• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.95-101
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• 2024

This paper aims to establish a reconfigurable flight simulation environment to conduct safety evaluation of various electric vertical take-off and landing (eVTOL) aircraft. Since the inceptor, aircraft dynamics model, and controller applied to each eVTOL aircraft are different, it was configured to be variable so that a simulation can be executed for each eVTOL aircraft. Test elements and performance indicators were set to perform safety evaluation of eVTOL aircraft. Ground auxiliary equipments were designed and implemented in a simulation environment according to test procedures for each test element. In addition, to analyze safety performance, a simulation flight data collection environment based on MATLAB/Simulink and a tool for safety performance analysis were implemented. Test flight and analysis were conducted in the implemented simulation environment in this paper. Finally, this study shows the environment was verified by confirming that it was performed normally.

• Biomolecules & Therapeutics
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• v.32 no.2
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• pp.214-223
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• 2024

Metabolic abnormalities in the liver are closely associated with diverse metabolic diseases such as non-alcoholic fatty liver disease, type 2 diabetes, and obesity. The aim of this study was to evaluate the ameliorating effect of robinetin (RBN) on the significant pathogenic features of metabolic failure in the liver and to identify the underlying molecular mechanism. RBN significantly decreased triglyceride (TG) accumulation by downregulating lipogenesis-related transcription factors in AML-12 murine hepatocyte cell line. In addition, mice fed with Western diet (WD) containing 0.025% or 0.05% RBN showed reduced liver mass and lipid droplet size, as well as improved plasma insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) values. CD38 was identified as a target of RBN using the BioAssay database, and its expression was increased in OPA-treated AML-12 cells and liver tissues of WD-fed mice. Furthermore, RBN elicited these effects through its anti-histone acetyltransferase (HAT) activity. Computational simulation revealed that RBN can dock into the HAT domain pocket of p300, a histone acetyltransferase, which leads to the abrogation of its catalytic activity. Additionally, knock-down of p300 using siRNA reduced CD38 expression. The chromatin immunoprecipitation (ChIP) assay showed that p300 occupancy on the promoter region of CD38 was significantly decreased, and H3K9 acetylation levels were diminished in lipid-accumulated AML-12 cells treated with RBN. RBN improves the pathogenic features of metabolic failure by suppressing the p300-CD38 axis through its anti-HAT activity, which suggests that RBN can be used as a new phytoceutical candidate for preventing or improving this condition.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.24 no.4
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• pp.220-227
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• 2013

Objectives : This study aims to investigate the clinical characteristics and neuropsychological profiles of children with attention-deficit hyperactivity disorder (ADHD) and their siblings. Methods : Eighteen children (age $8.2{\pm}1.7$ years, 12 boys) with ADHD and their 18 siblings (age $7.8{\pm}1.6$ years, 8 boys) completed Continuous Performance (CPT), Stroop, Children's Trail Making, Rey-Kim Memory, and Kim's Frontal Executive Function tasks. The parents of these subjects underwent the Attention-Deficit/Hyperactivity Disorder Rating Scale (ARS), 10-item Parent General Behavior Inventory (P-GBI), and the Social Responsiveness Scale (SRS). Paired t-tests were used. Results : The inattention (p=.020), and hyperactivity-impulsivity (p=.001), scores of the ARS and the P-GBI score (p=.004) were significantly higher in children with ADHD than in their siblings. Deficits in social communication and motivation on SRS were higher in children with ADHD than in their siblings (p=.017 and p=.011, respectively). Z-scores of omission and commission errors as well as response time variability on visual CPT and omission errors on auditory CPT were in clinically significant range, and z-score of omission errors on auditory CPT was in borderline range in siblings. Omission (p=.018) and commission errors on Visual CPT (p=.007) were significantly higher in children with ADHD compared to their siblings. Recognition efficiency on Kim's Frontal Executive Function Task was lower in children with ADHD compared to their siblings, but in normal range in both groups. Stroop interference and figure fluency on Kims Frontal Executive Function Task were in borderline range in ADHD group, and figure fluency was in borderline range in siblings. Conclusion : Our results support a preliminary evidence for mild degree of attention deficit in ADHD siblings. Further studies are needed to examine the cognitive functions of siblings with ADHD in larger samples.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.532-541
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• 2016

