• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.158-158
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• 2012

A new kind of organic-inorganic hybrid polymer, poly(tetraphenyl)silole siloxane (PSS), was invented and synthesized for realization of its unique charge trap properties. The organic portions consisting of (tetraphenyl)silole rings are responsible for electron trapping owing to their low-lying LUMO, while the Si-O-Si inorganic linkages of high HOMO-LUMO gap provide the intrachain energy barrier for controlling electron transport. Such an alternation of the organic and inorganic moieties in a polymer may give an interesting quantum well electronic structure in a molecule. The PSS thin film was fabricated by spin-coating of the PSS solution in THF organic solvent onto Si-wafer substrates and curing. The electron trapping of the PSS thin films was confirmed by the capacitance-voltage (C-V) measurements performed within the metal-insulator-semiconductor (MIS) device structure. And the quantum well electronic structure of the PSS thin film, which was thought to be the origin of the electron trapping, was investigated by a combination of theoretical and experimental methods: density functional theory (DFT) calculations in Gaussian03 package and spectroscopic techniques such as near edge X-ray absorption fine structure spectroscopy (NEXAFS) and photoemission spectroscopy (PES). The electron trapping properties of the PSS thin film of quantum well structure are closely related to intra- and inter-polymer chain electron transports. Among them, the intra-chain electron transport was theoretically studied using the Atomistix Toolkit (ATK) software based on the non-equilibrium Green's function (NEGF) method in conjunction with the DFT.

• 한국재료학회지
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• 제9권9호
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• pp.913-918
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• 1999

전자파 차폐특성 측정방법의 일환으로 매질의 전기전도도로부터 차폐효과를 정성적 수준에서 예측하는 연구를 수행하였다. 사용된 시편은 전도성 금속 (Cu, Ni)이 피복된 망사형 차폐재로 두께는 0.1 mm 정도이고, 전기전도도는 6.4$\times$10~2.4$\times$10(sup)5 mhos/m 범위 값을 가졌다. 물질상수와 시편의 두께로 표시되는 반사손실 및 흡수손실의 이론식을 도출하고 상기 시편에 대해 차폐효과를 계산하였다. 전도성 피복재의 경우 주된 차폐기구는 반사손실임을 밝힐 수 있었으며, 전기전도도가 증가함에 따라 차폐효과는 현저히 증가함을 알 수 있었다. 이들 이론치를 임피던스 실측치로부터 계산된 반사손실과 비교한 결과 10 dB 이내의 오차를 보임으로써 제안한 분석방법의 타당성을 입증하였다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권11호
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• pp.1059-1070
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• 2005

유전 알고리즘에서 개체군은 지역 최적치에 빠질 수 있지만 긴 지속시간이 지난 후에는 여기에서 빠져나을 수 있으며 이러한 현상을 단속평형 (punctuated equilibrium)이라고 한다. 자연계나 컴퓨터 생태계 (computational ecosystems) 에서 관찰되는 단속평형은 확산 방정식 (diffusion equation)으로 잘 설명된다. 본 연구에서는 단순 유전 알고리즘을 이론적으로 분석하여 개체군의 움직임이 확산 방정식으로 표현될 수 있다는 것을 보인다. 또한 적합도 (fitness) 함수를 단위화 (unitation) 함수로 국한하면 이 분석을 더 구체화하여 유전 알고리즘의 주요 변수들이 이 방정식에 나타나도록 할 수 있다. 이 경우 확산 방정식에 대한 이론적 결과를 이용하면 지역 최적치에서 빠져 나오기까지의 지속시간이 개체군의 크기, 1/(돌연변이 확률), 그리고 지역 최적치의 깊이에 대해 지수적으로 증가한다는 것을 알 수 있다. 이러한 이론적 결과는 이중안정 지형 (bistable landscapes)에서의 시뮬레이션 결과와 일치한다.

• 한국임상수의학회지
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• 제18권3호
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• pp.206-210
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• 2001

