수정된 화학전이 NMR 영상법에 의한 수분과 지질의 비율 측정에 관한 연구

신용진,장차익,홍광준,유상하,이관교,양경승,백창현,김남수,정준우 조선대학교 기초과학연구소 1996 自然科學硏究 Vol.19 No.1

다양한 화학종(化學種)의 선택적인 핵자기공명(nuclear magnetic resonance, NMR) 영상(imaging)을 얻기 위한 몇몇 기술들이 가장 일반적인 Dixon's, CHESS, SECSI 등 3가지 방법들과 함께 발전해 왔다. 모든 화학전이 영상법(chemical shift imaging method)에 있어서 가장 큰 문제점은 정자기장의 균일성과 RF(radiofrequency) 코일에 대전된 시료가 인가되었을 때 나타나는 자기장의 찌그러짐이다. 만약 자기장의 shimming이 없다면, 약 3.5ppm으로 분리된 수분(water)과 지질(fat)의 선택적 양성자 영상을 얻는데 위 세 가지 방법들은 이용될 수 없다. 2.5ppm에서 3.5ppm의 선폭(linewidth)을 가진 시료(phantom)를 이용한 실험으로 위의 세 가지 기술과 새로운 화학전이 영상기술을 정량적으로 분석할 수 있었다. 본 연구에서는 선택적인 포화(saturation)와 재집중(refocusing) pulse가 포함된 새로운 화학전이 영상기술(modified CHESS+SECSI technique)이 다양한 시료에서 수분과 지질의 정량적 비율을 측정하는데 이용될 수 있도록 개발되었다. There are several methods developed to achieve selective NMR image of differing chemical species with the three most popular being Dixon's, CHESS, and SECSI, A major problem common to all chemical shift imaging methods is the uniformity of the static magnetic field and distortions introduced when RF coils are loaded with a conducting specimen. Without magnetic field shimming, these methods cannot be used to selectively image protons in fat and water which are separated by approximately 3.5ppm. Experiments with a phantom, with linewidths of 2.5 to 3.5ppm, were quantitatively evaluated for the above three methods and a new chemical shift imaging method. In this study the new chemical shift imaging method (modified CHESS+SECSI technique) which included a selective saturation and refocusing pulse, was developed to determine the ratio of water and fat in different samples.

비정질 Fe_80B_20의 뫼스바우어 분광학적 연구

이흥수,한은주,백경선,옥항남 연세대학교 자연과학연구소 1985 學術論文集 Vol.14 No.-

비정질강자성체 Fe_80B_20의 뫼스바우어 스펙트럼을 액체질소 온도로부터 541K까지 여러 온도에서 취하였으며 이것을 분석하여 각 온도에서의 초미세자기장의 분포와 전기사중극자분렬의 분포로 인한 선폭증가의 분포 및 이성질체이동의 분포를 계산하였다. 또한 이와 같은 세가지 분포로 인한 뫼스바우어 공명흡수건의 선폭증가를 비교해 본 결과 6선 스펙트럼의 경우, 외곽의 네선에 대해서는 초미세자기장의 분포로 인한 선폭증가가 전기사중극자분렬의 분포로 인한 것보다 크나 두개의 내부선의 경우는 오히려 전기사중극자분렬의 분포로 인한 선폭증가가 더 컸다. 이성질체이동의 분포로 인한 선폭증가는 어느 선의 경우에도 제일 작았다. Mo"ssbauer spectra of amorphous ferromagnet, Fe_80B20 have been taken at various temperatures ranging from liquid nitrogen temperature to 541K, and analyzed to calculate distributions of the hyperfine field, isomer shift, and quadrupole broadening. Comparison of line broadenings due to the three kinds of distributions indicates that the four outer lines in six-line pattern are broadened much more by the distribution of the magnetic hyperfine field than by that of the quadrupole splitting whereas the two inner lines are broadened more by the distribution of quadrupole splitting. The line broadening due to the distribution of the isomer shift is smallest for any line of a six-line pattern.

Ultraviolet photodissociation spectroscopy of cold, isolated adenine complexes with a potassium cation

Baek, J.Y.,Choi, C.M.,Eun, H.J.,Park, K.S.,Choi, M.C.,Heo, J.,Kim, N.J. North Holland 2015 Chemical physics letters Vol.635 No.-

We obtain the ultraviolet photodissociation spectrum of adenine complexes with K<SUP>+</SUP> ion stored in a cold ion trap. The spectrum near the origin band of the S<SUB>0</SUB>-S<SUB>1</SUB> transition exhibits well-resolved vibronic bands, all of which are assigned from a single isomer by UV-UV hole-burning (HB) spectroscopy. Comparing the spectrum with theoretical spectra, we determine the structure of the isomer, where K<SUP>+</SUP> is bound not to 9H-adenine (A9) but to 7H-adenine (A7). We suggest that K<SUP>+</SUP>A7 ions are formed in solution through tautomerization, for which the energy barrier varies greatly depending on the binding site of the K<SUP>+</SUP> ion on A9.