The National Environmental Specimen Bank (NESB) has been collecting broad leave samples to monitor environmental pollution from five different designated sampling areas. In order to ensure the reproducibility and comparability of the results, all the procedures from selecting trees and pooling leaves to make the representative sample are defined in the standard operation procedures(the SOP). The representative samples were subjected to the chemical analyses for some heavy minerals and Polycyclic Aromatic Hydrocarbons(PAHs). The uncertainty levels involved in each step of the SOP, that is, the sampling and the chemical analysis, were derived using the Robust ANOVA, which enables the relative comparison among the different levels of pollutants concentrations with confidence. Furthermore, the effect of the varying degrees of precipitation on the pollutants concentration of the leaves was also examined. Overall, the biological difference estimated from the duplicate samples was found to exceed the variation across the site, implying even aerial deposition over site. Samples from Gwanak Mt. showed highest heavy metal concentrations than the other sites. Washing off effect of the pollutants adhering in the form of particles on the leaf surface was found to be affected by the cumulative precipitation.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.442-456
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• 2016

The Secretariat of the Convention on Biological Diversity (SCBD) encourages the use of the City Biodiversity Index (CBI) as a monitoring tool to assist local authorities in evaluating their progress in urban biodiversity conservation. The CBI has been applied to conserve the city biodiversity. This study has developed the City Ecological Soundness Index (CESI) based on the CBI and Korean city characteristics. The CESI includes total of 12 indicators grouped in three categories, which are 'biodiversity,' 'ecosystem services' and 'governance and management.' 85 cities in Korea were classified according to the city size and type. 18 cities have applicable biotope map, which were analyzed in the CESI pilot study. The CESI will contribute to collect and manage biodiversity data systematically and to promote biodiversity-related actions.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6913-6917
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• 2013

Background: Although the PSA test has been used in Korea for over 20 years, the incidence of prostate cancer has risen, and the associated mortality has increased about 13-fold over the 20-year period. Also, several investigators have suggested that Asians in America are more likely to present with more advanced prostate cancer than Caucasians. We compared the characteristics of native Koreans and Americans (Caucasians and African-Americans) undergoing radical prostatectomies in Korea and the US. Materials and Methods: Study subjects comprised patients at Korean and US hospitals from 2004 to 2012 who had undergone radical prostatectomies. We compared the characteristics of the subjects, including age, preoperative prostate-specific antigen (PSA) levels, body mass index (BMI), Gleason score, and pathological T stage. Results: In total, 1,159 males (502 Koreans, 657 Americans) were included. The Korean and American patients had mean ages of $67.1{\pm}6.6$ and $59.2{\pm}6.7$ years, respectively. The mean preoperative PSAs were $15.4{\pm}17.9$ and $6.2{\pm}4.6ng/mL$ (p=0.0001) and the mean BMIs were $23.6{\pm}2.6$ and $28.7{\pm}4.4kg/m^2$ (p=0.0001), respectively. Pathological localized prostate cancer represented 71.7% of cases for Koreans and 77.6% for Americans (p=0.07). According to age, Koreans had higher T stages than Americans in their 50s (p=0.021) and higher Gleason scores than Americans in all age groups. According to PSA, Koreans had higher Gleason scores than Americans for PSA >10 ng/mL (p<0.05). According to prostate size and Gleason scores, Koreans had higher PSA values than Americans (p<0.01). Conclusions: These results show that Korean patients have elevated risk of malignant prostate cancers, as indicated by the significantly higher Gleason scores and PSAs, suggesting a need for novel prostate cancer treatment strategies in Korea.

• Journal of Environmental Impact Assessment
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• v.21 no.6
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• pp.823-839
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• 2012

Environmental Specimen Banks (ESBs) are playing pivotal role in monitoring the effect of environmental pollution on the ecosystem based on the retrospective analysis of the representative samples collected regularly and stored in cryogenic condition. In Korea, National Environmental Specimen Bank (NESB) was established in 2009 and the standard operating procedures (SOPs) for sampling, and cryogenic milling and storage had been prepared during 2007-2010. Since then, the tentative SOPs for the seven kinds of specimens (shoots of Red Pine (Pinus densiflora) and Korean Pine (Pinus koraiensis), leaves of Mongolian Oak (Quercus mongolica) and Zelkova Tree (Zelkova serrata), eggs of Feral Pigeon (Columba livia var. domestica), muscles and organs of Common Carp (Cyprinus carpio), and Freshwater Bivalve (Unio (Nodularia) douglasiae)) have been put to test in the field and laboratory as well against the practicality and feasibility. The SOPs were improved by reflecting the findings from the research and the following discussion regarding the selection of specimen (Feral Pigeon suffering from a control management), sample size (a problem of decreasing number of sampling trees related to increasing sampling time) and period (a problem related to a bud growth), and sampling methods etc.. In addition, barcoding system for the management of the specimen information, and monitoring system of the cryogenic storage to regulate the optimum temperature and the liquid nitrogen level were also developed for the efficient and effective control of the samples. Lastly, the safety guide and emergency protocol were augmented to guarantee a safe work environment with the cryogenic facility. These improvements of the SOPs are expected to contribute to more stable operation of the NESB.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.745-751
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• 2013

