• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
• /
• pp.165-170
• /
• 1999

We have investigated the mixed-state Hall effect in HgBa$_2CaCu_2O_6$, HgBa$_2Ca_2Cu_3O_8$, and Tl$_2Ba_2Cau_2O_8$ thin films as functions of the magnetic field up to 18 T. At high fields and low temperatures, the scaling exponent in ${\rho}_{xy}$ = A${\rho}_{xx}\;^{\beta}$ shows a universal behavior, ${\beta}$ = 1 ${\pm}$ 0.1, regardless of the field, the number of CuO$_2$ layers, the types of defects, and even the types of compounds. At low fields and high temperatures, p = 1 ${\pm}$ 0.1 also appears as a universal number although the observed field range is rather limited. These observations show the universal scaling of Hall resistivity in the regions of the clean and the moderately clean limit, consistent with a theory based on the midgap states in the vortex core.

• Nutrition Research and Practice
• /
• 제16권2호
• /
• pp.173-193
• /
• 2022

BACKGROUND/OBJECTIVES: Alzheimer's disease (AD) is one of the most representative neurodegenerative disease mainly caused by the excessive production of amyloid beta (Aβ). Several studies on the antioxidant activity and protective effects of Populus tomentiglandulosa (PT) against cerebral ischemia-induced neuronal damage have been reported. Based on this background, the present study investigated the protective effects of PT against cognitive impairment in AD. MATERIALS/METHODS: We orally administered PT (50 and 100 mg/kg/day) for 14 days in an Aβ_25-35-induced mouse model and conducted behavioral experiments to test cognitive ability. In addition, we evaluated the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and measured the production of lipid peroxide, nitric oxide (NO), and reactive oxygen species (ROS) in tissues. RESULTS: PT treatment improved the space perceptive ability in the T-maze test, object cognitive ability in the novel object recognition test, and spatial learning/long-term memory in the Morris water-maze test. Moreover, the levels of AST and ALT were not significantly different among the groups, indicating that PT did not show liver toxicity. Furthermore, administration of PT significantly inhibited the production of lipid peroxide, NO, and ROS in the brain, liver, and kidney, suggesting that PT protected against oxidative stress. CONCLUSIONS: Our study demonstrated that administration of PT improved Aβ_25-35-induced cognitive impairment by regulating oxidative stress. Therefore, we propose that PT could be used as a natural agent for AD improvement.

• 구강생물연구
• /
• 제42권4호
• /
• pp.187-197
• /
• 2018

Chemical agents such as minocycline (MC) and citric acid (CA) were suggested in the treatment of contaminated implant surface. In this study, MC-HCl treatment was performed to enhance surface characteristics of titanium alloy surface. The purpose of this study was to assess the characteristics and the biocompatibility of Ti-6Al-4V surface treated by MC. Alpha-beta titanium alloy (Ti-6Al-4V) samples were prepared and they were divided into 6 groups according to chemical concentration and treatment time. These groups include 1) group I, non-treated smooth titanium alloy; 2) group II, MC 1.5 mg/mL for 1 hour; 3) group III, MC 1.5 mg/mL for 24 hours; 4) group IV, MC 15 mg/mL for 10 minutes; 5) group V, MC 100 mg/mL for 5 minutes; 6) group VI, pH1 CA for 3 minutes. The analysis of the surface characteristics of MC-treated titanium alloy was executed using scanning electron microscopy, roughness test, and X-ray photoelectron spectroscopy (XPS). Cell adhesion and MTT assay was done using MC3T3 cell. Titanium surfaces treated with MC indicated a more smoothened surface microstructure. For group II and III, the new peaks of rutile TiO2 were found. Group II and V have more basic group of Ti-OH form in XPS. In MTT assay, all MC-treated groups showed significantly higher cell viability compared to control. The surface roughness, crystal structure, surface hydrophilicity, cell viability of smooth titanium surface was improved by MC treatment. Compared with the control experiment and CA-treated group, smooth titanium surface treated with MC showed improved surface characteristics and cell biocompatibility.

