• 한국전자파학회논문지
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• 제20권9호
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• pp.900-905
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• 2009

본 논문에서는 전류 블리딩(bleeding)과 입력 인덕티브 직렬-피킹을 이용한 공통 드레인 귀환(Common Drain Feedback: CDFB) CMOS 광대역 저잡음 증폭기(Low Noise Amplifier: LNA)를 설계하였다. 캐스코드 증폭기와 귀환 증폭기를 DC 결합하여 블리딩 전류의 조정을 통해 LNA의 이득과 잡음 지수(Noise figure: NF)의 동적 제어를 실현하였다. 제작한 LNA는 2.5 GHz의 대역폭에서, 고이득 영역은 $1.7{\sim}2.8\;dB$ NF와 17.5 dB 이득, 그리고 27 mW의 전력 소비를 보이고, 저 이득 영역은 $2.7{\sim}4.0\;dB$ NF와 14 dB 이득, 그리고 1.8 mW의 전력 소비를 보인다.

• 국제물리치료학회지
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• 제1권2호
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• pp.136-142
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• 2010

This study aims to reveal how EA affects BAX and NF-kB involved in cell deaths from global ischemia, and to do this, observes the changes of BAX and NF-kB caused by EA application after transient global ischemia. The experimental method is to give rise to global ischemia and apply EA to 27 SD rats with the particulars of being six-week-old, male, around-300 gram-weighing, and adapted to laboratory environment for more than a week, and divide them into three groups, that is, GV20 EA group(n=9), L14 EA group(n=9), no-treatment GI group(n=9), and then observe their changes of BAX and NF-kB at the time lapse of 6 hours, 9 hours and 12 hours after ischemia, using western blotting. The numerical decrease of BAX expression at the time lapse of 9 hours after EA application, though not statistically significant, was observed in GV20 EA group and L14 EA group, and the NF-kB expression appeared statistically significant decrease in GV20 EA group and L14 EA group, but the expression was higher in the group with EA application. Therefore, EA application at the early phase of global ischemia is considered to affect BAX and NF-kB and play a positive role in decreasing apoptosis and cell deaths by inflammation.

• 동의생리병리학회지
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• 제21권4호
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• pp.1017-1024
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• 2007

Thymus and activation-regulated chemokine (TARC/CCL-17), produced by keratinocytes, is a CC chemokine known to selectively Th2 type T cells via $CCR4^+$ and is implicated in the development of atopic dermatitis (AD). TARC/CCL17 expression was induced by cytokines such as tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interferon-${\gamma}$ (IFN-${\gamma}$). We recently found that the wogonin, a flavone isolated from Scutellaria baicalensis, suppressed TARC expression via heme oxygenase 1 (HO1) in human keratinocytes induced with mite antigen. However, little is known about the inhibitory mechanism of wogonin on TARC/CCL-17 expression stimulated with cytokines. To investigate the inhibitory mechanism, I determined the inhibitory effects of wogonin on the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and $I{\kappa}B{\alpha}$ phosphorylation, and also examined the activation of p38 MAP kainase in HaCaT keratinocytes stimulated with TNF-${\alpha}$ and IFN-${\gamma}$. Wogonin inhibited NF-${\kappa}B$-DNA complex, NF-${\kappa}B$ binding activity, and the phosphorylation of $I{\kappa}B{\alpha}$ in a dose dependent manner. Wogonin also inhibited the translocation of NF-${\kappa}B$ from cytosol to nucleus. Moreover, the phosphorylation of of p38 MAP kinase in the TNF-${\alpha}$ and IFN-${\gamma}$-stimulated HaCaT keratinocytes were suppressed by wogonin in a dose dependent manner. These results suggest that wogonin may inhibit cytokine-induced NF-${\kappa}B$ activation by $I{\kappa}B{\alpha}$ degradation via suppression of p38 MAP kinase signaling pathway in keratinocytes and modulation of wogonin signaling pathway may be beneficial for the treatment of AD.

