• 대한치과보철학회지
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• 제60권2호
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• pp.195-201
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• 2022

편평세포암으로 하악골 절제술과 비골 피판 이식을 받은 경우 하악의 기능적 움직임이 저해될 수 있다. 하악골이 절제된 측은 근육부착의 소실로 인해 근기능이 약화되어 중심교합 및 편심교합에서 불안정한 교합접촉을 초래한다. 본 증례는 하악골절제술과 비골이식 재건술을 받은 63세 남성에서 전치부의 상실된 치아를 수복하기 위해 고정성 보철물이 필요했던 경우이다. 중심 및 편심교합에서 교합력의 크기에 따라 교합접촉 양상의 변화가 관찰되었다. Functionally generated path 기법과 디지털 영상기술을 적용하여 환자의 하악운동과 조화되고 적절한 수직고경이 있는 기능적으로 최적화된 고정성 보철물을 제작할 수 있었기에 보고하고자 한다.

• 대한화학회지
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• 제56권6호
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• pp.731-738
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• 2012

이 연구의 목적은 과학고등학교 학생들을 대상으로 설문지 조사와 면담을 통해 화학 전지에 대한 개념 이해를 분자적 수준의 미시적 관점에서 화학 평형과 연계하여 분석하는 것이다. 과학고등학교 학생들은 전극을 전해질에 담그자마자 전극의 금속이 산화되는 반응과 금속 이온이 환원되는 반응이 동시에 일어난다는 것과 화학 전지의 화학 평형 상태를 고르는 것에 대한 이해는 높았다. 그러나 전극과 전해질 사이에서 일어나는 상호작용을 미시적 관점으로 이해하는 데는 어려움을 겪고 있어, 화학 전지에서의 전위차 발생, 전자의 흐름, 반쪽 전지의 전위 측정, 산화전극과 환원전극 사이의 전지 전위값 계산하기 등에서는 어려움을 겪었다.

• 한국작물학회지
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• 제43권2호
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• pp.77-82
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• 1998

Aerenchyma development in rice (Oryza sativa L.) roots is quite important for adaptation to waterlogged or reduced soil conditions. Anatomical observations were carried out to clarify the development of schizogenous and lysigenous aerenchyma in elongating crown roots of rice. The crown roots of 3rd and 4th phytomer were taken from rice plants of the 8th leaf stage grown by hydroponic culture. The schizogenous intercellular spaces in the cortex of crown root tip were observed using a light microscope with semi ultra-thin sections and the lysigenous aerenchyma in mature tissue of crown root were observed using a cryo scanning electron microscope (cryo-SEM) with freezing fracture method. The schizogenous intercellular spaces in the root tip exist obviously in the middle portion of cortical cell layers close to the root-root cap junction, but not in root cap, stele and outer cell layers of cortex. The air spaces were formed at the junction of four neighbouring cells of inner cortex in the transverse sections, and between longitudinal cell layer connected along the root axis. Although many of those spaces were filled with liquid, some spaces seem to exist as air spaces. The lysigenous aerenchyma in the cortex, which hardly filled with liquid, emerged at 3-4 cm segment from the root tip and increased toward the basal region of root axis. The developing process of lysigenous aerenchyma was primarily separation of a radial row of cells caused by the shrinking and collapsing of cortical cells and then formation of septa along the radial cell rows by the fusion of cell wall with each other. These results suggest that the schizogenous and lysigenous aerenchyma playa role as a passage for the movement of oxygen into the root tip region where oxygen is required for respiration.

• 전기학회논문지
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• 제59권12호
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• pp.2218-2224
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• 2010

Dye-sensitized solar cell (DSC) is a promising alternative solar cell to the conventional silicon solar cell due to several advantages. Development of large scale module is necessary to commercialize the DSC in the near future. A scribing technology of the transparent conductive oxide (TCO) is one of the important technologies on the fabrication of DSC module. A quality of the scribed line on the TCO has a decisive effect on the efficiency of DSC module. Among several scribing technologies, the fiber laser is a suitable for scribing the TCO more precisely and accurately because of their own characteristics. In this study, we try to improve the quality of the TCO scribed line by using the fiber laser. Consequently, the operating parameter of fiber laser is optimized to get the TCO scribed line with good quality. And the fiber laser scribing technology of the TCO is applied to the fabrication of the DSC with optimal operating parameter, operating current 3900mA. As a result, the current density and fill factor are improved and the total efficiency is increased because the internal resistances of DSC such as TCO sheet resistance and the resistance concerned to the electron movement in the $TiO_2$ are reduced. This is analyzed by the electrochemistry impedance spectroscopy (EIS) and the equivalent circuit model of the DSC.

