• Journal of the Korean Society for Nondestructive Testing
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• 제24권4호
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• pp.354-361
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• 2004

This Paper describes a crack scattering model for SH wave based on the boundary integral equation(BIE) method, where the fundamental unknown is crack opening displacement(COD). When a time harmonic plane wave was incident on a 2-D isolated crack (slit) of width 2a, the COD distributions were numerically calculated as a function of ka. The calculated COD agreed well with results obtained with other methods. The far-field scattering amplitude, which completely characterizes the flaw response, was calculated in two ways. The Kirchhoff approximation and the BIE-COD exact formulation were compared in terms of incidence angle and frequency ka in a pulse-echo mode. Maximum response was obtained for both methods at the specular reflection direction. Away from the specular direction, the Kirchhoff approximation becomes less accurate. The time domain crack response was also calculated using a band-limited spectrum of center frequency 10 MHz. At oblique incidence to the crack both methods show the existence of an antisymmetric flash points occurring from the crack edge. The Kirchhoff approximation provides an exact time interval between flash points, although it unrealistically gives the same amplitude.

• Korean Journal of Food Science and Technology
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• 제23권4호
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• pp.442-446
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• 1991

Three peroxidase fractions (peak I, II, III) were isolated from Fuji apples using CM-cellulose chromatography. The homogeneity of the isolated peroxidase isozymes was established by isoelectric focusing and electrophoresis. Isoelectric points of the isozymes were 3.80, 3.82, and 3.85, respectively. The optimum pH of peroxidase isozymes were pH 5.0(peak I) or 5.5(peak II, III), and optimum temperature was $40^{\circ}C$ when assayed by using guaiacol and $H_{2}O_{2}$ as substrates. Inactivation rate of three peroxidase isozymes were different at temperature of $70^{\circ}C$ and at pH of 5.5. The isozyme of peak II was found to be more heat stable than those of peak I and III. D values at $70^{\circ}C$ of peroxidase isozymes (peak I, II, III) were estimated to be 660 sec, 1,320 sec, and 600 sec, respectively. The thermal stability of Fuji apple peroxidase was not influenced in the presence of 0.032 M sucrose or lactose. However, the thermal stability of the enzyme was decreased by fructose and glucose.

• Applied Microscopy
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• 제36권3호
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• pp.183-194
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• 2006

The threadlike structures of fascia were examined by tight and electron microscopy. In order to distinguish its tissue organization, we used staining methods including hematoxylin-eosin, Masson's trichrome, Van Gieson's collagen fiber stain and Kluver-Barrera's luxol fast blue for nerve stain. Under the light microscope, the threadlike structures were composed of many collagen fibers and nerve. In higher magnification, they looked like as the bundle of tubular structures. Many myoid cell-spindle nuclei were observed in the tissue, which were taken from the fascia. It was identical with Bonghan duct known as one of meridian network theory. In the early 1960's the North Korean Bong-Han Kim showed the anatomical structures of the acupuncture points, and explained the meridian system as the concrete duct network system. According to Bonghan theory the Bonghan ducts spread throughout the body Because it is believed that the duct could have the role of signal pathway, the theory was reinvestigated in these days. All of the threadlike structures isolated from fascia shows the abundance of collagen fibers. The electron microscope examination (TEM) could confirm the well arranged collagen fiber and nerve. This investigation reveals that superficial Bohghan duct are nerve fiber parallel running with collagen fibers. We conjectured that the intermingled structure of collagen fiber, blood vessel and nerve fiber might have the role of meridian system. And the more, regardless of histological research, the study on collagen fiber as response transmitter in acupuncture treatment are in need.

• The Plant Pathology Journal
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• 제26권4호
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• pp.386-393
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• 2010

