• Journal of Marine Bioscience and Biotechnology
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• v.8 no.1
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• pp.30-38
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• 2016

The objective of this study was to investigate the useful components and potential antioxidant activities of 30 marine algae, collected from Jeju Island in Korea. The contents of bioacitve substance of extracts from marine algae, such total polyphenol and carbohydrate, were determined. The extract of Distromium decumbens had the highest amount of total polyphenol content (21.27%), and that of Gracilaria incurvata Okamura had the highest amount of total carbohydrate content (10.18%). The antioxidant activities of extracts obtained from algae were tested through the evaluation of DPPH radical and hydroxyl radical scavenging activity. The extracts of Distromium decumbens, Sargassum hemiphyllum (Turner) C.Agardh, Sargassum serratifolium (C. Agardh) C. Agardh and Acrosorium yendoi Yamada were found to have more than 80% DPPH radical scavenging activity and that of Dictyota okamurae (Dawson) $H{\ddot{o}}tning$, Schnetter, et Prud'homme van Reine, Myagropsis myagroides (Martens ex Turner) Fensholt, Sargassum serratifolium (C. Agardh) C. Agardh and Cladophora wrightiana Harvey showed more than 50% hydroxyl radical scavenging activity. These results suggest that algae collected from Jeju Island would be good raw materials for antioxidant.

• Environmental Engineering Research
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• v.19 no.3
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• pp.261-268
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• 2014

Leachate quality and methane emission from pilot-scale lysimeters operated under semi-aerobic and anaerobic conditions were monitored for 650 days. Two semi-aerobic lysimeters were filled with un-compacted and compacted municipal solid wastes whereas two anaerobic lysimeters containing compacted wastes were operated with leachate storage at 50% and 100% of waste height, respectively. Despite having high moisture in wastes and operating under tropical rainfall events, leachate stabilization in semi-aerobic lysimeters took place much faster resulting in BOD reduction by 90% within 60 days, significantly shorter than 180-210 days observed in anaerobic lysimeters. Nitrogen concentration in leachate from semi-aerobic lysimeter could be reduced by 90%. In term of gas emission, semi-aerobic lysimeter with un-compacted wastes had much lower methane emission rate of $2.8g/m^2/day$ compare to anaerobic lysimeters ($62.6g/m^2/day$) through seasonal fluctuation was observed. Nevertheless, semi-aerobic lysimeter with waste compaction has similar performance to anaerobic lysimeter.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1433-1435
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• 2003

Very decisive progress was made in advancing fundamental POL-IN-SAR theory and algorithm development during the past decade. This was accomplished with the aid of airborne & shuttle platforms supporting single -to-multi-band multi-modal POL-SAR and also some POL-IN-SAR sensor systems, which will be compared and assessed with the aim of establishing the hitherto not completed but required missions such as tomographic and holographic imaging. Because the operation of airborne test-beds is extremely expensive, aircraft platforms are not suited for routine monitoring missions which is better accomplished with the use drones or UAVs. Such unmanned aerial vehicles were developed for defense applications, however lacking the sophistic ation of implementing advanced forefront POL-IN-SAR technology. This shortcoming will be thoroughly scrutinized resulting in the finding that we do now need to develop most rapidly POL-IN-SAR drone-platform technology especially for environmental stress-change monitoring with a great variance of applications beginning with flood, bush/forest-fire to tectonic-stress (earth-quake to volcanic eruptions) for real-short-time hazard mitigation. However, for routine global monitoring purposes of the terrestrial covers neither airborne sensor implementation - aircraft and/or drones - are sufficient; and there -fore multi-modal and multi-band space-borne POL-IN-SAR space-shuttle and satellite sensor technology needs to be further advanced at a much more rapid phase. The existing ENVISAT with the forthcoming ALOSPALSAR, RADARSAT-2, and the TERRASAT will be compared, demonstrating that at this phase of development the fully polarimetric and polarimetric-interferometric modes of operation must be viewed and treated as preliminary algorithm verification support modes and at this phase of development are still not to be viewed as routine modes.

• Mycobiology
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• v.44 no.4
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• pp.269-276
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• 2016

Aspergillus luchuensis is known as an industrially important fungal species used for making fermented foods such as awamori and shochu in Japan, makgeolli and Meju in Korea, and Pu-erh tea in China. Nonetheless, this species has not yet been widely studied regarding mating-type genes. In this study, we examined the MAT1-1 and MAT1-2 gene ratio in black koji molds (A. luchuensis, Aspergillus niger, and Aspergillus tubingensis) and in Aspergillus welwitschiae isolated from Meju, a fermented soybean starting material for traditional soy sauce and soybean paste in Korea. The number of strains with the MAT1-1 locus was 2 of 23 (A. luchuensis), 6 of 13 (A. tubingensis), 21 of 28 (A. niger), and 5 of 10 (A. welwitschiae). Fungal species A. tubingensis and A. welwitschiae showed a 1 : 1 ratio of MAT1-1 and MAT1-2 mating-type loci. In contrast, A. luchuensis revealed predominance of MAT1-2 (91.3%) and A. niger of MAT1-1 (75%). We isolated and identified 2 A. luchuensis MAT1-1 strains from Meju, although all strains for making shochu in Japan are of the MAT1-2 type. These strains may be a good resource for breeding of A. luchuensis to be used in the Asian fermented-food industry.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.168-168
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• 2000

