• 한국산림과학회지
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• 제87권3호
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• pp.429-444
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• 1998

Picea mariana 생장을 억제하는 Kalmia angustifolia에 영향을 주는 외생근균을 조사 선발하였다. 11개 외생근균중에서 19계통을 선발하여 Kalmia 잎침출물이 들어있는 배지에 P. mariana 치묘와 함께 근균을 접종하여 자라는 형태와 생장양상을 조사하였다. Kalmia 잎추출물을 첨가한 액체배지에서는 균사의 건중량을, 한천배지에서는 코로니의 직경을 측정한 결과 분리된 9개 균주에서는 현저하게 억제되었으나 나머지 10개 균주에서는 반대로 증가되거나 Kalmia의 영향이 나타나지 않았다. 배양배지의 pH가 3-4일 때는 생장을 억제 받는 근균도 있었으나 pH와 잎침출물을 조합한 조건하에서는 더욱 강하게 억제되었다. 분리된 13개 계통은 순수배양에서 Kalmia 잎침출물 25%와 함께 배양한 P. mariana에서 외생근균이 형성되었다. Paxillus involutus(NF4), Cenococcum geophilum(GB12), Laccaria laccata(GB23), E-strain(GB45)계통에서는 Kalmia 잎추출물 50%에서 배양한 결과 다른 계통보다 많은 외생근균이 형성이 되었다. 이러한 근균을 미리 접종한 P. mariana를 Kalmia 잎추출물과 같이 배양한 후 온실 안에서 4개월동안 Kalmia와 갈이 재배하였다. P. involutus, L. laccata 와 E-strain 미리 접종한 치묘에서는 많은 근균(흡수근외 77-91%)이 형성되었으나 C. geophilum를 미리 접종한 치묘에서는 근균이 비교적(흡수근의 32%) 적게 형성되었다. 외생균근이 대부분의 치묘에서 생겼음에도 불구하고 근균의 90% 이상이 접종근균에서 생겨났다. 근균의 지속적인 생장은 살아있는 Kalmia 식물개체에 영향을 받지 않았다. P. involutus, L.laccata와 E-strain과 같이 처리한 치묘 근균의 80% 이상과 C. geophilum을 처리한 치묘 근균의 53%가 접종된 균주의 영향을 받았다. 대조구에서는 토착균주에 의해 약 45%의 짧은 뿌리의 외생근균이 형성되었다. L. laccata와 C. geophidum는 Kalmia잎추출물과 같이 배양한 치묘의 근균행성을 촉진하였다. 균주를 접종한 경우 근균형성율은 pH5보다 pH4에서 4-15% 더 낮았으며 L. laccata를 접종한 경우 심하게 억제되었다. P. involtus에 접종한 치묘는 L. laccata를 E-strain를 접종한 치묘보다 줄기와 뿌리생장이 가장 높게 나타났다. P. involtus와 L. laccata를 접종한 치묘는 대조구의 치묘보다는 건중량이 많고 키가 훨씬 컸다. E-strain에 접종한 치묘는 대조구와 비교해서 1차 측근 수가 매우 작았으며 줄기 건중량은 매우 높게 나타났으나 다른 형질, 예를 들면 흡수근, 뿌리 건중량, 수고 등은 대조구와 크게 다르지 않았으나 C. geophilum에 접종한 치묘는 1차 측근수를 제외한 다른 생장 특징에서는 대조구와 크게 다르지 않았다.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.333-340
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• 2020

Macrophages are the cells of the first-line defense system, which protect the body from foreign invaders such as bacteria. However, Gram-negative bacteria have always been the major challenge for macrophages due to the presence of lipopolysaccharides on their outer cell membrane. In the present study, we evaluated the effect of phloretin, a flavonoid commonly found in apple, on the protection of macrophages from Escherichia coli infection. RAW 264.7 cells infected with standard E. coli, or virulent E. coli K1 strain were treated with phloretin in a dose-dependent manner to examine its efficacy in protection of macrophages. Our results revealed that phloretin treatment reduced the production of nitric oxide (NO) and generation of reactive oxygen species along with reducing the secretion of proinflammatory cytokines induced by the E. coli and E. coli K1 strains in a concentration-dependent manner. Additionally, treatment of phloretin downregulated the expression of E. coli-induced major inflammatory markers i.e. cyclooxygenase-2 (COX-2) and hemeoxygenase-1 (HO-1), in a concentration dependent manner. Moreover, the TLR4-mediated NF-κB pathway was activated in E. coli-infected macrophages but was potentially downregulated by phloretin at the transcriptional and translational levels. Collectively, our data suggest that phloretin treatment protects macrophages from infection of virulent E. coli K1 strain by downregulating the TLR4-mediated signaling pathway and inhibiting NO and cytokine production, eventually protecting macrophages from E. coli-induced inflammation.

