• Biomolecules & Therapeutics
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• 제29권2호
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• pp.211-219
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• 2021

Alopecia is a distressing condition caused by the dysregulation of anagen, catagen, and telogen in the hair cycle. Dermal papilla cells (DPCs) regulate the hair cycle and play important roles in hair growth and regeneration. Myristoleic acid (MA) increases Wnt reporter activity in DPCs. However, the action mechanisms of MA on the stimulation of anagen signaling in DPCs is not known. In this study, we evaluated the effects of MA on anagen-activating signaling pathways in DPCs. MA significantly increased DPC proliferation and stimulated the G2/M phase, accompanied by increasing cyclin A, Cdc2, and cyclin B1. To elucidate the mechanism by which MA promotes DPC proliferation, we evaluated the effect of MA on autophagy and intracellular pathways. MA induced autophagosome formation by decreasing the levels of the phospho-mammalian target of rapamycin (phospho-mTOR) and increasing autophagy-related 7 (Atg7) and microtubule-associated protein 1A/1B-light chain 3II (LC3II). MA also increased the phosphorylation levels of Wnt/β-catenin proteins, such as GSK3β (Ser9) and β-catenin (Ser552 and Ser675). Treatment with XAV939, an inhibitor of the Wnt/β-catenin pathway, attenuated the MA-induced increase in β-catenin nuclear translocation. Moreover, XAV939 reduced MA-induced effects on cell cycle progression, autophagy, and DPC proliferation. On the other hand, MA increased the levels of phospho (Thr202/Tyr204)-extracellular signal regulated kinases (ERK). MA-induced ERK phosphorylation led to changes in the expression levels of Cdc2, Atg7 and LC3II, as well as DPC proliferation. Our results suggest that MA promotes anagen signaling via autophagy and cell cycle progression by activating the Wnt/β-catenin and ERK pathways in DPCs.

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1392-1396
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• 2004

The micellization of dodecylpyridinum chloride (DPC) assembled on aqueous gold nanoparticles has been studied as a function of concentration using Surface-Enhanced Raman Scattering (SERS). At the low concentration, the strong SERS band of the benzene ring moiety was observed at 1025 $cm^{-1}$, and assigned to “trigonal ring breathing”. According to high concentration of DPC, a new strong band was also appeared at 1012 $cm^{-1}$, which was assigned to “totally symmetry ring breathing”. The difference of two spectra seems to ascribe to the geometry of polar head group, i.e., pyridinium cation. These geometry exist flat-down at low concentration, whereas standing-up or tilted geometry at high concentration. The critical micelle concentration (CMC) was first obtained from the ratio of intensities of the two bands related to the benzene ring moiety by vibrational spectroscopy, and was about 28 mM. After the CMC, the benzene ring moiety in the micelle state was more restricted than in monomer state because there is no more change of intensities at 1012 $cm^{-1}$. In addition, the size of gold-assembled micelle was estimated using light scattering and it was about 328.3 nm.

• 한국정보통신학회논문지
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• 제21권1호
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• pp.215-222
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• 2017

소형 수중무인체에 탑재 운용되는 능동 합성개구면소나는 외부 수중환경의 영향으로 진행경로에 여러 가지 궤적 교란이 발생한다. 이는 해저 물체에서 반사된 신호의 합성 개구면처리에 있어서 위상 부정합이 발생되어 탐지성능의 저하를 가져 온다. 본 논문에서는 수중무인체가 정속도 직선기동시 현측방향으로 주기적 궤적교란이 발생될 때 DPC를 이용한 능동 SAS 자동초점처리로 훼손된 이미지를 보상하고 탐지성능에 미치는 영향을 비교 분석하였다. 시뮬레이션을 통해 플랫폼의 주기적 교란 크기 및 변동 주기에 의한 훼손된 이미지는 인접된 송신 핑신호의 겹쳐진 위상중심점 위상차 적용으로 궤적교란 보상처리가 가능하고 3dB 기준 방위해상도 및 탐지 이미지의 성능개선 특성을 확인하였다.

