• Asian-Australasian Journal of Animal Sciences
• /
• 제14권4호
• /
• pp.548-552
• /
• 2001

This study was designed to find optimum conditions of four different factors (ratio of solvent to cholesterol-$\beta$-cyclodextrin complex, mixing speed, mixing temperature, and mixing time) for cholesterol dissociation in cream. Using the ratio of 6 to 1 (solvent to the complex) showed the highest cholesterol dissociation rate (82.50%) when mixed at 100 rpm at $50^{\circ}C$ for 1 h. Mixing speed did not significantly affect the cholesterol dissociation. Also, mixing time appeared to be insignificant. The optimum mixing temperature was $50^{\circ}C$ and mixing at $40^{\circ}C$ resulted in a significantly lower rate, compared with that at $50^{\circ}C$. In a subsequent experiment, using recycled $\beta$-cyclodextrin only showed 75.07% of cholesterol removal in cream, while the mixture of recycled to unused $\beta$-CD with the ratio of 6 to 4 increased cholesterol removal to 95.59%, which is highly close to that of 100% unused $\beta$-CD.

• Mass Spectrometry Letters
• /
• 제12권4호
• /
• pp.126-130
• /
• 2021

The mass spectrometry (MS) provides the mass-to-charge ratios of atoms, molecules, stable/metastable complexes, and their fragments. I have taken a long journey with MS to address outstanding issues and problems by experiments and theory and gain insights into underlying principles in chemistry. By looking through the mass-to-charge ratio, I have studied thermochemical problems in silicon chemistry, the infrared multiphoton dissociation spectroscopy of organometallic intermediates, unimolecular dissociations of halotoluene radical cations, and the kinetics of association/dissociation of alkali halide triple ions with Lewis bases. Various MS platforms have been used to characterize non-covalent interactions between porphyrins and fullerenes and those between the group IIB ions and trioctylchalcogenides, and to examine the binding of the group IA, IIA and porphyrin ions to G-quadruplex DNA. Recently, I have focused on mass-balanced H/D isotope dipeptide tags for MS-based quantitative proteomics, a simple chemical modification method for MS-based lipase assay, and the kinetics and dynamics of energy-variable collision-induced dissociation of chemically modified peptides. Now, I see an important role of MS in global issues in the post-COVID era, as the society demands high standards for indoor air quality to contain the airborne-pathogen transmission as well as in-situ monitoring and tracking of carbon emissions to reduce global warming.

• KSBB Journal
• /
• 제11권2호
• /
• pp.225-237
• /
• 1996

고정화된 단세포군 항체와 항원인 알부민과의 결 합시 결합속도기작을 조사하였다. 항체의 고정화에 는 극소의 폴리스타이렌(37^{\circ}C)을 담체로 사용하여 결합속도 측정시 물질저항의 영향을 최소화하였다. 이론적 해석과 실험 결과는 결합반응이 속도론으로 제어됨을 보였는데 결합속도는 2차이고 분리속도는 1차임을 보인다. 고정화 항체와 항원의 평형실험으 로부터의 평형상수는 결합속도상수와 분리속도상수 의 측정치로부터 계산한 값들과 잘 일치한다. 속도 상수들을 $^{\circ}C~37^{\circ}C$에서 측정하였는데 결합속도상 수의 활성화에너지는 9kcal/mole이고 분리속도상수 의 활성화에너지는 2kcal/mole이다. 위의 연구 결과 들은 작은 담체의 사용이 결합속도 기작을 연구하는 데 물질전탈 저항의 영향을 제거할 수 있음을 보이 고 위의 실험 방법들은 고정화 항체의 고유 결합속 도의 측정에 유용할 것이다.

• BMB Reports
• /
• 제29권4호
• /
• pp.286-293
• /
• 1996

Association of antigenic peptide with class I MHC is believed to be crucial for maintaining stable conformation of class I molecules. T2 cells that are defective in TAP gene function mainly express class I molecules with an unstable conformation due to little or no association with antigenic peptides, whereas T1 cells that are normal in TAP gene function mainly express the stable form of class I molecules. In this work, attempts were made to determine the molecular stability of stable and unstable class I molecules. Dissociation of HLA-A2 molecules on T1 and T2 cells was monitored by flow cytometry using anti-HLA-A2 antibody after the cells were treated with brefeldin A to shut down the transport of newly-assembled HLA-A2. Estimated dissociation rate constants for the stable and unstable forms of HLA-A2 were 0.076 $h^{-1}$ and 0.66 $h^{-1}$, respectively. It appeared that both T1 and T2 cells express stable and unstable class I complex, but with different ratios of the two forms. Furthermore, $interferon-{\gamma}$ treatment of T1 cells appeared to induce the expression of both the stable and unstable class I molecules. These results demonstrate that class I MHC molecules can be divided into two groups in terms of structural stability and that they exist on the cell surface in both forms in a certain ratio.

