• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.103-106
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• 1998

The oxidation product bis(2-oxo-3H-1,3,4-thiadiazolidinyl)-5,5-disulfide (5b) was obtained from an attempted synthesis of 5-thioxo-3H,4H-1,3,4-thiadiazolidin-2-one (1). Spectroscopic results indicate that the most stable tautomeric form of 1 is the lactam-thiol form (1b). The computed total energies and relative energies at the MP4 level also showed that the most stable tautomer is 1b.

• Animal cells and systems
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• v.3 no.3
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• pp.295-301
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• 1999

The nucleotide sequence of a 447 base pair fragment in the mitochondrial cytochrome b gene and the complete sequence of the mitochondrial 12S ribosomal RNA gene, 938 bp, were analyzed to infer inter- and intraspecific genetic relationships of Hyla japonica and H. suweonensis from Korea and H, japonica from Japan. In the mitochondrial cytochrome b gene, genetic differentiation among H. japonica populations were 9.62% and 15.66% between H. japonica and H. suweonensis. Based on the Tamura-Nei distance, the level of sequence divergence ranged from 0.45% to 2.75% within Korean H. japonica, while 8.31%-8.87% between Korean and Japanese H. japonica and 11.51%-12.46% between H. japonica and H. suweonensis. In the neigh-bor-joining tree, Korean populations of H. japonica were clustered first at 2.22% and followed by Japanese H. japonica and H. suweonensis at 8.51% and 12.29%, respectively. In mitochondrial 12S rRNA gene, genetic differentiation between H. japonica and H. suweonensis nras 7.17% (68 bp) including 7 gaps. Based on Tamura-Nei distance, the level of sequence divergence ranged 3.53% between Korean and Japanese H. japonica and from 4.93% to 5.41% between H. japonica and H. suweonensis. Phenogram pattern of the 12S rRNA gene sequence corresponded with that of the mitochondrial cytochrome b gene.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.273-277
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• 2010

Undecylprodiginine and streptorubin B are red-pigmented antibiotics produced by Streptomyces coelicolor A3(2). In this study, we investigated the correlation between productivity of these red-pigmented antibiotics and stress of pH shock. Biosynthesis of these red-pigmented antibiotics is enhanced at acidic pH shock on solid R2YE medium. The optimal pH shock is pH 4 which led to 1.6 fold and two-fold increase in the production of undecylprodiginine and streptorubin B as compared with control, respectively. In addition, the extract of pH 4 shocked cells exhibited a remarkable activity against Trichophyton mentagrophytes. However, neutral and basic pH shock did not give raise to promote a production of these red-pigmented antibiotics as well as antifungal activity. Thus, although the acidic pH shock is simple and easy method, it should be extremely effective approach to enhance a productivity of these red-pigmented antibiotics and other secondary metabolites.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.385-391
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• 2003

The influences of the extracts from Cinnamomi Cortex, Eucommiae Cortex, Puerariae Radix, Lycii Fructus, Zizyphi Fructus, Schisandrae Fructus, Mume Fructus, Chaenomelis Fructus on mycelial growth and aflatoxin $B_1$ production from Aspergillus parasiticus were analyzed. The pH of the culture media were reduced to below pH 4 by all the herbal extracts after 3 days incubation. However, the pH of the culture media increased above pH 6 after 6 days incubation using the extracts from Cinnamomi Cortex, Eucommiae Cortex, Puerariae Radix and Lycii Fructus. The mycelial growth of A. parasiticus was increased over the amount of the control. Puerariae Radix produced the largest amount of mycelial growth and Chaenomelis Fructus produced the smallest amount of mycelial growth. The productions of aflatoxin $B_1$ from A. parasticus culture were increased by the extracts of Puerariae Radix and Zizyphi Fructus, while inhibited by the extracts of Cinnamomi Cortex, Eucommiae Cortex, Lycii Fructus, Schisandrae Fructus, Mume Fructus and Chaenomelis Fructus. In particular, the extracts of Cinnamomi Cortex, Lycii Fructus and Schisandrae Fructus almost inhibited the production of aflatoxin $B_1$. The production of the total protein from Cinnamomi Cortex, which produced much less aflatoxin $B_1$, and Puerariae Radix, which produced a great deal of aflatoxin $B_1$ from A parasticus were slightly higher than the production of the total protein of the control medium.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.949-955
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• 2020

In this Study, Social Network Analysis of IoT related patents in South Korea, China, and Japan was conducted from the viewpoint of patent informatics. To this end, 2,526 patents filed by PCT until December 2019 were investigated up to the subclass level of the IPC code. As a result, in the case of South Korea, representative IPC codes are in the order of G06Q, H04L, G06F, H04W, and the highest frequency of interconnection is H04L→H04W, H04W→H04L, H04W→H04B. In China, the representative IPC codes are in the order of H04L, H04W, G05B, G06Q. South Korea has strong technological convergence centered on the G06Q, while China has strong convergence centered around H04L and H04W. Moreover, in China, H04L and H04W have more diverse combinations than in South Korea in Section A, B, G, and H. In the future, it is necessary to study the diversity of technology convergence of H04L and H04W in China.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1435-1447
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• 2012

