• Journal of the Korean earth science society
• /
• v.40 no.2
• /
• pp.109-118
• /
• 2019

Cloud-aerosol interactions are considered to be one of the most important forcing mechanisms in the climate system. However, there is considerable disagreement on the magnitude and even on the sign of how aerosol perturbations affect cloud fraction and lifetime. Furthermore, aerosol effects on clouds and precipitation are not readily separable from the effects of meteorology. This review paper summarizes the study of precipitation susceptibility $S_o$, which qualifies how aerosol perturbations alter the magnitude of the precipitation rate (R) while minimizing the effects of macrophysical factors such as cloud depth (H) and liquid water path (LWP). The analysis shows that the precipitation susceptibility $S_o$ for the warm marine boundary layer clouds is insensitive to aerosol perturbations at low LWP (equivalently low H). However, R decreases as aerosols increase at intermediate LWP. This is because aerosols act as cloud seed and produce numerous small-sized particles, which impede the collision and coalescence process that leads to precipitation. At high LWP, $S_o$ decreases with increasing LWP as there are enough water contents in the clouds. The LWP or H dependent $S_o$ behavior differs depending on the predominant cloud physics processes in the clouds.

• Journal of the Microelectronics and Packaging Society
• /
• v.26 no.2
• /
• pp.15-21
• /
• 2019

We investigated the structural, electrical and optical properties of zinc oxide (ZnO) ultra-thin films grown at $150^{\circ}C$ by atomic layer deposition (ALD). Diethylzinc and deionized water were used as metal precursors and reactants, respectively, for the deposition of ZnO thin films. The growth rate per ALD cycle was a constant 0.21 nm/cycle at $150^{\circ}C$, and samples below 50 cycles had amorphous properties due to the relatively thin thickness at the initial ALD growth stage. With the increase of the thickness from 100 cycles to 200 cycles, the crystallinity of ZnO thin films was increased and hexagonal wurtzite structure was observed. In addition, the particle size of the ZnO thin film increased with increasing number of ALD cycles. Electrical properties analysis showed that the resistivity value decreased with the increase of the thin film thickness, which is correlated with the decrease of the grain boundary concentration in the thicker ZnO thin film due to the increase of grain size and the improvement of the crystallinity. Optical characterization results showed that the band edge absorption in the near ultraviolet region (300 nm~400 nm) was increased and shifted. This phenomenon is due to the increase of the carrier concentration with the increase of the ZnO thin film thickness. This result agrees well with the decrease of the resistivity with the increase of the thin film thickness. Consequently, as the thickness of the thin film increases, the stress on the film surface is relaxed, the band gap decreases, and the crystallinity and conductivity are improved.

• 한국노년학
• /
• v.38 no.1
• /
• pp.243-259
• /
• 2018

The purpose of this study is to investigate the moderating effect of home-based welfare facilities for older adults on the associations between the activities of daily living (ADL) / instrumental activities of daily living (IADL) and the depressive symptoms among Koreans in later life. Multilevel analysis was conducted with Korean Longitudinal Study of Aging 5th data and the public report about welfare facilities from Ministry of Health and Welfare in Korea. Samples were 4,139 older adults over 65 years old. The dependent variable was depressive symptoms, and individual level independent variables were ADL and IADL. The ratio of home-based welfare facilities out of 10,000 older adults in each city and province was the moderator. As a result, the effects of ADL on depressive symptoms vary according to the proportion of elderly welfare facilities out of the old population in the community. In specific, the older adults who live in the place where the elderly welfare facility rate was higher were less affected by ADL. Also, the more IADL people had, the more depressive symptoms they had. However, the interaction effect between IADL and the proportion of home-based welfare facilities was not significant. It suggests that delivering welfare services helping ADL through the home-based welfare facilities may be useful for decreasing depressive symptoms. Moreover, considering the proportion of facilities and older population will be helpful to make the welfare facilities efficiently work.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.1
• /
• pp.86-92
• /
• 2019

Di-ethylhexyl phthalate (DEHP) is an environmental contaminant that is used as a plasticizer. Endometriosis is a complex disease with an unknown etiology that is believed to be associated with exposure to DEHP. The present study examined the potential toxicity of DEHP by exposing endometrial adenocarcinoma cells (Ishikawa cells) to DEHP. In the experiments, the cells were treated with stepwise DEHP concentrations (0, 0.01, 0.1, 1, and $5{\mu}M$) for different exposure times (24, 48, and 72 h). When the relationship between the resulting survival rate of the cells and initial inflammation was examined, the cell viability, expression of $TNF-{\alpha}$, an inflammatory mediator, and the expression of MMP-9, an ECM degradation protein, were increased remarkably when the cells were exposed to $5{\mu}M$ DEHP for 48 and 72 hours. These results suggest that the exposure of Ishikawa cells to certain concentrations of DEHP, estrogen mimics, may cause time-dependent toxicity that affects the cell viability and inflammation, implying a potential role in the etiology of endometriosis. Further research on the effects of endocrine disruptors on the pathogenesis of endometriosis may reveal strategies to prevent this disease.

