• Restorative Dentistry and Endodontics
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• 제28권2호
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• pp.134-145
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• 2003

Mechanical properties and microleakage of two composites [conventional hybrid type DenFil (VERICOM Co., Anyang, Korea) / micro matrix hybrid type Esthet X (Dentsply Caulk, Milford, DE, U.S.A.)] were evaluated to assess whether variable light intensity curing is better than conventional curing technique. Curing was done for 40 seconds in two ways of 2 step soft-start technique and 5 step ramping technique. Three kinds of light intensities of 50, 100, $200{\;}mW/\textrm{cm}^2$ were initially used for 10, 20, 30 seconds each and the maximum intensity of $600 {\;}mW/\textrm{cm}^2$ was used for the rest of curing time in a soft-start curing tech nique. In a ramping technique, curing was done with the same initial intensities and the light intensity was increased 5 times with the same rate to the maximum intensity of $600{\;}mW/\textrm{cm}^2$. After determining conditions that showed no different mechanical properties with conventional technique, Esthet X composite was filled in a class V cavity, which dimension was $4{\times}3{\times}1.5{\;}mm$ and cured under those conditions. Microleakage was evaluated in two ways of dye penetration and maximum gap estimation through SEM observation. ANOVA and Spearman's rho test were used to confirm any statistical significance among groups. The results were as follows : 1 Several curing conditions of variable light intensities resulted in the similar mechanical properties with a conventional continuous curing technique, except conditions that start curing with an initial light intensity of $50{\;}mW/\textrm{cm}^2$. 2. Conventional and ramping techniques were better than soft-start technique in mechanical properties of microhardness and compressive strength. 3. Soft-start group that started curing with an initial light intensity of $100{\;}mW/\textrm{cm}^2$ for 10 seconds showed the least dye penetration. Soft-start group that started curing with an initial light intensity of $200{\;}mW/\textrm{cm}^2$ for 10 seconds showed the smallest marginal gap, if there was no difference among groups. 4. Soft-start technique resulted in better dye-proof margin than conventional technique(p=0.014) and ramping technique(p = 0.002). 5. There was a very low relationship(p=0.157) between the methods of dye penetration and marginal gap determination through SEM evaluation. From the results of this study, it was revealed that ramping technique would be better than conventional technique in mechanical properties, however, soft-start technique might be better than conventional one in microleakage. It was concluded that much endeavor should be made to find out the curing conditions, which have advantages of both aspects or to solve these kinds of problems through a novel idea of polymerization.

• 한국식품영양과학회지
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• 제32권2호
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• pp.217-222
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• 2003

본 연구에서는 일반적으로 여러 종류의 질병에 약리 효과가 있다고 알려진 버섯류 중 표고버섯과 새송이 버섯을 택하여 열수추출하고 이 추출물을 인간의 대장암 세포인 HT-29및 Caco-2와 한국인 위암세포인 SNU484에 첨가한 후 세포증식과 세포사멸을 이끄는 caspase-3 활성을 알아보고자 하였다. 대장암 세포인 H-'29와 Caco-2에 표고버섯과 새송이버섯 추출물을 첨가한 결과 대조군에 비하여 유의 적으로 세포 수가 감소하였으며 첨가량이 많아질수록 유의적으로 세포증식이 더 억제되었다. 표고버섯과 새송이버섯을 HT-29에 첨가 후 배양시간에 따른 세포증식 억제효과를 살펴보았더니 배양시간이 경과함에 따라 세포증식이 억제되는 경향을 나타내었으며 특히 96시간의 처리에 HT-29증식이 매우 억제됨을 볼 수가 있었다. 세포의 caspase-3활성을 측정한 결과 표고버섯과 새송이버섯을 48 mg/mL 이 상의 농도로 첨가하였을 때 2배 이상 casuase-3 활성이 증가였으므로 알에서 본 HT-29세포의 증식억제는 세포사멸의 증가에 기인한다고 짐작된다. 위 암세포인 SNU484에 표고버섯과 새송이버섯을 첨가한 경우에는 세포증식의 억제효과가 없었을 뿐만 아니라 caspase-3 활성도 유의하게 증가하지는 않았다. 즉 위암에는 이 두 종류의 버섯은 효능이 없음을 알 수 있었다. 그러므로 표고버섯과 새송이버섯은 caspase-3 활성 을 증가 시켜 대장암세포의 증식을 억제하므로 대장암에 대한 항암 물질로 개발할 필요가 있을 것으로 사료된다

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권2호
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• pp.77-82
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• 2017

