• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.151-157
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• 2019

In geostationary satellite communications, which are widely used for broadcasting and communication, there is a path loss where the signal power on the path is largely reduced. It is important to consider rain attenuation when calculating link budget because the Ka band frequency is vulnerable to rain attenuation. In this study, rainfall trends were analyzed by using rainfall data from the year 2000 in four regions of Korea (Seoul, Incheon, Busan, Jeju) and the rainfall attenuation was calculated. This was used to analyse the satellite link budget and receiving performance for the down-link of the korea satellite COMS. In this study, the calculated G/T for the rainfall intensity of 0.5% per year using the rainfall data for 18 years increased by approximately $8.5dBK^{-1}$ compared to the ITU's zone-K rain model, and decreased by approximately $1dBK^{-1}$ compared to the precipitation data for 13 years from the TTA(Korea Telecommunications Technology Association). The results of this study can be used for the design of G/T in domestic-installed satellite ground station.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.3
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• pp.217-224
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• 2019

Phthalates, endocrine disrupting chemicals, are similar in structure to sex hormones and mainly show reproductive toxicity and developmental toxicity. In this study, we analyzed 11 phthalates, including 3 kinds of phthalates prohibited in cosmetic use and 8 kinds of phthalates regulated in 'Common standards for children's products safety' and EU cosmetic regulation (EC No. 1223/2009). The phthalate analysis was optimized using GC-MS/MS. In analytical method validation, this method was satisfied in specificity, linearity, recovery rate, accuracy and MQL. Therefore, we used this method to analyze 82 products of Nail cosmetics & polish. Although six phthalates such as DBP, BBP, DEHP, DPP, DIBP and DIDP were detected at concentrations of $1.0{\sim}59.8{\mu}g/g$g, they were suitable to Korean cosmetic standards. DIBP and DBP were detected at concentration of $1.1{\sim}2.6{\mu}g/g$ in artificial nail, DBP and DEHP were $1.4{\sim}2.5{\mu}g/g$ in glue for nails, and DIBP, DBP, and DEHP were $2.5{\sim}33.3{\mu}g/g$ in nail stickers. Although substances such as DBP and DEHP in artificial nail, Glue for nails, and nail stickers were detected, they were suitable to 'Common safety standards for children's products. DIBP is not a regulated substance in Korea but showed the third highest detection rate following DBP (84.6%) and DEHP (63.4%). The concentration of phthalates detected in nail products is considered to be safe in current standards but continuous monitoring and research about non-regulated substances are also needed to be considered.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.3
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• pp.171-179
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• 2019

Pituitary tumors are usually benign but can occasionally exhibit hormonal and proliferative behaviors. Dysregulation of the G1/S restriction point largely contributes to the over-proliferation of pituitary tumor cells. F-box protein S-phase kinase-interacting protein-2 (SKP2) reportedly targets and inhibits the expression of $p27^{Kip1}$, a well-known negative regulator of G1 cell cycle progression. In this study, SKP2 expression was found to be upregulated while $p27^{Kip1}$ expression was determined to be downregulated in rat and human pituitary tumor cells. Furthermore, SKP2 knockdown induced upregulation of $p27^{Kip1}$ and cell growth inhibition in rat and human pituitary tumor cells, while SKP2overexpression elicited opposite effects on $p27^{Kip1}$ expression and cell growth. The expression of microRNA-186 (miR-186) was reported to be reduced in pituitary tumors. Online tools predicted SKP2 to be a direct downstream target of miR-186, which was further confirmed by luciferase reporter gene assays. Moreover, miR-186 could modulate the cell proliferation and $p27^{Kip1}$-mediated cell cycle alternation of rat and human pituitary tumor cells through SKP2. As further confirmation of these findings, miR-186 and $p27^{Kip1}$ expression were downregulated, while SKP2 expression was upregulated in human pituitary tumor tissue samples; thus, SKP2 expression negatively correlated with miR-186 and $p27^{Kip1}$ expression. In contrast, miR-186 expression positively associated with $p27^{Kip1}$ expression. Taken together, we discovered a novel mechanism by which miR-186/SKP2 axis modulates pituitary tumor cell proliferation through $p27^{Kip1}$-mediated cell cycle alternation.

