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        검색결과 13

        1.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오늘날 새로운 지도 제작 기술을 도입하여 저비용으로 개인 용도에 맞는 촉지도를 제작할 수 있는 지도 제작 방식에 대한 연구가 증가하고 있다. 이 연구에서는 지도와 점역에 대한 지식이 없는 일반인이 촉지도를 제작할 수 있는 촉지도 자동제작 시스템의 구현 방안을 제안한다. 촉지도 자동 제작 시스템은 연속수치지도 기반의 지리정보 데이터베이스를 활용하여 지도용 자료를 구축한다. 그리고 촉지도 자동 제작 시스템은 촉지도 디자인 기능을 웹 환경에서 제공하는데, 지도 요소 및 지도 기호 디자인 규칙은 국내의 점자지도 제작규정을 준수한다. 마지막으로, 촉지도 자동 제작 시스템은 빠르고 쉽게 촉지도를 인쇄할 수 있는 장비를 채택하여 지도 제작자가 소량의 개인용 촉지도를 제작할 수 있도록 지원한다. 온라인 지도 서비스 기반의 지도 제작 방식이 개인용 지도 제작의 확산에 기여한 것처럼, 촉지도 자동 제작 시스템은 개인용 촉지도 제작에 활용될 수 있을 것으로 기대할 수 있다.
        4,000원
        2.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyurethane (PU) nanofibers containing graphene oxide (GO) and Ag doped functionalized reduced graphene oxide (Ag-RGO) were successfully prepared via the electrospinning technique. The uniform distribution of GO sheets along with Ag nanoparticle in the nanofibers was investigated by scanning electron microscopy and the elemental mapping technique. X-ray diffraction and thermal gravimetric analysis verified the presence of GO and Ag in the bicomposite nanofibrous mats. Antibacterial tests against Escherichia coli demonstrated that the addition of GO and Ag-RGO to the PU nanofiber greatly enhanced bactericidal efficiency. Overall, these features of the synthesized nanofibers make them a promising candidate material in the biomedical field for applications such as tissue engineering, wound healing, and drug delivery systems.
        4,000원
        3.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report the use of carrot, a new and inexpensive biomaterial source, for preparing high quality carbon dots (CDs) instead of semi-conductive quantum dots for bioimaging application. The as-derived CDs possessing down and up-conversion photoluminescence features were obtained from carrot juice by commonly used hydrothermal treatment. The corresponding physiochemical and optical properties were investigated by electron microscopy, fluorescent spectrometry, and other spectroscopic methods. The surfaces of obtained CDs were highly covered with hydroxyl groups and nitrogen groups without further modification. The quantum yield of as-obtained CDs was as high as 5.16%. The cell viability of HaCaT cells against a purified CD aqueous solution was higher than 85% even at higher concentration (700 μg mL−1) after 24 h incubation. Finally, CD cultured cells exhibited distinguished blue, green, and red colors, respectively, during in vitro imaging when excited by three wavelength lasers under a confocal microscope. Offering excellent optical properties, biocompatibility, low cytotoxicity, and good cellular imaging capability, the carrot juice derived CDs are a promising candidate for biomedical applications.
        4,000원
        4.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Well-dispersed Ag3VO4 nanoparticles @polyacrylonitrile (PAN) nanofibers were synthesized by an easily controlled, template-free method as a photo-catalyst for the degradation of methylene blue. Their structural, optical, and photocatalytic properties have been studied by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy equipped with rapid energy dispersive analysis of X-ray, photoluminescence, and ultraviolet–visible spectroscopy. The characterization procedures revealed that the obtained material is PAN nanofibers decorated by Ag3VO4 nanoparticles. Photocatalytic degradation of methylene blue investigated in an aqueous solution under irradiation showed 99% degradation of the dye within 75 min. Finally, the antibacterial performance of Ag3VO4 nanoparticles @PAN composite nanofibers was experimentally verified by the destruction of Escherichia coli. These results suggest that the developed inexpensive and functional nanomaterials can serve as a non-precious catalyst for environmental applications.
