• 한국식품영양과학회지
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• 제24권5호
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• pp.684-689
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• 1995

The molecular structure of rice starch was investigated using Korean rice[3 varieties of Japonica type and 3 varieties of Tongi type(Japonica-Indica breeding type)]. The λmax of iodine complex and inherent viscosity of Japonica type were higher than those of Tongil type. $\beta$-Amylolysis limit of the starches was not different between the two rice types. In the distribution of molecular weight of rice starch, the molecular size of amylose and amylopectin for Japonica type were smaller than those for Tongil type. The chain of rice starch distributed F1 of above DP 55, F2 of DP 40~50 and F3 of DP 15~20, and the ratio of F3 against F2 for Japonica type was higher than that of Tongil type. The results suggest that rice of Japonica and Tongil type was different molecular structure of starch.

• ALGAE
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• 제33권1호
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• pp.37-48
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• 2018

Alaria is the second largest genus of the Laminariales, which is distributed far into the northern Pacific and Atlantic oceans. Due to its high morphological plasticity, over 100 specific and sub-specific names have been used in Alaria, this has been tailored down to the present 17 species through morphological revision and molecular phylogenetic analysis. Endemic species of Alaria from Russian Far East have not been thoroughly revised since their original description, and few of them were confirmed using molecular data until recently. We carried out morphological and molecular studies on A. paradisea which is an endemic species distributed on the Kurile Islands, first described by Miyabe and Nagai in 1932 as Pleuropterum paradiseum. The range of morphological variability and its distribution was re-evaluated using the type specimen as well as other specimens. Analyses of partial mitochondrial cytochrome c oxidase subunit 1 and nuclear-encoded internal transcribed spacer sequences showed that A. paradisea nested within the genus Alaria, but differs morphologically from any other Alaria species in having additional sporophylls with a central midrib (${\beta}-sporophylls$). Our results showed that A. paradisea clearly belongs to the genus Alaria based on DNA data, although the key morphological character that was used to include this species to the genus Pleuropterum, ${\beta}-sporophylls$, is stable and distinguishes it from other Alaria species.

• 천문학회보
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• 제41권2호
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• pp.39.2-40
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• 2016

The molecular gas surrounding an H II region is thought to be a place where star formation can be induced. Such triggered star formation can arise form the overpressurization of existing density enhancements or thought the collapse of a swept up layers of material. In this talk, We will discuss the results of a study of star-formation activity associated with the outer Galaxy ring-shaped H II regions KR 7, KR 81, KR 120 and KR 140 using archival Spitzer and WISE data along with the JHK observations. We used CO data cubes from the FCRAO and TRAO in order to define extent of the molecular cloud associated each HII region. Using the infrared data sets, We identified and classified YSO populations within each molecular cloud using measures such as the class I/II ratio and YSO spatial density. Along with this, one of the main question in the study of star formation is how protostar accrete material from their parent molecular clouds and observations of infall motions are needed to provide direct evidence for accretion. Combining our observation of the YSO population distribution with time scales associated with YSO evolution and HII expansion, we investigated the possible significance of triggered star formation in the molecular cloud surrounding each region.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1203-1208
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• 2005

A computational study based on molecular dynamics (MD) simulations was performed in order to explain the difference in aqueous solubilities of two flavonoid/$\beta$-cyclodextrin ($\beta$-CD) complexes, hesperetin/$\beta$-CD and naringenin/$\beta$-CD. The aqueous solubility of each flavonoid/$\beta$-CD complex could be characterized by complexwater interaction not by flavonoid-CD interaction. The radial distribution of water around each inclusion complex elucidated the difference of an experimentally observed solubility of each flavonoid/$\beta$-CD complex. The analyzed results suggested that a bulky hydrophobic moiety (-$OCH_3$) of B-ring of hesperetin nearby primary rim of $\beta$-CD was responsible for lower aqueous solubility of the hesperetin/$\beta$-CD complex.

• BMB Reports
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• 제37권2호
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• pp.234-238
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• 2004

This study was designed to investigate, in the Turkish population, the association of methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism and left ventricular hypertrophy (LVH) in patients with type II diabetes mellitus. Our study included 249 patients with type II diabetes mellitus (102 men, 147 women) and 214 healthy volunteers as controls (91 men, 123 women). MTHFR C677T genotypes were determined by polymerase chain reaction, restriction fragment length polymorphism techniques. No differences were observed in the distribution of MTHFR genotypes or allele frequencies in the cases versus the controls. The frequency of the MTHFR-mutated allele (T) was 31.7% in the type II diabetes mellitus versus 31.1% of the controls. The homozygous mutation (T/T) in the MTHFR gene was identified in 12% of the type II diabetes mellitus versus 9.3% of the controls. Patients with the TT genotype showed a higher prevalence of LVH when compared to patients with the CC and CT genotypes (p = 0.01). The MTHFR gene C677T mutation may be a possible risk factor for the development of LVH in the type II diabetic patients.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.490-494
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• 1991

The ${\beta} to {\alpha}$ phase transition in silver iodide is studied with the (N, V, E) and (N, P, T) molecular dynamics (MD) method. In experiments, the phase transition temperature is 420 K. Upon heating of ${\beta}$ form, the iodine ions undergo hcp to bcc transformation and silver ions become mobile. MD simulations for the ${\beta}$ and ${\alpha}$ phases are carried out at several temperatures and the radial distribution functions (rdf) are obtained at those temperatures in the (N, V, E) ensemble. But the phase transition is not found in our calculation. Next the phase transition is studied with the (N, P, T) MD and we find some evidences of phase transition. At 3 Kbars and 2 Kbars the phase transition temperatu re is about 300 K. For 3.55 Kbars, the phase transition is higher (420 K) than the low pressure case. The phase transition temperature is somewhat dependent on the pressure in our calculations.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.349-353
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• 1994

The CN radical was generated in a jet with an inert buffer gas, helium from high voltage dc discharge of the precursor $CH_3CN$. The Fourier transform emission spectra of the O-O band of the $(B^2{\Sigma}^+{\to}X^2{\Sigma}^+)$ transition of CN have been obtained with a Bruker IFS-120HR spectrometer. The spectra show an anomalous distribution of rotational intensity which cannot be explained by a simple Boltzmann distribution. The analysis of the transition frequencies provides molecular constants with high accuracy for both the ground and the excited electronic states of the CN radical.