• 대한전자공학회논문지TC
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• 제49권2호
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• pp.32-38
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• 2012

이3GPP LTE Release 10에서 다중 사용자 환경의 다중 송수신 안테나 시스템을 위한 더티 페이퍼 코딩(Dirty Paper Coding, DPC)을 k user 사용자 채널에서 어떻게 해석하는지를 보였다. 다중 사용자 환경에서 더티 페이퍼 코딩은 송신단에서 모든 사용자와 채널에 대한 정보를 완벽하게 안다고 전제한 후, 미리 예상할 수 있는 모든 간섭을 제거하여 각 사용자에게 정보를 전송한다는 개념이다. 즉, 인접 채널이나 사용자로부터의 간섭을 제거하기 위한 추가적인 전력이 필요하지 않으므로, 더티 페이퍼 코딩을 통하여 가산성 백색 가우시안 잡음 (AWGN) 채널과 동일한 채널 용량을 달성할 수 있다. 본 논문에서는, 세 명의 다중 사용자가 존재하는 통신 환경에서, 대표적인 비선형 전처리 코딩 기법인 Dirty Paper 전처리 코딩이 직교 하삼각 행렬 분해와 Gram Schmidt 직교 정규화 기저를 이용하여 어떻게 채널을 분석하는지를 보였다.

• 한국자기공명학회논문지
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• 제19권2호
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• pp.54-60
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• 2015

Papiliocin, from the swallowtail butterfly, Papilio xuthus, shows high bacterial cell selectivity against Gram-negative bacteria. Recently, we designed a 22mer analog with N-terminal helix from $Lys^3$ to $Ala^{22}$, PapN. It shows outstanding antimicrobial activity against Gram-negative bacteria with low toxicity against mammalian cells. In this study, we determined the 3-D structure of PapN in 300 mM DPC micelle using NMR spectroscopy and investigated the interactions between PapN and DPC micelles. The results showed that PapN has an amphipathic ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$. STD-NMR and DOSY experiment showed that this helix is important in binding to the bacterial cell membrane. Furthermore, we tested antibacterial activities of PapN in the presence of salt for therapeutic application. PapN was calcium- and magnesium-resistant in a physiological condition, especially against Gram-negative bacteria, implying that it can be a potent candidate as peptide antibiotics.

• Journal of Periodontal and Implant Science
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• 제43권6호
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• pp.315-322
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• 2013

Purpose: In this study, we investigated the effect of silk scaffolds on one-wall periodontal intrabony defects. We conjugated nano-hydroxyapatite (nHA) onto a silk scaffold and then seeded periodontal ligament cells (PDLCs) or dental pulp cells (DPCs) onto the scaffold. Methods: Five dogs were used in this study. Bilateral 4 mm${\times}$2 mm (depth${\times}$mesiodistal width), one-wall intrabony periodontal defects were surgically created on the distal side of the mandibular second premolar and the mesial side of the mandibular fourth premolar. In each dog, four of the defects were separately and randomly assigned to the following groups: the PDLCcultured scaffold transplantation group (PDLC group), the DPC-cultured scaffold transplantation group (DPC group), the normal saline-soaked scaffold transplantation group, and the control group. The animals were euthanized following an 8-week healing interval for clinical, scanning electron microscopy (SEM), and histologic evaluations. Results: There was no sign of inflammation or other clinical signs of postoperative complications. The examination of cellseeded constructs by SEM provided visual confirmation of the favorable characteristics of nHA-coated silk scaffolds for tissue engineering. The scaffolds exhibited a firm connective porous structure in cross section, and after PDLCs and DPCs were seeded onto the scaffolds and cultured for 3 weeks, the attachment of well-spread cells and the formation of extracellular matrix (ECM) were observed. The histologic analysis revealed that a well-maintained grafted volume was present at all experimental sites for 8 weeks. Small amounts of inflammatory cells were seen within the scaffolds. The PDLC and DPC groups did not have remarkably different histologic appearances. Conclusions: These observations indicate that nHA-coated silk scaffolds can be considered to be potentially useful biomaterials for periodontal regeneration.

