• Polymer(Korea)
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• v.28 no.2
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• pp.121-127
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• 2004

The instantaneous removal of ethylene glycol is very important fur obtaining high molecular weight polymer because of the reversibility of the polycondensation reaction of poly(ethylene naphthalate)(PEN). In this study, we investigated the mass transfer phenomena in the thin film of PEN oligomer where the polycondensation reaction took place at 280$^{\circ}C$ and under 0.1mmHg. In case of less than 0.025cm film thickness the mass transfer resistance through the thin film of the polymer melt was not so high that the overall reaction rate was governed only by the polycondenstion reaction. Both the mass transfer model and the diffusion model predicted the experimenatal data well but the diffusion model showed faster reaction rate in the low molecular weight range than the mass transfer model . It was estimated from the two models that the diffusivity was 4.7${\times}$10$\^$-6/$\textrm{cm}^2$/sec and the mass transfer coefficient was 1.4 ${\times}$10$\^$-4/cm/sec both of which were smaller than In case of poly(ethylene terephthalate).

• International Journal of Molecular Medicine
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• v.44 no.5
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• pp.1741-1752
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• 2019

In the present study, a polyphenolic mixture was isolated from Seomae mugwort (SM; a native Korean variety of Artemisia argyi H.) via extraction with aqueous 70% methanol followed by the elution of ethyl acetate over a silica gel column. Each polyphenolic compound was analyzed using high-performance liquid chromatography coupled with tandem mass spectrometry, and compared with the literature. In addition to the 14 characterized components, one hydroxycinnamate, six flavonoids, and one lignan were reported for the first time, to the best our knowledge, in Artemisia argyi H. The anti-inflammatory properties of SM polyphenols were studied in lipopolysaccharide-treated RAW 264.7 macrophage cells. The SM polyphenols attenuated the activation of macrophages via the inhibition of nitric oxide production, nuclear factor-κB activation, the mRNA expression of inducible nitric oxide synthase, tumor necrosis factor α and interleukin-1β, and the phosphorylation of mitogen-activated protein kinase. Our results suggested that SM polyphenols may have therapeutic potential for the treatment of inflammatory-related diseases.

• Mass Spectrometry Letters
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• v.1 no.1
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• pp.13-16
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• 2010

The active components in a plant extract can be represented as mass profiles. We introduce here a new, multi-compound discovery method known as Scaling of Correlations between Activity and Mass Profiles (SCAMP). In this method, a correlation coefficient is used to quantify similarities between the extract activity and mass profiles. The method was evaluated by first measuring the anti-oxidation activity of eleven fractions of an Astragali Radix extract using DPPH assays. Next, 15 T Fouriertransform ion cyclotron resonance (FT-ICR) MS was employed to generate mass profiles of the eleven fractions. A comparison of correlation coefficients indicated two compounds at m/z 285.076 and 286.076 that were strong antioxidants. Principal component analyses of these profiles yielded the same result. FT-ICR MS, which offers a mass resolving power of 500,000, was used to discern isotopic fine structures and indicated that the molecular formula corresponding to the peak at m/z 285.076 was $C_{16}H_{13}O_5$. SCAMP in combination with high-resolution MS can be applied to any type of mixture to study pharmacological activity and is a powerful tool for active compound discovery in plant extract studies.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1247-1252
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• 2002

Mass-analyzed threshold ionization (MATI) technique is optimized to generate substantial amount of state-selected molecular ions sufficient for dynamics study. The main strategy is to stabilize intermediate (n = 100- 200) Rydberg states by l,m-mix ing induced by AC field. Electrical jitter inherent in high voltage switching is utilized for this purpose. A related technique to locate the MATI onset is also described.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.811-814
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• 2014

Bio-oil instability, or aging, is a significant problem for the long-term storage of fast pyrolysis oils. We investigated bio-oil aging at the molecular level using Fourier-transform ion cyclotron resonance mass spectrometry. Petroleomic analysis suggests that bio-oil aging is resulted from the oligomerization of phenolic lignin products whereas 'sugaric' cellulose/hemicellulose products have negligible effect.

