• Journal of Life Science
• /
• v.34 no.4
• /
• pp.215-226
• /
• 2024

Aralia continentalis is widely distributed in Far East Asian countries such as Korea, China, and Japan. A. continentalis has traditionally been used as an herbal remedy for various conditions, including analgesia, headache, inflammation, lameness, lumbago, rheumatism, and dental diseases in Korea. Previously, epi-continentalic acid, continentalic acid, and kaurenoic acid as major active biological compounds belonging to the diterpenoid class were identified. To synthesize diterpenoid derivatives with enhanced bioavailability, Fusarium fujikuroi was employed to biotransform diterpenoids due to its known antibacterial activity. This yielded two derivatives of kaurenoic acid, namely 16α-hydroxyent-kauran-2-on-19-oic acid and 2β, 16α-dihydroxy-ent-kauran-19-oic acid, with their chemical structures elucidated via NMR analysis. These derivatives exhibited increased polarity compared to kaur- enoic acid, as evidenced by their retention time on preparative HPLC using the ODS-A column and structural modifications. Evaluation of their antidiabetic activity targeting PTP1B, a negative regulator of the insulin signaling pathway, revealed inhibitory activities of 30.8% and 27.6%, respectively, at a concentration of 4 ㎍/ml. Additionally, both derivatives demonstrated low cytotoxicity, with an IC50 value 18 times higher than kaurenoic acid. Therefore, the augmented water solubility and reduced toxicity of 16α-hydroxy-ent-kauran-2-on-19-oic acid and 2β, 16α-dihydroxy-ent-kauran-19-oic acid, resulting from biotransformation by F. fujikuroi, render them promising candidates for industrial applications.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.34 no.2
• /
• pp.166-178
• /
• 2024

Objectives: The 12 occupational exposure limits(OELs) for chromium and its compounds in Korea were set by applying the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs). However, this is significantly different from the TLVs after the existing TLVs were integrated and withdrawn in 2018, so it is necessary to review the revision. Methods: Various documents related to chromium OELs were reviewed, including the ACGIH TLV Documentations for chromium and its compounds. A field survey was conducted targeting workplaces handling chromium and its compounds. Based on this, a revised OELs were proposed and a socio-economic evaluation was conducted. Results: The OELs for chromium compounds in Korea was first enacted in 2002, and in 2007, the OELs for chromium (hexavalent) compounds (insoluble) was lowered from 0.05 mg/m³ to 0.01 mg/m³. In 2008, the OELs for strontium chromate was newly established as 0.0005 mg/m³, and in 2018, the OELs for calcium chromate was newly established as 0.001 mg/m³. Total chromium and hexavalent chromium were measured for each of 6 samples at 2 welding sites, 4 plating sites, and 2 spray coating sites. When omparing the average of the results measured by ICP, a total chromium analysis method, and the analysis results by IC, a hexavalent chromium analysis method, only workplace 4 was the same, and total chromium was evaluated more, and total chromium was evaluated at 0.0004 to 0.0027 mg/m³. And hexavalent chromium was evaluated as non-detection ~ 0.0014 mg/m³. Amendment ①: The exposure standard for hexavalent chromium is not divided into water soluble, insoluble, chromium ore processing, and other hexavalent chromium compounds, and is integrated into 0.01 mg/m³, which is the level of chromium (hexavalent) compound (insoluble)., OELs for chromium (metal) and chromium (trivalent) compounds are integrated into chromium (trivalent) compounds, and the exposure level is maintained. Amendment ②: As in the amendment ①, the OELs are integrated, but the level is lowered to 0.005 mg/m³, which is the OELs of OSHA, and there is a grace period of 4 years. Amendment ③: As in the amendment ①, the OELs are integrated, but the level is lowered to 0.0002 mg/m³, which is the exposure standard of ACGIH, and there is a grace period of 5 years. Conclusions: Amendment ①: The change in the OELs is insignificant, so the cost required is small, and the benefit/cost ratio is greater than 1, so there is no problem in applying the amendment. Amendment ②: In all scenarios except chromium 6(insoluble), the benefit/cost ratio is greater than 1, so it is thought that there will be no major problem in applying the amendment. Amendment ③: Since the benefit/cost ratio is less than 1 in all scenarios, it is thought that the total social benefit that can be obtained when applying the amendment is not large.