Environmental Specimen Banks (ESBs) have been established widely in the world since 1979 for monitoring long-term bio-accumulation of environmental pollutants. The ESBs perform the retrospective analysis of representative biological samples collected regularly and store them in cryogenic condition. In Korea, National Environmental Specimen Bank (NESB) was established in 2009. Since then, NESB had prepared the standard operating procedures (SOPs) for the seven kinds of specimens (Red Pine (Pinus densiflora), Common Carp (Cyprinus carpio), and etc.) for monitoring the effect of environmental pollution on the terrestrial ecosystem and river ecosystem. In 2012, NESB added Black-tailed Gull (Larus crassirostris)'s eggs to the list of the environmental specimen for monitoring marine environmental pollution. In this study, we sampled the eggs of the Black-tailed Gull on two islands (Baekryeongdo of the West Sea and Hongdo of the South Sea). Especially, we selected eggs which remained in the early stages of embryo development for certifying the consistent and stable monitoring for environmental pollutants in egg contents. However, it was not considered to classify an order of eggs per clutch in this study. It is known that the concentration variations of pollutants exist among eggs in one clutch. Therefore, it is needed to consider the positions of eggs in the laying sequences to meet the objective of bioaccumulation monitoring. We collected 30 eggs in each site but the amount may be insufficient to achieve storage target (over 2,000 g). Therefore, we need to consider an optimal sampling size.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.122-133
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• 2014

Purpose: This study was to develop an effective process for fabricating biocompatible calcium phosphate powders (CPPs) using horse bones, and to investigate the characteristics of them. Methods: The characteristics of horse bone powders (HBPs) were investigated according to the different osseous tissue types (compact bone and cancellous bone), bone types (spine and tibia), pretreatment methods (cold water, $H_2O_2$, and hot water), sintering time (4, 8 and 12h), and sintering temperature (600, 900, 1100 and $1300^{\circ}C$). In addition, the grinding methods were compared based on the wet grinding (ball mill) and dry grinding (blade grinder) method to make it as powders. Finally, their cytotoxicity and cell viability were checked. Results: Regardless of the types of osseous tissues and bones, HBPs were well fabricated as biocompatible CPPs. It was also found that the pretreatment methods did not influence on the resultants, showing well-fabricated HBPs. Considering the processing time, the hot water method was the most suitable compared to other pretreatment methods. Further, 12h-sintering time was sufficient to remove residual organic compounds. The sintering temperatures greatly affected the properties of bone powders fabricated. The x-ray diffraction (XRD) peak of horse bone sintered at $600^{\circ}C$ was most closed to that of hydroxyapatite (HA). Our bioactivity study demonstrated that the HBPs fabricated by sintering horse bones at $1300^{\circ}C$ showed the best performance in terms of cell viability whereas the HBPs $1100^{\circ}C$ showed the cytotoxicity. Conclusions: Using various types of horse bone tissues, biocompatible CPPs were successfully developed. We conclude that the HBPs may have a great potential as biomaterials for various biological applications including bone tissue engineering.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.227-234
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• 2014

Purpose: The aim of this research was to develop and evaluate natural hydroxyapatite (HA) ceramics produced from the heat treatment of pig bones. Methods: The properties of natural HA ceramics produced from pig bones were assessed in two parts. Firstly, the raw materials were characterized. A temperature of $1,200^{\circ}C$ was chosen as the calcination temperature. Fine bone powders (BPs) were produced via calcinations and a milling process. Sintered BPs were then characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and a 2-year in vitro degradability test. Secondly, an indirect cytotoxicity test was conducted on human osteoblast-like cells, MG63, treated with the BPs. Results: The average particle size of the BPs was $20{\pm}5{\mu}m$. FE-SEM showed a non-uniform distribution of the particle size. The phase obtained from XRD analysis confirmed the structure of HA. Elemental analysis using XRF detected phosphorus (P) and calcium (Ca) with the Ca/P ratio of 1.6. Functional groups examined by FTIR detected phosphate ($PO{_4}^{3-}$), hydroxyl ($OH^-$), and carbonate ($CO{_3}^{2-}$). The EDX, XRF, and FTIR analysis of BPs indicated the absence of organic compounds, which were completely removed after annealing at $1,200^{\circ}C$. The BPs were mostly stable in a simulated body fluid (SBF) solution for 2 years. An indirect cytotoxicity test on natural HA ceramics showed no threat to the cells. Conclusions: In conclusion, the sintering temperature of $1,200^{\circ}C$ affected the microstructure, phase, and biological characteristics of natural HA ceramics consisting of calcium phosphate. The Ca-P-based natural ceramics are bioactive materials with good biocompatibility; our results indicate that the prepared HA ceramics have great potential for agricultural and biological applications.