• 천문학논총
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• 제32권1호
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• pp.131-133
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• 2017

We present the latest results from the Mission Program NIRLT (PI: I.Yamamura), the near-infrared spectroscopy of brown dwarfs using the AKARI/IRC grism mode with the spectral resolution of ~ 120. The near-infrared spectra in the wavelength range between 2.5 and $5.0{\mu}m$ are especially important to study the brown dwarf atmospheres because of the presence of major molecular bands, including $CH_4$ at $3.3{\mu}m$, $CO_2$ at $4.2{\mu}m$, CO at $4.6{\mu}m$, and $H_2O$ around $2.7{\mu}m$. We observed 27 sources, and obtained 16 good spectra. Our model fitting reveals deviations between theoretical model and observed spectra in this wavelength range, which may be attributed to the physical condition of the upper atmosphere. The deviations indicate additional heating, which we hypothesize to be due to chromospheric activity. We test this effect by modifying the brown dwarf atmosphere model to artificially increase the temperature of the upper atmosphere, and compare the revised model with observed spectra of early- to mid-L type objects with $H{\alpha}$ emission. We find that the chemical structure of the atmosphere changes dramatically, and the heating model spectra of early-type brown dwarfs can be considerably improved to match the observed spectra. Our result suggests that chromospheric activity is essential to understand early-type brown dwarf atmospheres.

• 한국초지조사료학회지
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• 제40권3호
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• pp.190-195
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• 2020

Cadmium (Cd) toxicity is a serious limitation for agricultural production. In this study, we explored tolerance mechanism associated with Cd toxicity tolerance in alfalfa plants. We used three distinct alfalfa cultivars M. sativa cv. Vernal, M. sativa cv. Zhung Mu, and M. sativa cv. Xing Jiang Daye in this study. Cd showed declined chlorophyll score in Xing Jiang Daye compared with Zhung Mu and Vernal. No significant change observed among the cultivars for root and shoot length. Atomic absorption spectroscopy analysis demonstrated a significant accumulation of Cd, Fe, S and PC in distinct alfalfa cultivars. However, Zhung Mu and Xing Jiang Daye declined Cd accumulation in root, where Fe, S and PC incremented only in Zhung Mu. It suggests that excess Cd in Zhung Mu possibly inhibited in root by the increased accumulation of Fe, S and PC. This was further confirmed by the response of Fe (MsIRT1) and S transporters (MsSULTR1;2 and MsSULTR1;3), and MsPCS1 genes associated with Fe, S and PC availability and translocation in roots and shoots. It suggests that specially the transcript signal inducing the responses to adjust Cd especially in Zhung Mu. This finding provides the essential background for further molecular breeding program for forage crops.

• 한국식품과학회지
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• 제29권2호
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• pp.369-375
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• 1997

식용버섯으로부터 항혈전제제 개발의 소재화연구로 항응고활성의 검색과정에서 높은 활성을 보였던 구름버섯에서 항응고성 다당류를 정제하여 정제다당의 화학적 특성을 검토하였다. 정제는 구름버섯의 알칼리 추출물(CV-0)을 메탄올환류, 에탄올침전 후 3개의 연속적인 DEAE-Toyopearl 650C 이온교환, Sepadex G-100 및 Sepharose CL-6B 겔여과 크로마토그래피와 HPLC에 의하여 실시하였으며 정제다당 CV-40-Va-1의 분자량은 $7.2{\times}105$으로 측정되었다. CV-40-Va-I은 구성당 잔기에 19.32%의 황산기를 함유하는 함황성다당으로서 구성당조성은 fucose:mannose:glucose:galactose가 1.00:0.22:0.20:0.11의 몰 비율로 존재하였다. CV-40-Va-1의 항응고활성은 농도의존성을 보였으며 특히 내인성경로를 통하여 혈액응고를 저해하는 것으로 확인되었다.

