for mapping the inspection result onto the 3D digital model and structuring a relational database for managing deterioration information history was proposed. As a result of measuring the labor and time required for safety inspection at the SYG Dam spillway, the drone photogrammetry method was found to have a 48% productivity improvement effect compared to the conventional manpower visual inspection method. The drone photogrammetry-based dam safety inspection is considered very effective in improving work productivity and data reliability.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.1
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• pp.10-21
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• 2009

Muan Bay has extensively undertaken artificial influences through a series of construction of dams and dykes nearby resulting in a substantial increase in highest high water level. To unravel sedimentary responses to the water level rise, we collected a number of surface sediment samples and hydrodynamic data from in-situ observations of tidal currents in Muan Bay in 1998 and 2007. Comparison of the data between 1998 and 2007 shows that the relative content of coarse fractions, sand and gravel, in the sediment samples has increased with a decreased mean size, on average, from 6.2 to 5.8${\phi}$ at the expense of silt contents. Such a coarsening trend, which is more evident around high water level, particularly on the tidal flats of Dongam-ri, Guro-ri and Aphae-do, is most likely attributable to rising water level. On the other hand, an increase of fine fractions locally in the western entrance of the bay can be explained with changes in characteristics of tidal currents imposed by construction of bridges therein, such as decreased velocities and varied direction and phase of the tidal currents.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.320-324
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• 2008

In order to identify the change of tidal characteristics on average in the Asan Bay due to the construction of the Hwaong (Namyang Bay) tidal barrier (HTB), the tide data at Pyongtack (PT) and Anheung (AH) for the periods from 1993 to 2006 were analyzed using the harmonic analysis method, and major and shallow water tidal constituents were compared. The semidiurnal tidal amplitudes at PT increased while those at AH decreased after the tidal barrier construction. In particular, the amplitudes at PT increased abruptly during the period of $2002{\sim}2003$ when HTB was completed. On the other hand, the amplitudes of the diurnal tides at PT and AH showed minimal change. This suggests that the tidal characteristics change in the Asan Bay may be related to the construction of HTB. The cause of this change is different from either blocking the tidal wave propagation by the Keum River tidal barrier or removing 'choking effect' by the Yeongsan River tidal barrier. The $M_4/M_2$ ratio increased and their phase difference decreased after the completion of HTB. Accordingly, these changes may result in increase of tidal range, decrease of the flood duration and increase of the flood current velocity, inducing more sediments into the Asan Bay.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.49-56
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• 2024

An automated dynamic structural analysis module stands as a crucial element within a structural integrated mitigation system. This module must deliver prompt real-time responses to enable timely actions, such as evacuation or warnings, in response to the severity posed by the structural system. The finite element method, a widely adopted approximate structural analysis approach globally, owes its popularity in part to its user-friendly nature. However, the computational efficiency and accuracy of results depend on the user-provided finite element mesh, with the number of elements and their quality playing pivotal roles. This paper introduces a computationally efficient adaptive mesh generation scheme that optimally combines the h-method of node movement and the r-method of element division for mesh refinement. Adaptive mesh generation schemes automatically create finite element meshes, and in this case, representative strain values for a given mesh are employed for error estimates. When applied to dynamic problems analyzed in the time domain, meshes need to be modified at each time step, considering a few hundred or thousand steps. The algorithm's specifics are demonstrated through a standard cantilever beam example subjected to a concentrated load at the free end. Additionally, a portal frame example showcases the generation of various robust meshes. These examples illustrate the adaptive algorithm's capability to produce robust meshes, ensuring reasonable accuracy and efficient computing time. Moreover, the study highlights the potential for the scheme's effective application in complex structural dynamic problems, such as those subjected to seismic or erratic wind loads. It also emphasizes its suitability for general nonlinear analysis problems, establishing the versatility and reliability of the proposed adaptive mesh generation scheme.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.169-189
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• 2024

In the current work, a series of three-dimensional finite element analyses have been carried out to understand the behaviour of pre-existing single piles and pile groups to adjacent Shield TBM tunnelling by considering various reinforcement conditions. The numerical modelling has analysed the effect of the pile cutting, ground reinforcement and pile cap reinforcement. The analyses concentrate on the ground settlements, the pile head settlements, the axial pile forces and the shear stress transfer mechanism at the pile-soil interface. In all cases of the pile tips supported by weathered rock, the distributions of shear stresses presented a similar trend. Also, when the pile tips were cut, tensile forces or compressive forces were induced on the piles depending on the relative positions of the piles. Furthermore, when the pile tips are supported by weathered rock, approximately 70% of the load is supported by surface friction, and only the remaining 30% is supported by the pile tip. Furthermore the final settlement of the piles without reinforcement showed approximately 70% more settlement than the piles for which ground reinforcement is considered. It has been found that the ground settlements and the pile settlements are heavily affected by the pile cutting and reinforcement conditions. The behaviour of the single pile and group piles, depending on the pile cutting, conditions of ground and pile cap reinforcement, has been extensively examined and analysed by considering the key features in great details.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.243-254
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• 2024