• Journal of Nutrition and Health
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• v.52 no.3
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• pp.243-249
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• 2019

Purpose: Platycodon grandiflorum (PG) is known to have effective antimicrobial and anticancer activity. The main bioactive components of PG are saponins, and these could contribute to anti-inflammatory activity. However, little is known about the anti-inflammatory effect of PG. In this study, we aim to assess the anti-inflammatory response to Red PG Extract (RPGE) in splenocytes under ex vivo conditions. Methods: The cell viability of isolated splenocytes taken from mice was analyzed by performing a Cell Counting Kit-8 assay. The productions of nitric oxide (NO) and cytokines (specifically interleukin-6 (IL-6) and interleukin-10 (IL-10)) were measured utilizing Griess reagent and ELISA, respectively. Results: We found that co-treatment with RPGE and Lipopolysaccharide (LPS) decreased isolated splenocyte proliferation as compared with that of the LPS-stimulated control. We also observed that RPGE markedly suppressed NO synthesis and IL-6 production that was induced by LPS. There were no significant differences of IL-10 production between co-treatment with RPGE plus LPS and treatment with LPS alone. Conclusion: When taken together, our data has shown that RPGE mitigates LPS-induced inflammation in splenocytes isolated from mice. Further research is surely needed to confirm the anti-inflammation effects of RPGE in an in vivo model.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.236-248
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• 2019

We investigated occurrence and molecular phylogeny of the toxic epiphytic dinoflagellate Ostreopsis at seven sampling sites in the coastal waters off Jeju Island of Korea in April, 2017. During the sampling period, surface water temperature ranged from 15.7 to $18.3^{\circ}C$ and salinity was relatively constant, ranging from 33.4 to 34.9. Of a total of 13 macroalgal species collected from all sampling sites, Ostreopsis cells were observed from 8 macroalgal species and the highest cell abundance ($157.5cells\;g^{-1}$) was recorded on the red alga Grateloupia filicina at St. 6. LSU rDNA D8/D10 sequences of all Korean Ostreopsis strains isolated from the 4 sampling sites were 100% identical. Molecular phylogentic analyses (BI and ML) inferred from LSU rDNA alignment showed that the Korean Ostreopsis strains placed into the previously described the Ostreopsis sp. 1 clade, which contained strains isolated from the temperate coastal waters of Japan. The Korean Ostreopsis sp. 1 strain grew in a wide range of temperature ($10-30^{\circ}C$) and salinity (25-30), with its maximum growth rate of $0.49d^{-1}$ at $25^{\circ}C$ and salinity of 30, indicating that they can be tolerated in temperate areas.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.303-307
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• 2019

Sophorolipid is a biological surfactant of the glycolipid structure produced by Candida bombicola, which generally exists as a mixture of acidic and lactonic forms. In this study, we investigated physico-chemical properties, antibacterial activities, and cytotoxicity of the sophorolipid containing more than 96% of the lactonic form, produced by the gene regulation of production strains and application of a metabolic engineering technique. The lactonic sophorolipid showed a weak acidity in the range of pH 3.2~4.6 when diluted in water at the concentrations from 1 to 0.001 wt%. The $pK_a$ value of the lactonic sophorolipid was estimated to be around 4.3 from the acid-base titration curve. The critical micelle concentration (CMC) of the lactonic sophorolipid was $10^{-2}wt%$, at which the surface tension of aqueous solution was reduced to 36 mN/m. The lactonic sophorolipid showed the minimum inhibitory concentrations (MIC) of $1{\times}10^{-3}$ and $5{\times}10^{-3}g/mL$ against Propionibacterium acnes and Corynebacterium xerosis, respectively. The MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay showed that cytotoxicity of the lactonic sophorolipid was ten times lower than that of triclosan.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.178-182
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• 2019

This study investigated the antibacterial effects of BioZone atmospheric plasma (AP) against Bacillus cereus (F4810/72) and Staphylococcus aureus (ATCC 6538) as the major foodborne bacteria on the surface of dried filefish (Stephanolepis cirrhifer) fillets. The fillets were experimentally contaminated with 7-8 log CFU/mL of B. cereus or S. aureus using a spot inoculation method. Bacterial counts were measured by standard plate method on tryptic soy agar, and were significantly reduced with the increase in the treatment time (1, 3, 5 or 20 min) of AP on the fillets (p < 0.05). The reductions of the pathogens by AP treatment ranged from 0.9 to 2.93 logCFU/g for B. cereus and from 1.04 to 2.55 logCFU/g for S. aureus. A reduction of >1-logCFU/g for B. cereus and S. aureus was observed on the fillets treated with AP for >3 min. The differences in color on the Hunter scale (L=light vs. dark, a=red vs. green, b=yellow vs. blue) of the fillets were not significantly different between the nontreated (control) and AP-treated fillets (p>0.05). This study suggested that 3 min of AP could be effective in reducing >90% of the bacteria without causing any concomitant changes in the color of the fillets.