• Korean Journal of Food Science and Technology
• /
• v.53 no.1
• /
• pp.46-54
• /
• 2021

The biological activities of non-edible extracts of asparagus stems and roots were investigated using hot water and ethanol. The highest contents of rutin and total polyphenol were 31.74 mg/g and 20.14 mg GAE/g, respectively, in the stem hot water extract. ABTS and DPPH radical scavenging activities were 541.1±21.0 and 649.5±6.6 ㎍/mL, respectively, in stem hot water extract. All extracts were non-cytotoxic in HepG2 cells, but 200 ㎍/mL stem extracts tended to decrease the viability of RAW 264.7 cells. The highest xanthine oxidase inhibitory activity was 43.68% in the root hot water extract at 200 ㎍/mL. The expression level of MMP-9 was significantly decreased in the asparagus extracts. The highest GGT, AST, and LDH activities showed a concentration-dependent decrease in the stem ethanol extract. In conclusion, the presence of bioactive substances in the non-edible extracts of asparagus was confirmed for the development of extracts with antioxidant, hepatoprotective and anti-gout activities.

• Journal of the Korean Vacuum Society
• /
• v.18 no.2
• /
• pp.116-126
• /
• 2009

It is becoming more difficult to improve the device operating speed by shrinking the size of semiconductor devices. Therefore, for a new leap forward in the semiconductor industry, the advent of silicon opto-electronic devices, i.e., silicon photonics is more desperate. Silicon Avalanche LED is one of the prospective candidates to realize the practical silicon opto-electronic devices due to its simplicity of fabrication, repeatability, stability, high speed operation, and compatibility with silicon IC processing. We conducted the measurement of the electrical characteristics and the observation of the light-emitting phenomena using optical microscopy. We analyzed the influence of the design elements such as the shape of the light-emitting area and the depth of the $n^{+}-p^{+}$ junction with simple device modeling and simulation. We compared the results of simulation and the measurement and explained the discrepancy between the results of the simulation and the measurement, and the suggestions for the improvement were given.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.310-310
• /
• 2012

최근 전자산업의 발달에 따른 전자제품의 소형화 및 고기능화 요구에 대응하기 위하여 저항(resistor), 커패시터(capacitor), IC (integrated circuit) 등의 수동소자를 개별 칩(discrete chip) 형태로 형성하여 기판의 표면에 실장하는 기술이 일반화되고 있다. 그러나, 수동 소자의 내장 기술은 기판의 패턴 밀도의 급격한 향상과 더불어 수동소자의 내장 공간도 협소해지는 문제점이 있다. 상기의 문제점을 해결하기 위해 개별 칩 형태의 내장형 저항체를 박막 형태의 내장 저항체를 구현하는 기술의 개발이 최근 주목을 받고 있다. 박막 저항체는 기존의 권선저항 및 후막저항과 비교하여 정밀한 온도저항계수를 가지며 이동통신에 적용시 고주파 영역(GHz)에서의 안정성과 주파수 특성이 좋다는 장점들을 가지고 있다. 박막 저항 물질로는 높은 경도와 우수한 열적 안정성을 가지고 있는 TaN (tantalum nitride)이 주로 사용되고 있다. 일반적으로, TaN 박막은 스퍼터링을 사용하며 제조되며 TaN 박막의 성질은 탄탈륨과 질소의 화학정량비, 박막의 결함 정도, 또는 공정압력 및 증착 온도, 플라즈마 파워 등과 같은 공정조건 등의 변화에 민감하게 변화하므로, TaN 박막의 다양한 연구가 더 필요한 실정이다. 본 연구에서는 반응성 마크네트론 스퍼터링을 사용하여 TaN 박막을 Si 기판 위에 증착하였고 TaN 박막의 원하는 특성을 제어할 수 있도록 질소 분압과 total gas volume을 조절하여 공정을 최적화하는 연구를 진행하였다. 또한 tensile pull-off 방법을 이용하여 TaN 박막의 부착강도를 평가하였고, 온도 사이클 및 고온고습 환경에 노출된 TaN 박막들의 열화 특성들에 대하여 연구하였다.

• Journal of the Korea Convergence Society
• /
• v.6 no.1
• /
• pp.49-55
• /
• 2015

In the FTA environment, it is necessary to comply with the rules of origin in order to receive duty-free benefits. To do this, they have to precede the Harmonized System(HS) tariff classification of the goods and understand thoroughly the basic principles that constitute the tariff schedule of HS classification. For the correct classification, they should understand exactly the product name of "Heading" about the items, "Legal Note" in the relevant "Section" or "Chapter" as well as provisions of the commentary. Therefore, this paper proposes to develop a HS classification services based on the performance system of knowledge convergence of field terms commonly used in various industries. In result, our services can provide users the conveniences which users first selects one of seven decision elements of the classification and perform the classification easily and accurately.