• 한국방사선학회논문지
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• 제12권5호
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• pp.623-630
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• 2018

비알코올성 지방간 질환은 만성 간질환의 가장 흔한 원인이다. 이 연구의 목적은 비알코올성 지방간 질환 동물모델을 확립하고 생체 내 짧은 양성자 자기공명분광법을 이용하여 비침습적으로 간의 대사물질과 지질의 변화를 정량 분석하고자 하였다. 각 실험은 고지방식 먹이를 먹고 나서 0주를 기준선으로 하고, 2, 4, 6, 8주에 쥐의 간 실질 조직으로부터 측정되었다. 0주를 기준선으로 하고 2주와 비교했을 때 0.9, 1.3, 2.3, 2.8 및 5.3 ppm 에서 유의미하게 증가하였다(p<0.01). 따라서 양성자 자기공명분광법은 고지방식 먹이를 먹고 2주 후부터 다양한 쥐의 간 지질 변화를 검출하고 특성화하는데 유용할 것이다.

• 폴리머
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• 제29권3호
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• pp.308-313
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• 2005

광감응성 azobenzene 그룹이 분자의 주위 환경에 따라 광이성화 반응이 변화하는 것을 in-situ UV/Vis 분광 실험법과 광학 이방성 측정법을 이용하여 조사하였다. 4-Hyhoxyazobenzene을 포함하는 필름에 광조사함과 동시에 trans-isomer와 cis-isomer 특성 피크의 세기 변화를 측정하여 azobenzene 그룹의 가역적이며 반복적인 광이성화 반응을 알수 있었다. Azobenzene 자기조립체 박막이 입혀진 기판을 액정 셀의 배향막으로 사용하여 액정의 배향을 유도하였을 때, trans-azobenzene 그룹들이 조밀한 packing을 하며 기판에 수직으로 배열한 자기조립체 구조 때문에 액정 분자들도 수직 homeotropic 배향을 하였다. 이와 같은 자기조립체 박막의 액정 셀에 UV 빛을 노광하면 azobenzene그룹이 광이 성화 반응을 일으켜 cis-isomer로 변하게 되며, 이로 인해 액정의 배향이 수직에서 수평 planar 배향으로 변함을 알 수있었다.

• BMB Reports
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• 제33권2호
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• pp.120-125
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• 2000

M2PI is an active single chain mini-proinsulin with a 9-residue linker containing the turn-forming sequence 'YPGDV' between the B- and A-chains, but which retains about 50% of native insulin receptor binding activity. The refolding efficiency of M2PI is higher than proinsulin by 20-40% at alkaline pH, and native insulin is generated by the enzymatic conversion of M2PI. The solution structure of M2PI was determined by NMR spectroscopy. The global structure of M2PI is similar to that of native insulin, but the flexible linker between the B- and A-chains perturbed the N-terminal A-chain and C-terminal B-chain. The helix in the N-terminal A-chain is partly perturbed and the ${\beta}$-turn in the B-chain is disrupted in M2PI. However, the linker between the two chains was completely disordered indicating that the designed turn was not formed under the experimental conditions (20% acetic acid). Considering the fact that an insulin analogue, directly cross-linked between the C-terminus of the B-chain and the N-terminus of the A-chain, has negligible binding activity, a flexible linker between the two chains is sufficient to keep binding activity of M2PI, but the perturbed secondary structures are detrimental to receptor binding.

• BMB Reports
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• 제45권6호
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• pp.337-341
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• 2012

Different from humans, who have a continuous dentition of teeth, mice have only three molars and one incisor separated by a toothless region called the diastema in the hemi mandibular arch. Although tooth buds form in the embryonic diastema, they regress and do not develop into teeth. In this study, we evaluated the proteins that modulate the diastema formation through comparative analysis with molar-forming tissue by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) proteome analysis. From the comparative and semi-quantitative proteome analysis, we identified 147 up- and 173 down-regulated proteins in the diastema compared to the molar forming proteins. Based on this proteome analysis, we selected and evaluated two candidate proteins, EMERIN and RAB7A, as diastema tissue specific markers. This study provides the first list of proteins that were detected in the mouse embryonic diastema region, which will be useful to understand the mechanisms of tooth development.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.86-86
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• 1997