피부질환에는 보조 치료로 다양한 치료용 샴푸가 빈번하게 적용되고 있으나 이들 샴푸의 피부수분에 미치는 영향은 일반적으로 평가되지 않고 있는 실정이다. 따라서 치료용 샴푸의 정확한 처방을 위해서는 피부의 수분을 측정하기 위한 측정법이 필요하다. 본 연구는 여러 종류의 치료용 샴푸의 피부 수분에 대한 영향을 알아보기 위해 Corneometer를 이용하여 피부에 샴푸를 적용후 수분을 측정하였다. 5두의 건강한 개를 대상으로 7가지 샴푸로 Humilac, Sebocalm, Sebolytics, Etiderm, Benzoyl peroxide, HyLyt, Zn-7 Derm를 선정하여 적용하였다. Humilac의 경우 통계학적으로 유의한 피부수분의 증가는 적용 후 17분(p<0.05), 77분(p<0.01)에 나타났으며, Benzoyl peroxide의 경우 적용 후 77분(p<0.05)에 피부의 수분이 유의하게 감소되었다. 다른 샴푸의 경우 통계학적으로 유의하지 않았으나 전반적으로 감소하는 경향을 보였으며 적용 후 77분에 최초 적용 수치에 근접하게 감소하였다. 어떤 샴푸도 피부에 부작용을 유발하지 않았다. Corneometer는 실제 임상에서 피부의 수분을 평가하는데 간단하고 유용한 측정방법을 사료된다.

• 한국축산식품학회지
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• 제34권6호
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• pp.829-835
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• 2014

Inflammatory bowel disease (IBD) is caused by dysregulation of colon mucosal immunity and mucosal epithelial barrier function. Recent studies have reported that lipoteichoic acid (LTA) from Lactobacillus plantarum K8 reduces excessive production of pro-inflammatory cytokine. In this study, we investigated the preventive effects of lysate of Lb. plantarum K8 in dextran sulfate sodium (DSS)-induced colitis. Male Sprague-Dawley rats were orally pretreated with lysate of Lb. plantarum K8 (low dose or high dose) or live Lb. plantarum K8 prior to the induction of colitis using 4% DSS. Disease progression was monitored by assessment of disease activity index (DAI). Histological changes of colonic tissues were evaluated by hematoxylin and eosin (HE) staining. Tumor necrosis factor-alpha (TNF-${\alpha}$), interleukin-6 (IL-6) levels were measured using enzyme-linked immunosorbent assay (ELISA). The colon mRNA expressions of TNF-${\alpha}$, IL-6, and toll like receptor-2 (TLR-2) were examined by quantitative real-time-transcription polymerase chain reaction (qPCR). Lysate of Lb. plantarum K8 suppressed colon shortening, edema, mucosal damage, and the loss of DSS-induced crypts. The groups that received lysate of Lb. plantarum K8 exhibited significantly decreased levels of the pro-inflammatory cytokines TNF-${\alpha}$ and IL-6 in the colon. Interestingly, colonic expression of toll like receptor-2 mRNA in the high-dose lysate of Lb. plantarum K8 group increased significantly. Our study demonstrates the protective effects of oral lysate of Lb. plantarum K8 administration on DSS-induced colitis via the modulation of pro-inflammatory mediators of the mucosal immune system.

• 한국재료학회지
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• 제8권2호
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• pp.147-153
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• 1998

$WN_x$ 는 리소그라피 마스크의 흡수체나 VLSI 기술에서 금속연결의 확산방지재로써 주목을 받고 있다. RF마르네트론 스퍼터링법으로 여러 증착변수에서 제조한 $WN_x$ 막을 고찰하였다. $SiN_x$ 멤브레인 위에 증착된 박막의 결정구조는 질소아르곤 가스유량비(0-30%), 가스압력(10-43mTorr), RF출력(0150W)및 기판과 타겟사이의 거리 6cm에서 증착한 $WN_x$ 박막은 비정질이였으며 다른 조건에서는 표면이 거친 다결정질이었다. 비정질 박막은 rms가 $3.1\AA$으로 아주 매끈하여 X-선 마스크용 흡착제로써 적합할 것으로 기대된다.

• Journal of Pharmaceutical Investigation
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• 제37권1호
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• pp.15-22
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• 2007

An oil-in-water solvent evaporation method was used to prepare the cyclosporin A (CyA)-loaded nanoparticles varying in poly (D,L-lactide-co-glycolide) (PLGA) polymer (RG 502H, RG 503H) and the amount of additive ethyl myristate (EM) or chitosan (CS). The particles were characterized for drug loading and entrapment efficiency by HPLC, surface morphology by scanning electron microscopy, particle size by dynamic light scattering and surface charge by Zetapotential. The results showed drug loadings ranging from 10.9% to 15.8% with high encapsulation efficiency (82.0-97.8%). SEM and DLS studies showed discrete and spherical particles with smooth surfaces and mean size ranging 257.6-721.7 nm. The additive EM or CS did not change the mean sizes of the nanoparticles, whereas by the coating effect of CS, the Zetapotential values of the CS-added nanoparticles were moved to the more positive direction as the amount of CS was increased. From the pharmacokinetic analysis, the nanoparticles formulations showed the higher bioavailability and MRT than $Neoral^{\circledR}$ While little adding effect of EM or CS was detected in pharmacokinetic profile when RG 503H was used as polymer carrier, more noticeable different pharmacokinetic behaviors could be observed in case of RC 502H. EM incorporation was found to elevate the $K_{el}$, whereas CS coating resulted in the decrease of F and $K_{el}$, which seems to be due to the function of CS as a barrier and a mucoadhesive coating.