• 한국식품과학회지
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• 제25권6호
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• pp.703-709
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• 1993

쌀가루의 압출 조리조건과 단순 열처리조건에 따른 쌀전분의 분자량 분포와 ${\alpha}-amylase$ 민감성 변화를 조사하였다. 압출조리는 단일축 압출성형기를 이용하였으며 원료의 수분함량 $17{\sim}29%$, 압출온도 $100{\sim}150^{\circ}C$ 범위에서 처리하였다. 단순 열처리는 원통형 ???L슐에 시료를 밀봉하여 $100{\sim}200^{\circ}C$ 유탕기내에서 일정시간 가열하였다. 이들 가열처리된 시료를 다시 ${\alpha}-amylase$를 처리하여 가수분해속도를 측정하였다. 쌀 전분 원료미분의 수분함량이 23% 이하일 때 압출조리시 수분용해도와 분자량 감소가 크게 일어났으며 이러한 변화는 extruder의 기계적 에너지 투입량(MEI)과 비례하였다. 한편 단순 열처리에서는 원료 수분함량이 높아짐에 따라 가열에 의한 분자량 감소가 감지되었으나 그 변화정도는 압출조리에 비교하여 저조하였다 열처리된 시료를 ${\alpha}-amylase$로 처리하였을 경우 수분함량 23% 이하에서 압출조리된 시료는 효소적 가수분해가 크게 일어나 대부분의 전분입자가 5백만 dalton 이하의 분자량을 가지게 되었으나 고수분 압출물과 단순 열처리에서는 효소처리에 의한 분자량 감소가 크게 나타나지 않았다. 이러한 분자량 변화 현상은 전분용액의 고유점도 변화에 의하여 확인되었다. 이러한 결과는 쌀전분의 저분자화에 의한 수용성 증가 및 효소반응 민감성 증대는 단순 열처리보다는 압출조리에 의하여 크게 일어나며 이것도 extruder 내에서 가열과 동시에 가해지는 강한 압력과 층밀림에 의하여 전분입자의 변형이 크게 일어나는 것을 입증하는 것이다.

• 공업화학
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• 제23권4호
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• pp.388-393
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• 2012

말단캡핑제(end capping agent) 4종류와 함량별로 분지형 폴리카보네이트를 용융중합법으로 제조하였다. 합성된 분지형 폴리카보네이트의 화학구조는 FT-IR과 $^{1}H-NMR$ 스펙트럼을 이용하여 확인하였으며, 말단캡핑제의 반응여부는 FT-IR 스펙트럼의 수산기($3500\;cm^{-1}$) 존재여부로 확인하였다. 평균 분자량 및 분자량 분포도, 유리전이 온도 및 분해온도는 GPC, DSC와 TGA를 이용하여 측정하였다. 말단캡핑제의 화학구조에 따라 평균 분자량이 증가 또는 감소를 나타내었으며, 말단캡핑제로 4-tert-butylphenol (TBP)이 사용되었을 때 최적의 분자량 조절 결과를 나타내었다. 말단캡핑제의 함량이 증가할수록 평균분자량은 감소하였고, 4-tert-butylphenol이 0.05 mol%가 첨가될 때 폴리카보네이트의 대형 사출물 가공에 적합한 20000 정도의 수평균분자량을 나타내었다. 분지형 폴리카보네이트의 용융점도는 분자량이 감소할수록 감소하였으며, shear thinning effect에는 큰 영향을 주지 않음을 확인하였다.

• 한국식품영양과학회지
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• 제25권5호
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• pp.791-795
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• 1996

우리나라 전남의 전통 발효식품인 토하젓(salt-fer-mented Toha shrimp)은 주 원료인 토하(Toha: Caridina denticulata denticulata $D_{E}$ $H_{AAN}$)를 살아 있는 생토하의 껍질(갑각)이 붙어 있는 채로 소금에 절여서 제조하였다. 토하 껍질을 구성하는 토하 chitin이 토하젓의 숙성과정 중 발효에 의해 저분자량의 chitin oligosaccharides 생성이 예상되므로 본 연구에서는 토하젓 숙성과정의 기간별로 토하 chitin 분자량의 감소와 점도 변화 그리고 chitin 분자량 분포를 측정하였다. 토하젓 숙성과정 중 chitin의 점도와 평균 분자량은 숙성기간이 길어짐에 따라 뚜렷히 감소하였다. $10^3의$ 저분자량인 chitin oligosaccharides는 숙성 60일까지는 거의 나타나지 않았으나 숙성 75일 이후부터 6.85% 이상의 많은 양을 보였으며 $10^2의$ 분자량은 숙성 75일 이후부터 생성되기 시작하였다. 이 결과로부터 토하젓의 숙성과정 중 $10^{7}$ 이상 고분자량인 chitin이 가수분해됨에 따라 $10^2과$ $10^3의$ chitin oligosaccharides가 생성됨이 확인되었다.다.