• International Journal of Oral Biology
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• 제34권2호
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• pp.53-59
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• 2009

Periodontal ligament (PDL) tissue is a connective tissue that is interposed between the roots of the teeth and the inner wall of the alveolar bone socket. PDL is always exposed to physiologic mechanical force such as masticatory force and PDL cells play important roles during orthodontic tooth movement by synthesizing and secreting different mediators involved in bone remodeling. The Wnt/${\beta}$-catenin signaling pathway was recently shown to play a significant role in the control of bone formation. In the present study, we applied cyclic tensile stress of 20% elongation to cultured human PDL cells and assessed its impact after six days upon components of the Wnt/${\beta}$-catenin signaling pathway. RTPCR analysis showed that Wnt1a, Wnt3a, Wnt10b and the Wnt receptor LRP5 were down-regulated, whereas the Wnt inhibitor DKK1 was up-regulated in response to these stress conditions. In contrast, little change was detected in the mRNA expression of Wnt5a, Wnt7b, Fz1, and LRP6. By western blotting we found decreased expression of the ${\beta}$-catenin and p-GSK-3${\beta}$ proteins. Our results thus show that mechanical stress suppresses the canonical Wnt/${\beta}$-catenin signaling pathway in PDL cells.

• 한국통신학회논문지
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• 제35권6C호
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• pp.530-538
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• 2010

본 논문에서는 선형 등간격 어레이를 갖는 이동 릴레이를 위한 셀 탐색 및 입사각 추정 기법을 제안한다. 제안된 기법은 이동 릴레이에 수신되는 각 기지국 신호간에 심볼 타이밍 옵셋이 존재하는 경우에 심볼 타이밍 옵셋의 영향을 제거하여 셀 탐색 및 입사각 추정 성능을 향상시킨다. 또한 제안된 기법은 이동 릴레이가 이동함에 따라 발생하는 도플러 주파수 천이가 존재하는 경우에 입사각 추정 성능을 크게 향상시킬 수 있다. Mobile WiMAX 환경 하에서 제안된 기법의 셀 탐색 및 입사각 추정 성능과 복잡도를 모의실험을 통해 검증한다.

• 약학회지
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• 제60권2호
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• pp.92-99
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• 2016

Parkinson's disease (PD) is one of the representative neurodegenerative movement disorders with the selective loss of dopaminergic neurons in the substantia nigra. 6-Hydroxydopamine (6-OHDA) is widely used as an experimental model system to mimic PD and has been reported to cause neuronal cell death via oxidative and/or nitrosative stress. Therefore, daily intake of dietary or medicinal plants which fortifies cellular antioxidant capacity can exert neuroprotective effects in PD. In the present study, we have investigated the protective effect of Korean red ginseng (KRG) against 6-OHDA-induced nitrosative death in C6 glioma cells. Treatment of C6 cells with 6-OHDA decreased cell viability and increased expression of inducible nitric oxide synthase, production of nitric oxide as well as peroxynitrite, and formation of nitrotyrosine. 6-OHDA led to apoptotic cell death as determined by decreased Bcl-2/Bax, phosphorylation of JNK, activation of caspase-3, and cleavage of PARP. Conversely, pretreatment of C6 cells with KRG attenuated 6-ODHA-induced cytotoxicity, apoptosis, and nitrosative damages. To further elucidate the molecular mechanism of KRG protection against 6-OHDA-induced nitrosative cell death, we have focused on the cellular self-defense molecules against exogenous noxious stimuli. KRG treatment up-regulated heme oxygenase-1 (HO-1), a key antioxidant enzyme essential for cellular defense against oxidative and/or nitrosative stress via activation of Nrf2. Taken together, these findings suggest KRG may have preventive and/or therapeutic potentials for the management of PD.

• 약학회지
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• 제39권2호
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• pp.161-168
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• 1995