• 한국식품위생안전성학회지
• /
• 제26권2호
• /
• pp.114-119
• /
• 2011

본 연구에서는 신선편의 채소와 과일에서 주로 검출되는 대장균(E. coli Ol577:H7), 리스테리아(L. monocytogenes), 살모넬라(Salmonella, spp.), 형색포도상구균(S. aureus)을 검출하고 동정할 수 있는 real time PCR 방법을 melting curve 분석을 활용하여 single tube 반응으로 두 종의 식중독균을 동시 검출하는 방법을 개발하고자 하였다. 대장균의 ${\beta}$-glucuronidase (uidA), 황색포도상구균의 thermonuclease (nuc), 리스테리아의 hemolycin (hly), 살모넬라의 tetrahionate reductase (ttr) 를 특이적으로 검출할 수 있는 4종의 프라이머 세트에 대한 real-time PCR의 melting curve 분석을 통하여 황색포도상구균과 대장균 동시분석 시 $T_m$ 값이 $80.6{\pm}0.9^{\circ}C$와 $86.9{\pm}0.5^{\circ}C$, 리스테리아와 살모넬라 동시분석 시 Tm 값이 $80.4{\pm}0.6^{\circ}C$와 $88.1{\pm}0.11^{\circ}C$로 확인하였고, 그 결과 정제되어진 각 식중독균의 genomic DNA를 주형으로 한 duplex real-time PCR 방법이 uniplex real-time PCR 방법과 마찬가지로 10 genome equivalents 까지 검출할 수 있는 민감도를 나타내었다. 또한, 양배추에 네 종의 식중독균을 접종하고, 증균배양 없이 DNA를 추출하여 duplex real-time PCR 을 수행한 결과 모든 식종목균에서 $10^3$ CFU/g의 검출 한계를 나타내었다. 결과적으로 개발된 melting curve 분석을 이용한 duplex real-time PCR 방법은 식품안전 증진을 위한 시간, 노동력, 비용 절감에 있어서 유효한 방법이 될 것으로 판단된다.

• Molecular & Cellular Toxicology
• /
• 제2권4호
• /
• pp.266-272
• /
• 2006

Carpal tunnel syndrome (CTS) is one of the most common disorders by under pressure of the median nerve at the wrist in these days. However, pathological mechanism of CTS is unknown. We carried out this study to identify the changes of gene expression and to evaluate possible mechanism in CTS. 120 CTS patients and 30 control patients were included in this study. Patients with a history of diabetes, hypertension, thyroid diseases, and arthritis were excluded. CTS patients were divided to three experimental groups-Mild, Moderate, and Severe group-according to elecrodiagnosis. Radioactive cDNA microarrays (Nylon membrane including 1,152 genes) were used to examine the difference of gene expression profile in CTS. We identified up-regulated genes by more than 2.0 value of z-ratio, and down-regulated genes by less than-2.0 value of z-ratio. 20 genes such as the ITGAL, ITGAM, PECAM1, VIL2, TGFBR2, RAB7, RNF5 and NFKB1 were up-regulated, and 28 genes such as PRG5, CASP8, CDH1, IGFBP5, CBX3, HREV107, PIN, and WINT2 were down-regulated. These genes were related with TGF beta signaling pathway, NF-Kb signaling pathway, antiapoptotic pathway and T cell receptor signaling pathway. However, there were no differences in gene expression profiles according to severities of symptoms. We suggest that CTS could be related with proinflammatory mechanism and antiapoptotic mechanism.

• Journal of Microbiology and Biotechnology
• /
• 제9권4호
• /
• pp.488-497
• /
• 1999

