• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1621-1623
• /
• 1996

The dielectric and polarizable properties of 0.85Pb$Mg_{1/3}Nb_{2/3}$)$O_3$-$0.125PbTiO_3$-$0.25BaTiO_3$ Ceramics have been investigated as a addition of the amount of $La_{2}O_{3}$($0{\leq}x{\geq}0.05$). The Temperature-dependant electrostictive characteristics of 0.85PMN-0.125PT-0.25BT relaxor ferroelectic system were improved by enhencing the extent of the diffuse phase transition(DPT). This was achieved using PMN-PT-BTceramics by the partial substitution of La at the Pb site. The curie temperature and the maximum dielectic permittivity decreased by substituting $La_{2}O_{3}$ and the electic field-related hysteresis phenomena decreased with increasing $La_{2}O_{3}$ substitution amount. It is showed decreasing in induced strain for electric field with increasing $La_{2}O_{3}$ substitution.

• Genomics & Informatics
• /
• 제12권4호
• /
• pp.247-253
• /
• 2014

Osteosarcoma is the most common primary bone tumor, generally affecting young people. While the etiology of osteosarcoma has been largely unknown, recent studies have suggested that cyclooxygenase-2 (COX-2) plays a critical role in the proliferation, migration, and invasion of osteosarcoma cells. To understand the mechanism of action of COX-2 in the pathogenesis of osteosarcoma, we compared gene expression patterns between three stable COX-2-overexpressing cell lines and three control cell lines derived from U2OS human osteosarcoma cells. The data showed that 56 genes were upregulated, whereas 20 genes were downregulated, in COX-2-overexpressed cell lines, with an average fold-change > 1.5. Among the upregulated genes, COL1A1, COL5A2, FBN1, HOXD10, RUNX2, and TRAPPC2 are involved in bone and skeletal system development, while DDR2, RAC2, RUNX2, and TSPAN31 are involved in the positive regulation of cell proliferation. Among the downregulated genes, HIST1H1D, HIST1H2AI, HIST1H3H, and HIST1H4C are involved in nucleosome assembly and DNA packaging. These results may provide useful information to elucidate the molecular mechanism of the COX-2-mediated malignant phenotype in osteosarcoma.

• 대한한의학회지
• /
• 제19권1호
• /
• pp.234-250
• /
• 1998

Bujeonghangamtang(扶正抗癌湯) has been used for cure of tumor as a traditional medicine without any experimental evidence to support the rational basis for its clinical use. This study was carroed out to evaluate the possible therapeutic or antitumoral effects of Bujeonghangamtang extract against tumor, and to carry out some mechanisms responsible for its effect. Some kinds of tumor were induced by .the typical application of 3-methylcholanthrene (MCA) or by the implantation(s.c) of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(Sl80 cells). Treatment of the Bujeonghangamtang water-extract (dailly 1mg/mouse, i. p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 20 days. Against squamous cell carcinoma induced by MCA, Bujeonghangamtang decreased not only the frequency of tumor production but also the number and the weight of tumors per tumor bearing mice (TBM). Bujeongmngamtang also significantly suppressed the development of 3LL cell and S180 cell-implanted tumors in occurence-frequency and their size, and some developed tumors were regressed by the continuous treatment of Bujeonghangamtang extract into TBM. In vitro, treatment of Bujeonghangamtang extract had no effect on the growth of some kinds of cell line such as FsaII, A431 strain but significantly inhibited the proliferation of 3LL, S180 cells and augmented the DNA synthesis of mitogen-activated lymphocytes. Bujeonghangamtang also stimulated the migrative ability of leukocyte, the MIF and IL-2 production of T lymphocytes, but not IL 6 production of B cells. Bujeonghangamtang-administration to mice enhanced NK cells attivities. These results demonstrated that Bujeonghangamtang extract exhibited a significant prophylactic benefits against tumors and its antitumor activity was manifested depending on the type of tumor cells. And these results also suggested that effect of Bujeonghangamtang might be chiefly due to nonspecific enhancement of NK cell activities and cell-mediated immune responses.

• Restorative Dentistry and Endodontics
• /
• 제39권4호
• /
• pp.296-302
• /
• 2014

Objectives: It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of $CO_2$ and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods: In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness) were assigned to 3 groups (n = 15). In control group (CNT) no laser treatment was used. In groups COL and EYL, $CO_2$ and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results: The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were $8.65{\pm}1.75$, $12.12{\pm}3.02$, and $5.97{\pm}1.14MPa$, respectively. Data showed that application of $CO_2$ and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001). The highest bond strength was recorded in the COL group (p < 0.0001). In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions: Pretreatment of zirconia ceramic via $CO_2$ and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the $CO_2$ laser treated samples.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 C
• /
• pp.1496-1498
• /
• 2003

The $(Sr_{0.85}Ca_{0.15})TiO_3$(SCT) thin films were deposited on Pt-coated electrode (Pt/TiN/$SiO_2$/Si) using RF sputtering method according to the deposition condition. The optimum conditions of RF power and Ar/$O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about 18.75[${\AA}/min$] at the optimum condition. The capacitance characteristics had a stable value within ${\pm}4[%]$. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films were observed above 200[kHz].