        4,000원
        6.
        2015.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to study the impact of atmosphere during electron beam irradiation (EBI) of polyacrylonitrile (PAN) precursor fibers, the latter were stabilized by EBI in both air and oxygen atmospheres. Gel-fraction determination indicated that EBI-stabilization under an oxygen atmosphere leads to an enhanced cyclization in the PAN fibers. In the Fourier-transform infrared spectroscopy analysis, the PAN fibers stabilized by EBI under an oxygen atmosphere exhibited a greater decrease in the peak intensity at 2244 cm-1 (C≡N vibration) and a greater increase in the peak intensity at 1628 cm-1 (C=N absorption) than the corresponding PAN fibers stabilized under an air atmosphere. From the X-ray diffraction analysis it was found that oxygen uptake in PAN fibers leads to an increase in the amorphous region, produced by cyclization.
        3,000원
        7.
        2015.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The process of oxidizing polyacrylonitrile (PAN)-based carbon fibers converts them into an infusible and non-flammable state prior to carbonization. This represents one of the most important stages in determining the mechanical properties of the final carbon fibers, but the most commonly used methods, such as thermal treatment (200°C to 300°C), tend to waste a great deal of process time, money, and energy. There is therefore a need to develop more advanced oxidation methods for PAN precursor fibers. In this review, we assess the viability of electron beam, gamma-ray, ultra-violet, and plasma treatments with a view to advancing these areas of research and their industrial application.
        4,000원
        8.
        2015.09 서비스 종료(열람 제한)
        Harmonized actions of ovarian estrogen (E2) and progesterone (P4) regulate cell proliferation and differentiation in the uterus with a spatiotemporal manner. Imbalance between the actions and levels of two major regulators often lead to infertility and gynecological diseases, such as endometriosis and endometrial cancer. While numerous works have shown that reduced expression and/or deletion of uterine factors associated with P4 signaling could disturb uterine physiology, local factor(s) to mediate E2 actions has not been extensively studied yet. Here we demonstrate that early growth response 1 (Egr1), a transcription factor which is rapidly induced in the uterus by E2, is required to maintain coordinated actions of E2 and P4 for uterine receptivity for embryo implantation. Given exogenous gonadotrophins to overcome LHβ deficiency in the pituitary of Egr1(-/-) mice, ovulation, fertilization and embryo development normally occurred in these mice. However, they showed complete failure of embryo implantation with reduced uterine responses to artificial decidualization stimuli. While serum levels of E2 and P4 in Egr1(-/-) mice were comparable, genes regulated by E2 and/or P4 in uterine epithelial cells (ECs) were aberrantly expressed on day 4 of pregnancy. Impaired P4 signaling along with absence of PR in ECs caused hypersensitive E2 responses shown as enhanced expression of E2-responsive genes such Muc1 and Ltf as well as reduced levels of P4-dependent genes, such as Ihh and Areg, in ECs of Egr1(-/-) mice. This is consistent with persistent proliferation in ECs and severely impaired proliferation in stromal cells (SCs) in Egr1(-/-) mice treated with E2+P4. Furthermore, primary co-culture of Egr1(-/-) ECs with Egr1(+/+) SCs and vice versa supported a notion that Egr1 itself is required for proper responses to two major regulators, E2 and P4, in both uterine cell compartments. Collectively, our results show that E2-induced Egr1 participates in P4-dependent modulation on E2 activities in the uterus by regulating a spectrum of genes essential for uterine receptivity and embryo implantation.
        9.