• Journal of Ginseng Research
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• 제41권4호
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• pp.456-462
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• 2017

Background: Abnormal activation of matrix metalloproteinases (MMPs) plays an important role in UV-induced wrinkle formation, which is a major dermatological problem. This formation occurs due to the degeneration of the extracellular matrix (ECM). In this study, we investigated the cutaneous photoprotective effects of Ultraflo L treated ginseng leaf (UTGL) in hairless mice. Methods: SKH-1 hairless mice (6 weeks of age) were randomly divided into four groups (8 mice/group). UTGL formulation was applied topically to the skin of the mice for 10 weeks. The normal control group received nonvehicle and was not irradiated with UVB. The UV control (UVB) group received nonvehicle and was exposed to gradient-UVB irradiation. The groups (GA) receiving topical application of UTGL formulation were subjected to gradient-UVB irradiation on $0.5mg/cm^2$ [GA-low (GA-L)] and $1.0mg/cm^2$ [(GA-high (GA-H)] of dorsal skin area, respectively. Results: We found that topical treatment with UTGL attenuated UVB-induced epidermal thickness and impairment of skin barrier function. Additionally, UTGL suppressed the expression of MMP-2, -3, and -13 induced by UVB irradiation. Our results show that topical application of UTGL protects the skin against UVB-induced damage in hairless mice and suggest that UTGL can act as a potential agent for preventing and/or treating UVB-induced photoaging. Conclusion: UTGL possesses sunscreen properties and may exhibit photochemoprotective activities inside the skin of mice. Therefore, UTGL could be used as a potential therapeutic agent to protect the skin against UVB-induced photoaging.

• IMMUNE NETWORK
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• 제13권6호
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• pp.240-248
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• 2013

In this study, we compared the immune cell populations in rheumatoid arthritis (RA) synovial fluid, which shows lymphoid tissue-like structure, with those in tonsils, which are normal secondary lymphoid tissues. Firstly, we found that $CD4^-CD11b^+$ macrophages were the major population in RA synovial fluid and that B cells were the major population in tonsils. In addition, synovial fluid from patients with osteoarthritis, which is a degenerative joint disease, contained $CD4^+CD11b^+$monocytes as the major immune cell population. Secondly, we categorized three groups based on the proportion of macrophages found in RA synovial fluid: (1) the macrophage-high group, which contained more than 80% macrophages; (2) the macrophage-intermediate group, which contained between 40% and 80% macrophages; and (3) the macrophage-low group, which contained less than 40% macrophages. In the macrophage-low group, more lymphoid tissue inducer (LTi)-like cells were detected, and the expression of OX40L and TRANCE in these cells was higher than that in the other groups. In addition, in this group, the suppressive function of regulatory T cells was downregulated. Finally, CXCL13 expression was higher in RA synovial fluid than in tonsils, but CCL21 expression was comparable in synovial fluid from all groups and in tonsils. These data demonstrate that increased lymphocyte infiltration in RA synovial fluid is correlated with an increase in LTi-like cells and the elevation of the chemokine expression.

• 대한화학회지
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• 제28권3호
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• pp.163-169
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• 1984

칼륨이온이 dibenzo-18-crown-6(DBC)에 의해 $H_2O-CHl_3-H_2O$액체막을 통하여 운반되는 속도를 10가지 칼륨염의 농도를 변화시키면서 $25^{\circ}C$에서 측정하였다. 운반속도는 농도와 음이온의 특성에 크게 의존했으며 농도효과로 부터 피크르산칼륨의 경우에는 이온쌍 형성으로 인하여 1.0 ${\times}10^{-3}$M을 전후하여 각기 다른 양상을 보였다. 이온의 운반과정은 다단계 착물반응 및 확산과정에 의한 것으로 운반 메카니즘을 체계화하기 위해 비균질성 액체막의 각상에서 갖는 화학종의 에너지 장벽모델을 제시하였다. 또한 이를 음이온의 수화자유 에너지와의 관계를 비교함으로써 새로이 7단계 운반과정을 제시하고 그 운반 메카니즘을 고찰하였다.