In order to study disease resistance mechanisms in rice against the rice blast fungus Magnaporthe grisea, we screened fungal elicitor-responsive genes from rice suspension-cultured cells treated with fungal elicitors employing differential hybridization (DH). By DH screening, 31 distinct rice clones were isolated and a majority of them were full-length cDNAs encoding pathogenesisrelated (PR) genes. Sixteen of the 31 genes were upregulated at 4, 8, and 12 h following fungal elicitor treatment. To elucidate the effect of signal molecules and biotic elicitors on the regulation of rice defense genes, we further characterized the transcriptional expression patterns of representative isolated PR genes; OsGlu1, OsGlu2, OsTLP, OsRLK, and OsPR-10, following treatment with fungal elicitor, phytohormones, cycloheximide, and inhibitors of protein phosphorylation. Jasmonic acid (JA) induced transcriptional expression of OsGlu1, OsTLP, and OsRLK, but not of OsGlu2 and OsPR-10 at any of the tested time points. Salicylic acid (SA) and abscisic acid weakly induced the expression of OsTLP and OsRLK. SA showed an antagonistic effect with fungal elicitor and JA. Cycloheximide suppressed all these genes upon elicitor treatment, except for OsGlu2. Staurosporine only induced the expression of OsRLK. Application of calyculin A strongly induced OsRLK expression, but suppressed the expression of OsGlu2. Our study yielded a number of PR genes that play a role in defense mechanisms against the rice blast fungus, as well as contribute towards the elucidation of crosstalk between phytohormones and other modifications during defense signaling.

• Science of Emotion and Sensibility
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• 제26권4호
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• pp.3-14
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• 2023

Recently, the effect of using social media on psychological well-being has been highlighted. However, studies exploring factors that may predict the quality of social media relationships are relatively rare. The present study investigated whether social media activity and psychological states, such as loneliness and depression, can predict the quality of social media relationships during the COVID-19 quarantine period using a machine learning technique. Ninety-five participants completed a self-report survey on loneliness, Instagram activity, quality of social media relationships, and depression at different time points (during the self-isolation and after the release of self-isolation). Similarity analyses, including multidimensional scaling (MDS), representational similarity analysis (RSA), and classification analyses, were conducted separately at each point in time. The results of MDS revealed that time spent on social media and depression were distinguished from others in the first dimension, and loneliness and passive use were distinguished from others in the second dimension. We divided the data into two groups based on the quality of social media relationships (high and low), and we conducted RSA on each group. Findings indicated an interaction between the quality of the social media relationships and the situation. Specifically, the effect of self-isolation on the high-quality social media relationship group is more pronounced than that on the low-quality group. The classification results also revealed that the predictors of social media relationships depend on whether or not they are isolated. Overall, the results of this study imply that social media relationship could be well predicted when people are not in isolated situations.

• Restorative Dentistry and Endodontics
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• 제30권5호
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• pp.409-422
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• 2005

The aim of this study was to identify the bacteria isolated from acute endodontic lesions by cell culture and 16S rDNA sequencing. The necrotic pulpal tissue was collected from 17 infected root canals, which were diagnosed as being either an acute pulpitis or acute periapical abscess. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ul of 1 XPBS. The sample solution was briefly mixed and plated onto a BHI-agar plate containing $5\%$ sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 7 days. The bacteria growing on the agar plate were identified by 16S rRNA coding gene (rDNA) cloning and sequencing at the species level. Among the 71 colonies grown on the agar plates, 56 strains survived and were identified. In dental caries involving the root canals, Streptococcus spp. were mainly isolated. Actinomyces, Clostridia, Bacteroides and Fusobacteria were isolated in the periapical lesion without dental caries. Interestingly, two new Actinomyces spp. (ChDC B639 and ChDC B631) were isolated in this study. These results showed that there was diversity among the species in endodontic lesions, This suggests that an endodontic infection is a mixed infection with a polymicrobial etiology. These results may offer the bacterial strains for pathogenesis studies related to an endodontic infection.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2937-2942
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• 2012

We have theoretically investigated the magnetic properties of N-confused porphyrin (NCP), tetraphenyl-N-confused porphyrin (TPNCP) and their substituted derivatives with O, S and Se heteroatoms (2ONCP, 2STPNCP, 2SeNCP, 2OTPNCP, etc.) by using DFT method. In the minimum energy structures of the 2OTPNCP, the two couples opposite phenyl substitutes are staggered. In the case of TPNCP, 2STPNCP and 2SeTPNCP, two phenyls being respectively close to or opposite to N-confused pyrrole are found to be pointed the same direction, whilst others are in the opposite direction. Based on the equilibrium structures, the $^1H$ chemical shifts and nucleus-independent chemical shifts (NICS) are calculated in this paper. The ${\pi}$ current density being induced by the tridimensional perpendicular magnetic field transmits the inner section of the pyrrole segments for NCP and TPNCP. As for their substituted derivatives with O, S and Se atoms, the current path passes through the outer section of the two heterorings. The NICS values at the ring critical points of the heterorings are much lower (in absolute value) than those of which is at the center of an isolated pyrrole molecule. The $^1H$ NMR for ${\beta}H$ atoms of the heterorings decreases from O, S to with Se.