Yamada 등의 덩어리 증착에 관한 연구 이후 낮은 기판 온도에서 결정성이 뛰어난 금속박막성장(thin film growth)을 얻을 수 있는 방법으로 최근 덩어리 증착(cluster depositon) 방법에 관하여 많은 연구들이 진행되어 덩어리 충돌이 원자 충돌인 경우와 큰 차이를 보이는 결과를 얻었으며, 덩어리 증착시 기판 내부에 점결함(point defect)이 발생되지 않는다는 중요한 결과를 얻었다. 금속 덩어리를 사용한 금속박막성장은 높은 박막성장속도와 뛰어난 구조 재배열 효과를 얻을 수 있으며 기판의 격자 손상을 감소시키기 때문에 향후 나노미터 소자 개발에 응용성이 클 것으로 예상된다. 그러나 금속 덩어리와 금속 표면사이의 상호작용에서 발생되는 기본적인 역학(mechanism)은 분명하게 알려져 있지 않다. 지금까지 알루미늄 덩어리의 원자구조와 특성에 관한 연구는 수행되어졌지만 (4,5), 알루미늄 덩어리 증착에 관한 연구는 수행되지 않았다. 본 연구에서는 13~177개로 이루어진 큰 알루미늄 덩어리들의 증착에 관하여 Md(molecular dynamics) 방법을 사용하여 연구하였다. MD 시뮬레이션을 사용하여 덩어리 증착시 기판 표면과의 충돌 초기에 나타나는 덩어리 내부 원자들의 상관충돌효과(correlated collisions effect)에 의하여 덩어리 크기에 따른 증착현상과 여러 물리적 현상들을 관찰하였다. 덩어리 총 에너지가 증가할수록 기판의 최고 온도는 증가하며, 덩어리 크기가 클수록 상관충돌효과가 커지기 때문에 덩어리의 총 에너지에 다른 최고 증가 비율은 적어졌다. 시간에 따른 비정렬 원자수(disordered atom number) 비교를 통하여 덩어리가 클수록 구조 재배열이 더 잘 이루어진다는 것을 알 수 있었고, 원자당 에너지가 클수록 덩어리 원자들이 기판 내부로 더 깊이 들어갔고, 덩어리 크기가 클수록 상관충돌효과로 인하여 덩어리 원자들이 기판 내부로 더 깊이 들어가는 것을 알 수 있었고, 덩어리 크기가 클수록 상관충돌효과는 커지고 더욱 부드러운 증착이 이루어졌으며, 무엇보다도 덩어리 증착시 표면에서 구조 재배열이 잘 이루어지는 특징을 살펴볼 수 있었다. 이러한 알루미늄 덩어리를 생성하여 증착할 수 있을 경우, 뛰어난 재배열 효과를 이용하여 품질이 향상된 반도체 소자를 제조할 수 있을 것으로 사료된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.4-5
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• 2010

The surface phonon is defined as a coherent vibrational excitation of surface atoms propagating along the surface. It is characterized by a phonon dispersion curves, which were extensively studied in 1990's using helium atom scattering and high-resolution electron-energy-loss spectroscopy (HREELS)[1].The understanding is mainly based on the theoretical framework of a classical bond model or cluster calculations. The recent sample preparation and first principles calculations open the naval way to deep insight for surface phonon problems. The surface phonon dispersion on the hydrogen-terminated Si(111)-($1{\times}1$) surface [H:Si(111)] is the typical system and already reported experimentally [2] and theoretically [3], although the understandingis incomplete. The sample contaminated by the oxygen atoms on the surface and the calculations were also classical. In this study, firstly, we have prepared an ultra-clean H:Si(111) surface [4] and measured the surface phonon dispersion curvesusing HREELS. Secondly, we have performed first-principles density functional calculations with the projector augmented wave functionals, as implemented in VASP, using generalized gradient approximations. We used aslab of six silicon layers and both top and bottom surfaces were terminated with hydrogen atoms. Finally, we have compared with the surface phonon dispersion of deuterium-terminatedSi(111)-($1{\times}1$) surface[5] and led to our conclusions. The Si-H stretching and the bending modes are observed at 258.5 and 78.2 meV, respectively. These energies are the same as the previously reported values [2], but the energy-loss peaks at the lower energy regions are dramatically shifted. Through this combination study, we have formulated the procedure of preparing ultra-clean H:Si(111)/D:Si(111), which was confirmed by HREELS vibrational analysis. The Si surface will be utilized for further nano-physics research as well as for the materials for nano-fubrication.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.545-545
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• 2003

