http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
산겨릅나무 목질부에서 분리한 페놀성 화합물의 DPPH 라디칼 소거활성
권동주 ( Dong Joo Kwon ),김진규 ( Jin Kyu Kim ),배영수 ( Young Soo Bae ) 한국목재공학회 2011 목재공학 Vol.39 No.1
There have been few reports on the constituents and biological activity of stem bark of Acer tegmentosum, and no phytochemical and biological studies have been reported for stem wood of A. tegmentosum. Two flavan 3-ols (1 and 2), three phenolic acid/alcohols (3~5), and two coumarins (6 and 7) were isolated from the stem wood of A. tegmentosum by repeated column chromatography. The structure of isolated compounds were identified as (+)-catechin (1), (-)-epicatechin (2), p-hydroxybenzaldehyde (3), syringic alcohol (4), p-tyrosol (5), scopoletin (6), and cleomiscosin A (7) on the basis of spectroscopic evidences such as 1H-NMR, 13C-NMR, 2D-NMR and MS spectrum. P-Hydroxybenzaldehyde (3), syringic alcohol (4), scopoletin (6), and cleomiscosin A (7) have not been reported from this plant so far. (+)-Catechin (1) and (-)-epicatechin (2) showed the higher 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than hutylated hydroxyanisole (BHA) used as a positive control.
치과 임플란트 치료환자의 치아상실 요인에 대한 후향적 연구
권동주 ( Dong-joo Kwon ),이찬현 ( Chan-hyun Lee ),임나희 ( Na-hee Lim ) 국군의무사령부 2018 대한군진의학학술지 Vol.49 No.1
Objectives; The purpose of this retrospective study was to investigate the incidence and the factors of tooth loss in the patients with dental implant treatment in Armed Forces Capital Dental Hospital. Methods; 62 teeth which were lost during the duty, 278 teeth which were lost in the patients who serve over 20 years were included. Number of tooth loss by rank, location of tooth loss, reason for tooth loss, and percentage of fracture of oral and maxillofacial area was evaluated in the teeth lost during the duty. Location, period, reason of tooth loss, medical history, smoking, and additional treatment such as bone graft and sinus lift was evaluated in the teeth of the patients who serve over 20 years. Results; Most of tooth loss during the duty occurred in the soldier class, and maxillary central incisors. The reason for tooth loss was crown-root fracture(38.7%), root fracture(24.2%), crown fracture(17.7%), tooth avulsion(16.1%), and alveolar bone fracture(3.3%). Most of the tooth loss was located in the maxillary and mandibular molars in the patients who serve over 20 years. The reason for tooth loss in the patients was already lost(unknown cause, 48.4%), periodontal disease(39.4%), dental caries(7.7%), root fracture(2.8%), crown fracture(1.0%). More than half of the patients who serve over 20 years were smoker. Conclusions; Many soldiers are experiencing tooth loss, and dental implant could be a good treatment for functional aesthetic restoration. However, more efforts should be made to prevent tooth loss in the Army.
투명 유-무기 하이브리드 하드코팅 필름 제조 및 SiO<sub>2</sub> 또는 ZrO<sub>2</sub>함량에 따른 필름의 물성
설현태,나호성,권동주,김정섭,김대성,Seol, Hyun Tae,Na, Ho Seong,Kwon, Dong Joo,Kim, Jung Sup,Kim, Dae Sung 한국재료학회 2017 한국재료학회지 Vol.27 No.1
Transparent organic-inorganic hybrid hard coating films were prepared by the addition of $SiO_2$ or $ZrO_2$, as an inorganic filler to improve the hardness property, filler was highly dispersed in the acrylic resin. To improve the compatibility in the acrylic resin, $SiO_2$ or $ZrO_2$ is surface-modified using various silanes with variation of the modification time and silane content. Depending on the content and kind of the modified inorganic oxide, transparent modified inorganic sols were formulated in acryl resin. Then, the sols were bar coated and cured on PET films to investigate the optical and mechanical properties. The optimized film, which has a modified $ZrO_2$ content of 4 wt% markedly improved in terms of the hardness, haze, and transparency as compared to neat acrylate resin and acrylate resin containing modified $SiO_2$ content of 8 wt%. Meanwhile, the low transparency and high haze of these films slowly appeared at $SiO_2$ content above 10 wt% and $ZrO_2$ content of 5 wt%, but the hardness values were maintained at 2H and 3H, respectively, in comparison with the HB of neat acrylate resin.
Antioxidative activities of Paulownia coreana extractives
사전령,김진규,권동주,배영수,Si, Chuan-Ling,Kim, Jin-Kyu,Kwon, Dong-Joo,Bae, Young-Soo Institute of Forest Science 2006 Journal of Forest Science Vol.22 No.-
오동나무잎, 열매, 내수피, 외수피 그리고 목질부를 채취하여 건조시킨 후 분말로 제조하여 각 시료 약 5.0 kg을 아세톤-물(7:3. v/v) 혼합용액으로 추출하고 유기용매를 제거한 후 헥산, 메틸렌클로라이드, 에틸아세테이트 및 물 등 네 개의 분획으로 분리하였다. 오동나무 각 부위별 추출물 수율은 내수피(11.35%)가 가장 높았고 잎(7.87%), 열매(6.94%), 외수피(4.24%)의 순 이었으며 목질부가 4.10%로 가장 낮게 나타났다. 오동나무 각 부위별 조추출물, 고형분과 분획물을 가지고 DPPH radical 소거법을 이용하여 기초적인 항산화 실험을 실시하였다. 기준물질로는 천연 항산화제인 ${\alpha}$-tocopherol과 합성항산화제인 BHT를 사용하여 항산화효능을 비교하였다. 그 중에서는 모든 EtOAc용성 분획이 기준물질 보다 더 우수한 항산화 활성을 나타내었다. Approximately each 5 kg dried Paulownia coreana leaves, seeds, outer barks, inner barks and wood were ground, extracted with acetone-$H_2O$ (7:3. v/v). concentrated under reduced pressure and successively fractionated using n-hexane. $CH_2Cl_2$, EtOAc and $H_2O$ on a separation funnel. Each fraction was then freeze dried and weighed. The extraction yield of each sample was investigated and the yield of inner barks was the highest, while the wood was the lowest. Antioxidative activities of crude extracts, precipitates and partitioned fractions were evaluated by DPPH radical scavenging method. The results indicated that all EtOAc soluble fractions, including some of $H_2O$ soluble fractions, showed significantly high antioxidative potential compared with ${\alpha}$-tocopherol and BHT used as controls.