Objectives: The aim of this study was to compare the mechanical resistance of four different osteosyntheses modeled in two different sagittal split ramus osteotomy (SSRO) designs and to determine the linear loading in a universal testing machine. Materials and Methods: An in vitro experiment was conducted with 40 polyurethane hemimandibles. The samples were divided into two groups based on osteotomy design; Group I, right angles between osteotomies and Group II, no right angles between osteotomies. In each group, the hemimandibles were distributed into four subgroups according to the osteosynthesis method, using one 4-hole 2.0 mm conventional or locking plate, with or without one bicortical screw with a length of 12.0 mm (hybrid technique). Each subgroup contained five samples and was subjected to a linear loading test in a universal testing machine. Results: The peak load and peak displacement were compared for statistical significance using PASW Statistics 18.0 (IBM Co., USA). In general, there was no difference between the peak load and peak displacement related to osteotomy design. However, when the subgroups were compared, the osteotomy without right angles offered higher mechanical resistance when one conventional or locking 2.0 mm plate was used. One locking plate with one bicortical screw showed higher mechanical resistance ($162.72{\pm}42.55N$), and these results were statistically significantly compared to one conventional plate with monocortical screws (P=0.016) and one locking plate with monocortical screws (P=0.012). The difference in peak displacement was not statistically significant based on osteotomy design or internal fixation system configuration. Conclusion: The placement of one bicortical screw in the distal region promoted better stabilization of SSRO. The osteotomy design did not influence the mechanical behavior of SSRO when the hybrid technique was applied.

• 자원리싸이클링
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• 제24권2호
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• pp.55-61
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• 2015

본 연구는 폐타이어 재활용을 위하여 수행된 전처리 공정이 재생 고무분말의 기계적 물성에 미치는 영향을 조사하는 것을 목적으로 하였다. 이를 위하여 분쇄 및 탈황공정을 통하여 생산된 폐타이어 고무분말을 재가황한 후 인장시험, 충격시험 및 파단면 관찰을 수행하였다. 분쇄 공정을 거쳐서 생산된 고무분말은 입자크기가 작아질수록 그 표면적이 증가되며 인장강도와 연신율이 모두 증가되었다. 반면에 탈황공정을 거친 고무분말은 내부에 존재하는 황과의 가교결합이 줄어들어서 이후의 가황처리 후에도 인장강도와 연신율이 모두 증가되었다. 따라서 폐타이어 재활용을 위한 전처리 공정은 재활용 분말을 일정크기로 분쇄한 후 탈황공정까지를 수행한 고무분말을 제조하는 것이 단순 분쇄공정만을 거친 재활용 고무분말에 비하여 가황 시에 연신율을 보다 효율적으로 증가시킬 수 있음을 확인하였다.

• 한국재료학회지
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• 제26권3호
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• pp.117-122
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• 2016

White organic light-emitting diodes with a structure of indium-tin-oxide [ITO]/N,N-diphenyl-N,N-bis-[4-(phenylm-tolvlamino)-phenyl]-biphenyl-4,4-diamine [DNTPD]/[2,3-f:2, 2-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile [HATCN]/1,1-bis(di-4-poly-aminophenyl) cyclo -hexane [TAPC]/emission layers doped with three color dopants/4,7-diphenyl-1,10-phenanthroline [Bphen]/$Cs_2CO_3$/Al were fabricated and evaluated. In the emission layer [EML], N,N-dicarbazolyl-3,5-benzene [mCP] was used as a single host and bis(2-phenyl quinolinato)-acetylacetonate iridium(III) [Ir(pq)2acac]/fac-tris(2-phenylpyridinato) iridium(III) $[Ir(ppy)_3]$/iridium(III) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate [FIrpic] were used as red/green/blue dopants, respectively. The fabricated devices were divided into five types (D1, D2, D3, D4, D5) according to the structure of the emission layer. The electroluminescence spectra showed three peak emissions at the wavelengths of blue (472~473 nm), green (495~500 nm), and red (589~595 nm). Among the fabricated devices, the device of D1 doped in a mixed fashion with a single emission layer showed the highest values of luminance and quantum efficiency at the given voltage. However, the emission color of D1 was not pure white but orange, with Commission Internationale de L'Eclairage [CIE] coordinates of (x = 0.41~0.45, y = 0.41) depending on the applied voltages. On the other hand, device D5, with a double emission layer of $mCP:[Ir(pq)_2acac(3%)+Ir(ppy)_3(0.5%)]$/mCP:[FIrpic(10%)], showed a nearly pure white color with CIE coordinates of (x = 0.34~0.35, y = 0.35~0.37) under applied voltage in the range of 6~10 V. The luminance and quantum efficiency of D5 were $17,160cd/m^2$ and 3.8% at 10 V, respectively.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.584-592
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• 2004

