Relaxor-like improper ferroelectricity induced by S_i.S_j-type collinear spin ordering in a M-type hexaferrite PbFe₆Ga₆O₁₉

Na, E.H.,Song, S.,Koo, Y.M.,Jang, H.M. Elsevier Science 2013 Acta materialia Vol.61 No.20

M-type hexaferrites with the magnetoplumbite structure are industrially mass produced uniaxial magnets that possess the simplest crystal structure among various hexaferrites. Herein we present an intriguing phenomenon of relaxor-like ferroelectricity observed in a M-type hexaferrite PbFe<SUB>6</SUB>Ga<SUB>6</SUB>O<SUB>19</SUB> (PFGO) single crystal. The unique feature of the present discovery is that the improper polarization (~30nCcm<SUP>-2</SUP> at 5K) with a direction parallel to hexagonal [11@?0] arises from the collinear S<SUB>i</SUB>.S<SUB>j</SUB>-type spin exchange coupling. This collinear coupling, in turn, is triggered by selective local spin reversal of the Fe<SUP>3+</SUP> magnetic moment at the octahedral 2a sublattice. The frequency-dependent dielectric data indicated relaxor-like responses of PFGO with the Vogel-Fulcher freezing temperature of ~17K. This freezing temperature for the polar-cluster reorientation coincided with the onset of a rapid decrease in polarization with temperature.

Dehydroepiandrosterone sulfate(Mylis)^(�)의 자궁경부 숙화작용에 대한 영향

許準容,梁賢模,羅重烈,丘秉參,洪性鳳 최신의학사 1983 最新醫學 Vol.26 No.11

Interconversion between cyclodimer and cyclotrimer: Synthesis and characterization of cyclo-[Pd(II)Cl₂(N-N)] complexes

Kang, H.J.,Noh, T.H.,Na, Y.M.,Yoo, K.H.,Jung, O.S. Elsevier Sequoia [etc.] 2009 Inorganica chimica acta Vol.362 No.6

The reaction of (COD)PdCl<SUB>2</SUB> (COD=1,5-cyclooctadiene) with (3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB> (3-Py=3-pyridyl; R<SUB>1</SUB>=Ph, R<SUB>2</SUB>=Ph (m-pdps); R<SUB>1</SUB>=Ph, R<SUB>2</SUB>=Me (m-pmps)) in acetone affords single crystals consisting of cyclodimers, [PdCl<SUB>2</SUB>((3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB>)]<SUB>2</SUB>, whereas the same reaction in a mixture of dichloromethane and ethanol yields amorphous spheres consisting of cyclotrimers, [PdCl<SUB>2</SUB>((3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB>)]<SUB>3</SUB>. In a boiling chloroform solution, the cyclodimers are completely converted to cyclotrimers. These cyclotrimers, in the 10-60<SUP>o</SUP>C range, are partly returned to cyclodimers. By contrast, the reaction of (COD)PdCl<SUB>2</SUB> with (3-Py)<SUB>2</SUB>SiR<SUB>1</SUB>R<SUB>2</SUB> (R<SUB>1</SUB>=Bu, R<SUB>2</SUB>=Me (m-pbms); R<SUB>1</SUB>=dodecyl, R<SUB>2</SUB>=Me (m-pddms)) yields amorphous spheres consisting of cyclotrimers irrespective of solvents. Both [PdCl<SUB>2</SUB>(m-pbms)]<SUB>3</SUB> and [PdCl<SUB>2</SUB>(m-pddms)]<SUB>3</SUB> are initially cyclotrimers in chloroform, but they exist as a mixture of cyclodimers and cyclotrimers in solution in the 10-60<SUP>o</SUP>C range. The metallacycles tend to form cyclodimers in the order m-pdps>m-pmps>m-pbms>m-pddms. The equilibrium between cyclodimers and the cyclotrimers is sensitive to solvent, temperature, and concentration as well as molecular structure.