• IEIE Transactions on Smart Processing and Computing
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• 제6권3호
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• pp.183-192
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• 2017

k-nearest neighbor (K-NN) is a well-known classification algorithm, being feature space-based on nearest-neighbor training examples in machine learning. However, K-NN, as we know, is a lazy learning method. Therefore, if a K-NN-based system very much depends on a huge amount of history data to achieve an accurate prediction result for a particular task, it gradually faces a processing-time performance-degradation problem. We have noticed that many researchers usually contemplate only classification accuracy. But estimation speed also plays an essential role in real-time prediction systems. To compensate for this weakness, this paper proposes correlation coefficient-based clustering (CCC) aimed at upgrading the performance of K-NN by leveraging processing-time speed and plurality rule-based density (PRD) to improve estimation accuracy. For experiments, we used real datasets (on breast cancer, breast tissue, heart, and the iris) from the University of California, Irvine (UCI) machine learning repository. Moreover, real traffic data collected from Ojana Junction, Route 58, Okinawa, Japan, was also utilized to lay bare the efficiency of this method. By using these datasets, we proved better processing-time performance with the new approach by comparing it with classical K-NN. Besides, via experiments on real-world datasets, we compared the prediction accuracy of our approach with density peaks clustering based on K-NN and principal component analysis (DPC-KNN-PCA).

• 한국지반환경공학회 논문집
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• 제24권11호
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• pp.11-17
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• 2023

최근 건설 3D 프린팅 분야의 연구는 주로 장비와 재료에 집중되고 있다. 건설 분야에서 3D 프린팅 기술은 무인시공 등 경제적인 이점으로 인해 빠르게 성장하고 있지만 건축물의 안전을 확보하기 위한 3D 프린팅 건축물의 화재 성능에 대한 연구는 상대적으로 부족한 상황이다. 본 연구는 간이 내화시험에 의한 3D프린팅 벽체의 내화 성능을 평가하고 화재에 노출된 3D 프린팅 벽체의 차열성 및 차염성에 대하여 검토하였다. 이 연구 결과는 건설 산업에서 3D 프린팅 기술의 안전성과 신뢰성을 향상하는데 기여할 수 있을 뿐만 아니라, 건축 구조물의 화재 안전 기준을 향상하고 미래 건설 프로젝트에서 3D 프린팅 기술의 활용을 확대할 수 있는 잠재력을 가지고 있다.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3437-3442
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• 2011

An on-line flow injection analysis with dual pre-concentration method was developed to determine the ultra trace tri and hexavalent chromium in water. In this system, the cation and anion pre-concentration columns were combined with a 10-port injection valve and then used to separate and concentrate Cr (III) and Cr (VI) selectively. The two species of concentrated chromium were sequentially eluted and determined by using HCl-KCl buffer of pH 1.8 as an eluent. Cr (III) was oxidized by hydrogen peroxide to Cr (VI). It was detected spectrophotometrically at 548 nm by complexation with DPC (diphenylcarbazide). Several factors such as concentration of $H_2O_2$, DPC and coil length in reaction condition were optimized. The linear range for Cr (III) and Cr (VI) was 0.1-50 ${\mu}g$/L. The limit of detections ($3{\sigma}$) of Cr (III) and Cr (VI) were 52 ng/L and 44 ng/L under the optimized FIA system, and their recoveries 98% and 103%, respectively. This method was applied to analyze contamination level of chromium species in tap water, groundwater and bottled water.

• 에너지공학
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• 제20권3호
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• pp.185-190
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• 2011

본 논문은 초전도 에너지 저장장치(SMES)용 전도냉각형 고온초전도 자석의 설계, 제작 및 평가에 대해 기술한다. 고온초전도 자석은 황동 안정화재를 갖는 2개의 Bi-2223 다심 선재가 적층된 4-ply 도체로 제작된 22개의 double pancake coil(DPC)로 구성된다. 그리고, 각 DPC는 내경과 외경이 각각 500 mm, 691 mm이고 높이가 10 mm인 2개의 single solenoid coil로 구성된다. 코일 내부의 전기적 손실에 의해 발생된 열의 냉각을 위하여 DPC 사이에 두께 3 mm의 알루미늄 판이 내재된다. 고온초전도 자석은 2단 Gifford McMahon 냉동기에 의해 5.6 K까지 냉각된다. 충전전류가 증가할수록 방전시 고온초전도에서의 최대 온도가 증가 하였다. 충전전류가 360 A일 때 ��치 없이 고온초전도 자석에 1 MJ의 자기에너지가 성공적으로 저장되었다. 본 연구에서는 SMES용 전도 냉각형 고온초전도자석에 대한 열적, 전자기적 특성을 보이고, 본 연구를 통해 얻어진 결과는 전도냉각형 고온초전도자석의 최적설계 및 안정도 평가에 활용될 것이다.