A thermostable $\beta$-glycosidase gene, tfi $\beta$-gly, was cloned from the genomic library of Thermus filiformis Wai33 A1. ifi $\beta$-gly consists of 1,296 bp nucleotide sequence and encodes a polypeptide of 431 amino acids. It shares a strong amino acid sequence similarity with the $\beta$-glycosidases from other Thermus spp. belonging to the glycosyl hydrolase family 1. In the present study, the enzyme was overexpressed in Escherichia coli BL21 (DE3) using the pET21b(+) vector system. The recombinant enzyme was purified to homogeneity by heat treatment and a $Ni^{2+}$-affinity chromatography. Polyacrylamide gel electrophoresis (PAGE) showed that the recombinant Tfi $\beta$-glycosidase was a monomeric form with molecular mass of 49 kDa. The temperature and pH range for optimal activity of the purified enzyme were 80- $90^{\circ}C$ and 5.0-6.0, respectively. Ninety-three percent of the enzyme activity was remained at $70^{\circ}C$ after 12 h, and its half-life at $80^{\circ}C$ was 6 h, indicating that Tfi $\beta$-glycosidase is highly thermostable. Based on its K_m$, or $K_{cat}K_m$, ratio, Tfi $\beta$-glycosidase appeared to have higher affinity for $\beta$-D-glucoside than for $\beta$-D-galactoside, however, $K_{cat} for \beta$-D-galactoside was much higher than that for $\beta$-D-glucoside. The activity for lactose hydrolysis was proportionally increased at $70^{\circ}C$ and pH 7.0 without substrate inhibition until reaching 250 mM lactose concentration. The specific activity of Tfi TEX>$\beta$-glycosidase on 138 mM lactose at $70{^\circ}C$ and pH 7.0 was 134.9 U/mg. Consequently, this newly cloned enzyme appears to have a valuable advantage of conducting biotechnological processes at elevated temperature during milk pasteurization in the production of low-lactose milk.

• 생물환경조절학회지
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• 제18권1호
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• pp.51-59
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• 2009

양파의 재배 지역 확대 및 재포 기간을 단축하고자 동절기 플러그 육묘를 통한 춘파재배를 위한 품종별 생육 특성과 수량, 저장성을 검토하였다. 중부지방의 평지에서 양파를 춘파재배한 결과 품종별로 육묘시의 생육차이가 수확시의 생육이나 수량에는 큰 영향을 미치지 못하였다. 수량은 도복시기가 관련 있어 구비대가 6월 말 정도로 다소 늦게 이루어지는 경우가 충분한 구비대로 수량이 증가하는 경향을 보였다. 품종에 따른 도복시기는 '천주대고(Cheonjudaego)' 등의 품종들은 6월 말이 지나도 도복이 이루어지지 않아 중부지방 평지에서 춘파 양파 재배 시 도복시기에 따른 품종선택에 대한 고려가 필요하다. 구중은 '센슈추쿠키(Senshuchukooki)', '아톰(Atom)', '하이볼EX(Hiball EX)'등이 컸으나 '와세소닉(Wase sonic)' 같은 품종과는 차이가 컸다. 그러나 수량은 구중 이외에 상품성에 의해서 수량이 결정되어, 비교적 구중이 무겁고 상품성이 좋았던 '아톰(Atom)', '에이스(Ace)', '럭키(Lucky)', 'OP' 등이 경우가 전체적인 상품수량에서 좋은 경향을 나타내었다. 춘파재배한 양파를 3개월간 처장한 경우 상품률이 '에이스(Ace)'의 93%에서 '와세 소닉(Wase sonic)'의 13%까지 품종에 따른 차이가 컸는데, 도복시기가 빠른 품종들이 저장성이 낮게 나타나는 경향을 보였다. 이러한 결과로 볼 때, 양파 평지 춘파재배를 할 경우 도복이 빠른 품종을 피해서 재배하는 것이 유리하나 계절적인 특성을 고려하여 도복이 너무 늦게 되는 품종도 피해야 할 것으로 생각된다. 일반적으로 생산되는 대부분의 양파는 바로 창고에 입고하여 저장되어 이용되나, 평지의 춘파 양과는 재배목적을 뚜렷이 하여 수확과 동시에 이용하는 것이 바람직할 것으로 생각한다.

