Mössbauer Studies of Spin-Orbit Coupling in LiCo<tex> $_{0.99}$</tex> <tex> ${}^{57}$</tex> Fe<tex> $_{0.01}$</tex> PO<tex> $_{4}$</tex>

Chan Hyuk Rhee,Sam Jin Kim,Chul Sung Kim IEEE 2011 IEEE transactions on magnetics Vol.47 No.10

<P>The polycrystalline LiCo<SUB>0.99</SUB><SUP>57</SUP>Fe<SUB>0.01</SUB>PO<SUB>4</SUB> was synthesized by solid-state reaction method. The crystal structure was determined to be orthorhombic with a space group of Pnma by x-ray diffractometer (XRD). The temperature dependence of the magnetization was investigated by superconducting quantum interference device (SQUID) magnetometer. Although LiCo<SUB>0.99</SUB><SUP>57</SUP>Fe<SUB>0.01</SUB>PO<SUB>4</SUB> showed a typical anti-ferromagnetic behavior at temperatures below <I>T</I><SUB>N</SUB> = 23 K, a rapid increase in magnetization was observed at temperatures below 9 K. The microscopic magnetic properties of LiCo <SUB>0.99</SUB><SUP>57</SUP>Fe<SUB>0.01</SUB>PO<SUB>4</SUB> were characterized by <SUP>57</SUP>Fe external field Mössbauer spectroscopy. At temperatures below 9 K, the magnetic hyperfine field (<I>H</I><SUB>hf</SUB>) showed a rapid increase, while the electric quadrupole splitting (Δ<I>E</I><SUB>Q</SUB>) decreased rapidly. The <I>H</I><SUB>hf</SUB> and Δ<I>E</I><SUB>Q</SUB> under external field of 4.8 T changed significantly compared to the value without external magnetic field. These are originated from orbital angular moment contribution by spin-orbit coupling at temperatures below 9 K, while orbital angular moment is quenched by the crystalline field due to distorted CoO<SUB>6</SUB>(FeO<SUB>6</SUB>) asymmetric structure at temperatures above 9 K.</P>

Comparison of intraoral scanning and conventional impression techniques using 3-dimensional superimposition

Rhee, Ye-Kyu,Huh, Yoon-Hyuk,Cho, Lee-Ra,Park, Chan-Jin The Korean Academy of Prosthodonitics 2015 The Journal of Advanced Prosthodontics Vol.7 No.6

PURPOSE. The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. MATERIALS AND METHODS. Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The three-dimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For two-dimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. RESULTS. In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (P<.05). In three-dimensional analysis, the biggest difference was seen between intraoral scanning and dual-arch impression and the smallest difference was seen between dual-arch and full-arch impression. CONCLUSION. The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P<.05). The second premolar showed significantly bigger three-dimensional deviations than the second molar in the three-dimensional deviations (P>.05).

원전 2차 계통에서 아민의 pH 제어 특성 연구

이인형(Rhee In-Hyoung),안현경(Ahn Hyun-Kyoung),박병기(Park, Byung-Gi),권혁준(Jun, Gwon-Hyuk),송찬호(Ho, Song-Chan) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.8

최근 경수로형 원전 2차 계통의 건전성 유지를 위해 수처리제를 암모니아에서 에탄올아민으로 전환하였으나, 적용 후 복수 및 저압급수가열기 영역에서의 pH가 감소하므로 본 연구에서는 최적의 pH 제어제로 사용 할 수 있는 아민을 조사하였다. 대체아민 조사 결과 최적 조건을 만족시키는 단일 아민은 존재하지 않았다. 암모니아는 상대휘발 도가 높아 증기에 많이 분포되어 증기 응축수인 복수에서 pH가 높으며, 상대휘발도가 낮은 에탄올아민은 습증기 영 역의 pH를 높여 유체가속부식을 억제하므로 증기발생기 철 슬러지 유입을 감소하는데 효과적인 것으로 나타났다. 따 라서 복수 및 저압급수계통에서 pH가 높은 암모니아와 습증기영역의 유체가속부식 측면에서 특성이 우수한 에탄올아 민(ETA)을 혼합 주입하는 복합아민을 선택하면 2차 계통 재질의 손실을 최소화하여 증기발생기 건전성을 확보할 수 있을 것이다. The pH control agent in PWRs, to insure the integrity of steam generator, was changed from ammonia to ethanolamine(ETA) which decreased pH at condensate system and low pressure feedwater heater drain system, so that several amines were investigated for the selection of the optimum amine. There was no single alternative amine to meet the optimum condition. The more volatile ammonia provides the higher pH in condensate, while the less volatile ETA increases the pH in wet steam area. Thus, the combined amine of ammonia and ETA is able to equally raise the pH in both region so that the flow accelerated corrosion be reduced in the every system of the secondary side and the integrity of steam generator be also improved in pressurized water reactors (PWRs).