Th17 and IL-17 Cause Acceleration of Inflammation and Fat Loss by Inducing α₂-Glycoprotein 1 (AZGP1) in Rheumatoid Arthritis with High-Fat Diet

Na, H.S.,Kwon, J.E.,Lee, S.H.,Jhun, J.,Kim, S.M.,Kim, S.Y.,Kim, E.K.,Jung, K.,Park, S.H.,Cho, M.L. American Association of Pathologists and Bacteriol 2017 The American journal of pathology Vol.187 No.5

<P>Rheumatoid arthritis (RA) is a chronic autoimmune disorder that affects the joints. High-fat diet (HFD) is a risk factor for RA and is related to inflammation but responds minimally to medication. Given the association between HFD and inflammation, it is important to understand the function of inflammation-related T cells in RA with HFD. Collagen-induced arthritis (CIA), a model of RA, was induced in HFD mice by injection of collagen II, and metabolic markers and T cells were analyzed. The metabolic index and IgG assay results were higher in HFD-CIA mice than in nonfat diet-CIA mice. Numbers of inflammation-related T cells and macrophages, such as Th1 and Th17 cells and M1 macrophages, were higher in spleens of HFD-CIA mice. HFD-CIA mice had a high level of alpha(2)-glycoprotein 1 (Azgp1), a soluble protein that stimulates lipolysis. To examine the association between Azgp1 and Th17 cells, the reciprocal effects of Azgp1 and IL-17 on Th17 differentiation and lipid metabolism were measured. Interestingly, Azgp1 increased the Th17 population of splenocytes. Taken together, our data suggest that the acceleration of fat loss caused by Azgp1 in RA with metabolic syndrome is related to the increase of IL-17. Mice injected with the Azgp1-overexpression vector exhibited more severe CIA compared with the mock vector-injected mice.</P>

고온변형시 Alloy 718 의 동적 및 준동적 재결정 거동

나영상,김인수,박노광,손성만 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.10

Compression tests were carried out on Alloy 718 to investigate the microstructure development following dynamic recrystallization, meta-dynamic recrystallization and grain growth. Tests were performed in the temperature range of 927∼1066℃ and strain rate range of 5∼5×10^(-4)s^_(-1), with true strains up to 0.8. Dynamically recrystallized grain size decreases consistently with increasing Zener-Hollomon parameter (Z=ε exp(Q/RT)) which is function of strain rate and temperature. The extent of recrystallization increases with a decrease in Zener-Hollomon parameter due to an increase in the critical strain (ε_c) corresponding to the initiation of dynamic recrystallization. The fraction of meta-dynamically recrystallized grain, however, increases with increasing the strain rate from 0.01s^(-1) to 1s^(-1). This paper outlines the microstructural evolution of Alloy 718 during the high temperature deformation.

유해화학물질 대기확산 예측을 위한 RAMS 기상모델의 적용 및 평가 : CARIS의 바람장 모델 검증 Validation of the Operational Wind Field Generation System in CARIS

김철희,나진균,박철진,박진호,임차순,윤이,김민섭,박춘화,김용준 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.5

The statistical indexes such as RMSE(Root Mean Square Error), Mean Bias errer, and IOA(Index of agreement) are used to evaluate 3 Dimensional wind and temperature fields predicted by operational meteorological model RAMS(Regional Atmospheric Meteorological System) implemented in CARIS(Chemical Accident Response Information System) for the dispersion forecast of hazardous chemicals in case of the chemical accidents in Korea. The operational atmospheric model, RAMS in CARIS are designed to use GDAPS, GTS, and AWS meteorological data obtained from KMA(Korean Meteorological Administration) for the generation of 3-dimensional initial meteorological field. The predicted meteorological variables such as wind speed, wind direction, temperature, and precipitation amount, during 19~23, August 2002, are extracted at the nearest grid point to the meteorological monitoring sites, and validated against the observations located over the Korean peninsula. The results show that Mean bias and Root Mean Square Error are 0.9(m/s), 1.85(m/s) for wind speed at 10m above the ground, respectively, and 1.45(℃), 2.82(℃) for surface temperature. Of particular interest is the distribution of forecastion error predicted by RAMS with respect to the altitude; relatively smaller error is found in the near-surface atmosphere for wind and temperature fields, while it grows larger as the altitude increases. 0verall, some of the overpredictions in comparisons with the observations are detected for wind and temperature fields, whereas relatively small errors are found in the near surface atmosphere. This discrepancies are partly attributed to the oversimplified spacing of soil, soil contents and initial temperature fields, suggesting some improvement could probably be gained if the sub-grid scale nature of moisture and temperature fields was taken into account. However, IOA values for the wind field(0.62) as well as temperature field(0.78) is grater than the 'good' value criteria(>0.5) implied by other studies. The good value of IOA along with relatively small wind field error in the near surface atmosphere implies that, on the basis of current meteological data for initial fields, RAMS has good potentials to be used as a operational meteorogical model in predicting the urban or local scale 3-dimensional wind fields for the dispersion forecast in association with hazardous chemical releases in Korea.