• 한국토양비료학회지
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• 제39권1호
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• pp.15-20
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• 2006

최근 들어서 생물학적 제어 방법의 하나로써 키틴분해 미생물을 이용한 제어 수단이 식물병제어에 일정한 효과가 있는 것으로 보고되고 있다. Fusarium 시들음병을 억제하기 위하여 40kg의 키틴퇴비를 면적이 $7.5m^2$ 인 토양에 정식 7일전 처리하였으며 토마토가 시들음병 증세를 보이기 시작하는 날(정식 후 66일)로부터 시작하여 4번에 걸쳐 시료를 채취하였다. 키틴퇴비 처리구(CTC)의 근권토양의 키틴효소와 ${\beta}$-1,3-glucan 효소 활성은 일반퇴비 처리구 (CC) 토양 보다 항상 높은 값을 나타냈다. 그러나 식물체 뿌리에서 측정된 chitinase, ${\beta}$-1,3-glucanase, peroxidase과 같은 병 관련 효소들은 CNC에서 실험기간동안 증가 추이를 보였다. 실험의 마지막 단계인 정식 후 96일째에는 CTC의 토마토는 CC 와 비교 할 때 25% 낮은 치사율을 나타냈다.

• 생명과학회지
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• 제29권2호
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• pp.256-264
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• 2019

Lymphotoxin ${\beta}$ receptor ($LT{\beta}R$)는 TNF 계열로 림프조직의 미세구조와 기관형성에 중요한 역할을 한다. MLCK와 ROCK는 세포의 stress fiber 형성조절에 관여하는 주요 신호전달자이다. Fibroblastic reticular cell (FRC)에서 $LT{\beta}R$ 자극을 통한 이런 신호전달자들의 관련성을 알아보기 위해 ML-7 (MLCK 저해제)이 사용되었다. ML7 처리된 FRC에서 SF가 완전히 파괴되었고 anti-$LT{\beta}R$ antibody 처리 세포와 유사하게 ML7 처리 FRC에서 응축된 세포형태를 관찰 할 수 있었다. Y27632로 ROCK를 저해 했을 때 FRC의 액틴 세포골격과 세포형태 변화가 유도 되었다. FRC에서 p-MLC가 액틴과 함께 SF 구성성분을 이루었다. FRC세포 추출물로 Rho-guanosine diphosphate (GDP)/guanosine triphosphate (GTP) 교환활성을 확인했다. Agonistic anti-$LT{\beta}R$ antibody로 $LT{\beta}R$을 자극 했을 때 Rho-GDP/GTP 교환활성이 크게 감소했다. MLCK 저해처럼 $LT{\beta}R$ 자극은 MLC의 인산화를 감소시켰다. Agonistic anti-$LT{\beta}R$ antibody-treated FRC에서 세포골격 구성요소인 세포막과 세포골격 링커 역할을 하는 p-ezrin의 인산화는 감소 되었고 b- actin, 그리고 tubulin 발현도 줄었다. 이런 결과는 FRC의 $LT{\beta}R$ 신호전달을 통한 SF 조절에는 MLCK와 ROCK가 관여하고 있다는 것을 알 수 있었다.

• 대한본초학회지
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• 제33권5호
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• pp.105-110
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• 2018

Objectives : We tried to observe the fluorescence anisotropy and intensity of ethidium ion in the intercalating binding interaction between DNA and ethidium ions in the presence of berberine, and then tried to explain the effect of berberine on the intercalating interaction of ethidium ion with DNA. Methods : DNA(calf thymus DNA), berberine and ethidium bromide(EtBr) were purchased from Sigma-Aldrich Co. Proper amount of each compound was dissolved in 20 mM sodium phosphate buffer(pH 7.0) containing 100 mM of NaCl to prepare stock solutions. Collections of the fluorescence anisotropy and intensity data were performed on JASCO FP-8300 spectrofluorometer equipped with a polarizer and a Peltier temperature controller. The excitation of ethidium ion was done at 550 nm and the emission data were collected at 600 nm. For Stern-Volmer plot, the fluorescence data were collected at $18^{\circ}C$ and $30^{\circ}C$. Results : According to the results of this research, the weak competitive binding pattern between ethidium ion and berberine appeared in binding with DNA at low ratio of DNA to ethidium ion. But at high ratio of DNA to ethidium ion, this weak competition disappeared. Instead, berberine might bind to DNA by intercalating way. In other words, berberine could de-intercalate ethidium ion from DNA at low concentration of DNA relative to ethidium ion, but could not at high concentration of DNA relative to ethidium ion. In addition, the mechanism of fluorescence quenching of ethidium ion could also proceed differently, depending on the ratio of the amount of DNA to that of ethidium ion. Conclusions : The effect of berberine on the DNA-ethidium ion intercalating interaction could work differently, depending on the relative ratio of the amount of DNA to that of ethidium ion. This study also showed that fluorescence anisotropy analysis is very useful method to obtain detailed information for investigation of the complex binding interactions. In order to fully understand the mechanism of action of the pharmacological effect by berberine, studies on the effect of berberine on the action of proteins such as various enzymes closely related to berberine-induced medicinal effects should be continued.