• Journal of Ginseng Research
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• 제32권4호
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• pp.315-323
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• 2008

In the previous studies, we isolated the compound K rich fractions (CKRF) and showed that CKRF inhibited Toll-like receptor (TLR) 4- or TLR9-induced inflammatory signaling. To extend our previous studies,1) we investigated the molecular mechanisms of CKRF in the TLR4-associated signaling via nuclear factor (NF)-${\kappa}B$, and in vivo role of CKRF for induction of tolerance in lipopolysaccharide (LPS)-induced septic shock. In murine bone marrow-dervied macrophages, CKRF significantly inhibited the induction of mRNA expression of proinflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase. In addition, CKRF significantly attenuated the transcriptional activities of TLR4/LPS-induced NF-${\kappa}B$. Nuclear translocation of NF-${\kappa}B$ in response to LPS stimulation was significantly abrogated by pre-treatment with CKRF. Furthermore, CKRF inhibited the recruitment of p65 to the interferon-sensitive response element flanking region in response to LPS. Finally, oral administration of CKRF significantly protected mice from Gram-negative bacterial LPS-induced lethal shock and inhibited systemic inflammatory cytokine levels. Together, these results demonstrate that CKRF modulates the TLR4-dependent NF-${\kappa}B$ activation, and suggest a therapeutic role for Gram-negative septic shock.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.369-377
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• 2018

Spinal tuberculosis (ST) is the tuberculosis caused by Mycobacterium tuberculosis (Mtb) infections in spinal curds. Isoliquiritigenin (4,2',4'-trihydroxychalcone, ISL) is an anti-inflammatory flavonoid derived from licorice (Glycyrrhiza uralensis), a Chinese traditional medicine. In this study, we evaluated the potential of ISL in treating ST in New Zealand white rabbit models. In the model, rabbits (n=40) were infected with Mtb strain H37Rv or not in their $6^{th}$ lumbar vertebral bodies. Since the day of infection, rabbits were treated with 20 mg/kg and 100 mg/kg of ISL respectively. After 10 weeks of treatments, the adjacent vertebral bone tissues of rabbits were analyzed through Hematoxylin-Eosin staining. The relative expression of Monocyte chemoattractant protein-1 (MCP-1/CCL2), transcription factor ${\kappa}B$ ($NF-{\kappa}B$) p65 in lymphocytes were verified through reverse transcription quantitative real-time PCR (RT-qPCR), western blotting and enzyme-linked immunosorbent assays (ELISA). The serum level of interleukin (IL)-2, IL-4, IL-10 and interferon ${\gamma}$ ($IFN-{\gamma}$) were evaluated through ELISA. The effects of ISL on the phosphorylation of $I{\kappa}B{\alpha}$, $IKK{\alpha}/{\beta}$ and p65 in $NF-{\kappa}B$ signaling pathways were assessed through western blotting. In the results, ISL has been shown to effectively attenuate the granulation inside adjacent vertebral tissues. The relative level of MCP-1, p65 and IL-4 and IL-10 were retrieved. $NF-{\kappa}B$ signaling was inhibited, in which the phosphorylation of p65, $I{\kappa}B{\alpha}$ and $IKK{\alpha}/{\beta}$ were suppressed whereas the level of $I{\kappa}B{\alpha}$ were elevated. In conclusion, ISL might be an effective drug that inhibited the formation of granulomas through downregulating MCP-1, $NF-{\kappa}B$, IL-4 and IL-10 in treating ST.

• 한국물환경학회지
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• 제29권4호
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• pp.559-567
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• 2013

In recent years, NF (nanofiltration) membrane has been receiving great attention for hardness removal and has begun to replace traditional lime soda ash softening process, particularly in Florida, USA, mainly due to less sludge production and easy operation. This study aimed to provide detailed surface characteristics of various commercial NF membranes by performing sophisticated surface analysis, which would help more fundamentally understand the performance of NF membranes. More specifically, a total of 7 NF membranes from top NF/RO manufacturers in the world were examined for basic performance tests, surface analysis, and fouling potential assessment. The results demonstrated that NF membranes are classified into two groups in terms of surface zeta potential; they are highly negatively charged ones, and neutral and/or less negatively charged ones. Their hydrophobicities, measured by contact angle, varied from hydrophilic to slightly hydrophobic ones. The AFM measurements showed various surface roughness, ranging from 23 nm (smooth) to 162 nm (rough) of average peak height. Lab-scale fouling experiments were performed using feedwater obtained from conventional water treatment plants in the province of Korea, and their results attempted to correlate to surface characteristics of NF membranes. However, unlike typical RO membranes, no clear correlation was found in this study, indicating that fouling mechanisms of NF membrane may be different from those of typical RO membranes, and both cake deposition and pore blocking mechanisms should be considered simultaneously.