• Journal of the Korean Vacuum Society
• /
• v.16 no.1
• /
• pp.74-78
• /
• 2007

Much interests has been drawn for noble micro-engineering processes for the continuous size reduction on bulk materials from the field of micro-electronics with much downsized IC chips. A traditional microprocessing based on mechanical blade as well as a relatively long pulsed laser usually influence the physico-chemical properties of intact materials when the techniques are applied to process materials with a spatial resolution less than 10 microns. Meanwhile, ultrafast laser pulses are known to exhibit a very small heat-affect zone(HAE) compared to the traditional laser processing and to be applicable for the new functional materials with high performance in optical and electrical properties. In this report, we will review in brief the recent research works on the enhancement of micro-cutting speed of thin silicon wafer as well as the formation of Ge nanostructures based on ultrafast laser pulses.

• Microbiology and Biotechnology Letters
• /
• v.37 no.1
• /
• pp.49-54
• /
• 2009

Rhapontin is the glycosylated stilbene compound, and comprising major component of rhubarb root extract. Rhapontin has been used as a raw material of skin-whitening cosmetics in Korea. Rhapontigenin, the aglycone of rhapontin, has been suggested to be more active than its glycosylated form. Therefore, the rhubarb root extract was treated with commercial enzyme, Pectinex to remove glycosylated moiety of rhapontin and rhapontigenin was prepared. The resulting material was analysed and identified as rhapontigenin by proton NMR and MALDI-Mass. Rhapontigenin exhibited tyrosinase inhibitory activity with an $IC_{50}$ of $126.72{\mu}g/mL$. The tyrosinase inhibitory activity of rhapontigenin was six times higher than that of rhapontin. In melanin biosynthesis inhibition assay using Streptomyces bikiniensis, rhapontigenin showed wider inhibition zone than that of rhapontin. From these results, we expect that rhapontigenin has stronger skin whitening effect than rhapontin and has advantages in cosmetic industry.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.05a
• /
• pp.695-698
• /
• 2005

최근 국외의 전력회사들은 미래 디지털 사회의 기반이 되는 신전력시스템을 구현하는데 필요한 핵심기술중의 하나로서 IT(Information Technology)기반 전력부가서비스 기술의 중요성에 대해 강조하고 있으며, 이를 위해 원격검침 데이터를 기반으로 하는 다양한 전력부가서비스를 개발하여 적용하고 있다. 한편 국내의 경우 원격검침 데이터는 전력요금 산출용도로 활용되고 있는 수준이다. 전력회사는 원격검침 데이터가 고객과의 관계에서 부가가치를 높일 수 있는 무한한 잠재력을 지닌 전략적인 자산으로 보고, 원격검침 데이터 가공 및 활용기술의 선진화를 통하여 전력회사와 전력소비자 모두에게 필요한 전력부가서비스의 적용이 필요하다. 본 논문에서는 국내 전력산업 환경에 적합한 새로운 전력부가서비스 적용방안으로 제안한 전력 에너지 컨설팅 서비스에 대해 소개하고자 한다. 본 논문에서 제안한 전력부가서비스의 적용은 전력소비자 측면에서는 요금절감 효과가 전력회사 측면에서는 부하 수요관리 및 투자비 절감 효과가 예상된다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.992-1001
• /
• 2022

The maritime traffic analysis has been conducted in various ways to solve problems arising from the complex marine environment. However, recent trends in the maritime industry, such as the development of the maritime autonomous surface ships (MASS), suggest that maritime traf ic analysis needs change. Accordingly, based on the studies conducted over the past decade for improvements, automatic identification system (AIS) data is mainly used for maritime traffic analysis. Moreover, the use of geographic information that directly af ects ship operation is relatively insufficient. Therefore, this study presented a method of using a combination of shape format data and AIS data to enhance maritime traffic analysis in preparation for the commercialization of autonomous ships. Consequently, extractable marine traffic characteristics were presented when shape format data were used for marine traffic analysis. This is expected to be used for marine traffic analysis for the introduction of autonomous ships in the future.