• Journal of the Korean Wood Science and Technology
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• v.49 no.1
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• pp.67-81
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• 2021

This study aimed to conduct tree-ring dating and analysis of the materials used for the wooden coffins excavated from the ruins of Sipjeong-dong, Incheon. The tree species for the 10 wooden coffin materials was identified as pine. For accurate tree-ring measurement, the cross section was polished using sandpaper. The annual ring width was measured with an accuracy of 0.01 mm. Since the five materials were consistent with each other in dendrochronology, a representative annual ring chronology of 83 years was prepared. The prepared representative annual ring chronology was compared with the standard annual ring chronology, and the outermost ring of the wooden coffin was confirmed to correspond to the year 1575, suggesting that the wooden coffin was produced in the late 16th century. In addition, microscopic observation and FT-IR analysis revealed that the fibers attached to the surface of the wooden coffin were fibroin (Silk), and infrared spectroscopy (FT-IR) and Py-GC/MS analysis showed that the paint left on the surface of the wooden coffin was lacquer.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.469-474
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• 2001

The actinomycete strain AMLK-335 was antagonistic to vancomycin-resistant enterococci (VRE). Based on the diaminopimelic acid (DAP) type, and morphological and physiological characteristics revealed by scanning electron microscopy (SEM), AMLK-335 was confirmed to belong to the genus Streptomyces. Analysis of the 16S rDNA nucleotide sequences found AMLK-335 to have a relationship with Streptomyces platensis. The production of antibiotic from this strain was most favorable when cultured on glucose, polypeptone, yeast extract (PY) medium for 6 days at $27^{\circ}$. The antibiotic was identified as cyclo(L-phenylalanyl-L-prolyl) by comparing ti with the reported MS and NMR spectral data. Cyclo(phe-pro) from the PY cultures of AMLK-335 was most effective (K-98-258). Futhermore, cyclo(phe-pro) had antimicrobial activity against Bacillus subtilis, Microcuccs luteus, Staphylococcus aureus, and Saccharomyces cerevisiae, but it wa ineffective against Candida albicans, Streptomyces murinus, and Aspergillus niger.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1672-1676
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• 2010

The Actinomycete strain KH29 is antagonistic to the multidrug-resistant Acinetobacter baumannii. Based on the diaminopimelic acid (DAP) type, and the morphological and physiological characteristics observed through the use of scanning electron microscopy (SEM), KH29 was confirmed as belonging to the genus Streptomyces. By way of its noted 16S rDNA nucleotide sequences, KH29 was found to have a relationship with Streptomyces cinnamonensis. The production of an antibiotic from this strain was found to be most favorable when cultured with glucose, polypeptone, and yeast extract (PY) medium for 6 days at $27^{\circ}C$. The antibiotic produced was identified, through comparisons with reported spectral data including MS and NMR as a cyclo(L-tryptophanyl-L-tryptophanyl). Cyclo(L-Trp-L-Trp), from the PY cultures of KH29, was seen to be highly effective against 41 of 49 multidrug-resistant Acinetobacter baumannii. Furthermore, cyclo(L-Trp-L-Trp) had antimicrobial activity against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus niger, and Candida albicans, However, it was ineffective against Streptomyces murinus.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.118-124
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• 2007

GRLs(Guidance Residue Levels) of agricultural chemicals for tobacco are recommended by the CORESTA Agro-Chemical Advisory Committee guide. In the GRLs list, organochlorine group is one of pesticides commonly used on tobacco cultivation. In this model study, the quantitative correlation in the transfer rate of pesticide residue into tobacco smoke by spiking of organochlorine pesticides to cigarette and pyrolysates were investigated. The spiking concentration referred to the range of GRLs list and the organochlorine pesticides in mainstream smoke were analyzed by GC-MS. For the understanding of the composition variation versus temperature, the behavior of pesticides was investigated by pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS). In this study, the transfer rate of pesticide residue into tobacco smoke at four different spiking concentration and the composition of pyrolysates were analyzed differently. At $10\;{\mu}g/cig$ spiking concentrations, the organochlorine pesticides were transferred into tobacco smoke in $0.02\;{\sim}\;10.19\;%$ each of component and the most of pesticides were pyrolyzed during smoking. It was found that the decomposition compounds from organochlorine pesticides were mainly composed of oxygenated and nitrogenous compounds. This study could estimate that the transfer rate of pesticides into tobacco smoke is very small amount.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.4
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• pp.763-780
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• 2024

As the domestic and international landscape undergoes rapid changes, the importance of implementing security measures in response to the growing threats that businesses face is increasing. In this context, the need for Security by Design (SbD), integrating security from the early design stages, is becoming more pronounced, with threat modeling recognized as a fundamental tool of SbD. Particularly, to save costs and time by detecting and resolving security issues early, the application of the Shift Left strategy requires the involvement of personnel with limited security expertise, such as software developers, in threat modeling. Although various automated threat modeling tools have been released, their lack of user-friendliness for personnel lacking security expertise poses challenges in conducting threat modeling effectively. To address this, we conducted an analysis of research related to threat modeling tools and derived usability evaluation criteria based on the GQM(Goal-Question-Metric) approach. An expert survey was conducted to validate both the validity and objectivity of the derived criteria. We performed usability evaluations of three threat modeling tools (MS TMT, SPARTA, PyTM), and the evaluation results led to the conclusion that MS TMT exhibited superior usability compared to other tools. This study aims to contribute to the creation of an environment where personnel with limited security expertise can effectively conduct threat modeling by proposing usability evaluation criteria.

