• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.4
• /
• pp.205-212
• /
• 2021

Offshore jacket structures generally comprise steel members, and the safety standard for jacket structures typically focuses on the steel components. However, large amounts of concrete grouting is filled in the legs of the Gageocho jacket structure to aid in the recovery from typhoon damage. This paper proposes a safe and lightweight design for the Gageocho ocean research station comprising steel members instead of large amounts of concrete reinforcement in the legs. Based on the actual design, the structural members are grouped according to their functional roles, and the inner diameter of the cross-section in each design group is defined as a design variable. Structural optimization is carried out using a genetic algorithm to minimize the total weight of the structure. To satisfy the conservative safety standards in the offshore field, both the maximum stress and the unity check criteria are considered as design constraints during optimization. For enhanced safety confidence, extreme environmental conditions are assumed. The maximum marine attachment thickness and the section erosion in the splash zone are applied. Additionally, the design load is defined as the force induced by extreme waves, winds, and currents aligned in the same direction. All the loading directions surrounding the structure are considered to design the structure in a balanced and safe manner. As a result, compared with the current structure, the proposed structure features a 45% lighter design, satisfying the strict offshore safety criteria.

• Journal of the Korean Society of Floral Art and Design
• /
• no.42
• /
• pp.97-116
• /
• 2020

In this paper, the need for lifelong education and distance education is increasing due to the decrease of population and the increase of life expectancy. In addition, the popularization and everydayization of education, which combines daily life and learning, is an educational feature. Individuals can more easily access knowledge, and video plays an important role. Video content is the most basic medium that leads to the popularization and daily life of education. With the development of information and communication technology, popularization of media content production and editing technology, anyone can easily create and share. The video education contents business is expected to increase globally through SNS. Especially, the video contents education industry related to flower design is regarded as a suitable content field in an era where environment is essential. In the modern era, characterized by the "one-person household, one-person media" era, the environment of plants protects people from stress by restoring human emotional efficiency, environmental comfort, and stability. In other words, because humans have a preference for nature, plants play an important role for humanity recovery. Against this backdrop, flower design is expected to be a promising industrial sector with high growth, high value added and high job creation effects. In the era of the fourth revolution of the human race, competitive video contents are expected to influence the growth of the future country. will be.

• Wind and Structures
• /
• v.35 no.1
• /
• pp.1-20
• /
• 2022

This research work presents an experimental study's outcomes to reveal the impact of an O-ring on the flow control over a sphere placed in a turbulent boundary layer. The investigation is performed quantitatively and qualitatively using particle image velocimetry (PIV) and dye visualization. The sphere model having a diamater of 42.5 mm is located in a turbulent boundary layer flow over a smooth plate for gap ratios of 0≤G/D≤1.5 at Reynolds number of 5 × 10³. Flow characteristics, including patterns of instantaneous vorticity, streaklines, time-averaged streamlines, velocity vectors, velocity fluctuations, Reynolds stress correlations, and turbulence kinetic energy (), are compared and discussed for a naked sphere and spheres having O-rings. The boundary layer velocity gradient and proximity of the sphere to the flat plate profoundly influence the flow dynamics. At proximity ratios of G/D=0.1 and 0.25, a wall jet is formed between lower side of the sphere and flat plate, and velocity fluctuations increase in regions close to the wall. At G/D=0.25, the jet flow also induces local flow separations on the flat plate. At higher proximity ratios, the velocity gradient of the boundary layer causes asymmetries in the mean flow characteristics and turbulence values in the wake region. It is observed that the O-ring with various placement angles (𝜃) on the sphere has a considerable alteration in the flow structure and turbulence statistics on the wake. At lower placement angles, where the O-ring is closer to the forward stagnation point of the sphere, the flow control performance of the O-ring is limited; however, its impact on the flow separation becomes pronounced as it is moved away from the forward stagnation point. At G/D=1.50 for O-ring diameters of 4.7 (2 mm) and 7 (3 mm) percent of the sphere diameter, the -ring exhibits remarkable flow control at 𝜃=50° and 𝜃=55° before laminar flow separation occurrence on the sphere surface, respectively. This conclusion is yielded from narrowed wakes and reductions in turbulence statistics compared to the naked sphere model. The O-ring with a diameter of 3 mm and placement angle of 50° exhibits the most effective flow control. It decreases, in sequence, streamwise velocity fluctuations and length of wake recovery region by 45% and 40%, respectively, which can be evaluated as source of decrement in drag force.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.36 no.6
• /
• pp.209-212
• /
• 2022