효모배양물 첨가 사료가 계사내 유해가스 발생 및 육계의 생산성에 미치는 영향

박재홍,류명선,김상호,나종삼,김종승,류경선 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.1

본 연구는 효모배양물을 육계에 수준별로 급여하여 두 차례의 사양실험을 시행하였다. 각각의 실험에서 처리구는 사료내 효모배양물 수준을 0, 0.1, 0.2, 0.4%로서 전체 4개의 처리구를 두었다. 실험 1에서는 처리구당 60수씩 총 240수를 환경조절형 계사에 수용하였으며, 계사내 유해가스에 미치는 영향을 고찰하였다. 실험 2에서는 처리구당 5반복, 반복당 16수로 80수씩 전체 320수를 이용하였으며, 육계의 생산성, 장내 미생물의 변화, 혈중 콜레스테롤 및 ND 항체가를 측정하였다. 사육 전기 3주간에 급여된 사료의 조단백질과 에너지 수준은 각각 21.5%, ME 3,100㎉/㎏으로 하였으며 후기 2주에는 19%, ME 3,100㎉/㎏ 수준으로 급여하였다. 실험 1에서 효모배양물을 수준별로 급여시 0.4% 급여구에서 암모니아 가스 발생량은 다른 처리구에 비하여 감소하였고, 이산화탄소는 모든 효모배양물 급여구에서 대조구보다 유의하게 낮았다. 실험 2에서 증체량은 효모배양물 0.2% 급여구가 대조구에 비하여 증가하는 경향을 보였으나 통계적인 차이는 없었고, 사료섭취량 또한 처리구간에 차이가 없었다. 사료요구율은 효모배양물 0.2% 급여구가 대조구보다 유의적으로 개선되었다(P<0.05). 효모배양물의 급여가 육계의 장내 미생물에 미치는 영향은 0.1, 0.2% 급여구에서 회장의 E. coli가 대조구와 비교하여 유의하게 감소하였고(P<0.05), 매장의 Latobacillus는 0.1% 급여구에서 유의하게 증가하였다. 혈중 총 콜레스테롤은 0.1% 급여구에서 유의적인 차이는 없었으나 감소하는 경향을 보였고, LDL-cholesterol 함량은 효모배양물 0.1% 급여구가 대조구에 비하여 유의하게 감소하였다. ND 항체가는 효모배양물의 급여구에서 대조구보다 높아지는 경향을 보였지만 처리구간에 통계적인 차이는 없었다. 본 연구의 결과, 육계 사료에 효모배양물의 급여로 계사내 유해가스를 감소하였으며, 사료 요구율이 개선되었다. 그리고 장내 미생물과 콜레스테롤 수준에서도 변화를 나타내었다. Two experiments were conducted to investigate the effect of dietary supplementation of yeast culture on the performance of broiler chicks and noxious gas emission in broiler houses. Two hundred forty and three hundred and twenty, one day old Cobb male broiler chicks in Expt 1, and 2, respectively were alloted to four treatment levels of yeast culture (0, 0.1, 0.2, 0.4%). To each treatment, 60 birds were assigned in Expt 1 and 5 replicates of 16 birds each were assigned in Expt 2. Basal diets contained 21.5% and 19.0% CP, and 3,100㎉/㎏ ME for the starting and finishing periods, respectively. Ammonia and CO_2 gas emission were detected twice a day for seven days during the five week period of Expt 1. Weight gain, feed intake and feed efficiency were measured for five weeks in Expt 2. Intestinal microbes, blood cholesterol and ND antibody titer were examined at the end of Expt 2. In Expt 1, the concentration of NH_3 in the house of birds fed yeast culture tended to be lower than the control. It was significantly lower in the 0.4% yeast culture treatment than the control (P<0.05). CO_2 concentration was significantly lower in all yeast culture treatments regardless of its dietary supplemental level than the control (P<0.05). In Expt 2, weight gain of birds fed 0.2% yeast culture tended to be higher, but not significantly different from others. Feed efficiency (feed/gain), however, was significantly improved in all yeast culture treatments relative to that of the control for starting period (P<0.05) and that of 0.2% yeast culture treatment was significantly lower than those of the control and 0.4% for the overall period. Total number of E. coli in the ileum of birds fed yeast culture at 0.1 and 0.2% was significantly lower than those of the control and 0.4% in the ileum. The CFU of Lactobacillus spp. of birds fed yeast culture at 0.1% was higher in the cecum compared to other treatments (P<0.05). Total cholesterol level of chicks fed 0.1% yeast culture seemed to be lower compared to that of other treatments, whereas LDL-cholesterol level was significantly lower than those of the control and 0.4% treatment. ND antibody titer tended to be higher in the yeast culture treatments than the control. but was not significantly different. The results of these experiments indicated that 0.2% yeast culture may have a potential to reduce the noxious gas emission in broiler houses and maximize the performance of broiler chicks.