[P8-238] The Effects of Antioxidant on Extracts of White Ginseng (Panax ginseng, C. A. Meyer) Fermented Ginseng

Young-Chan Kim,Seong Il Lim,Joo Hyuk Yim,Young-Chul Lee,Kyung-Tack Kim,Jeonghae Rho,Sang-Yoon Choi,Chang-Won Cho,Young Kyung Rhee,Hee-Do Hong 한국식품영양과학회 2008 한국식품영양과학회 학술대회발표집 Vol.2008 No.10

수삼의 증숙 횟수에 따른 페놀산 함량 변화와 라디칼 소거활성

김영찬(Young-Chan Kim),홍희도(Hee-Do Hong),노정해(Jeonghae Rho),조장원(Chang-Won Cho),이영경(Young-Kyung Rhee),임주혁(Joo Hyuk Yim) 고려인삼학회 2007 Journal of Ginseng Research Vol.31 No.3

본 연구는 증숙 횟수에 따른 인삼의 총페놀 화합물 함량과 페놀산 획분의 DPPH, ABTS 라디칼 소거활성을 시험하고, 개별 페놀산 조성과 함량을 GC로 분석하였다. 총페놀 함량은 0.53-2.89%로 증숙 횟수에 비례하여 증가하였다. 결합 형태에 따른 페놀산 획분의 함량은 결합형>에스테르형>유리형 순으로 나타났으며, 이들 세 획분의 총량 (1.03-1.41%)은 증숙 횟수에 영향을 받지 않았다. 각 획분에서 salicylic, cinnamic, ρ-hydroxybenzoic, gentisic, vanillic, syringic, caffeic, ferulic aicd가 확인되었으며, 이 중 gentisic acid와 ferulic acid가 주된 페놀산으로 50% 이상을 차지하였다. 각 페놀산 획분은 50% 이상의 DPPH와 ABTS 라디칼 소거활성을 보였으며, 결합형태에 따른 페놀산 획분 간에는 큰 차이가 없었다. 반면 각 획분별로 증숙 횟수에 따라 라디칼 소거활성이 차이를 보였으며, 증숙 횟수가 증가할수록 라디칼 소거활성도 증가하는 경향을 보였다. This study was conducted to investigate the contents of the total phenolic compounds, and DPPH, ABTS radical scavenging activities of phenolic acid fractions of ginseng according to steaming times. Also the individual phenolic acid compositions and contents were analyzed by GC. The contents of the total phenolic compounds proportionally increased from 0.530 to 2.893% according to steaming times. Phenolic acid fractions were separated according to bound types, and the insoluble bound form fraction showed the highest contents followed by ester form fraction and free form fraction. The total contents of these three fractions (1.031-1.416%) were not significantly influenced by steaming times. Salicylic, cinamic, p-hydroxybenzoic, gentisic, vanillic, syringic, caffeic, ferulic acid were found in each fraction, and gentisic and ferulic acid were the major phenolic acid. Each phenolic acid fraction showed over 50% of DPPH and ABTS radical scavenging activities. There were no differences between the phenolic acid fractions according to binding types. Free radical scavenging activities were affected by a number of steaming times and augmented as steaming times increased.

Comparison of intraoral scanning and conventional impression techniques using 3-dimensional superimposition

Ye-Kyu Rhee,Yoon-Hyuk Huh,Lee-Ra Cho,Chan-Jin Park 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.6

PURPOSE. The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. MATERIALS AND METHODS. Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The threedimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For twodimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. RESULTS. In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (P<.05). In three-dimensional analysis, the biggest difference was seen between intraoral scanning and dual-arch impression and the smallest difference was seen between dual-arch and full-arch impression. CONCLUSION. The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P<.05). The second premolar showed significantly bigger three-dimensional deviations than the second molar in the three-dimensional deviations (P>.05).

효소처리에 의한 백삼 저분자 화합물의 V79-4 세포주에 대한 항산화 활성

김영찬(Young-Chan Kim),임주혁(Joo Hyuk Yim),노정혜(Jeonghae Rho),조장원(Chang-Won Cho),이영경(Young-Kyung Rhee) 고려인삼학회 2007 Journal of Ginseng Research Vol.31 No.3

본 연구는 효소분해를 통하여 인삼의 저분자 화합물을 추출하고 추출수율, 총페놀 함량, V79-4 세포주를 이용한 항산화 활성을 시험하였다. 조추출물의 추출 수율은 29.5-76%였으며, 총페놀 함량은 0.45-2.21%로 처리 효소에 따라 차이를 보였으며, pectinase 처리구가 추출 수율과 총페놀 함량이 가장 높았다. V79-4 세포주에 대해서는 pectinase 처리구와 α-amylase 처리구에서 50% 이상의 세포 보호효과를 나타내었다. 세포내 항산화 관련 효소계의 활성을 시험한 결과 SOD활성은 처리 효소에 따른 유의적인 차이가 없었으나, CAT와 GPx 활성은 pectinase 처리구에서 유의적으로 높은 활성을 보였다. 또한 지질과산화 활성을 시험한 결과에서도 pectinase 처리구와 protease 처리구에서 50% 이상의 MDA 생성 억제를 보였다. This study examined the extraction yields, total phenolic compounds content and the antioxidant activities on V79-4 cells of white ginseng extracts prepared by enzyme treatment. Yields of crude extract were 29.5-76%, and total phenolic compounds content showed 0.45-2.2% according to enzyme treatments. Pectinase treatment group showed the highest values of extraction yields and total phenolic compounds content. Pectinase and a-amylase treatment groups protected V79-4 cell viability(above 50%) against H₂O₂-induced oxidative damage. In the result of antioxidant enzyme activity evaluation in cells, enzyme treatments did not show the significant difference of SOD activity (p>0.05). However, pectinase treatment group exhibited increased CAT and GPx activities (p>0.05). Also, pectinase and protease treatment group inhibited MDA formation (>50%) in the lipid peroxidation protection experiment.