• Journal of Microbiology
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• 제37권4호
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• pp.256-262
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• 1999

Latent membrane protein 1 (LMP1) of the Epstein-Barr virus (EBV) is an integral membrane protein with six transmembrane domains, which is essential for EBV-induced B cell transformation. LMP1 functions as a constitutively active tumor necrosis factor receptor (TNFR) like membrane receptor, whose signaling requires recruitment of TNFR-associated factors (TRAFs) and leads to NF-${\kappa}B$ activation. NF-${\kappa}B$ activation by LMP1 is critical for B cell transformation and has been linked to many phenotypic changes associated with EBV-induced B cell transformation. Deletion analysis has identified two NF-${\kappa}B$ activation regions in the carboxy terminal cytoplasmic domains of LMP1, termed CTAR1 (residues 194-232) and CTAR2 (351-386). The membrane proximal C-terminal domain was precisely mapped to a PXQXT motif (residues 204-208) involved in TRAF binding as well as NF-${\kappa}B$ activation. In this study, we dissected the CTAR2 region, which is the major NF-${\kappa}B$ signaling effector of LMP1, to determine a minimal functional sequence. A series of LMP1 mutant constructs systematically deleted for the CTAR2 region were prepared, and NF-${\kappa}B$ activation activity of these mutants were assessed by transiently expressing them in 293 cells and Jurkat T cells. The NF-${\kappa}B$ activation domain of CTAR2 appears to reside in a stretch of 6 amino acids (residues 379-384) at the end of the carboxy terminus.

• Journal of Electrochemical Science and Technology
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• 제8권4호
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• pp.338-343
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• 2017

Activated carbon has lower electrical conductivity and reliability than other carbonaceous materials because of the oxygen functional groups that form during the activation process. This problem can be overcome by doping the material with heteroatoms to reduce the number of oxygen functional groups. In the present study, N, F co-doped activated carbon (AC-NF) was successfully prepared by a microwave-assisted hydrothermal method, utilizing commercial activated carbon (AC-R) as the precursor and ammonium tetrafluoroborate as the single source for the co-doping of N and F. AC-NF showed improved electrical conductivity ($3.8\;S\;cm^{-1}$) with N and F contents of 0.6 and 0.1 at%, respectively. The introduction of N and F improved the performance of the pertinent supercapacitor: AC-NF exhibited an improved rate capability at current densities of $0.5-50mA\;cm^{-2}$. The rate capability was higher compared to that of raw activated carbon because N and F codoping increased the electrical conductivity of AC-NF. The developed method for the co-doping of N and F using a single source is cost-effective and yields AC-NF with excellent electrochemical properties; thus, it has promising applications in the commercialization of energy storage devices.

• Molecular & Cellular Toxicology
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• 제5권2호
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• pp.141-146
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• 2009

Toll-like receptors (TLRs) induce innate immune responses by recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor kappa-B (NF-$\kappa$B) leading to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Deregulated activation of TLRs can lead to the development of severe systemic inflammation. Divalent heavy metals, cadmium and mercury, have been used for thousands of years. While cadmium and mercury are clearly toxic to most mammalian organ systems, especially the immune system, their underlying toxic mechanism(s) remain unclear. Here, we report biochemical evidence that cadmium, but not mercury, inhibits NF-$\kappa$B activation and COX-2 expression induced by TLR2 or TLR4 agonists, while cadmium does not inhibit NF-$\kappa$B activation induced by the downstream signaling component of TLRs, MyD88. Thus, the target of cadmium to inhibit NF-$\kappa$B activation may be upstream of MyD88 including TLRs themselves, or events leading to TLR activation by agonists.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1294-1298
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• 2008

Toll-like receptors (TLRs) induce innate immune responses recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$). The activation of NF-${\kappa}B$ leads to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Guggul has been used for centuries to treat a variety of diseases. Guggulstreone, one of the active ingredients in guggul, has been used to treat many chronic diseases. However, the mechanism as to how guggulsterone mediate the health effects is largely unknown. Here, we report biochemical evidence that guggulsterone inhibits the NF-${\kappa}B$ activation and COX-2 expression induced by TLR2, TLR3, and TLR4 agonists. Guggulsterone also inhibits the NF-${\kappa}B$ activation induced by downstream signaling components of TLRs, myeloid differential factor 88 (MyD88), $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$), and p65. These results imply that guggulsterone can modulate the immune responses regulated by TLR signaling pathways.