• BMB Reports
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• 제53권5호
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• pp.260-265
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• 2020

Scorpion venom comprises a cocktail of toxins that have proven to be useful molecular tools for studying the pharmacological properties of membrane ion channels. HelaTx1, a short peptide neurotoxin isolated recently from the venom of the scorpion Heterometrus laoticus, is a 25 amino acid peptide with two disulfide bonds that shares low sequence homology with other scorpion toxins. HelaTx1 effectively decreases the amplitude of the K⁺ currents of voltage-gated Kv1.1 and Kv1.6 channels expressed in Xenopus oocytes, and was identified as the first toxin member of the κ-KTx5 subfamily, based on a sequence comparison and phylogenetic analysis. In the present study, we report the NMR solution structure of HelaTx1, and the major interaction points for its binding to voltage-gated Kv1.1 channels. The NMR results indicate that HelaTx1 adopts a helix-loop-helix fold linked by two disulfide bonds without any β-sheets, resembling the molecular folding of other cysteine-stabilized helix-loop-helix (Cs α/α) scorpion toxins such as κ-hefutoxin, HeTx, and OmTx, as well as conotoxin pl14a. A series of alanine-scanning analogs revealed a broad surface on the toxin molecule largely comprising positively-charged residues that is crucial for interaction with voltage-gated Kv1.1 channels. Interestingly, the functional dyad, a key molecular determinant for activity against voltage-gated potassium channels in other toxins, is not present in HelaTx1.

• Korean Journal of Medicinal Crop Science
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• 제17권4호
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• pp.266-272
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• 2009

Cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.95), catalyzes the reduction of hydroxycinnamaldehydes to give hydroxycinnamyl alcohols, or "monolignols," the monomeric precursors of lignin. Lignins are important components of cell walls and lignified secondary cell walls play crucial roles in long distance transport of water and nutrients during plant growth and development and in plant defense against biotic and abiotic stresses. Here a cDNA clone containing a CAD gene, named as PgCAD, was isolated from a commercial medicinal plant Panax ginseng. PgCAD is predicted to encode a precursor protein of 177 amino acid residues, and its sequence shares high homology with a number of other plant CADS. The expression of PgCAD in adventitious roots and hairy roots of P. ginseng was analyzed using reverse transcriptase (RT)-PCR under various abiotic stresses such as salt, salicylic acid, wounding and chilling treatment that triggered a significant induction of PgCAD at different time points within 2-48 h post-treatment. This study revealed that PgCAD may help the plants to survive against various abiotic stresses.

• Journal of Environmental Health Sciences
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• 제44권2호
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• pp.133-142
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• 2018

Objectives: The pathogenic Vibrios genus denotes halophilic bacteria that are distributed in aquatic environments, including both sea and freshwater. Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus are the most important species since they can be potent human pathogens and leading causes of septicemia, wound infections, and seafood borne gastroenteritis. The recent emergence of a potential pandemic clone, V. cholera serotype O1 and the cholera outbreak in South Korea in 2016 indicates the importance of consistent surveillance of pathogenic Vibrio genus within coastal areas. Methods: The present study was undertaken to determine where and how vibrios live in the aquatic environment adjacent to coastal areas of South Korea. For this survey, a total of 838 samples were obtained at 35 different sites in South Korean coastal areas during the period from January 2016 to December 2016. Pathogenic vibrios was determined using the real-time PCR method, and its clones were isolated using three selective plating media. We also monitored changes in seawater and atmospheric temperature, salinity, turbidity, and hydrogen ion concentration at the collection points. Results: The total isolation rates of V. vulnificus, V. cholera (non-pathogenic, non-O1, non-O139 serogroups), and V. parahaemolyticus from seawater specimens in 2016 were 14.2, 13.48, and 67.06%, respectively. Conclusions: The isolation rates of pathogenic vibrios genus showed a positive correlation with temperature of seawater and atmosphere but were negatively correlated with salinity and turbidity.