• Journal of Life Science
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• v.10 no.6
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• pp.617-620
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• 2000

Methanol extract of Sarcodon aspratus Berk. (S. Ito) was analyzed by thi layer chromatography, gas chromatography and mass spectrophotometer. Nine fractions from primary methanol extract were observed by TLC. Six fractions were observed by the second TLC analysis of the second and the third fractions. 27,28-digydrolanosterol({TEX}$C_{30}H_{52}${/TEX}O), ergost-7-en-3-ol({TEX}$C_{28}H_{48}${/TEX}O) were identified from two fractions of the second TLC analysis by mass spectrophotometer. The molecular weights of 27,28-dihydrolanosterol and ergost-7-en-3-ol were 413 and 400 respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.113-114
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• 2013

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging is a powerful technique for producing chemical images of small biomolecules (ex. metabolites, lipids, peptides) "as received" because of its high molecular specificity, high surface sensitivity, and submicron spatial resolution. In addition, matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) imaging is an essential technique for producing chemical images of large biomolecules (ex. genes and proteins). For this talk, we will show that label-free mass imaging technique can be a platform technology for biomedical studies such as early detection/diagnostics, accurate histologic diagnosis, prediction of clinical outcome, stem cell therapy, biosensors, nanomedicine and drug screening [1-7].

• Asian Journal of Turfgrass Science
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• v.10 no.4
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• pp.331-339
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• 1996

The mass action on the assimilation and dissimilation of a living system from bio-molecules to bio-spheres has been demonstrated by the theoretical models as the bio- and trophic-functions From the viewpoint of this bio-mechanics, the general principle on the pre-equilibrium of the bio-molecular system is found. Key words: Mass action, Living system, Bio-molecule, Bio-sphere, Bio- and trophic function.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.523-530
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• 1998

Rapid and quantitative analysis of physiological change and clavulanic acid production was studied by the combination of pyrolysis mass spectrometry (PyMS) and artificial neural network (ANN) in Streptomyces clavuligerus. Firstly, the continuous culture studies were carried out to get the physiological background and PyMS samples. Clavulanic acid production was inversely related to growth rate: Mycelium growth and $q_{cal}$ were optimum at 0.1 $h^{-1}\; and \;0.025 h^{-1}$ respectively. Changes in specific nutrient uptake rates ($q_{gly}$ and $q_{amn}$) also affected clavulanic acid production since clavulanic acid production appeared to be stimulated by the limitation of carbon and nitrogen. Fermentation broth containing mycelium taken from continuous cultures was analyzed by PyMS, and the PyMS spectra were analyzed with multivariate statistics. PCCV plots revealed that samples harvested under the same culture condition were clustered together but samples from different culture conditions formed separate clusters. To deconvolute the pyrolysis mass spectra so as to obtain quantitative information on the concentration of clavulanic acid, ANN was trained on Py MS data using a radial basis function classifier. The results showed that the physiological stages with different growth rate were successfully differentiated and it was possible to monitor the clavulanic acid production precisely and rapidly.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.74-77
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• 2012

Organic acid (OA) profiling analysis was performed in culture media from Lactobacillus pentosus K34 (L. pentosus K34) and Pediococcus lolli PL24 (P. lolli PL24) by gas chromatography-mass spectrometry (GC-MS) following methoxime/tert-butyldimethylsilyl derivatives. 12 OAs were positively identified in culture media. Most of OA levels from L. pentosus K34 of hetero lactic fermentation were found to be higher when compared with those from P. lolli PL24 of homo lactic fermentation, which may explain different OA metabolism in each strain. In addition, the distorted dodecagonal star patterns were readily distinguishable, and the characteristics of each strain were well represented. The present study demonstrates that the OA metabolic profiling method by GC-MS combined with star pattern recognition is useful for the monitoring study of characteristic OA metabolism in various microorganisms.