Human annexin I is a member of annexin family of calcium dependent phospholipid binding proteins, which have been implicated in various physiological roles including phospholipase A$_2$ (PLA$_2$) inhibition, membrane fusion and calcium channel activity. In this work, the structure of N-terminally truncated human annexin I (Δ-annexin I) and its interactions with Ca$\^$2+/, ATP and cAMP were studied at atomic level by using $^1$H, $\^$15/N, $\^$l3/C NMR (nuclear magnetic resonance) spectroscopy. The effect of Ca$\^$2+/ binding on the structure of Δ-annexin I was investigated, and compared with that of Mg$\^$2+/ binding. The addition of Ca$\^$2+/ to Δ-annexin I caused some changes in the high field and low field regions of $^1$H NMR spectra. Whereas, upon addition of Mg$\^$2+/ to Δ-annexin I, almost no change could be observed. Also we found that the binding ratio of ATP to Δ-annexin I is 1. Because Δ-annexin I is a large protein with 35 kDa molecular weight, site-specific (carbonyl-$\^$l3/C, amide-$\^$15/N) labeling technique was used to determine the interaction sites of Δ-annexin I with Ca$\^$2+/ and ATP. Assignments of all the histidinyl carbonyl carbon resonances have been completed by using Δ-annexin I along with its specific 1,2-subdomain. The carbonyl carbon resonances originating from His52 and His246 of Δ-annexin I were significantly affected by Ca$\^$2+/ binding, and some Tyr and Phe resonances were also affected. The carbonyl carbon resonances originating from His52 is significantly affected by ATP binding, therefore His52 seems to be involved in the ATP binding site of Δ-annexin I.

• 분석과학
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• 제26권1호
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• pp.61-66
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• 2013

얇은 유리판 위에 잘 정렬된 인지질 이중막에 작용하는 항균성 펩타이드 protegrin-1의 활성작용을 고체 $^2H$ 핵자기 공명 분광법을 이용하여 조사하였다. 수화 전후에 있어서 인지질 분자의 배향분포와 그 운동성을 고체 $^2H$ 핵자기 공명 스펙트럼을 통하여 확인하였다. 진공으로 건조된 상태에서는 인지질 분자의 운동성이 작다는 사실 외에는 인지질 분자들의 배향분포에 대한 정확한 상태를 알 수 없었다. 그러나 시료가 수화된 이후에는 시간이 지남에 따라 인지질 분자들이 잘 정렬되어 간다는 것과 원환체 기공이 형성되어 간다는 것을 확인할 수 있었다. Protegrin-1과 같은 항균성 펩타이드에 의한 인지질 이중막 변화를 본 연구논문에서 사용한 방법으로 확인하기 위해서는 상당히 긴 반응시간이 필요하다는 것을 확인하였다.

• 한국응용과학기술학회지
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• 제26권4호
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• pp.467-472
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• 2009

Ultraviolet curable coating solution was prepared with poly(ethylene glycol) acrylate oligomer and various mono and multi-functional acrylate monomers. The optical properties of UV cured coating layer on PET film with acrylate coating solution containing metal oxides, such as fumed silica and alumina, were also investigated to reduce light reflection on films. Poly(ethylene glycol) diacrylate which has 575 of average molecular weight was used as oligomer acrylate, and pentaerythritol triacrylate and dipentaerythritolpenta-/hexa acrylate were used as multi-functional acrylate monomers. Also, butyl acrylate was used to improve the adhesion as well as to reduce glass transition temperature to give a better flexability. 1-hydroxy cyclohexyl phenyl ketone was used as photoinitiator. We found out the metal oxides in acrylate coating solution showed a homogeneous dispersion from energy dispersive spectroscopy data. Transmittance and light reflection of coated PET film was measured with UV/vis spectrometer and gloss meter, respectively. When 1.00 g of both metal oxides was added into coating solution, the transmittance and the glossiness were reduced from 90% to 30% and from 190 GU to 35 GU, respectively. However, adding up to 1.00 g of the metal oxide into coating solution did not affect on the hardness of coating layer and adhesion between coated layer and PET film. Conclusively, we can control transmittance and light reflection of coated film by adjusting the amounts of metal oxide in coating solution.