• 한국전자파학회논문지
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• 제17권6호
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• pp.597-604
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• 2006

[ $3.1{\sim}5.15$ ] GHz 대역의 광대역 저잡음 증폭기를 새로운 입력 매칭 방식과 귀환회로 방식으로 구현하였다. 제안된 광대역 증폭기는 $0.18{\mu}m$ RF CMOS 공정을 사용하여 제작하였다. 측정된 값은 잡음지수가 $3.4{\sim}3.9$ dB, 전력 이득은 $12.8{\sim}14$ dB, 입력 매칭은 -9.4이고 입럭 IP3는 -1 dBm이고, 소비 전력은 14.5 mW이다.

• 한국전자통신학회논문지
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• 제9권9호
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• pp.1027-1034
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• 2014

3G부터 4G LTE까지의 전체 대역에 적용이 가능한 저전력, 광대역 저잡음증폭기를 설계하였다. 설계한 광대역 다중입력 저잡음증폭기는 기존의 3G인 CDMA의 대역인 1.2GHz대역과 LTE대역인 2.5GHz대역까지 넓은 주파수 대역을 안정적으로 증폭이 가능하고, 다중입력방식을 통해 입력신호의 크기에 관계없이 안정적인 증폭이 가능하도록 설계하였다. 설계된 저잡음증폭기는 1.2V의 공급전압에서 약 0.6mA의 전류를 소모하고, 이는 Cadence사의 컴퓨터 시뮬레이션을 통해 검증하였다. 낮은 입력신호에 대응한 증폭은 최대 20dB이고, 신호에 따라 최저 -10dB의 이득값을 얻을 수 있었다. 잡음특성(NF : Noise Figure)은 High Gain모드에서 15dB이하, Low Gain 모드에서 3dB이하를 가진다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1399-1403
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• 2006

A total of 80 cows, including 40 top mastitis resistant and 40 top mastitis susceptible animals as Group I and Group II, were selected from a population of 520 cows based on clinical mastitis occurrence. PCR-SSCP analysis on four fragments within the 5'region and two fragments of Exons 4,15 of bovine lactoferrin (bLF) revealed that four fragments-P1,P4,E4,E15-had polymorphisms which totally included six base mutations, and only two of them had significant differences in allele frequencies between resistant and susceptible groups, P1 (53.7% vs. 70.0%, p<0.05) and P4 (55.0% vs. 68.8%, p<0.05). Further study on these two promising markers combined with the milk performance traits of cows demonstrated that their selection would result in higher fat percentage (p<0.05), lower Somatic Cell Score (SCS) (p<0.05) and Clinical Mastitis Residuals (CMR) (p<0.01) indicating higher mastitis resistance and lower milk yield (p<0.05). The putative transcription factor binding sites in the 5'region were also studied by using MatInspector 7.2.2 software, and two signal pathways regulating the expression of bLF including the NF-${\kappa}B$ pathway and nuclear hormone receptor pathway were predicted.

• 한국해양공학회지
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• 제4권2호
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• pp.250-250
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• 1990

In this paper, fatigue tests were carried out at stress test levels of 461 MPa, 441 MPa, and 431 MPa by using smooth specimen of$2_{1/4}$ Cr-1 Mo steel with the stress ratio(R) of 0.05. The initiation, growth and coalescense process of the major cracks and sub-cracks among the fatigue cracks on the smooth specimen are investigated and measured under each stress level at a constant cycle ratio by the replica technique with optical microscope. Some of the important results are as follows: In spite of the difference of stress levels, the major crack data gather into a small band in the curve of surface crack length and crack depth against cycle ratio N/Nf. The sub-crack data, however, deviate from the band of the major crack. The growth rates, da/dN, of major and sub-crack plotted against the stress intensity factor range, ${\Delta}K$, have the tendency to be compressed on a relatively small band. But it is more effective to predict fatigue life through major cracks. The propagation behavior of surface microcracks on the smooth specimens coincides with that of the specimen having an artificial small surface defect or through crack.