Blood pressure–targeted stepwise resuscitation for hemorrhagic shock in rats

Lee, Jae Hyuk,Kim, Kyuseok,Jo, You Hwan,Kim, Min A,Lee, Kyoung-Bun,Rhee, Joong Eui,Doo, Ah-Reum,Lee, Min Ji,Park, Chan Jong,Kim, Joonghee,Chung, Heajin Lippincott Williams Wilkins, Inc. 2014 The journal of trauma and acute care surgery Vol.76 No.3

BACKGROUND: Generation of reactive oxygen species (ROS) is an important mechanism of ischemia-reperfusion injury. Abrupt reoxygenation compared with slow reoxygenation has been known to increase ROS generation. Thus, slow and stepwise reperfusion can reduce ROS generation and subsequent ischemia-reperfusion injury. This study investigated the effect of slow reperfusion by blood pressure–targeted stepwise resuscitation (PSR) in hemorrhagic shock. METHODS: Pressure-controlled hemorrhagic shock was induced in male Sprague-Dawley rats for 1 hour. Rats were then allocated to one of three groups (no-resuscitation group, n = 14; PSR group, n = 15; rapid normalization of blood pressure (RR) group, n = 15). Survival time and hemodynamic changes were recorded and compared. Blood samples and liver tissue were harvested after 6 hours of resuscitation in surviving rats. RESULTS: All of the rats in the no-resuscitation group were expired before the end of the 6-hour observation period. Survival times were significantly longer in the PSR group than in the RR group (survival rates, 11 of 15 vs. 5 of 15, log rank p = 0.032). Plasma amino alanine transferase, histologic liver injury, and ROS generation in the liver tissue were significantly lower in the PSR group than in the RR group (all findings significant, p < 0.05). In addition, PSR significantly decreased plasma nitric oxide, liver interleukin 1&bgr;, and liver interleukin 6 compared with rapid resuscitation in addition to augmenting Akt survival pathways (all p < 0.05). CONCLUSION: Slow reperfusion by PSR decreased mortality, ROS generation, and liver injury in rats undergoing hemorrhagic shock. Stepwise resuscitation also decreased inflammatory cytokine production and augmented Akt survival pathways.

Cotransplantation of Cord Blood Hematopoietic Stem Cells and Culture-Expanded and GM-CSF-/SCF-Transfected Mesenchymal Stem Cells in SCID Mice

이영호,황태호,Rhee Young Goh,Hyuk Chan Kwon,Su Yeong Seo,Sung Hyun Kim,Jae Seok Kim,Hyo Jin Kim,한진영 대한의학회 2007 Journal of Korean medical science Vol.22 No.2

Cotransplantation of Cord Blood Hematopoietic Stem Cells and Culture-Expanded and GM-CSF-/SCF-Transfected Mesenchymal Stem Cells in SCID Mice

Han, Jin-Yeong,Goh, Rhee Young,Seo, Su Yeong,Hwang, Tae Ho,Kwon, Hyuk Chan,Kim, Sung Hyun,Kim, Jae Seok,Kim, Hyo Jin,Lee, Young Ho KOREAN ACADEMY OF MEDICAL SCIENCE 2007 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.22 No.2

<P>Mesenchymal stem cells (MSC) are multipotent in nature and believed to facilitate the engraftment of hematopoietic stem cells (HSC) when transplanted simultaneously in animal studies and even in human trials. In this study, we transfected culture-expanded MSC with granulocyte macrophage-colony stimulating factor (GM-CSF) and stem cell factor (SCF) cytokine genes and then cotransplanted with mononuclear cells (MNC) to further promote HSC engraftment. MNC were harvested from cord blood and seeded in long-term culture for ex vivo MSC expansion. A total of 1×10<SUP>7</SUP> MNC plus MSC/µL were introduced to the tail vein of nonobese diabetic/severe combined immunodeficiency mice. After 6-8 weeks later, homing and engraftment of human cells were determined by flow cytometry and fluorescence in situ hybridization studies. The total nucleated cell count and the engraftment of CD45+/CD34+ cells and XX or XY positive human cells were significantly increased in cotransplanted mice and even higher with the cytokine gene-transfected MSC (GM-CSF>SCF, <I>p</I><0.05) than in transplantation of MNC alone. These results suggest that MSC transfected with hematopoietic growth factor genes are capable of enhancing the hematopoietic engraftment. Delivering genes involved in homing and cell adhesions, CXCR4 or VLA, would further increase the efficiency of stem cell transplantation in the future.</P>