Reduced-Intensity Conditioning with Busulfan, Fludarabine, and Antithymocyte Globulin for Hematopoietic Cell Transplantation from Unrelated or Haploidentical Family Donors in Patients with Acute Myeloid Leukemia in Remission

Lee, K.H.,Lee, J.H.,Lee, J.H.,Kim, D.Y.,Park, H.S.,Choi, E.J.,Ko, S.H.,Seol, M.,Lee, Y.S.,Kang, Y.A.,Jeon, M.,Baek, S.,Kang, Y.L.,Kim, S.H.,Yun, S.C.,Kim, H.,Jo, J.C.,Choi, Y.,Joo, Y.D.,Lim, S.N. Kluge Carden Jennings Pub. Co 2017 BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Vol.23 No.9

To investigate the role of antithymocyte globulin (ATG)-containing reduced-intensity conditioning (RIC) in hematopoietic cell transplantation (HCT) from unrelated (UD) or haploidentical family donors (HFD), we conducted a phase 2 trial of 237 patients (age range, 16 to 69 years) with acute myeloid leukemia (AML) in remission. Patients undergoing UD-HCT (n@?=@?93) or HFD-HCT (n@?=@?59) received RIC comprising busulfan, fludarabine, and ATG, 9@?mg/kg, whereas those undergoing HCT from matched sibling donors (MSD, n@?=@?85) received myeloablative busulfan and cyclophosphamide conditioning or aforementioned RIC with ATG, 4.5@?mg/kg. For graft-versus-host disease (GVHD) prophylaxis, cyclosporine and methotrexate were administered. The median follow-up period was 44.7 months after HCT for 161 survivors. For UD-HCT versus HFD-HCT, there were no significant differences in leukemia recurrence, nonrelapse mortality, relapse-free survival, grades 2 to 4 acute GVHD, and moderate-to-severe chronic GVHD. Furthermore, when the outcomes of UD-HCT and HFD-HCT were combined and compared with those of MSD-HCT, there were no significant differences in leukemia recurrence (3-year cumulative incidence, 30% versus 29%), nonrelapse mortality (3-year cumulative incidence, 7% versus 8%), relapse-free survival (3-year estimate, 63% versus 63%), and grades 2 to 4 acute GVHD (120-day cumulative incidence, 16% versus 13%). Moderate-to-severe chronic GVHD, however, occurred less frequently in UD/HFD-HCT (2-year cumulative incidence, 22% versus 40%; P@?=@?.006). The addition of ATG to conditioning regimen was a significant predictor for less chronic GVHD (subdistribution hazard ratio, .59). In AML in remission, UD/HFD-HCT after ATG-containing RIC achieved leukemia control equivalent to that of MSD-HCT. Despite HLA disparity in UD/HFD-HCT, chronic GVHD occurred less frequently after ATG-containing RIC, suggesting a strong GVHD-modulating effect of ATG.

거세 및 도축시기가 한우 등심의 이화학적 특성에 미치는 영향

이경춘,박노형,정준,이성수,오영숙,백경훈,정근기,최창본 한국동물자원과학회 2004 한국축산학회지 Vol.46 No.2

This study was conducted to investigate changes in physico-chemical characteristics of Hanwoo carcass according to different castration and slaughtering ages. Total 75 Hanwoo calves(average 4 months old) were randomly assigned to Control(bulls), Treatment Ⅰ, Ⅱ, Ⅲ, or Ⅳ(castrated on 4, 9, 12, and 16 months of age, respectively) and slaughtered at 7, 9, 12, 16, and 28 months of age. Moisture contents in M. Longissimus dorsi of both Hanwoo bulls and steers were decreased as the slaughtering age increased. Moisture contents in all steer groups were significantly(P<0.05) lower(average 68.63%) than that in bulls(72.18%) at 28 months of age. Crude fat contents tended to increase as the slaughtering age increased. Crude fat contents in Treatment Ⅲ(castrated at 12 months of age) at 28 months of age were 10.24% which was the highest among all steer groups. Crude protein contents in M. Longissimus dorsi of Hanwoo bulls were around 23% regardless of slaughtering age. Water holding capacity(WHC) of both bulls and steers tended to increase as the animals aged. Steers showed rapid increase in WHC after 16 months of age and showed higher(78.39%) WHC than bulls(70.00%) at 28 months of age. Palmitic acid(C18:0) contents in Hanwoo bulls were increased as the slaughtering age increased(20.92→24.22%) whereas stearic acid(C18:0) contents were decreased(18.15→11.32%). Oleic acid(C18:1), a major unsaturated fatty acid, significangly(P<0.05) increased(25.59→37.90%) when slaughtering age of Hanwoo increased. Changes in fatty acid composition in Hanwoo steers were similar to those in bulls except oleic acid contents were higher and stearic acid contents were lower than bulls at 28 months of age.

Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells

Kim, E.H.,Kim, M.K.,Yun, H.Y.,Baek, K.J.,Kwon, N.S.,Park, K.C.,Kim, D.S. North-Holland ; Elsevier Science Ltd 2013 european journal of pharmacology Vol.718 No.1

Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3β and β-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation.

Conformation-specific ultraviolet spectroscopy of benzo-18-crown-6 complexes with a potassium cation

Choi, C.M.,Baek, J.Y.,Park, K.S.,Heo, J.,Kim, N.J. North Holland ; Elsevier Science Ltd 2014 Chemical physics letters Vol.593 No.-

We investigate conformation-specific UV spectra of benzo-18-crown-6 complexes with a potassium cation using a UV-UV hole burning (HB) technique developed for ions in a quadrupole ion trap. Three different UV-UV HB spectra are obtained: two spectra represent the electronic spectra of conformers, K-a and K-b, respectively, and the third exhibits the transitions of a vibrationally 'hot' K-b conformer. These demonstrate that the UV-UV HB technique, of which the applicability was first tested only for ions of a single isomer, can be used to differentiate vibronic peaks of ions existing as two or more different conformers including their vibrationally 'hot' species.

Screening and isolation of a natural dopamine D₁ receptor antagonist using cell-based assays

Yu, S.,Park, J.S.,Paredes, V.,Song, M.C.,Baek, N.I.,Lee, S.I.,Lim, J.S.,Cho, N.Y.,Yoon, J.,Baek, K. Elsevier Science Publishers 2010 Journal of biotechnology Vol.145 No.3

To develop a cell-based assay to screen for human dopamine D<SUB>1</SUB> receptor agonists or antagonists from medicinal plant extracts, a stable Chinese hamster ovary (CHO) cell line (CHO-D1R) expressing the human dopamine D<SUB>1</SUB> receptor was established using an expression vector containing a scaffold attachment region (SAR) element. CHO-D1R cells showed specific binding to [<SUP>3</SUP>H]-SCH23390 with high affinity (K<SUB>d</SUB>=1.47+/-0.17nM) and dose-dependent responses for the dopamine-mediated stimulation of cAMP concentrations (EC<SUB>50</SUB>=20.6+/-1.44nM). The screening of medicinal plant extracts using cell-based cAMP assays revealed that an extract of Gleditsia sinensis Lam., which is known to be rich in saponin, had strong antagonist activity for the D<SUB>1</SUB> receptor. From the activity-guided fractionation and chemical structural analysis of the G. sinensis extract, a compound called gleditsioside F was isolated and was identified to have antagonist activity for the D<SUB>1</SUB> receptor. Gleditsioside F showed very effective D<SUB>1</SUB> antagonist activity by inhibiting ligand binding to the D<SUB>1</SUB> receptor as well as by inhibiting dopamine-mediated increases in cAMP concentration.

汎用 高分子物質의 物理的 高 機能化

양경승,백창현,김남수,신용진 조선대학교 기초과학연구소 1997 自然科學硏究 Vol.20 No.1

The multilayer structure material contained ductile and brittle layer simultaneously was compared, examined with singlelayer's property through the breaking dynamics strain process of amorphous area in multilayer structure polymer material. As a result, we know that impact strength of multilayer structure material is strictly higher than singlelyer's and the toughness is enhanced about two or more times in the glass transition temperature(T_g) and same dimension. Also superposition principle of impact pulse was used for interpretation of kinetic stress wave when the high velocity crack is going on in the plastic. Consequently, the optimum condition of ductile/brittle thickness ratio could be designed in the final toughness enhancement of multilayer. Therefore the physical property(impact strengh and tensile strength synchronously are high) of this multilayer structure material is higher than any ENPLA(engineering plastic) so that high physical functionization of general polymer material could be accomplished.

^(113)Cd NMR 분광법에 의한 금속결합단백질 측정에 관한 연구

백창현,양경승,김남수,신용진 조선대학교 기초과학연구소 1997 自然科學硏究 Vol.20 No.1

It is real condition that the possibility of the Multinuclear NMR spectroscopy is evaluating carefully, not only the papers which are submitted at the academic world but also the applications of relating to this NMR are rare until the recent. As the application example of the multinuclear NMR apectroscopy, we can detected cadmium of low concentration in the MT which is interested in many branch related with biochemistry. Phantom experiment os executed with known samples which contained the minimum quantity of cadmium. The new RF(radio-frequency) pulse sequence can be demonstrated by the finding of chemical shift and PW(pulse width) value which os parameter of ^113Cd NMR spectrometer. With the use of modified RF pulse sequence at the MT measurement, the ^113Cd NMR signal intensity can be increased.