• Biomolecules & Therapeutics
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• 제22권1호
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• pp.27-34
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• 2014

Curcumin is naturally occurring polyphenolic compound found in turmeric and has many pharmacological activities. The present study was undertaken to evaluate anti-allergic inflammatory activity of curcumin, and to investigate its inhibitory mechanisms in immunoglobulin E (IgE)/Ag-induced mouse bone marrow-derived mast cells (BMMCs) and in a mouse model of IgE/Ag-mediated passive systemic anaphylaxis (PSA). Curcumin inhibited cyclooxygenase-2 (COX-2) dependent prostaglandin $D_2$ ($PGD_2$) and 5-lipoxygenase (5-LO) dependent leukotriene $C_4$ ($LTC_4$) generation dose-dependently in BMMCs. To probe the mechanism involved, we assessed the effects of curcumin on the phosphorylation of Syk and its downstream signal molecules. Curcumin inhibited intracellular $Ca^{2+}$ influx via phospholipase $C{\gamma}1$ ($PLC{\gamma}1$) activation and the phosphorylation of mitogen-activated protein kinases (MAPKs) and the nuclear factor-${\kappa}B$ (NF-${\kappa}B$) pathway. Furthermore, the oral administration of curcumin significantly attenuated IgE/Ag-induced PSA, as determined by serum $LTC_4$, $PGD_2$, and histamine levels. Taken together, this study shows that curcumin offers a basis for drug development for the treatment of allergic inflammatory diseases.

• Natural Product Sciences
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• 제22권3호
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• pp.193-200
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• 2016

This study describes the anti-inflammatory, anti-oxidant, and melanogenesis inhibition activities of methanol extract and various organic solvent fractions of Arecae Pericarpium. We examined the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, 1,1-diphenyl-2-picrylhydrazine (DPPH) scavenging activity, mushroom tyrosinase inhibition activity and melanin contents. The study showed that, among all tested fractions, methylene chloride fraction showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells ($IC_{50}$ value $8.89{\mu}g/mL$) and DPPH radical scavenging activity ($EC_{50}$ value $21.39{\mu}g/mL$). Methylene chloride and ethyl acetate fractions similarly inhibited mushroom tyrosinase activity. Methanol extract exhibited strongest reduction of melanin content in B16F10 melanoma cells. Based on the bioactivity assay results, methylene chloride and ethyl acetate fractions were further separated. Eight phenolic compounds were isolated, which are dimeric syringol (1), catechol (2), 4-hydroxybenzaldehyde (3), vanillin (4), 4-hydroxyacetophenone (5), apocynin (6), protocatechuic acid (7) and 4-hydroxybenzoic acid (8). Among the isolated compounds tested, catechol showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells. Catechol also showed the concentration-dependent NF-${\kappa}B$ inhibition activity. Arecae Pericarpium might have potentials to be developed as anti-inflammatory agent or dermatological product for skin-whitening agent.

• Molecules and Cells
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• 제27권2호
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• pp.251-255
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• 2009

Sepsis is the leading cause of death in critically ill patients. Today, around 60% of all cases of sepsis are caused by Gram-negative bacteria. The cell wall component lipopolysaccharide (LPS) is the main initiator of the cascade of cellular reactions in Gram-negative infections. The core receptors for LPS are toll-like receptor 4 (TLR4), MD-2 and CD14. Attempts have been made to antagonize the toxic effect of endotoxin using monoclonal antibodies against CD14 and synthetic lipopolysaccharides but there is as yet no effective treatment for septic syndrome. Here, we describe an inhibitory effect of a phosphatidylethanolamine derivative, PE-DTPA (phosphatidylethanolamine diethylenetriaminepentaacetate) on LPS recognition. PE-DTPA bound strongly to CD14 ($K_d$, $9.52{\times}10^{-8}M$). It dose dependently inhibited LPS-mediated activation of human myeloid cells, mouse macrophage cells and human whole blood as measured by the production of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and nitric oxide, whereas other phospho-lipids including phosphatidylserine and phosphatidylethanolamine had little effect. PE-DTPA also inhibited transcription dependent on $NF-{\kappa}B$ activation when it was added together with LPS, and it rescued LPS-primed mice from septic death. These results suggest that PE-DTPA is a potent antagonist of LPS, and that it acts by competing for binding to CD14.

• 한국멀티미디어학회논문지
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• 제6권2호
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• pp.352-359
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• 2003

본 논문에서는 마이크로스트립 대역통과 여 파기와 0.2$\mu\textrm{m}$ CMOS 공정을 이용한 저 잡음 증폭기를 이용하여 블루투스 리시버를 설계하였다. 설계한 저잠음 증폭기는 캐스코드 인버터를 이용하였으며, 레퍼런스 전압원을 가지며 쵸크 인덕터를 사용하지 않는 1단으로 설계하였다. 설계된 2.4GHz 저잡음 증폭기는 2.8dB의 NF값과 18dB의 전력이득을 가지고 있으며, 2.5V 공급 전원에서 255mW의 소모전력을 가지고 있다. 또한 마이크로스트립리시버 여파기는 중심주파수는 2.45GHz이고 대역폭은 4%이고 삽입손실은 -l.9dB를 가지고 있다. 마이크로스트립 대역통과 여과기와 저잡음 증폭기를 시뮬레이션 하였을 경우 16.3dB의 전력이득을 나타내 어 블루투스 대역에서 대역통과의 좋은 특성을 얻을 수 있었다.