Probing Streptomyces albus ATCC 21838 chromosomal DNA with a proline tRNA sequence resulted in an isolation of a putative integrating element in the 6.4-kb EcoRI fragment. It was found that Streptomyces lividans TK-24 transformed with a cloned DNA fragment on a multicopy plasmid, produced a higher level of spore pigment and mycelial red pigment on a regeneration agar. Furthermore, the transformant S. lividans TK-24 produced a markedly increased level of undecylprodigiosin in a broth culture. A nucleotide sequence analysis of the cloned region revealed several open reading frames homologous to the integrases of integrating plasmids or temperate bacteriophages, signal-transducing regulatory proteins with a conserved ATP-binding domain, oxidoreductases ($\beta$-ketoacyl reductase), and an AraC-like transcriptional regulator. To examine the effect on antibiotic production, each coding region was overexpressed separately from the other genes in the region in S. lividans TK-24 with; pJHS3044 for the expression of the signal-transducing regulatory protein homologue, pJHS3045 for the homologue of oxidoreductase, and pJHS3051 for the homologue of the AraC-like transcriptional regulator. Phenotypic studies of S. lividans TK-24 strains harboring plasmids for the overexpression of individual genes suggested the following effects of the genes on antibiotic production: The oxidoreductase homologue stimulated the production of actinorhodin and undecylprodigiosin, which was influenced by the culture conditions; the homologue of the AraC-like transcriptional regulator was the most effective factor in antibiotic production within all the culture conditions tested; the signal-transducing regulatory protein homologue repressed the effect due to the homologue of the AraC-like transcriptional regulator, however, the antibiotic production was derepressed upon entering the stationary phase.

• 생명과학회지
• /
• 제18권9호
• /
• pp.1305-1311
• /
• 2008

본 연구는 바나바 잎 추출 용매에 따른 항당뇨 효과에 관한 것으로 세포 독성 실험을 통하여 인체에 대한 독성이 없음을 확인하였고 $\beta$-cell 인슐린 분비 실험을 통하여 항당뇨 효과를 알아보았다. 또한 당뇨 유발쥐를 이용한 인슐린 분비 실험, 체중변화 측정, 혈중 및 혈청의 glucose 농도, 총콜레스테롤 수치, HDL-cholesterol 농도, triglyceride 농도, free fatty acid 농도, langerhans islet에서의 인슐린 분비 의 확인을 통해 혈당조절 효과를 비교하였다. 물 혹은 에탄올을 단독으로 이용하여 추출한 추출물이나 70%, 90% 에탄올로 추출한 추출물 보다 열수로 먼저 추출한 후 에탄올로 다시 추출하여 혼합안 추출물이 항당뇨 효과가 더 뛰어남을 알 수 있었다. 이는 친수성(hydrophilic) 유효성분들과 소수성(hydrophobic) 유효성분들의 추출 유무나 함량에 의한 것이다. 특히, 많은 문헌에 언급된 코로소린산이라는 단일 성분(unique)에 의한 항당뇨 효과라기보다는 친수성 및 소수성 폴리페놀 및 항산화성분과 같은 유효성분들이 조합되어(mixture) 항당뇨 효과에 영향을 미치는 것으로 사료된다.

• BMB Reports
• /
• 제44권5호
• /
• pp.329-334
• /
• 2011

Many proteins with poor transduction efficiency were reported to be delivered to cells by fusion with protein transduction domains (PTDs). In this study, we investigated the effect of levosulpiride on the transduction of PEP-1 ribosomal protein S3 (PEP-1-rpS3), and examined its influence on the stimulation of the therapeutic properties of PEP-1-rpS3. PEP-1-rpS3 transduction into HaCaT human keratinocytes and mouse skin was stimulated by levosulpiride in a manner that did not directly affect the cell viability. Following 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice, levosulpiride alone was ineffective in reducing TPA-induced edema and in inhibiting the elevated productions of inflammatory mediators and cytokines, such as cyclooxygenase-2, inducible nitric oxide synthase, interleukin-6 and -1${\beta}$, and tumor necrosis factor-${\alpha}$. Anti-inflammatory activity by PEP-1-rpS3 + levosulpiride was significantly more potent than by PEP-1-rpS3 alone. These results suggest that levosulpiride may be useful for enhancing the therapeutic effect of PEP-1-rpS3 against various inflammatory diseases.