We recently reported that Gastrodia elata extracts (GEE) had an effects to protect against lipopolysaccharide-induced cognitive impairment in vivo model. In this study, we investigated the neuroprotective effects and the mechanism of action of GEE in hydrogen peroxide (H₂O₂)-induced cell death of SH-SY5Y human neuroblastoma cell. The SH-SY5Y cells were divided into five groups, including control(non-treated group), 100 μM H₂O₂, 100, 200, 500 ㎍/㎖ GEE+ 100 μM H₂O₂ groups. Pre- and co-treatment with GEE prevented cell death induced by 100 μM H₂O₂ for 24 h in SH-SY5Y cells. Our findings also showed that anti-oxidants enzymes (Cu/Zn superoxide dismutase, Mn superoxide dismutase, catalase) were up-regulated by 100 μM H₂O₂. But GEE suppressed H₂O₂-induced anti-oxidants enzymes decrease in a dose-dependent manner. Treatment with GEE also inhibited phosphorylation of eukaryotic initiation factor-2α (eIF-2α) and p38 by H₂O₂. Taken together, the neuroprotective effects of GEE in terms of recovery of antioxidant enzymes expression, down-regulation of eIF-2α and p38 phosphorylation, and inhibition of cell death are associated with reduced oxidative stress in SH-SY5Y cells.

• Korean Journal of Culture and Social Issue
• /
• v.30 no.1
• /
• pp.1-33
• /
• 2024

This study analyzed the experiences of victims of state violence, discovered differences between state violence and general trauma, and proposed ways to help heal trauma. Participants were composed of state violence victims and their families in total, including 11 from the Jeju 43 Incident, 11 from the Yeos u·Sunchoen 10.19 Incident and 6 form May 18th Democratic Uprising. As a result of using the grounded theory to analyze data, a total of 170 concepts, 57 subcategories, and 20 categories were derived. The central phenomenon was direct damage caused by state violence. This included 'post-traumatic stress', 'social stigma', 'isolation from community', 'socio-economical issues' and 'family dissolution'. As a result of the process analysis, the participants experienced six phases: 'trauma', 'isolation', 'resistance', 'resignation', 'recovery', and 'growth.' Each phase is sequential but at the time mutually affect each other. Based on the results, this study verified the difference between state violence and general trauma, and emphasized social and cultural factors, such as community support, were important factors in healing state violence trauma. Besides, the implications and limitations as well as suggestions for future research were mentioned.

• Tuberculosis and Respiratory Diseases
• /
• v.52 no.4
• /
• pp.355-366
• /
• 2002

Background : The heat shock protein (HSP) 70 families are known to protect cells against the irreversible tissue injury induced by stress and to induce the recovery of cell function during stress. Heat pretreatment was reported to decrease the acute lung injury (ALI) of rats induced by lipopolysaccharide (LPS). However, the role of heat shock with LPS co-treatmenton ALI is unclear. The purpose of this study was to investigate the effect of heat treatment, which was given immediately after the beginning of ALI induced by LPS intratracheally administered in rats. Methods : Either saline (saline group) or LPS was intratracheally instilled without heat treatment (LPS group). In addition, heat was conducted 18 hours prior to the instillation of LPS (pre-treatment group) and conducted immediately after instillation of LPS (co-treatment group). Six hours after the LPS or saline treatment, blood, bronchoalveolar lavage (BAL) fluid and lung tissue samples were obtained. The myeloperoxidase (MPO) activity and the heat shock protein expression in the lung tissue, the differential counts of the polymorphonuclear leukocytes (PMN) in the BAL fluids, and the LDH, protein, $IL-1{\beta}$, $TNF-{\alpha}$ and IL-10 levels in BAL fluid and serum were measured. Results : 1) The MPO activity, the differential PMN counts in the BAL fluid, BAL fluid and serum cytokines were higher in the LPS, the heat pre-treatment and co-treatment group than those of the saline group (p value <0.05). 2) The MPO activity and the protein level in the BAL fluid from the heat co-treatment group were similar to those of the LPS group. 3) The serum $TNF-{\alpha}$ level of the heat co-treatment group was significantly higher than that of the LPS group (p=0.01). Conclusion : Heat shock response administered immediately after a LPS instillation did not attenuate the ALI in this model.

• Journal of Bio-Environment Control
• /
• v.24 no.1
• /
• pp.13-20
• /
• 2015

This study was conducted to evaluate influence of short-term application of abscisic acid (ABA) in nutrient solution on growth and drought tolerance of tomato seedlings. The treatments included four ABA concentrations (0.5, 1, 2, $3mg{\cdot}L^{-1}$) and control (non-treatment) were applied to the nutrient solution in a hydroponic system. On the $5^{th}$ and $10^{th}$ day after growing in the nutrient solution containing ABA, seedlings were transferred to -5 bars of PEG-8000 in a growth chamber to induce water stress. Except for stem diameter and fresh and dry weight of root, there were no statistical differences in other growth parameters among control, 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments. Seedlings growths were strongly inhibited in nutrient solution containing 2 and $3mg{\cdot}L^{-1}$ of ABA. The root growth such as fresh and dry weigh of root, total root surface area, and average root diameter was slightly enhanced in $1mg{\cdot}L^{-1}$ of ABA treatment. The elevation of ABA concentrations in nutrient solution resulted in the decrease in transpiration rate and increase in stomatal diffusive resistance and leaf temperature of tomato seedlings. The initiations of seedling wilting after treating in -5 bars of PEG were delayed from 10 hrs in control to 30 hrs in ABA applied treatments. Additionally, the high percentages of recovered seedlings were observed in 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments after re-irrigation. Therefore, short-term application of $1mg{\cdot}L^{-1}$ of ABA in the nutrient solution stimulated the root growth and drought tolerance of tomato seedlings by delaying the start time of wilting point and enhancing the recovery after re-irrigation.