• 산경연구논집
• /
• 제10권11호
• /
• pp.35-47
• /
• 2019

Purpose: Current study focused on investigating the effects of the self-dissociation as a thought in which consumers dis-identify or dissociate with the threatened in-group and the escapism as a tendency of consumers' distracting themselves and avoiding their thoughts about the in-group under severe but adoptable criticism by turning their attention elsewhere on across-domain compensatory consumption intention. And It explored not only the positive roles of undesirability thought against the in-group in consumers' forming the self-dissociation and the escapism, but also the effects of negative emotion to the in-group felt at the place of being exposed to the criticism against the in-group on the escapism. Research design, data, and methodology: The experiment was performed with the in-group-threatening single factor within-subject design. Questionnaire data were collected from 196 undergraduate students, and the data were used to testing research hypotheses by structural equation model of Amos 21.0. Results: First, both the self-dissociation of consumers' dis-identifying with the in-group criticized severely by others and the escapism of their deliberately directing their thoughts and distracting their attention away from thinking the in-group positively influenced on the across-domain compensatory consumption intention. Second, the negative emotion positively influenced on the escapism. Third, the undesirability thought to the in-group under the severe criticism positively effected on the self-dissociation as well as the escapism. Putting in the nutshell, the findings of this study are consistent with the idea that consumers can overcome the negative self-discrepancy on one dimension of their social identity by distracting themselves and avoiding thinking about the threatened in-group to find meaning on another dimension which might lead them to the place of doing the across-domain compensatory consumption. Conclusions - Focusing on the results of this study, checking which aspects of consumers' social identity are linked to products or brands is at issue to marketers when the consumers are faced with the criticism against the in-group. The marketers should build the messages about their products or brand not related to the checked aspects, and communicate the messages, to lead the consumers to the place of doing the across-domain compensatory consumption by their products or brands.

• 대한수학회논문집
• /
• 제14권2호
• /
• pp.429-440
• /
• 1999

In this paper an electrochemistry model which consists of three charged species is considered. A dissociation-association reaction is allowed to take place between these species. The species of ions diffuse owing to concentration gradients and migrate because of electric forces. We prove that any initial distribution of species concentrations will settle down to the unique steady state as time becomes large.

• 공업화학
• /
• 제2권2호
• /
• pp.127-137
• /
• 1991

고진공계에서의 열탈착실험을 통하여 $MoO_3$ 촉매상에서의 $CH_3OH$ 분해 및 부분산화반응에 관한 연구를 수행하였다. $CH_3OH$는 촉매표면에 methoxy($-OCH_3$)와 수소원자(-H)의 형태로 흡착되어 있다가 흡착수소원자가 methoxy 와 재결합하면서 425 K에서 $CH_3OH$로 탈착하였으며, methoxy로부터 수소원자가 떨어져 나가면서 545 K에서 HCHO가 탈착되었다. 이때 반응에 의해서 생성된 물은 428 K에서 탈착하는 ${\alpha}$-피크와 586 K에서 탈착하는 ${\beta}$-피크를 보였으며, ${\alpha}$-피크는 표면에 형성된 hydroxyl 에 기인하는 탈착피크, ${\beta}$-피크는 methoxy가 수소를 잃으면서 HCHO의 형태로 촉매표면에서 탈착하면서 남긴 표면수소원자와 격자산소가 반응하여 생성된 물에 각각 기인하는 것으로 보였다. 선흡착된 산소원자는 $CH_3OH$의 분해흡착을 촉진시킴으로써 $CH_3OH$의 흡착량을 증가시킨 반면, 선흡착된 물은 분해흡착하여 $CH_3OH$의 흡착점을 점유함으로써 $CH_3OH$의 흡착량을 감소시켰다.