• Clinical and Experimental Pediatrics
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• v.63 no.6
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• pp.226-231
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• 2020

Background: Probiotics and prebiotics have strain-specific effects on the host. Synbiotics, a mixture of probiotics and prebiotics, are proposed to have more beneficial effects on the host than either agent has alone. Purpose: We performed a randomized controlled trial to investigate the effect of Lactobacillus and Bifidobacterium together with oligosaccharides and lactoferrin on the development of necrotizing enterocolitis (NEC) or sepsis in very low birth weight neonates. Methods: Neonates with a gestational age ≤32 weeks and birth weight ≤1,500 g were enrolled. The study group received a combination of synbiotics and lactoferrin, whereas the control group received 1 mL of distilled water as placebo starting with the first feed until discharge. The outcome measures were the incidence of NEC stage ≥2 or late-onset cultureproven sepsis and NEC stage ≥2 or death. Results: Mean birth weight and gestational age of the study (n=104) and the control (n=104) groups were 1,197±235 g vs. 1,151±269 g and 29±1.9 vs. 28±2.2 weeks, respectively (P>0.05). Neither the incidence of NEC stage ≥2 or death, nor the incidence of NEC stage ≥2 or late-onset culture-proven sepsis differed between the study and control groups (5.8% vs. 5.9%, P=1; 26% vs. 21.2%, P=0.51). The only significant difference was the incidence of all stages of NEC (1.9% vs. 10.6%, P=0.019). Conclusion: The combination of synbiotics and lactoferrin did not reduce NEC severity, sepsis, or mortality.

• Tribology and Lubricants
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• v.35 no.4
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• pp.199-205
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• 2019

Two-dimensional materials such as graphene, h-BN, and $MoS_2$ have attracted increased interest as solid lubricant and protective coating layer for nanoscale devices owing to their superior mechanical properties and low friction characteristics. In this work, the frictional properties of single-layer graphene, h-BN, and $MoS_2$ are experimentally investigated under various normal forces using atomic force microscope (AFM) tips with a spherical and flat end, with the aim to gain a better understanding of frictional behaviors. The nonlinear relationship between friction and normal force friction was clearly observed for single-layer graphene, h-BN, $MoS_2$ specimens slid against the spherical and flat AFM tips. The results also indicate that single-layer graphene, h-BN, $MoS_2$ exhibit low frictional properties (e.g., friction coefficient below 0.1 under 70~100 nN normal force). In particular, graphene is found to be superior to h-BN and $MoS_2$ in terms of frictional properties. However, the friction of single-layer graphene, h-BN, $MoS_2$ against the flat tip is larger than that against the spherical tip, which may be attributed to the relatively large adhesion. Furthermore, it is shown that the fluctuation of friction is more significant for the flat tip than the spherical tip. The resutls of this study may be helpful to elucidate the feasibility of using two-dimensional materials as solid lubricant and protective coating layer for nanoscale devices.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.411-419
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• 2019

The purpose of this study was to analyze the growth and functional differences between C. rotundus and G. littoralis according to different electrical conductivity (EC) conditions in reclaimed soil conditions. C. rotundus and G. littoralis seeds were sown in a tray and managed for seedlings stage for eight weeks. They were transplanted in the pots containing reclaimed soils sampled in the Saemangum region. The plants were grown in the reclaimed land soil for 12 weeks under the control, 1, 2, 4, and $8dS{\cdot}m^{-1}$ conditions and in horticultural soils with EC $1.0dS{\cdot}m^{-1}$. Plant height, leaf length and width of C. rotundus were the highest in EC $1dS{\cdot}m^{-1}$. Leaf, flower and tuber numbers of C. rotundus were the highest in EC $2dS{\cdot}m^{-1}$ and the lowest in EC $8dS{\cdot}m^{-1}$, and SPAD was the highest in EC 2 and $4dS{\cdot}m^{-1}$ and the lowest in EC $8dS{\cdot}m^{-1}$. The fresh weights of shoot and root of C. rotundus grown under EC $2dS{\cdot}m^{-1}$ increased and then decreased as the concentration increased. When compared plant growth between reclaimed soil and horticulture soil with EC $1dS{\cdot}m^{-1}$, the fresh weights of shoot and root, SPAD, leaf number, flower number, and tuber number were higher in horticultural soils. Although G. littoralis grown under EC $8dS{\cdot}m^{-1}$ was the lowest in all growth parameters, there were no significant differences among other EC treatments. C. rotundus had the highest p-coumaric acid content in EC $1dS{\cdot}m^{-1}$. And the catechin content in shoot of G. littoralis was the highest in the control, and root of Glehnia littoralis had the highest benzoic acid contents in EC $1dS{\cdot}m^{-1}$. If the soil EC is well managed within $4.0dS{\cdot}m^{-1}$, two plants would be cultivated in reclaimed land.