Chitosan is applied as a dressing for oral mucous wound and a tampon following radical treatment of maxillary sinus. Furthermore, it is being investigated as an absorbing membrane for endodontic and periodontic surgeries. A few studies have reported osteoconduction and osteogenesia at the site of chitosan implant in vivo. However, compared with soft tissue healing processes, the mechanisms concerning effects of chitosan for biological mineralization have not yet been resoil In the present study, we studied the gene expression pattern using cDNA microarray and RT-PCR analyses in hard tissue forming osteoblasts cultured with water-soluble and low molecular weight chitooligosaccharide. cDNA microarray analysis revealed that 16 genes were expressed at 〉1.5-fold higher signal ratio levels in the experimental group compared with the control group after 3 days. RT-PCR analysis showed that chitosan oligomer induced an increase in the expression of two genes, CD56 antigen and tissue-type plasminogen activator. Furthermore, the expression of mRNAs for BMP-2 was almost identical in the experimental and control groups after 3 days of culture, but slightly increased after 7 days of culture with chitosan oligomer. These results suggest that a super-low concentration of chitooligosaccharide could modulate the activity of osteoblastic cells through mRNA levels and that the genes concerning cell proliferation and differentiation can be controlled by water-soluble chitosan.

• Nutrition Research and Practice
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• v.13 no.6
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• pp.480-487
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• 2019

BACKGROUND/OBJECTIVES: Osteoarthritis (OA) is a major public health issue in Japan and other countries, and foods that prevent or treat OA are in strong demand. Proteins and peptides in chicken meat and bones are known for being rich in functional and nutritional ingredients for the improvement of osteoporosis. We speculated that chicken legs, a food consumed in many regions of the world, may also contain such ingredients. In this study, we aim to (i) evaluate the effect of chicken leg extract (CLE) on the promotion of cartilage matrix production and (ii) identify the active ingredient in CLE that contributes to this function. MATERIALS/METHODS: Artificial CLE digest was prepared, and the acid mucopolysaccharide production-promoting activity of the CLE digest was evaluated by alcian blue staining of ATDC5 cells. CLE was orally administered to rabbits with burr holes in the knee joint of the femur, and the degree of regeneration of cartilage matrix was evaluated. Furthermore, we investigated orally administered CLE-derived peptides in human plasma using LC-MS. From measuring the acid mucopolysaccharide production-promotion activity of these peptides, a molecule considered to be an active ingredient in the CLE digest was identified. RESULTS: CLE digest promoted acid mucopolysaccharide production and facilitated regeneration of cartilage matrix in in vitro and in vivo experiments. Four peptides including phenylalanyl-hydroxyproline (Phe-Hyp) were detected as CLE-derived peptides in human plasma. The effect of CLE was inferred to be due to Phe-Hyp, which was confirmed to be present in the CLE digest. CONCLUSIONS: It was shown that CLE stimulated the production of articular cartilage matrix both in vitro and in vivo, and that CLE could be an effective food for preventing or treating OA. Furthermore, only Phe-Hyp was confirmed as the active compound in the CLE digest, suggesting that the activity of CLE was due to Phe-Hyp.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.169-171
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• 2008

The objective of this paper is to explore the short-term variability of sea surface temperature (SST) and chlorophyll a (Chl-a) derived from satellite in the upwelling region of the southeast coast of Korea in summer. We particularly emphasize the spatial variability of SST and Chl-a in the East Korean Warm Current (EKWC) during summer monsoon. Spatial distribution of SST and Chl-a in the EKWC are described using SeaWiFS and AVHRR images in August, 2007. Spatial distribution of SST and Chl-a around EKWC can be classified into four categories in the profile of SST and Chl-a images: (1) coastal cold water region, (2) cold water region of thermal front, (3) warm water region, (4) cold water of offshore region.

• Knee surgery & related research
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• v.30 no.4
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• pp.293-302
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• 2018

Purpose: High tibial valgus osteotomy (HTO) is a well-established surgical procedure for patients with medial compartment osteoarthritis (OA) of the knee. The hybrid closed-wedge HTO (CWHTO) procedure permits extensive correction in patients with severe deformities or patellofemoral joint OA. The aim of this study was to report the short-term results in a consecutive series of patients treated with hybrid CWHTO. Materials and Methods: We retrospectively evaluated the clinical outcomes and radiographic parameters in 29 consecutive knees that underwent hybrid CWTHO to correct medial compartment OA at an average follow-up of 52.6 months. Clinical outcomes were assessed using the Lysholm score and knee scoring system of the Japanese Orthopedic Association (JOA). The Kellgren-Lawrence grading system and pre- and postoperative mechanical axis (MA), femorotibial angle (FTA), posterior tibial slope, and patella height were assessed. Results: The FTA and MA significantly changed from $180.7^{\circ}$ to $170.4^{\circ}$ and from $22.0^{\circ}$ to $60.2^{\circ}$, respectively. No significant differences were observed between the mean pre- and postoperative posterior tibial slope, Insall-Salvati ratio, or Caton-Deschamps index. The postoperative JOA and Lysholm scores significantly improved from 76.7 to 95.8 and from 58.8 to 90.2, respectively. Conclusions: Satisfactory outcomes can be achieved with hybrid CWHTO in patients with medial OA.