• 한국잠사곤충학회지
• /
• 제50권1호
• /
• pp.15-19
• /
• 2012

최근 다양한 생체재료를 이용하여 연골재생과 관련한 많은 연구가 진행되고 있다. 실크단백질은 생체적합성이 뛰어나며, 우수한 기계적 강도를 가지고 있는 천연 고분자 물질로서 최근 생체재료로 사용하기위한 연구가 세계적으로 많이 이루어지고 있다. 본 연구는 실크단백질이 연골재생에 효과가 있는지를 확인하기위하여 수행되었다. 우리는 연골세포를 코뼈로부터 분리하고, 3종류의 배지 (DMEM, DMEM/F12, RPMI)와 서로 다른 농도의 ascorbic acid를 사용하여 최적 배양조건을 확립하였다. 그 결과 우리가 분리한 연골세포는 10% FBS와 $100{\mu}M$ ascorbic acid가 함유된 DMEM배지에서 가장 잘 생장하였다. 연골에 대한 실크의 영향을 관찰하기위해서, 실크 피브로인 용액을 제작하고 이를 멸균한것과 멸균하지 않은 것으로 구분하여 연골세포 배양 시 첨가하여 연골분화에 대한 마커인자인 제2형 콜라겐의 발현량을 측정하였다. 멸균하지 않은 실크 피브로인 첨가시 제2형 콜라겐의 발현량이 2.7배 증가하였으나, 멸균된 실크 피브로인의 첨가는 제2형 콜라겐의 발현량을 오히려 감소시켰다. 또한 실크 피브로인은 제10형 콜라겐의 발현을 증가시키는 것을 확인하였다. 이 효과는 특히 연골세포를 3차원 배양할 때 더 컸다. 본 연구결과를 통하여 우리는 연골을 재생하는데 있어서 실크 단백질을 가능성을 보았으며, 향후 연구에서 연골재생과 실크의 관계를 좀 더 정밀하게 파악하고자 한다.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제8권1호
• /
• pp.25-32
• /
• 2001

Let A be a nonnegative matrix of size $n \times n$. A is said to be nearly convertible if A(i│j) is convertible for all integers i, j$\in${1,2,…, n} where A(i│j) denote the submatrix obtained from A by deleting the i-th row and the j-th col-umn. We investigate some properties of nearly convertible matrices and existence of (maximal)nearly convertible matrices of size n is proved for any integers $n(\geq 3)$.

• 대한유전성대사질환학회지
• /
• 제15권1호
• /
• pp.49-54
• /
• 2015

다발성 골단이형성증은 비교적 흔한 골이형성증으로 소아기에 관절통과 관절 강직, 뒤뚱거리면 걸어가는 보행 및 일부에서 경한 저신장을 특징으로 하며 영상의학적 검사에서는 여러 관절에서 골단의 불규칙한 소견과 골화 지연을 보인다. 본 증례 환자는 임상적, 영상의학적으로 다발성 골단이형성증을 진단 할 수 있었으며 환자의 넓적다리 관절 영상 검사는 MATN3 유전자 변이를, 무릎 관절 영상 검사는 COMP 유전자 변이를 시사하였기에 MATN3과 COMP 유전자 변이에 대해 시퀀싱(sequencing)을 하였으나, 변이는 발견되지 않았다. 이후 엑솜시퀀싱(exomesequencing)을 시행하였으나, 기존에 다발성 골단이형성증과 관련이 있는 것으로 알려진 유전자에 대한 변이가 발견되지 않았다. 본 증례와 같이 임상적, 영상의학적으로 다발성 골단이형성증으로 진단가능 하였으나 분자유전학적으로 기존에 알려진 변이 유전자가 발견되지 않은 환자들을 위해 추가적인 연구가 필요할 것으로 보인다.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.312.2-312.2
• /
• 2002

The metal-ligand complex, ［Ru(phen)$_2$(dppz)]^{2＋}$ (phen = 1.10-phenanthroline, dppz = dipyrido［3.2-a:2', 3'-c］phenazine) (RuPD), was used as a spectroscopic probe for studying nucleic acid dynamics. The RuPD complex displays a long lifetime and a molecular light switch property upon DNA binding due to shielding of its dppz ligand from water. (omitted)

• Biomolecules & Therapeutics
• /
• 제15권2호
• /
• pp.95-101
• /
• 2007

Resveratrol (3,5,4’-trihydroxy-trans-stilbene), a naturally occurring phytoallexin abundant in grapes and several plants, has been shown to be active in inhibiting proliferation and inducing apoptosis in several human cancer cell lines. On the line of the biological activity of resveratrol, a variety of resveratrol analogs were synthesized and evaluated for their growth inhibitory effects against several human cancer cell lines. In the present study, we found that one of the resveratrol analogs, 3,4,5-trimethoxy-4’-bromo-cis-stilbene, markedly suppressed human colon cancer cell proliferation (EC$_{50}$ = 0.01 ${\mu}$g/ml), and the inhibitory activity was superior to its corresponding trans-isomer (EC$_{50}$ = 1.6 ${\mu}$g/ml) and resveratrol (EC$_{50}$ = 18.7 ${\mu}$g/ml). Prompted by the strong growth inhibitory activity in cultured human colon cancer cells (Col2), we investigated its mechanism of action. 3,4,5-Trimethoxy-4’-bromo-cis-stilbene induced arrest of cell cycle progression at G2/M phase and increased at sub-G1 phase DNA contents of the cell cycle in a time- and dose-dependent manner. Colony formation was also inhibited in a dose-dependent manner, indicating the inhibitory activity of the compound on cell proliferation. Moreover, the morphological changes and condensation of the cellular DNA by the treatment of the compound were well correlated with the induction of apoptosis. These data suggest the potential of 3,4,5-trimethoxy-4’-bromo-cis-stilbene might serve as a cancer chemotherapeutic or chemopreventive agent by virtue of arresting the cell cycle and inducing apoptosis for the human colon cancer cells.