        2015.09 서비스 종료(열람 제한)
        DGCR8 is a RNA-binding protein working with DROSHA to produce pre-microRNA in the nucleus, while DICER does not only mature microRNA but also endogenous siRNAs in the cytoplasm. Here, we have produced Dgcr8 conditional knock-out mice using progesterone receptor (PR)-Cre (Dgcr8flox/flox; PRcre/+ mice, Dgcr8d/d) and demonstrated that canonical microRNAs dependent of DROSHA-DGCR8 complex are required for uterine development as well as female fertility in mice. Adult Dgcr8d/d females did not undergo regular reproductive cycle and produce any pups when housed with fertile males, whereas administration of exogenous gonadotropins induced normal ovulation with corpus luteal formation in these mice. Ovulated oocytes from Dgcr8d/d mice had comparable fertilization potentials and were normally developed to the blastocyst after fertilization as compared to those in control Dgcr8f/f mice. Interestingly, PR-Cre-dependent Dgcr8 deletion showed aberrant infiltration of acute inflammatory immune cells to female reproductive organs only when Dgcr8d/d mice were mated with male mice. With respect to uterine development, gross morphology, histology, and weight of Dgcr8d/d uterus were similar to those of control at 3-week-old age. However, multiple uterine abnormalities were noticeable at 4-week-old age when PR expression is significantly increased, and these deformities became severe onwards. Gland formation and myometrial layers were significantly reduced, and stromal cell compartment did not expand and became atrophic during uterine development in these mice. These results were consistent with aberrantly reduced cell proliferation in stromal cell compartments of Dgcr8d/d mice. Collectively, our results suggest that DGCR8 dependent-canonical microRNAs are essential for development and physiology of the uterus with respect to morphogenesis, proper immune modulation, reproductive cycle, and steroid hormone responsiveness in mice.
        10.
        2010.09 서비스 종료(열람 제한)
        Some mutations in FOXL2 are responsible for premature ovarian failure accompanied with blepharophimosis-ptosis-epicanthusinversus syndrome (BPES) typeI disease, and FOXL2-null mice exhibit developmental defects of granulosa cells. Recently, a new somatic mutation in FOXL2,c.402C>G, leading top. C134W change, has been identified in a vast majority of adult-type ovarian garnulosa cell tumors (GCTs). In the current study, we investigated possible mechanisms by which the C134W mutation could contribute to GCT development. The wild-type (WT) FOXL2 and its mutant form displayed differential apoptotic activities, in which WT induced a significant granulosa cell death while the mutant exhibited a minimal cell death effect. The FOXL2-induced apoptotic response was greatly dependent on caspase8, BID, or BAK since the depletion of either of them prevented FOXL2 to elicitits full apoptotic responses. Stimulated activation of caspase8, consequently resulting increased production of truncated BID (tBID), up-regulation and oligomerization of BAK, and release of cytochromec were all associated with the apoptosis followed by WT FOXL2 expression. In contrast, the mutant FOXL2 was deficient to elicit the full apoptotic signaling responses. In addition, we found the differential up-regulations of expression of death receptors including Fas and TNF-R1 between the WT and the mutant. Moreover, granulosa cells expressing either the WT FOXL2 or its variant form (C134W) exhibited distinct cell death sensitivities by the activation of death receptors. Thus, these differential activities of FOXL2 and it mutant may partly account for the pathophysiology of GCT development occurred by the somatic mutation (C134W) of FOXL2.
        11.
        2010.09 서비스 종료(열람 제한)
        Although fenarimol is a widely used chlorinated fungicide applied to fruits and vegetables and considered as a suspected endocrine disrupter (ED), transgeneration studies of fenarimol at its low doses are not available. Objectives: The aims of this study are to address the effect of perinatal exposure to low doses of fenarimol on reproductive performance and to investigate molecular and cellular mechanisms which are associated with. Methods: The body and organ weights and anogenital distance (AGD) of mice offspring (F1) maternally exposed to fenarimol were determined, and their reproductive performances were assessed by mating and ovarian follicular and sperm analyses. In addition, differentially expressed genes (DEGs) in F1 ovaries were identified by DNA microarray. Up-regulated genes were confirmed by quantitative real-time PCR (qRT-PCR) and immunohistochemical analysis. Results: Fenarimol-exposed F1 mice showed the shortened AGD, increased body weight with altered organ weights, increased number of pub, abundant follicles, and enhanced sperm count and quality. Microarray data showed 82 up-regulated and 742 down-regulated genes on the ovaries of fenarimol-exposed mice, in which Cyp17a1 and Cyp19a1 were up-regulated. Conclusions: Low doses of perinatal fenarimol exposure caused reproductive dysfunction in mice and thus can possibly impose risks on reproductive activities of human and wild-life.