The present study was conducted to determine the effect of hexaconazole (HEX), a triazole fungicide, on the growth, yield, photosynthetic response and antioxidant potential in cucumber (Cucumis sativus L.) plants subjected to UV-B stress. UV-B radiation and HEX were applied separately or in combination to cucumber seedlings. The growth parameters were significantly reduced under UV-B treatment, however, this growth inhibition was less in HEX treated plants. HEX caused noticeable changes in plant morphology such as reduced shoot length and leaf area, and increased leaf thickness. HEX was quite persistent in inhibiting shoot growth by causing a reduction in shoot fresh and dry weight. HEX noticeably recovered the UV-B induced inhibition of biomass production. Significant accumutation in anthocyanin and flavonoid pigments in the leaves occurred as a result of HEX or UV-B treatments. HEX permitted the survival of more green leaf tissue preventing chlorophyll content reduction and higher quantum yield for photosystemII under UV-B exposure. HEX treatment induced a transient rise in ABA levels in the leaves, and combined application of HEX and UV-B showed a significant enhancement of ABA content which activates $H_2O_2$ generation. UV-B exposure induced accumulation of $H_2O_2$ in the leaves, while HEX prevented UV-B induced increase in $H_2O_2$, indicating that HEX serves as an antioxidant agent able to scavenge $H_2O$ to protect cells from oxidative damage. An increase in the ascorbic acid was observed in the HEX treated cucumber leaves affecting many enzyme activities by removing $H_2O_2$ during photosynthetic processes. The activities of antioxidant enzymes including catalase(CAT), ascorbate peroxidase(APX), superoxide dismutase(SOD) and peroxidase(POD) in the leaves in the presence of HEX under UV-B stress were higher than those under UV-B stress alone. These findings suggest that HEX may participate in the enhanced tolerance to oxidative stress. From these results it can be concluded that HEX moderately ameliolate the effect of UV-B stress in cucumber by improving the components of antioxidant defense system.

• Journal of Magnetics
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• v.16 no.3
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• pp.229-233
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• 2011

Phase evolution during the hydrogen-assisted disproportionation of $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy was investigated mainly by using a magnetic balance-type thermomagnetic analyser (TMA). In order to avoid any undesirable phase change in the course of heating for TMA, a swift TMA technique with very high heating rate (around 2 min to reach $800^{\circ}C$ from room temperature) was adopted. The hydrided $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy started to be disproportionated in hydrogen from around $600^{\circ}C$, and the alloy after the early disproportionation (from 600 to $660^{\circ}C$) has been partially disproportionated. The partially disproportionated alloy consisted of a mixture of $NdH_x$, $Fe_3B$, ${\alpha}$-Fe, and the remaining undisproportionated $Nd_2Fe_{14}BH_x$-phase. During the subsequent heating to $800^{\circ}C$ in hydrogen, two additional phases of $Fe_{23}B_6$ and $Fe_2B$ were formed, and the material consisted of a mixture of $NdH_x$, $Fe_{23}B_6$, $Fe_3B$, $Fe_2B$, and ${\alpha}$-Fe phases. During the subsequent isothermal holding at $800^{\circ}C$ for 1 hour, the phase constitution was further changed, and one additional unknown magnetic phase was formed. Eventually, the fully disproportionated $Nd_{12.5}Fe_{80.6}B_{6.4}Ga_{0.3}Nb_{0.2}$ alloy consisted of $NdH_x$, $Fe_{23}B_6$, $Fe_3B$, $Fe_2B$, ${\alpha}$-Fe, and one additional unknown magnetic phase.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.97-103
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• 2007

Purpose : Lewis antigen has been known to have a role in the attachment of H. pylori to the gastric mucosa, but its expression pattern in children with H. pylori infection is still unclear. The recently described blood group antigen-binding adhesin BabA is known to mediate adherence of H. pylori to Lewis B receptors on gastric epithelium. We investigated the expression of Lewis antigen in gastric mucosa of Korean children with H. pylori infection. Methods : The expression of Lewis A ($Le^a$), B ($Le^b$), X ($Le^x$), and Y ($Le^y$) was evaluated by immunohistochemistry in H. pylori positive biopsy specimens from 35 children (antral gastritis in 30, peptic ulcer in 5) and in H. pylori negative specimens from 19 children. PCR assays for cagA and babA2 gene of H. pylori were performed. Results : We confirmed the expression of $Le^a$ in 60%, $Le^b$ in 97%, $Le^x$ in 100%, and $Le^y$ in 100% of the superficial epithelium of the 35 H. pylori positive children. In H. pylori negative patients, $Le^a$, $Le^b$, $Le^x$, and $Le^y$ expression was 52%, 100%, 89%, and 100%, respectively. The cagA gene was detected in 65% and babA2 gene in 25% of 35 patients. No differences in neutrophil activity and chronic inflammation were found according to the presence of cagA and babA2 genes in H. pylori. Conclusion : $Le^b$, $Le^x$ and $Le^y$ antigen were highly expressed in gastric mucosa of Korean children, but they were not associated with the status of H. pylori infection and the positivity of babA2 gene. Further studies for other mucosal receptors and toxins are needed to define the immune responses to H. pylori infection in gastric mucosa of Korean children.

• The Bulletin of The Korean Astronomical Society
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• v.24 no.2
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• pp.21-22
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• 1999

• Proceedings of the Korean Vacuum Society Conference
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• 1997.07a
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• pp.162-162
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• 1997