Currently, due to industrial development in domestic regions, buildings are saturated not only in major city centers but also in surrounding urban areas. Accordingly, people's attention has focused on underground spaces, and tunnels are being widely used, especially in urban development. Research on tunnels and tunnel excavation methods is actively underway. However, there is a lack of research on the wear and tear problems of sludge discharge pipes when using a slurry shield TBM. Therefore, in this paper, the L-shaped bend pipe used in the existing sludge discharge pipe was transformed into a T-shaped bend pipe to move sludge. As a result, it was confirmed that compared to the L-shaped bend pipe, the impact of the T-shaped bend pipe on the bend pipe when discharging sludge was reduced. Based on these results, it is expected that wear of the sludge discharge pipe can be minimized by using a T-shaped bend pipe when using slurry shield TBM equipment. This is expected to ultimately lead to economic benefits, such as reducing costs due to replacement of curved pipes or additional welding during tunnel construction.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.05a
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• pp.37-54
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• 1998

This study was conducted to investigate the effects of mugwort extracts on the blood ethanol concentration, liver function and low level of cadmuim(Cd) in rats. The effects of mugwort extracts on the blood ethanol concentration was studied in Sprague-Dawley rats (10 weeks old) administered p.o. with 25% ethanol (5g/1kg body weight) and then injected with mugwort extracts (at the 2% levels of daily feed consumption compared with the concentration of catechins level in mugwort extracts) in caudal vein. SD rats were divided into five groups : control group (CON-E, only ethanol and 0.85% saline sol'n treated instead of each extracts), water extracts of mugwort treated to the control (MDW-E), ethanol extracts of mugwort treated to the control (POH-E). And then rat plasma of each time (0hr, 1hr, 2hr, 3hr) was investigated ethanol concentration by gas chromatography. Another rats were measured at the time of 0 and 5hr for the test of GOD(Glutamic Oxaloacetic Transaminase) and GPT(Glutamic Pyruvic Transaminase). Components of each extracts were analyzed by using high performance liquid chromatography. The effects of mugwort extracts on the liver function were studied in culture of rat hepatocyte composed of three groups : Control group and two groups treated with each extracts (1% & 2% MDW, 1% & 2% MOH). Condition of rat hepatocytes cultured for 36hr at $37^{\circ}C$(5% $CO_2$ incubator), number of cells, GOT and GPT activity were investigated. The results obtained were summarized as follows ; 1. Catechins level of mugwort extracts was $8{\sim}10mg/100g(MDW)$, $3{\sim}4mg/100g(MOH)$ 2. The contents of (-)-Epigallocatechin was high in MDW 3. The effects of mugwort extracts on the blood ethanol concentration were as follows; 1) The order in ethanol degradation efficiency was MDW-E > MOH-E > CON-E. 2) Ethanol concentration significantly decreased (p<0.05) in MDW-E and MOH-E. 4. The effects of mugwort extracts on the liver function were as follows; (rat hepatocytes cultured for 36hr at $37^{\circ}C$) 1) Cells condition of MDW-L was better than other groups. 2) The order in number of cells (rat hepatocytes) was 2% MDW-L >1% MDW-L >1% MOH-L > Con-L > 2% MOH-L 5. Cd treatment increased concentrations of hepatic GSH level, and decreased GOT activity in plasma. Therefore, this results suggest that the effects of mugwort extracts may an important rols in degradation ethanol and recovery liver function in body. Also, Mugwort extracts may modify the toxicities of Cd in Cd-treated rats and play an important roles in preventing the liver from various toxicants including Cd in Cd treated rats.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.906-914
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• 1994

Plastic behavior of two-phase intermetallic compounds based on $LI_{2}$-type $(Al, Cr)_3$ Ti was investigated using compression test at R.T. and 77K. $LI_{2}$ single phase alloys and two-phase alloys consisting of mainly $LI_{2}$ phase and a few or 20% second phases were selected from AI-Ti-Cr phase diagram. In general, compared with Llz single phase, two-phase alloys consisting of 20% second phase showed relatively high yield strength and poor ductility. Among the alloys, however, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ phase showed available ductility as well as high yield strength. Plastic behavior of $LI_{2}$ single phase alloys and two-phase alloys consisting of a few% $Cr_{2}Al$ was also investigated. Homogenization of arc melted ingots substantially reduced the amount of second phases but introduced extensive pore. When Cr content increased in $Ll_{2}$ single phase alloys after the homogenization, the volume fraction of pore in the alloys decreased, and no residual pore was observed in two-phase alloys consisting of a few% $Cr_{2}Al$ phase. Environmental effect on the ductility of the alloys was investigated using compression test at different strain rates($1.2 \times 10^{-4}/s$ and $1.2 \times 10^{-2}/s$). Environmental embrittlement was least significant in A1-25Ti-10Cr alloy consisting of LIZ single phase among the alloys tested in this study. However, based on the combined estimation of the pore formation, environmental embrittlement and ingot cast structure, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ as the second phase is expected to show the best tensile elongation behavior.