• Bulletin of the Korean Mathematical Society
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• v.27 no.2
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• pp.189-196
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• 1990

In this paper, we try to generalize ultraproducts in the category of locally convex spaces. To do so, we introduce D-ultracolimits. It is known [7] that the topology on a non-trivial ultraproduct in the category T $V^{ec}$ of topological vector spaces and continuous linear maps is trivial. To generalize the category Ba $n_{1}$ of Banach spaces and linear contractions, we introduce the category L $C_{1}$ of vector spaces endowed with families of semi-norms closed underfinite joints and linear contractions (see Definition 1.1) and its subcategory, L $C_{2}$ determined by Hausdorff objects of L $C_{1}$. It is shown that L $C_{1}$ contains the category LC of locally convex spaces and continuous linear maps as a coreflective subcategory and that L $C_{2}$ contains the category Nor $m_{1}$ of normed linear spaces and linear contractions as a coreflective subcategory. Thus L $C_{1}$ is a suitable category for the study of locally convex spaces. In L $C_{2}$, we introduce $l_{\infty}$(I. $E_{i}$ ) for a family ( $E_{i}$ )$_{i.mem.I}$ of objects in L $C_{2}$ and then for an ultrafilter u on I. we have a closed subspace $N_{u}$ . Using this, we construct ultraproducts in L $C_{2}$. Using the relationship between Nor $m_{1}$ and L $C_{2}$ and that between Nor $m_{1}$ and Ba $n_{1}$, we show thatour ultraproducts in Nor $m_{1}$ and Ba $n_{1}$ are exactly those in the literatures. For the terminology, we refer to [6] for the category theory and to [8] for ultraproducts in Ba $n_{1}$..

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.376.1-376.1
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• 2014

그래핀은 차세대 2차원 물질로서 지금까지 활발히 연구되어 왔으나 밴드갭이 없기 때문에 전자소자로서의 응용이 매우 제한적이다. 최근에 그래핀을 대체할 수 있는 물질로서 Transition Metal Dichalcogenides (TMDs)가 주목을 받고 있다. 특히, TMDs 중에서 $MoS_2$는 bulk일 때 indirect한 1.2 eV인 밴드 갭을 갖고 있으나, layer가 줄어들면서 direct한 1.8 eV인 밴드갭을 가진다. 국내외 여러 연구 그룹에서 $MoS_2$를 이용하여 제작한 Field Effect Transistor (FET)는 high-$\small{K}$ gate가 산입되지 않은 경우에 on-off ratio와 mobility가 각각 $10^6$와 약 $3cm^2/Vs$로 나타나고 있다. 이와 같이 아주 우수한 전기적, 광학적 특성을 갖는 소자 응용성을 가지고 있다. 최근까지의 연구결과들은 대부분 mechanical exfoliation method (MEM) 로 제작된 $MoS_2$ monolayer를 이용하였으나, 이 방법은 large scale 및 layer controllable에는 적합하지 않다. 본 연구에서는 대면적의 집적회로 응용에 적합한 chemical vapor deposition법을 이용하여 $MoS_2$를 성장하였다. 높은 결정성을 위해 sulphur (powder purity 99.99%)와 molybdenum trioxide(powder purity 99.9%)를 이용하고, Ar 가스 분위기에서 sulphur powder 및 molybdenum trioxide powder를 각각 $130^{\circ}C$ 및 $1000^{\circ}C$로 유지하며 $MoS_2$ 박막을 성장하였다. 성장된 $MoS_2$ 박막은 Atomic force Microscopy (AFM)을 통해 박막의 단차와 roughness을 확인하였다. 또한, X-ray Diffraction (XRD) pattern 분석으로 박막의 결정성을 확인하였으며, Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Photoluminescence (PL) 측정으로 광학적 특성을 분석하였다.

• Journal of the Korean Society for information Management
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• v.25 no.3
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• pp.27-39
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• 2008

In bibliographic data, the use of personal names to indicate authors makes it difficult to specify a particular author since there are numerous authors whose personal names are the same. Resolving same-name author instances into different individuals is called author resolution, which consists of two steps: calculating author similarities and then clustering same-name author instances into different person groups. Author similarities are computed from similarities of author-related bibliographic features such as coauthors, titles of papers, publication information, using supervised or unsupervised methods. Supervised approaches employ machine learning techniques to automatically learn the author similarity function from author-resolved training samples. So far however, a few machine learning methods have been investigated for author resolution. This paper provides a comparative evaluation of a variety of recent high-performing machine learning techniques on author disambiguation, and compares several methods of processing author disambiguation features such as coauthors and titles of papers.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.231-232
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• 1998