• Bulletin of the Korean Chemical Society
• /
• 제31권12호
• /
• pp.3588-3592
• /
• 2010

Second-order rate constants ($k_N$) have been measured spectrophotometrically for nucleophilic substitution reactions of 2-pyridyl X-substituted benzoates 8a-e with a series of alicyclic secondary amines in $H_2O$ at $25.0{\pm}0.1^{\circ}C$. The $k_N$ values for the reactions of 8a-e are slightly smaller than the corresponding reactions of 4-nitrophenyl X-substituted benzoates 1a-e (e.g., $kN^{1a-e}/k_N^{8a-e}$ = 1.1 ~ 3.1), although 2-pyridinolate in 8a-e is ca. 4.5 $pK_a$ units more basic than 4-nitrophenolate in 1a-e. The Br$\o$nsted-type plot for the aminolysis of 8c (X = H) is linear with $\beta_{nuc}$ = 0.77 and $R^2$ = 0.991 (Figure 1), which is typical for reactions reported previously to proceed through a stepwise mechanism with breakdown of a zwitterionic tetrahedral intermediate $T^{\pm}$ being the rate-determining step (RDS), e.g., aminolysis of 4-nitrophenyl benzoate 1c. The Hammett plot for the reactions of 8a-e with piperidine consists of two intersecting straight lines (Figure 2), i.e., $\rho$ = 1.71 for substrates possessing an electron-donating group (EDG) while $\rho$ = 0.86 for those bearing an electron-withdrawing group (EWG). Traditionally, such a nonlinear Hammett plot has been interpreted as a change in RDS upon changing substituent X in the benzoyl moiety. However, it has been proposed that the nonlinear Hammett is not due to a change in RDS since the corresponding Yukawa-Tsuno plot exhibits excellent linear correlation with $\rho$ = 0.85 and r = 0.62 ($R^2$ = 0.995, Figure 3). Stabilization of substrates 8a-e in the ground state has been concluded to be responsible for the nonlinear Hammett plot.

• 한국식품영양학회지
• /
• 제25권3호
• /
• pp.570-578
• /
• 2012

인삼 조사포닌 추출물 내의 ginsenoside를 CK로 전환을 하기 위하여 T. reesei 유래 cellulolytic 복합 효소를 사용하였다. 온도, pH, 인삼 조사포닌 추출물 농도, 효소 농도와 반응시간별 T. reesei 효소의 인삼 조사포닌 추출물로부터 CK 전환에 대한 적정조건을 살펴본 결과, 온도는 $50^{\circ}C$에서 691.51 mg/100 g으로, pH는 조건별 큰 차이는 보이지 않았지만 pH 5.0일때 701.88 mg/100 g으로 가장 높은 함량을 나타내었다. 인삼 조사포닌 추출물과 효소 농도에 있어서는 각각 2%(w/v) 농도(678.82 mg/100 g)와 9%(v/v) 농도(691.51 mg/100 g)일 때 가장 높은 CK 농도를 보였다. 온도 $50^{\circ}C$, pH 5.0, 인삼 조사포닌 추출물 농도 2%(w/v)와 효소농도 9%(v/v)에서 반응시간에 따른 CK 생산을 분석한 결과, 반응 48시간까지 급격히 증가하다가 그 이후에는 반응속도가 현저하게 느려지는 경향을 보였지만, 반응 96시간에 784.97 mg/100 g으로 가장 높은 CK 농도를 나타내었다. 이러한 결과를 토대로 인삼 조사포닌 추출물의 농도 2%(w/v), 효소 농도 7%(v/v)와 반응 시간 48 hr를 CK 생산에 중요 요인변수로 선정하여 pH 5.0와 온도 $50^{\circ}C$에서 반응표면분석법 실험을 진행하였다. 그 결과, 인삼 조사포닌 추출물 농도 2.38%, 효소농도 6.07%와 효소반응 시간 64.04 hr를 최적조건으로 설정하였으며, CK 생산 예측 값은 840.77 mg/100 g이었다. 반응표면분석법으로 선정한 최적조건에서 플라스크와 생물반응기를 이용하여 효소반응을 수행한 결과 플라스크에서는 CK 생산 예측 값 보다 약 1.2배 높은 1,017.93 mg/100 g이 생성되었고, 생물반응기에서는 예측 값과 비슷한 862.31 mg/100 g의 CK가 생성되었다.