장내바이러스성 질환 예방을 위한 공통항원 분석과 조기 진단법 및 백신 후보물질 개발에 관한 연구

윤재득,지영미,김기순,천두성,이윤성,정윤석,송철용,이광호,나병구 국립보건연구원 1999 국립보건원보 Vol.36 No.-

Effect of bamboo oil on antioxidative activity and nitrite scavenging activity

Choi, D.,Cho, K.A.,Na, M.S.,Choi, H.S.,Kim, Y.O.,Lim, D.H.,Cho, S.J.,Cho, H. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.6

The purposes of this study were to investigate the effects of the bamboo oil on antioxidative activity and nitrite scavenging activity in vitro and in vivo. When the bamboo oil concentration was increased from 10 to 90μL/mL, the DPPH scavenging rate increased from 15.6 to 98.2%. However, at bamboo oil concentrations above 110μL/mL, it was not increased. The superoxide anion radical scavenging rate increased from 54.8 to 89.1% when the bamboo oil concentration increased from 110 to 150μL/mL. When the bamboo oil was incubated for 20h, the linoleic acid scavenging rate was approximately 91.2%, similar to that of ascorbic acid. The glutathione production using bamboo oil in vivo was 59.0μM/g of liver, which was about 6.5-fold higher than that of the control. In the case of the activities of glutathione peroxidase and catalase, they were 16.8U/mg of protein and 295KU/mg of protein, respectively, approximately 5.6-fold higher and 3.0-fold higher than that of the control. The nitrite scavenging activity was increased from 60.1 to 93.9% at pH of 1.2 when the saturation time was increased from 2 months to 8 months. However, at more than 10 months of saturation, this level was not increased. These results suggest that the bamboo oil of Phyllostachys nigra var. henonis can be used in bioactive and functional materials.

농촌 중년여성의 자기효능감과 사회적지지가 갱년기대처에 미치는 영향

임정은,강홍비,김소희,나누리,민수빈,오승희,이예원,정유선,조원진,최서윤,신주현,이민경 이화여자대학교 간호과학대학 2017 이화간호학회지 Vol.- No.51

Purpose: The purpose of this study was to identify the effects of self-efficacy, and social support on climacteric coping, of middle-aged women in rural area. Method: The study subjects included 172 women aged 40-65 years based on eup, myoen, and ri areas of Incheon, Ulsan, Gyeonggi-do, and Gyeongsangbuk-do. The instruments used in this survey were the &self-efficacy scale& (SES) developed by Sherer, M., Maddux et al(1982), which was translated by Hong(1995), &the social support scale& developed by Park(1985), and &the adaptation of the symptoms of menopausal& developed by Bae(1999) and modified by Choi(2008). The data were collected by the face to face interview with a questionnaire from December 9th to 31st 2016. Data was statistically analyzed using t-test, one-way ANOVA, Pearson correlation coefficient and linear regression. Results: There were statistically no significant difference in climacteric coping and self-efficacy. The climacteric coping were significantly associated with informational social support. Also there were statistically significant difference in self-efficacy and social support. Conclusion: These finding suggest the need to develop nursing intervention to improve climacteric coping of middle-aged women in rural area. To improve the climacteric coping of middle-aged women in rural area, factors such as status of education and living with or without husband should be considered.