The purpose of this study was to examine whether the precipitation of calcium phosphate on titanium surface was affected by surface modification. To improve the bone conductivity, of titanium, samples were devided into 4 groups. Group 1 was immersed in 5M-NaOH solution at $60^{\circ}C$ for 24 hours. Group 2 was immersed in 5M-NaOH solution at $60^{\circ}C $ for 24 hours and heat-treated at $600^{\circ}C$ for 1 hour. Group 3 was anodized in Hanks' solution at 1V, $25^{\circ}C$ for 1 hour. Group 4 was anodized in Hanks' solution at 5V, $80^{\circ}C$ for 5 minutes. And then, all specimens were immersed in the MEM Eagle's medium whose composition was similar to that of extracellular fluid for 30 days. The precipitation of the calcium phosphate on implant surface was increased by the immersion in the NaOH solution, and more highly accelerated by heat treatment at $600^{\circ}C$. The precipitation of the calcium phosphate on titanium implant was increased with the treatment of the anodic oxidation in Hanks' solution at 5V, $80^{\circ}C$.

• Journal of Life Science
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• v.18 no.6
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• pp.897-901
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• 2008

Deep seawater (DSW; deep ocean water) is pure, rich in inorganic materials which have attracted attention for various applications. In this study we investigated the effects of the DSW upwelled from the East Sea, offshore Yang Yang (Korea) on the morphological differentiation of cultured rat hippocampal neurons, which were grown in the minimal essential medium containing 10% (v/v) fetal bovine serum and 25% (v/v) DSW with various hardness. DSW had no effect on initial morphological differentiation (17 hr post-plating). When observed on DIV3, 7, 14, and 17, low hardness (0 and 200) DSW reduced dendritic branching. However, dendritic branches within $80\;{\mu}m$ diameter from the center of soma nearly doubled in neurons grown in hardness 1,000 DSW-containing media. DSW with hardness 600 was more or less same as control groups. These results indicate that DSW with appropriate hardness ameliorates neuronal health.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.216-225
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• 2002

Hyaluronic acid (HA) is an almost essential component of extracellular matrices. Early in embryogenesis mesenchymal cells migrate, proliferate and differentiate, in part, because of the influence of HA. Since the features of embryogenesis are revisited during wound repair, including bone fracture repair, this study was initiated to evaluate whether HA has an effect on calcification and bone formation in an in vitro system of osteogenesis. Mouse calvaria Pre-osteoblast (MC3T3-E1) cells were cultured in ${\alpha}-MEM$ medium with microorganism-derivative hyaluronic acid that was produced by Strep. zooepidemicus which of molecular weight was 3 million units. The dosages were categorized in each 0.5, 1.0 and 2.0 mg/ml concentration experimental groups. After 2 and 4 days cultures in expeirmental and control groups, the tendency of cell proliferation, MTT assay, protein synthesis ability, collagen synthesis and alkaline phosphatase activity were analysed and bone nodule formation capacity were measured with Alizarin Red S stain after 29 days cultures. The cell proliferation was increased in time, especially the group of 0.5 and 1.0 mg/ml concentration of HA were showed prominent cell proliferation. After 2 and 4 days culture, experimental groups in general were greater cell activity in MTT assay. The protein synthesis was increased in all experimental groups compared to control group, especially most prominent in 1.0 mg/ml concentration group. The collagen synthesis capacity were increased in HA experimental groups, especially prominent in 1.0 mg/ml group and the activity of alkaline phosphatase were increased, especially also prominent in 1.0 mg/ml group, compared to control group. Above these, the activity of mouse carvarial pre-osteoblast cells was showed greater bone osteogenesis activity in all applied HA experimental group, especially group of 1.0 mg/ml concentration of HA.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.823-832
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• 2001

Periodontal therapy has dealt primarily with attempts at arresting progression of disease, however, more recent techniques have focused on regenerating the periodontal ligament having the capacity to regenerate the periodontium. The effect of chitosan(poly-N-acetyl glucosaminoglycan), a carbohydrate biopolymer extracted from chitin, on periodontal ligament regeneration is of particular interest. The purpose of this study was to evaluate the effect of chitosan on the human periodontal ligament fibroblasts(hPDLFs) in vitro, with special focus on their proliferative properties by M'IT assay, the synthesis of type I collagen by reverse transcription-polymerase chain reaction(RT-PCR) and the activity of alkaline phosphatase(ALP). Fibroblast populations were obtained from individuals with a healthy periodontium and cultured with ${\alpha}MEM$ as the control group. The experimental groups were cultured with chitosan in concentration of 0.01,0.1, 1,2mg/ml. The results are as follows; 1. Chitosan-induced proliferative responses of hPDLFs reached a plateau at the concentration of O.lmg/ml(p<0.05). 2. When hPDLFs were stimulated with 0.lmg/ml chitosan, mRNA expression of type I collagen was up-regulated. 3. When hPDLFs were stimulated with 0.lmg/ml chitosan, ALP activity was significantly up-regulated(p<0.05). In summary, chitosan(0.lmg/ml) enhanced the type I collagen synthesis in the early stage, and afterwards, facilitated differentiation into osteogenic cells. The results of this in vitro experiment suggest that chitosan potentiates the differentiation of osteoprogenitor cells and may facilitate the formation of bone.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.324-329
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• 2009

