• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.5
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• pp.175-181
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• 2005

Ingots of rutile single crystals were grown by the skull melting method, and their characteristics were compared in terms of melt-dwelling time for each melt. The method is based on direct inductive heating of an electrically conducted melt by an alternating RF field, and the heating is performed by absorption of RF energy. $TiO_2$ is an insulator at room temperature but its electric conductivity increases elevated temperature. Therefore, titanium metal ring(outside diameter : 6cm, inside diameter : 4cm, thickness 0.2cm) was embedded into $TiO_2$, powder (anatase phase, CERAC, 3N) for initial RF induction heating. Important factors of the skull melting method are electric resistivity of materials at their melting point, working frequency of RF generator and cold crucible size. In this study, electric resitivity of $TiO_2$, $(10^{-2}\~10^{-1}\;{\Omega}{\cdot}m)$ at its melting point was estimated by compairing the electric resitivities of alumina and zirconia. Inner diameter and height of the cold crucible was 11 and 14cm, respectively, which were determined by considering of the Penetration depth $(0.36\~1.13cm)$ and the frequency of RF generator.

• Molecules and Cells
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• v.38 no.1
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• pp.40-50
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• 2015

In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense.

• The Korea Journal of Herbology
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• v.34 no.2
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• pp.15-23
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• 2019

Objective : Reflux esophagitis (RE) is a disease that caused gastric acid reflux and inflammation due to unstable gastroesophageal sphincter, as increasing worldwide respectively. This study was conducted to evaluate the effect of Evodiae Fructus (EF) extract on chronic reflux esophagitis in rats. Methods : The EF was measured antioxidant activity, such as total polyphenol and total flavonoid contents, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2'-azinobis-3-ethyl-enzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Rats were divided into 3 groups; Nor (normal group), Con (chronic acid reflux esophagitis rats treatment with water), EF (chronic acid reflux esophagitis rat treatment with EF 200 mg/kg body weight group). A surgically-induced chronic acid reflux esophagitis (CARE) model was established in SD rats, and treated with water or EF 200 mg/kg body weight for 14 consecutive days. Results : Administration of EF to rats of induction of chronic acid reflux esophagitis was found to reduce esophagus tissues injury. Reactive oxygen species (ROS) and produces peroxynitrite ($ONOO^-$) levels of esophagus tissues were significantly decreased in EF compared to Con group. As results of esophagus protein analyses, EF effectively reduce inflammatory-related factors ($NF-{\kappa}Bp65$, $p-I{\kappa}B{\alpha}$, iNOS, $TNF-{\alpha}$, IL-6), and increase anti-oxidant enzyme (Nrf2, HO-1, SOD, catalase, GPx-1/2). Conclusions : These results suggest that EF administration comfirmed that decreased esophagus tissues injury, oxidantive stress, anti-inflammation effect, and increased anti-oxidant effect. Therefore, EF was the potential to be used as a natural therapeutic drug.

• Journal of Life Science
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• v.16 no.6
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• pp.904-910
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• 2006

Dendritic cells (DCs) are the only antigen presenting cells (APCs) capable of initiating immune responses, which is crucial for priming the specific cytotoxic T lymphocyte (CTL) response and tumor immunity. Upon activation by DCs, CD4+ helper T cells can cross-prime CD8+ CTLs via IL-12. However, recently activated DCs were described to prime in vitro strong T helper cell type 1 $(Th_1)$ responses, whereas at later time points, they preferentially prime $Th_2$ cells. Therfore, we examined in this study the optimum kinetic state of DCs activation impacted on in vivo priming of tumor-specific CTLs by using ovalbumin (OVA) tumor antigen model. Bone-marrow-derived DCs showed an appropriate expression of surface MHC and costimulatory molecules after 6 or 7-day differentiation. The 6-day differentiated DCs pulsed with OVA antigen for 8 h (8-h DC) and followed by restimulation with LPS for 24 h maintained high interleukin (IL)-12 production potential, accompanying the decreased level in their secretion by delayed re-exposure time to LPS. Furthermore, immunization with 8-h DC induced higher intracellular $interferon(IFN)-{\gamma}+/CD8+T$ cells and elicited more powerful cytotoxicity of splenocytes to EG7 cells, a clone of EL4 cells transfected with an OVA cDNA, than immunization with 24-h DC. In the animal study for the evaluation of therapeutic or protective antitumor immunity, immunization with 8-h DC induced an effective antitumor immunity against tumor of EG7 cells and completely protected mice from tumor formation and prolonged survival, respectively. The most commonly used and clinically applied DC-based vaccine is based on in vitro antigen loading for 24 h. However, our data indicated that antigen stimulation over 8 h decreased antitumor immunity with functional exhaustion of DCs, and that the 8-h DC would be an optimum activation state impacted on in vivo priming of tumor-specific CTLs and subsequently lead to induction of strong antitumor immunity.

• IMMUNE NETWORK
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• v.5 no.2
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• pp.78-88
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• 2005

Background: Collagen-induced arthritis (CIA) in mice is animal model of autoimmune disease known as rheumatic arthritis in human. We investigated CII-specific CD4+ T cell receptor usage in CIA mice. Methods: In CIA model, draining lymph node (dLN) CD4+ T cells and splenocytes at $3^{rd},\;5^{th},\;8^{th}$ week, we investigated CII-specific T cell proliferation, production of IL-17, IFN-${\gamma}$, TNF-${\alpha}$, IL-4 and IL-10. And we also performed anti-CII IgG Ab measurements in serum level, TCRV ${\beta}$ usage and T cell clonality with RT-PCR-SSCP analysis. Also, we performed proliferative response against CII when CII-specific T cell subset is deleted. Results: CIA mice showed more increase in the serum level of anti-CII IgG than normal mice after induction of arthritis. And the level of anti-CII IgG2a in CIA mice was increased after $3^{rd}$ week after primary immunization, while anti-CII IgG1 was decreased. Draining LN CD4+ T cells have proliferated against CII stimulation at $3^{rd}$ week after $1^{st}$immunization. CD4+T cells derived from dLN of CIA mice produced proinflammatory cytokine IFN-${\gamma}$, IL-17 etc. Draining LN CD4 T cells of CIA presented higher proportion of CD4+V ${\beta}3$+subset compared to those of normal mice at $3^{rd}$ week after $1^{st}$ immunization, and they were increased in proportion by CII stimulation. Draining LN CD4+ T cells without TCRV ${\beta}3+/V{\beta}8.1/8.2+/V{\beta}$10b+cells were not responsive against CII stimulation. But, CII-reactive response of TCRV ${\beta}3-/V{\beta}8.1/8.2-/V{\beta}$10b- T cells was recovered when $V{\beta}3+$ T cells were added in culture. Conclusion: Our results indicate that CD4+$V{\beta}3+$ T cells are selectively expanded in dLN of CIA mice, and their recovery upon CII re-stimulation in vitro, as well as the production Th1-type cytokines, may play pivotal role in CIA pathogenesis.