• KSBB Journal
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• v.6 no.2
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• pp.175-180
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• 1991

The quantitative effects of molecular weight and concentrations of two phase-forming polymers-polyethylene glycol and crude dextran on the two phase extractive ethanol fermentation were investigated using a Box-Wilson central composite protocol. The regression model obtained was used in order to determine optimum compositions of aqueous two phase system. In the aqueous two phase extractive ethanol fermentation of Kluyueromyces fragilis CBS 1555 with Jerusalem artichoke juice, it was found from the regression model that the variables influenlcing on ethanol fermentation were PEG concentration, time, Dx concentration, and PEG molecular weight strongly in order. The interaction of PEG concentration and PEG molecular weight was also found, and the effect of PEG concentration decreased with increase in molecular weight of PEG. The ethanol concentration incresed with increase in molecular weight of PEG, and with decrease in concentration of PEG. In conolusion, maximum concentration of ethanol produced was obtained at the following compositions; PEG MW 20000, Dx concentration ranged from 4% to 5%, and PEG concentration ranged from 3% to 7%.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.535-540
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• 2016

Effects of compositions and sintering conditions on glaze properties are shown in the diagram constructed by using the unity molecular formula (UMF) method in this study. Glossy characteristics of glaze were clearly differentiated by compositional area in the diagram and sintering process. As alumina and silica contents were increased, texture of the glaze became rough and opaque, akin to having been devitrified or underfired. The correlation between glossiness and surface roughness was found to be non-linear and inversely proportionate. Crystalline phases formed in the glaze were also influenced by the compositional area. Due to the high concentration of CaO, anorthite and wollastonite were formed depending on the compositions. Hardness was increased with an increase of alumina and silica concentrations in the glaze.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.181-191
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• 2009

To investigate the genetic variation of high-and low-molecular-weight glutenin subunits (BMW-GS and LMW-GS), granule-bound starch synthase I (GBSSI) and puroindoline in 24 Korean wheat cultivars. At the BMW-GS compositions, three Glu-A1 alleles, five Glu-B1 alleles and three Glu-D1 alleles were identified. The high frequency of alleles at each locus was Glu-A1c allele (15 cultivars), Glu-B1b allele (16 cultivars) and Glu-D1f allele (16 cultivars). Four alleles were identified at the Glu-A3 and Glu-B3 loci and three at Glu-D3 locus and Glu-A3d, Glu-B3d and Glu-D3a were mainly found at each Glu-3 locus. Glu-A3d, Glu-B3d, Glu-D3b or c (4 cultivars, respectively) and Glu-A3d, Glu-B3d, Glu-D3a and Glu-A3c, Glu-B3d or h, Glu-D3a (3 cultivar, respectively) were predominantly found in Korean wheats. At the GBSS compositions, 2 waxy wheat cultivars, Shinmichal and Shinmichal1, showed null alleles on the Wx loci and other cultivars were wild type in GBSS compositions. At the puroindoline gene compositions, Korean wheat cultivars carried 3 genotypes, which 10 cultivars (41.7%) were Pina-D1a and Pinb-D1a, 11 cultivars (45.8%) had Pina-D1a and Pinb-D1b and 3 cultivars (12.5%) carried Pina-D1b and Pinb-D1a. These genetic variations could present the information to improve flour and end-use quality in Korean wheat breeding programs.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.663-674
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• 2007

Starches from different botanical sources differ in the ratio of amylose to amylopectin contents, molecular structures of amylose and amylopectin, granule morphology, and minor-component contents. These structural features result in different gelatinization, pasting, retrogradation properties, and enzyme digestibility of starch granules. In this review, compositions and molecular structures of starches and their effects on the physicochemical properties are summarized and discussed.

• Tribology and Lubricants
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• v.9 no.2
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• pp.16-21
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• 1993

Alkylbenzenes used as the synthetic lubricant base stocks were composed of the mixture of the various kinds of aromatic hydrocarbons. Their compositions have affected on the quality of synthetic alkylbenzene lubricants. Therefore, the rapid and accurate methods for the composit ional analysis are important. In this study, the compositions of the alkylbenzenes (Hv. LAB, FHv. LAB, Hv, BAB, DAB[HF], DAB[$AlCl_3$]) as synthetic base stocks have been investigated according to six average structural parameters(Tar, Nal, Asub, $\bar{n}$, nb, $T\alpha$) in the view of the molecular structures by $^{13}C-NMR$ spectroscopy. The experimental results of the oxidation $\varepsilon$ thermal stability tests have been related to the results of the molecular structural analysis.