• Journal of Life Science
• /
• v.29 no.4
• /
• pp.455-460
• /
• 2019

In previous studies, we confirmed the effective antimicrobial activity of fermented Dendropanax morbifera leaf/branch extracts with Lactobacillus plantarum ilchiwhangchil 1785 and Lactobacillus plantarum ilchiwhangchil 2020. In this study, we investigated the hair growth effect of D. morbifera leaf/branch extracts fermented with L. plantarum ilchiwhangchil 1785 and L. plantarum ilchiwhangchil 2020 on human hair dermal papilla cells. The growth rate of human hair dermal papilla cells treated with fermented extracts in the range of 1 to $10{\mu}g/ml$ significantly increased in a concentration-dependent manner, without increasing cell death. Double staining studies showed that the growth of cells treated with fermented D. morbifera leaf/branch extracts was more active than that of control cells. Moreover, the cells treated with the fermented D. morbifera leaf/branch extracts exhibited a 18.84% and 23.31% increase in cell mobility, respectively, as compared with that of the untreated cells. High-performance liquid chromatography (HPLC) was used to determine the active agents responsible for hair growth. The results showed that the content of ${\beta}$-sitosterol, which is known to affect hair growth, increased about 10 times in the fermentation process of D. morbifera leaf/branch extracts. Taken together, the findings confirm that fermented Dendropanax morbifera leaf/branch extracts promote hair growth.

• Korean Journal of Environmental Biology
• /
• v.37 no.1
• /
• pp.72-81
• /
• 2019

Bisphenol A (BPA), a representative endocrine disrupting chemicals, has adverse effects on growth, development and reproduction in aquatic organisms. The object of this study was to investigate the modulation of antioxidant enzyme-coding genes using quantitative real time RT-PCR (qRT-PCR), enzyme activity and total protein content, to understand oxidative stress responses after exposure to BPA for 48 h in brackish water flea Diaphanosoma celebensis. The BPA ($3mg\;L^{-1}$) significantly upregulated the expression of Cu/Zn-SOD, Mn-SOD, and catalase (CAT) mRNA. Three GST isoforms (GST-kappa, GST-mu, and GST-theta) mRNA levels significantly increased at the rate of $0.12mg\;L^{-1}$ of BPA. In particular, GST-mu showed the highest expression level, indicating its key role in antioxidant response to BPA. SOD activity was induced with a concentration-dependent manner, and total protein contents was reduced. These findings indicate that BPA can induce oxidative stress in this species, and these antioxidants may be involved in cellular protection against BPA exposure. This study will provide a better understanding of molecular mode of action of BPA toxicity in aquatic organisms.

• Journal of Korea Water Resources Association
• /
• v.54 no.5
• /
• pp.335-345
• /
• 2021

The one-dimensional solute transport models have been developed for recent decades to predict behavior and fate of solutes in rivers. Transient storage model (TSM) is the most popular model because of its simple conceptualization to consider the complexity of natural rivers. However, the TSM is highly dependent on its parameters which cannot be directly measured. In addition, the TSM interprets the late-time behavior of concentration curves in the shape of an exponential function, which has been evaluated as not suitable for actual solute behavior in natural rivers. In this study, we suggested a stochastic approach to the solute transport analysis. We delineated the model development and model application to a natural river, and compared the results of the proposed model to those of the TSM. To validate the proposed model, a tracer test was carried out in the 4.85 km reach of Gam Creek, one of the first-order tributaries of Nakdong River, South Korea. As a result of comparing the power-law slope of the tail of breakthrough curves, the simulation results from the stochastic storage model yielded the average error rate of 0.24, which is more accurate than the 14.03 and 1.87 from advection-dispersion model and TSM, respectively. This study demonstrated the appropriateness of the power-law residence time distribution to the hyporheic zone of the Gam Creek.