• Ecology and Resilient Infrastructure
• /
• v.5 no.3
• /
• pp.163-173
• /
• 2018

The biopolymer (BP) used in this study is mainly composed of xanthan gum and ${\beta}$-glucan derived from microorganism and has been introduced as a novel material for soil stabilization. However, the broad applicability of BP has been suggested in the field of geotechnical engineering while little information is available about the effects of BP on the vegetation. The goal of this study is to find the BP effects on the growth of Camelina sativa L. (Camelina) under drought condition. For more thorough evaluation of BP effects on the plant growth, we examined not only morphological but also physiological traits and gene expression patterns. After 25 days of drought treatment from germination in the soil amended with 0, 0.25, 0.5, and 1% BP, we observed that the BP concentration was strongly correlated the growth of Camelina. When plants were grown under drought stress, Camelina in 0.5% BP mixture showed better physiological parameters of the leaf stomatal conductance, electrolyte leakage and relative water content compared to those in control soil without BP. Plant recovery rate after re-watering was higher and the development of lateral root was lower in BP amended soil. RNA expression of Camelina leaf treated with/without drought for 7 and 10 days showed that aquaporin genes transporting solutes at bio-membrane, CsPIP1;4, 2;1, 2;6 and TIP1;2, 2;1, were induced more in the plants with BP amendment and drought treatment. These results suggest that the soil amended with BP has a positive effect on the transport of nutrients and waters into Camelina by improving water retention in soil under drought condition.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2232-2239
• /
• 2012

This study set out to investigate the effects of the same amount of resting(30 minutes) after $VO_2max$ 20%, 40%, and 60% exercise on the variation of cortisol and catecholamine, serum stress hormones. The research efforts led to the following conclusions: First, there were no significant differences in serum cortisol concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.002 in the $VO_2max$ 60% group. Second, there were no significant differences in serum catecholamine concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.001 in the $VO_2max$ 60% group. Third, no significant differences were found in the changing rates of serum cortisol concentration between right after exercise and during break among different levels of exercise intensity according to measuring time. Fourth, there were significant differences in the changing rates of serum catecholamine concentration in the significance level of p=.000 right after exercise and in the significance level of p=.034 during break In short, there were significant differences only in the $VO_2max$ 60% group according to exercise intensity when the different groups took the same amount of break after exercise. The $VO_2max$ 60% group was also the only group that showed significant differences in the changing rates of cortisol and catecholamine. In conclusion, taking a break after exercise can generate huge effects only when the exercise intensity level is moderate or higher. That is, taking a break will have no significant effects when the exercise intensity level is lower than moderate.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.5
• /
• pp.545-551
• /
• 2017

Curcuma longa L. (CL) is widely used as a spice and coloring agent in several foods, such as curry and mustard, as well as cosmetics and drugs. In this study, we investigated the protective effects of CL extracted with various solvents [methanol (MC), ethanol (EC), acetone (AC)] on $H_2O_2-induced$ DNA damage in human leukocytes along with total polyphenol contents (TPC) and antioxidant properties. The antioxidant effects of CL were determined by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and superoxide dismutase (SOD)-like activity. The preventive effect of CL on oxidative stress-induced DNA damage and DNA repair capacities were assessed using comet assay. MC showed the highest TPC (11.17 g gallic acid equivalents/100 g) and antioxidant properties among the solvent extracts. The $SC_{50}$ for DPPH RSA was MC: 35.0 > AC: 45.8 > EC: $57.8{\mu}g/mL$ and SOD-like activity was MC: 46.6 > EC: 141.5 > AC: $296.4{\mu}g/mL$. In the comet assay, the $ED_{50}$ value of MC showed the highest inhibition ($86.7{\mu}g/mL$) of $H_2O_2-induced$ DNA damage, followed by AC ($110.0{\mu}g/mL$) > EC ($115.8{\mu}g/mL$). Analysis of the percentage of damaged cells showed that repair capacity significantly decreased at 4, 8, and 12 h from $H_2O_2-induced$ oxidative stress in each extract. After 12 h, level of DNA damage recovery was similar to the negative control level. These results suggest that CL has potential antioxidant activity and a protective effect against oxidation-induced DNA damage, and the methanol extract of CL was the most effective.