        12.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        본 논문은 인공적인 단백질인 MCL-1ES BH3M에 관한 것으로 MCL-1ES BH3M를 과발현시 세포사멸을 유도한다. MCL-1L을 주형으로 재조합 PCR을 통해서 MCL-1ES BH3M를 클로닝하였다. 새롭게 클로닝한 단백질인 MCL-1ES BH3M 단백질은 안정성을 유지하기 위해서 PEST 도메인이 제거되어 있으며, 다른 BCL-2 패밀리 단백질과의 결합을 조절하기 위해서 BH3도메인의 Leu-Arg-Arg-Val-Gly-Asp-Gly 서열을 7개의 Ala 잔기로 인위적으로 돌연변이를 유도하였다. MCL-1ES BH3M를 293T 세포에서 과발현할 경우 세포사멸을 유도하였고, 항-세포사멸 단백질인 MCL-1L을 같이 과발현하더라도 세포사멸을 유도하였다. 또한, 과발현시 Caspase 9과 3를 활성화하였으며 면역염색법을 통해서 MCL-1ES BH3M 과발현시 미토콘드리아에 MCL-1ES BH3M 단백질이 부분적으로 위치하는 것을 확인하였다. 이상의 결과로 MCL- 1ES BH3M는 Caspase 9과 3의 활성을 통해서 세포사멸을 유도한다. 결론적으로 본 연구는 세포사멸을 유도하는 새로운 molecule을 클로닝하였고, 이 molecule에 의한 세포사멸 기능을 확인하였다.
        13.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        BPES(Blepharophimosis/Ptosis/Epicanthus inversus Syndrome)는 FOXL2 유전자의 돌연변이에 의해 유발되는 상염색체 우성질환이다. 눈꺼풀이 갈라지거나 쳐지고 넓은 미간이 나타나는 특징이 있으며, 여성의 조기 난소 부전증(prema-ture ovarian failure, POF)을 일으켜 불임을 유발한다. FOXL2는 forkhead family에 속하는 전사인자로서 FOXL2가 결여된 난소에서는 granulosa cell의 분화가 진행되지 않아 난포 성숙과정의 멈춤과 난자의 폐쇄증을 유발한다. FOXL2를 bait로 하여 rat의 난소 cDNA 라이브러리의 yeast two-hybrid screening을 시행하여 FOXL2 단백질과 상호작용을 하는 small ubiquitin-related modifier(SUMO)-conjugating E2 효소인 UBE2I 단백질을 찾았다. UBC9이라고도 알려진 UBE2I 단백질은 SUMO 변형 과정을 위한 필수적인 단백질이다. Sumoylation은 수 많은 전사인자의 전사능력의 조절을 포함하여 다양한 신호전달체계에 관여하는 번역 후 변형과정이다. 본 연구에서 인간세포인 293T 내에서 면역침전반응 실험을 통해 FOXL2와 UBE2I의 단백질-단백질간의 상호작용을 확인하고, FOXL2의 돌연변이형을 제작하여 yeast two-hybrid system을 이용해 UBE2I와 결합에 필요한 FOXL2의 부분을 규명하였다. 따라서, FOX2에 상호작용하는 UBE2I의 규명은 sumoylation에 의한 FOXL2의 새로운 조절 메커니즘을 시사한다.