• Journal of Ginseng Research
• /
• v.43 no.4
• /
• pp.676-683
• /
• 2019

Background: Korean Red Ginseng (KRG) is widely used for strengthening the immune system and fighting fatigue, especially in people with deficiency syndrome. However, there is concern that the long-term application or a high dose of KRG can cause "fireness" (上火 in Chinese) because of its "dryness" (燥性 in Chinese). The aim of this study was to assess the safety and efficacy of a 4-week treatment with KRG in participants with deficiency syndrome. Methods: This was a 4-week, randomized, double-blind, placebo-controlled clinical trial. A total of 180 Chinese participants were randomly allocated to three groups: placebo control group, participants were given a placebo, 3.6 g/d; KRG 1.8 g and 3.6 g groups. The primary outcomes were the changes in fireness and safety evaluation (adverse events, laboratory tests, and electrocardiogram). The secondary outcomes were the efficacy of KRG on fatigue, which include the following: traditional Chinese medicine (TCM) symptom scale and fatigue self-assessment scale. Results: Of the 180 patients, 174 completed the full study. After 4 weeks of KRG treatment, the Fire-heat symptoms score including Excess fire-heat score and Deficient fire-heat score showed no significant change as compared with placebo treatment, and no clinically significant changes in any safety parameter were observed. Based on the TCM syndrome score and fatigue self-assessment score, TCM symptoms and fatigue were greatly improved after treatment with KRG, which showed a dose- and time-dependent effect. The total effective rate was also significantly increased in the KRG groups. Conclusion: Our study revealed that KRG has a potent antifatigue effect without significant adverse effects in people with deficiency syndrome. Although a larger sample size and longer treatment may be required for a more definite conclusion, this clinical trial is the first to disprove the common conception of "fireness" related to KRG.

• Journal of Life Science
• /
• v.29 no.11
• /
• pp.1192-1199
• /
• 2019

The intention of this study was to confirm the possible use of an ethanol extracts of Nelumbinis Rhizomatis Nodus (NRN) as a cosmetic material. To this end, we extracted NRN with 70% ethanol and performed biological activity evaluation of whitening efficacy and wrinkle reduction. We performed cellular tyrosinase inhibition and melanin contents assay to check the whitening activity of NRN and carried out a toxicity evaluation of NRN via an MTT assay and the amounts of associated proteins that affect melanin production in a melanoma cell line (B16F10). And collagenase inhibitory assay was performed for the evaluation of anti-wrinkle of samples. In addition, a toxicity evaluation using an MTT assay and matrix metalloprotease (MMP-1) and procollagen synthesis inhibition by NRN were evaluated in a fibroblast cell line (CCD-986sk). Western blot results for the whitening activity evaluation revealed that the levels of two proteins related to melanin production, tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2), were decreased in a dose-dependent manner. Moreover, collagenase inhibition activity at a concentration of $500{\mu}g/ml$ NRN by measuring epigallocatechin-3-gallate (EGCG) was increased by more than 80% compared to the control group. Meanwhile, procollagen synthesis was reduced by 68.8% in the UVB-induced CCD- 986sk cells group whereas collagen synthesis recovered by 80.2% with $25{\mu}g/ml$ NRN. The MMP-1 expression rate showed 20.2% reduction at $25{\mu}g/ml$. The results of the experiments verified the whitening and wrinkle suppression effects of NRN and confirmed that it could be used as a safe natural cosmetic material in the future.

• Food Engineering Progress
• /
• v.22 no.4
• /
• pp.315-320
• /
• 2018

This study examined the effects of drying methods of Aronia melanocarpa on contents of total polyphenols and flavonoids, antioxidant activity and anti-inflammatory activity. As a result, freeze-dried aronia extract (FDAE) significantly exhibited higher contents of total polyphenols and flavonoids (155.76 mg GAE/g and 105.70 mg QE/g) than hot-air dried aronia extract (HDAE) (134.93 mg GAE/g and 82.29 mg QE/g). Also, FDAE showed greater antioxidant activity than HDAE in both DPPH and ABTS. For anti-inflammatory activity, NO production from lipopolysaccharide activated RAW264.7 cell reduced at a dose-dependent manner in both FDAE and HDAE. However, reduction rate of NO production is higher in FDAE (62.7%) than in HDAE (33.5%). These results suggest that comparatively, freeze-drying is a better method for preserving the antioxidant and anti-inflammatory activities and of aronia.