Brain dopamine systems play a central role in the control of movement, hormone release, and many complex behavior. The action of dopamine at its synapse is terminated predominately by high affinity reuptake into presynaptic terminals by dopamine transporter (DAT). The dopamine transporter(DAT) is membrane protein localized to dopamine-containing nerve terminals and closely related with cocaine abuse, Parkinsonism, and schizophrenia. In present study, the recombinant plasmid pRc/CMV-DAT, constructed by subcloning of a cDNA encoding a bovine DAT into eukaryotic expression vector pRc/CMV, was stably transfected into CV-1 cells(monkey kidney cell line). The DAT activities in the cell lines selected by Geneticin$^{R}$ were determined by measuring the uptake of $[^3H]$-dopamine. The transfected cell lines showed 30-50 fold higher activities than untransfected CV-1 cell line, and this result implies that DAT is well expressed and localized in transfected cells. The transfected cells accumulated $[^3H]$-dopamine in a dose-dependent manner with a $K_{m}$ of 991.6nM. Even though high doses of norepinephrine, epinephrine, serotonin, and choline neurotransmitters inhibited the uptake of $[^3H]$-dopamine, DAT in transfected cell line was proven to be much more specific to dopamine. The psychotropic drugs such as GBR12909, CFT, normifensine, clomipramine, desipramine, and imipramine inhibited significantly the dopamine uptake in tissue culture cells stably transfected with DAT cDNA. Radioactive in situ hybridization was done to map the cellular localization of DAT mRNA-containing cells in the adult rat central nervous system. The strong hybridization signals were detected only in the substantia nigra pars compacta and ventral tegmental area. The restricted anatomical localization of DAT mRNA-containing cells confirms the DAT as a presynaptic marker of dopamine-containing cells in the rat brain.

• 대한치과교정학회지
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• 제14권1호
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• pp.65-81
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• 1984

In order to observe the responses of the periodontal tissue on the tension side following the experimental tooth movement, 35 Guinea pigs were divided into the control group (5 animals) and 6 experimental groups (3 movement groups and 3 retention groups) consisting of each 5 animals. The experimental tooth movement of Guinea pig's upper incisors installing open helical loop were carried out by rendering continuous force : 5g (1st groups) 35g (2nd groups), 100g (3rd groups), respectively for 7 days. 3 movement groups (15 animals) were sacrificed soon after the continuous force, and 3 retention groups (15 animals) were sacrificed after the retention period of another 7 days. The following results were obtained from the observation of the surrounding tissues of teeth on the tension side through light microscopy any transmission electron microscopy. 1. The vessel walls in the experimental groups were thinner than those of the control group, the number of blood vessel had the tendency to increase. The greater the strong force applied to each group, the more the destruction of cells and fibers was found and the more the number of the red blood cell of vessel outside appeared. 2. New collagen fibers were produced from fibroblasts in the 1st groups (light force), but were produced rather less in the 2nd groups (medium force) and the 3rd groups (heavy force). 3. In the forming patterns of the new alveolar bone of the 3rd groups (heavy force), the bone trabeculae were formed towards the direction of the force to be applied, but the new alveolar bone in the 1st groups (light force) was produced evenly throughout the all surfaces of the alveolar bone rather than the patterns of bone trabeculae ; therefore, the patterns of new alveolar bone were observed differently according to the magnitude of the force applied. 4. In the retention group, it was observed that the collagen fibers were produced from the osteoblasts in the marginal areas of the periodontal ligaments being widely opened and were deposited on the alveolar bone surface but the production of collagen fibers from the osteoblasts in the other area of the periodontal ligaments was almost ceased, and a rest line on the new alveolar bone surface was found.

• 환경생물
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• 제34권2호
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• pp.124-131
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• 2016

Euglena agilis의 운동성 반응을 자동으로 측정하는 장치인 E. agilis 시스템 (E-Tox)을 이용하여 8종의 중금속 (Ag, Cd, Cr(VI), Cu, Hg, Ni, Pb, Zn)에 대한 독성시험을 실시하였다. E. agilis 운동성 시험 (biomonitoring test)으로부터 도출된 $EC_{50}$과 문헌상의 자료 조사로 얻은 기존 생태독성 시험 생물 종들(D. magna, V. fischeri, 그리고 E. gracilis)의 $EC_{50}$을 비교하여 시험물질에 대한 E. agilis의 독성 민감도를 평가하였다. 또한 축산폐수 방류수, 도금폐수 방류수, 도금폐수 1차 처리 시료에 대해 D. magna 급성 독성시험과 E. agilis 운동성 반응 시험을 수행 후 TU를 비교하여 E. agilis 운동성 시험의 현장 적용 가능성을 평가하였다. E. agilis는 시험 중금속에 대해 D. magna보다 독성민감도가 전반적으로 낮았으나 V. fischeri 또는 E. gracilis와 유사하거나 좀 더 민감하였다. E. agilis는 D. magna test로 유독성으로 판명된 도금폐수 1차 처리수에 대해 신속한 독성반응을 나타내었다. E-Tox 시스템은 기존의 생태독성시험장비에 비해 빠르고 작동이 간편한 자동화 기기라는 장점이 있다. 본 연구의 결과 E-Tox 시스템을 이용한 E. agilis 운동성 시험은 향후 독성폐수에 대한 조기경보를 위한 생태독성시험법으로 적용될 수 있을 것으로 판단된다.