• 한국광학회지
• /
• 제28권1호
• /
• pp.9-15
• /
• 2017

실리콘 기판으로 만든 바이오센서에서 펩타이드-항체의 접합 동특성을 회전 타원분광계로 정밀하게 측정하고 분석하였다. 극도로 낮은 몰농도의 펩타이드를 측정할 때, 시료가 놓이는 바이오센서의 표면의 불완전한 편평도와 완충용액 굴절률 변화로 인한 측정오차를 줄이기 위하여 금속박막의 유리 프리즘 대신에 실리콘 기판 위에 덱스트란 SAM을 직접 적층하여 바이오센서를 만들었다. $100{\mu}l/min$의 완충용액 주입속도에서 바이오센서에 올려진 항체 및 펩타이드의 접합특성을 각각 측정하였다. 리터당 5 ng의 낮은 항체농도에서도 항체-덱스트란 SAM 사이의 동특성을 쉽게 측정할 수 있었다. 또한 100 nM까지의 펩타이드에 대한 미세한 흡착 및 해리 특성을 정밀하게 측정할 수 있었으며, 접합 동특성 식에 이 실험결과를 피팅하여 흡착계수와 해리계수를 구할 수 있었다. 이 결과로부터 펩타이드의 평형상태의 해리상수인 $K_D$는 97 nM이었고, 이 수치는 Class I에 속함을 알 수 있었다.

• 한국엔터테인먼트산업학회논문지
• /
• 제13권2호
• /
• pp.79-91
• /
• 2019

엔터테인먼트 산업은 투자 위험성으로 인해 경쟁력 확보를 통한 리스크 관리가 중요한 산업이다. 콘텐츠의 경쟁력은 산업 환경과 같은 외적 요인과 함께 몰입 기제를 중심으로 하는 내적 요소가 동시에 갖추어졌을 때 강화된다. 몰입 기제는 관람자의 인지 반응의 한 형태로 영상 콘텐츠 관람 시 뇌의 신호처리 과정을 통해 발생한다. 콘텐츠 시청과 관련된 뇌의 신호처리는 주로 작업기억(working memory) 영역에서 이루어지며 몰입도가 높은 콘텐츠의 경우 관람자에게 전달되는 콘텐츠 이외의 정보를 차단함으로써 일시적인 해리 상태를 발생시킨다. 최면이나 기억상실과 같은 증세와 유사한 해리상태는 관람객의 몰입도가 높은 수준에 도달했을 때 발생한다. 반면 관람자가 주의를 집중하고 있는 콘텐츠 정보는 외부정보 유입이 상대적으로 차단 또는 지연된 상태에서 일화 완충기(episodic buffer)를 통한 미래 사고(future thinking)의 구성을 위해 집중적으로 사용된다. 관람자의 미래사고 구성은 가설구성 행위(hypothesis forming activity)의 형태로 진행되며 뇌의 예측성(predictability)에 기반을 둔다. 이와 같은 가설 구성 행위가 뇌의 본질적 기능인 예측성과 스토리의 진화적 기능인 문제 해결 시뮬레이션과 조응할 때 관람자의 뇌는 콘텐츠에 높은 수준으로 몰입하게 된다. 가설 구성 행위가 효과적으로 이루어지기 위해서는 가설 구성의 배경, 가설구성의 주체, 인물의 내적 정보, 가설 발생 정보의 종류와 위치 및 규모, 정보의 가설 연관성과 유형 같은 요소들이 중요하다. 이와 같은 요소를 기준으로 김은숙 드라마<도깨비>를 분석한 결과 위의 요소들이 유기적이고도 효과적으로 작동하고 있음을 관찰할 수 있었다.

• 약학회지
• /
• 제32권2호
• /
• pp.101-111
• /
• 1988

$[^3H]$ Quinuclidinyl benzilate(QNB) binding assays were performed in the dog ventricular sarcolemma fraction enriched approx. 32-fold in sarcolemma compared to the starting homogenate to elucidate the effect of antihistaminics on cardiac muscarinic receptor. Chlorpheniramine(CHP) inhibited specific binding of $[^3H]$QNB and delayed the equilibrium binding. The rate constants at $37^{\circ}C$ for formation and dissociation of the QNB receptor complex were $0.38{\times}10^9\;M^{-1}$ and $1.6{\times}10^{-2}\;min^{-1}$, respectively. The mean value for the dissociation constant from the pairs of the rate constants was 43. 2 pM and this value was similar to the value(44.8pM) determined from Scatchard analysis. CHP decreased association rate constant, indicating increase in $K_D$ value. Decrease in affinity without affecting the binding site concentration$(B_{max})$ for $[^3H]$QNB binding by CHP was also demonstrated by Scatchard analysis. $K_i$ values for $H_i$-blockers that inhibited specific $[^3H]$QNB binding were $0.02{\sim}4.8{\mu}M$. Cimetidine with $K_i$ value of $230{\mu}M$, however, was ineffective in displacing $[^3H]$QNB binding at concentration of $50{\mu}M$. The Hill coefficient for $H_1$-blockers were about one. The results indicate that $H_1$-antihistaminics inhibit $[^3H]$ QNB binding by interaction with myocardiac muscarinic cholinergic receptor and anticholinergic side effects of these drugs are mainly due to this receptor blocking mechanism.