• Analytical Science and Technology
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• v.26 no.3
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• pp.190-198
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• 2013

Ambers have been used mostly as beads, jewelry and ornaments from ancient times and excavated as a buried artifact. When excavated, they are severely weathered to be cracked, exfoliated and disintegrated. Monitoring of changes in composition of amber according to weathering is very important for diagnosing the condition of amber and applying conservation materials and techniques. In this study, we tried to find the components of amber by analyzing amber with pyrolysis/GC/MS. The changes in the composition of pyrolzates after artificial ageing for 60 days under heat and oxygen were also observed. Abietic acid was detected as a main component of fresh amber and monoterpene, alkene, aromatic hydrocarbon were detected as major pyrolyzates. Changes with artificial ageing was estimated by comparing the peak area ratio of 23 components, and it was found that abietic acid abruptly decreased in the presence of heat and oxygen together, revealing that oxygen is a key factor to the deterioration of amber. It was also tried to understand the weathered surface of original amber gemstone based on the result of this ageing experiment.

• Fibers and Polymers
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• v.5 no.2
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• pp.83-88
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• 2004

In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3'-dihydroxy benzidine and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored. by $^1{H-nuclear}$ magnetic resonance. N-(2-hydroxyphenyl) phthalamic acid is converted to N-(2-hydroxyphenyl) phthalimide at ca. 175$^{\circ}C$, showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. $400^{\circ}C$. These results are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2542-2548
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• 2009

Direct methylation behaviors of 20 amino acids with tetramethylammonium hydroxide (TMAH) were studied under diluted conditions with silica. Amino acid concentration was controlled by dilution with silica ($SiO_2$) and the molar ratios of amino acid/silica were 0.20, 0.50, and 2.0. The molar ratios of amino acid/TMAH (0.51 - 4.64) also varied. It was found that arginine, asparagine, aspartic acid, cysteine, glutamic acid, and glutamine did not generate any directly methylated pyrolysis products, whereas alanine, glycine, isoleucine, leucine, methionine, phenylanaline, valine, and proline generated all the directly methylated pyrolysis products. Tri- and tetra methylated products of lysine consisted of two types. Histidine and threonine hardly generated the partly methylated products. Mono- and dimethylated products of serine, tryptophan, and tyrosine were not observed. Relative intensities of the methylated products varied with the amino acid concentration, TMAH concentration, and pyrolysis temperature. Direct methylation behaviors of amino acids were explained by the structural characteristics of amino acids.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1441-1444
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• 2013

Hetero-dimer anions of naphthalene (Np), anthracene (An), phenanthrene (Ph) and pyrene (Py) were investigated using the time-of-flight mass spectrometer (TOF-MS), anion photoelectron spectroscopy (PES) and theoretical calculation. There are two possible geometries with their electron affinity (EA) difference: parallel displaced (PD) and T-shaped. Dispersion force plays a key role in PD structure with the formation of a new anionic core while ${\pi}$-hydrogen interaction plays a key role in T-shaped structure with the monomer anionic core. The optimized structures and charge distributions can simply be explained by the relative difference of EA.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.152-164
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• 2018

Fermented seasoning pastes were prepared by Aspergillus oryzae and Bacillus subtilis using three edible insects, Tenebrio molitor larvae (TMP), Gryllus bimaculatus (GBP), and Bombyx mori pupa (SPP), with soybean (SBP) as a negative control. Volatile compounds were extracted by the headspace solid-phase microextraction (HS-SPME) method and confirmed by gas chromatograph-mass spectrometry (GC-MS). In total, 121 volatiles from four samples were identified and sub-grouped as 11 esters, 18 alcohols, 23 aldehydes, 5 acids, 10 pyrazines, 2 pyridines, 7 aromatic hydrocarbons, 10 ketones, 19 alkanes, 9 amides, 4 furans and 3 miscellaneous. TMP, GBP, SPP and SBP had 48, 54, 36, and 55 volatile compounds, respectively. Overall, 2,6-dimethylpyrazine and trimethylpyrazine were found by a high proportion in all samples. Tetramethylpyrazine, a main flavor of doenjang, a Korean fermented seasoning soybean paste, was identified as one of the major compounds in TMP, SPP, and SBP. SBP had benzaldehyde, hexanal, n-pentanal, and aldehydes and SPP with pyrazines.