Cell-cell adhesion managed by various adhesion molecules is known to be one of pathophysiological phenomena found in numerous immunological diseases such as rheumatoid arthritis and allergic diseases. In this study, we examined the regulatory role of ginsenosides (G)- Rh1, reported to display anti-inflammatory and anti-allergic effects, on CD29-mediated cell adhesion. G-Rh1 significantly suppressed U937 cell-cell adhesion mediated by CD29 but not CD43. It also blocked U937 cell-fibronectin adhesion, mediated by activated CD29, up to 30%. In agreement, this compound also significantly decreased the surface level of CD29 but not CD43 as well as other costimulatory molecules such as CD69, CD80, and CD86. Therefore, these results suggest that G-Rh1 may have inhibitory function on CD29-mediated cell adhesion events, probably contributing to its anti-inflammatory and anti-allergic activities.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.2
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• pp.92-106
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• 2006

Purpose : To address the ability of Olibanum to induce cell death, we investigated the effect of olibanum on cell apoptosis. Twenty-four hours later, apoptosis occurred following olibanum exposure in a dose-dependent manner. Methods : We culture HeLa cell which is human metrocarcinoma cell in D-MEM included 10% fetal bovine serum(Hyclone Laboratories) below $37^{\circ}C$, 5% CO2. Then we observed apoptosis of log phage cell which is changed cultivation liquid 24 Hours periodically. Results : The treatment of BAPTA-AM regulated olibanum-induced apoptosis in HeLa human cervical carcinoma cells. The 24 hr-earlier -thapsigargin-pretreated cell showed the resistance against olibanum-induced apoptosis and the Ru360-mitochondrial uniporter-inhibited olibanum-induced apoptosis, too. It means that olibanum leads to the accumulation of calcium and the resultant apoptosis in HeLa cells. Immunoblotting data also shows that the expression of GRP78, ER stress marker protein, was induced by the olibanum. Bcl-2, anti-apototic protein, was decreased and that the expression of Bax, pro-apoptotic protein, was increased by the addition of olibanum. Interestingly, the olibanum increased the activity of caspase-8 as well as calpain cysteine pretense in HeLa cervical carcinoma cells. Calpain inhibitor-calpastatin as well as caspase-8C/A expression abrogated olibanum-induced apoptosis in the carcinoma cells. The inhibition of caspase-8 regulated olibanum-induced calpain activation but the inhibition of calpain did not have any effect on the caspase-8 activation in HeLa human cervical carcinoma cells. Conclusion : We conclude that olibanum induces the accumulation of calcium and the resultant apoptosis in which caspase-8 and calpain are involved.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.2
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• pp.77-91
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• 2006

Purpose : To address the ability of Dohaekseungkitang (DST: a commonly used herb formulation in Korea, Japan and China to have anti-cancer effect on cervical carcinoma), we investigated the effects of DST on programmed cell death (apoptosis) in HeLa human cervical carcinoma cells. Methods : We cultured HeLa cell which is human metrocarcinoma cell in D-MEM included 10% fetal bovine serum(Hyclone Laboratories) below $37^{\circ}C$, 5% CO2. Then we observed apoptosis of log phage cell which is changed cultivation liquid 24 Hours periodically. Results : After the treatment of DST for 48 hours, apoptosis occurred in a dose-dependent manner. In this study, we have shown that DST induces calpain and the associated caspase-8 and -9 activations. Apoptosis was prevented by pre-incubation of the cells with the calcium cHeLator-BAPTA-AM, calcium channel blocker-Nif edipine or Ryonidine agonist-Ryonidine peptide, implicating calcium in the apoptotic process. Ubiquitous calpains (mu- and m-calpain) have been repeatedly implicated in apoptosis, especially in calcium-related apoptosis. However this study showed 1hat either calpain inhibitor-calpastin or caspase-3 inhibitor-DEVD- did not blocked the herb formulation-induced apoptosis in HeLa human cervical carcinoma cells. D ST initiates a cell death pathway that is partially dependent of caspases. DST-induced apoptosis requires caspase-independent mechanism. Conclusion : We conclude that DST-induced calpain activation triggers the intrinsic apoptotic pathway in which caspase-independent mechanism is also involved.