• Mass Spectrometry Letters
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• v.9 no.3
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• pp.81-85
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• 2018

In this study, the chemical composition of bacterial melanin isolated from the Streptomyces glaucescens strain was elucidated by ultra-high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Ultra-high-resolution mass profiles of the microbial melanin product were acquired using a 15 Tesla FT-ICR mass spectrometer in positive and negative ion modes via electrospray ionization to obtain more complete descriptions of the molecular compositions of melanin-derived organic constituents. A mass resolving power of 500,000 (at m/z 400) was achieved for all spectra while collecting 400 scans per sample with a 4 M transient. The results of this analysis revealed that the melanin pigment isolated from S. glaucescens predominantly exhibits CHON and CHO species, which belong to the proteins class of compounds, with the mean C/O and C/N ratios of 4.3 and 13.1, thus suggesting that the melanin could be eumelanin. This analytical approach could be utilized to investigate the molecular compositions of a variety of natural or synthetic melanins. The compositional features of melanins are important for understanding their formation mechanisms and physico-chemical properties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.259-263
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• 1998

High molecular weight glutenin (HMW-Glu) subunit compositions of 73 Korean wheat cultivars and experimental lines were evaluated by using one dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This method is suitable for obtaining a good resolution of 1Dx2 and 1Ax2$^*$ without adverse effects on separation of other HMW-Glu subunits. Korean wheats examined in this study could be divided into 15 different groups on the basis of HMW-Glu subunit compositions. From the wheat lines tested, it was identified that there were three alleles at the Glu-Al, five at the Glu-Bl and three at the Glu-D1 loci. The null allele of the Glu-Al was occurred in high frequency (79.4%), while low frequencies for 1Ax1 (12.3%) and 1Ax2$^*$(8.2%) were found. High frequency (75.3%) of the subunit pairs of 1Bx7+1By8 at the Glu-Bl loci compared with other subunits was found. The frequencies of subunits 1Dx2. 2+1Dy12 and 1Dx2+1Dy12 from the Glu-D1 loci were 54. 8% and 37.0%, respectively. However, a few Korean wheat lines (8.2%) carried 1Dx5 + 1Dy10 subunit pair which are responsible for good breadmaking quality. The information of HMW-Glu subunit compositions provide a useful tool to characterize wheat lines, and can be directly used in selection of breeding lines of different end-use properties.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.46.2-46.2
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• 2021

Presolar silicon carbide (SiC) grains form around in the envelopes of asymptotic giant branch (AGB) stars by satisfying C/O>1 which is an optimal condition for SiC grains to condense in the stellar outflows. Ruthenium (Ru) isotopes are locked into the SiC grains during the condensation of SiC grains. We investigate the isotopic compositions of Ru in the stellar winds by using the NuGrid data, which are obtained by nucleosynthesis calculations during the stellar evolution. We compare the isotopic compositions of Ru obtained from the NuGrid data with measurements and the predictions obtained from different codes. Our results present a piece of evidence that SiC grains in the presolar system came from low-mass and low-metallicity AGB stars, also confirming that they were not from massive stars. We also suggest a new scenario in which the total stellar yields are also considered because SiC grains can condense during the collapse of molecular clouds.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.282-291
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• 2022

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.361-370
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• 2005

In this review, the field of biosurface organic chemistry is defined and some examples are presented. The aim of biosurface organic chemistry, composed of surface organic chemistry, bioconjugation, and micro- and nanofabrication, is to control the interfaces between biological and non-biological systems at the molecular level. Biosurface organic chemistry has evolved into the stage, where the lateral and vertical control of chemical compositions is achievable with recent developments of nanoscience and nanotechnology. Some new findings in the field are discussed in consideration of their applicability to nanobiotechnology and biomedical sciences.