• Journal of Ginseng Research
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• 제30권4호
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• pp.188-193
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• 2006

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet B (UVB) irradiation and observed the effect of red ginseng (RG) on the formation, and decrease of UVB-induced epidermal mel-anocytes. C57BL/6 mice were irradiated by UVB $80mJ/cm^2$ (0.5 mW/sec) daily for 7 days, and RG was intraperitoneally or topically applied pre- or post-irradiation. For the estimation of change of epidermal melanocytes, light microscopic observation with dihydroxyphenylalanine (DOPA) stain was performed. Split epidermal sheets prepared from the ear of untreated mice exhibited 11-16 $melanocytes/mm^2$, and one week after UV irradiation, the applied areas show an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal or topical treatment with RG before each irradiation interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to radiation control skin. The number and size of DOPA-positive epidermal mel-anocytes were also significantly decreased in intraperitoneally injected or topically applicated group after irradiation with RG at 3rd and 6th weeks after irradiation. The present study suggests the RG as inhibitor of UVB-induced pigmentation and depigmenting agent.

• 한국화재소방학회논문지
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• 제27권4호
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• pp.41-46
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• 2013

본 연구는 가구류를 구성하는 주요 재료의 열적조건에 따른 반응특성과 화염전파해석에 필요한 열해리 물성을 제공하기 위해 열중량분석을 수행하였다. 실험대상 시편은 가구류에 널리 적용되는 MDF 판재와 코팅재, 합성피혁과 쿠션재 등이며 가열율 $10^{\circ}C/min$, 최대 온도 $600^{\circ}C$까지 실험을 수행하였다. 실험결과 MDF 소재의 경우 $324^{\circ}C$에서 피크 반응을 나타냈었으며 MDF 코팅재의 경우 초기 피크반응온도가 $270{\sim}280^{\circ}C$로 감소하였다. 합성피혁과 폼 소재의 경우 재료를 구성하는 폴리머의 종류에 따라 기준온도와 기준 반응율이 차이를 보였으나 기준온도는 $270^{\circ}C$와 $420^{\circ}C$ 정도로 비교적 유사한 경향을 나타냈다. Lyon 등이 제시한 방법에 의해 반응상수와 활성화 에너지를 산정하기 위해 시편의 기준 온도와 기준 반응율을 제시하였으며 이러한 기초 물성연구를 통해 화염전파특성을 이해함과 동시에 화재해석의 신뢰성을 향상시키는데 기여하고자 한다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제10권2호
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• pp.125-139
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• 2007

본 연구는 교구활용을 강화한 수업이 학업 성취와 수학적 성향 및 태도에 어떠한 영향을 미치는지 살펴봄으로써 교구활용을 활성화할 수 있는 방안을 모색하는 데 있다. 본 연구에서 실험반과 비교반에 적용한 변수는 교구활용 빈도를 제외하고 기타 수업 환경은 동일에게 적용하였다. 연구 결과 학업 성취도를 t-검정한 결과 사전검사 점수는 두 집단 사이에 유의한 차이가 없는 것으로 나타났으나, 사후검사에서는 실험반이 비교반보다 10점 정도(t=0.519, p<0.01) 평균적으로 높은 것으로 나타났다. 또 실험 집단 내에서 교구활용이 학습 수준별 학업 성취에 미치는 효과는 사전점수를 공변인으로 하는 공변량분산분석(ANCOVA)을 실시한 결과 5% 유의수준에서 수준별 차이를 보였으며 (F=4.885, p<0.05), 중 상위 수준의 학생보다 하위 수준의 학생들에게 더 긍정적인 효과를 미치는 것으로 나타났다.

• Restorative Dentistry and Endodontics
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• 제42권2호
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• pp.105-110
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• 2017

Objectives: This study investigated the cleaning ability of ultrasonically activated irrigation (UAI) and a novel activation system with reciprocating motion (EC, EasyClean, Easy Equipamentos $Odontol\acute{o}gicos$) when used with a relatively new chelating agent (QMix, Dentsply). In addition, the effect of QMix solution when used for a shorter (1 minute) and a longer application time (3 minutes) was investigated. Materials and Methods: Fifty permanent human teeth were prepared with K3 rotary system and 6% sodium hypochlorite. Samples were randomly assigned to five groups (n = 10) according to the final irrigation protocol: G1, negative control (distilled water); G2, positive control (QMix 1 minute); G3, QMix 1 minute/UAI; G4, QMix 1 minute/EC; G5, QMix 3 minutes. Subsequently the teeth were prepared and three photomicrographs were obtained in each root third of root walls, by scanning electron microscopy. Two blinded and pre-calibrated examiners evaluated the images using a four-category scoring system. Data were statistically analyzed using Kruskal-Wallis and Dunn tests (p < 0.05). Results: There were differences among groups (p < 0.05). UAI showed better cleaning ability than EC (p < 0.05). There were improvements when QMix was used with auxiliary devices in comparison with conventional irrigation (p < 0.05). Conventional irrigation for 3 minutes presented significantly better results than its use for 1 minute (p < 0.05). Conclusions: QMix should be used for 1 minute when it is used with UAI, since this final irrigation protocol showed the best performance and also allowed clinical optimization of this procedure.

• 융합신호처리학회논문지
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• 제4권3호
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• pp.49-54
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• 2003

본 논문에서는 PID 제어기 응답을 보상하기위해 자기구성 신경망 보상기를 추가한 제어기를 제안한다. 기존의 PID 제어기는 제어기 설계가 간단하나 계수값을 설정하는데 많은 시행착오가 필요하다. 그리고, 신경망 제어 방식은 여러 파라미터들을 설계자의 임의에 따라 결정함으로써 최적의 구조를 갖지 못하는 단점이 있다. 본 논문에서는 이러한 문제를 해결하기위해 역전파 알고리즘을 기본으로 하여 은닉계층 노드의 활성화 함수로 가우시안 포텐셜함수를 사용하는 자기구성 신경망을 사용해, PID 제어기의 출력을 보상하도록 하였다. 자기구성 신경망은 학습을 진행함에 따라 가우시안 함수의 위치와 모양, 갯수가 자동으로 조정 되도록 하였다. 자기구성 신경망 보상기를 추가한 PID 제어기의 성능을 확인하기 위해서 2차 플랜트에 적용하여 모의 실험하였으며 DSP 프로세서를 사용하여 제어기를 구현한 후 유압 서보시스템의 속도 제어에 적용하여 실험결과를 관찰하였다.

• 대한물리의학회지
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• 제9권2호
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• pp.233-242
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• 2014

PURPOSE: The purpose of this study was to determine the correlation between the hip adductor muscles and abdominal muscles during bridge exercise. METHOD: Participants who met the criteria for this study(n=36) were divided into the three groups. The first experimental group performed normal bridge exercises and the second group performed bridge exercises with the contraction of the hip adductor muscles and the control group didn't perform any exercise. Transversus abdominis muscle thickness was measured by ultrasound imaging with a special transducer head device, at pre exercise, after 2 weeks, 4 weeks, and 6 weeks. RESULT: Data were analyzed using repeated ANOVA with the level of significance set at ${\alpha}=.05$. Transversus abdominis muscle thickness was influenced by contraction of the hip adductor muscles during bridge exercise in people without lower back pain. Compared with normal bridge exercise, transversus abdominis muscle thickness significantly increased in thickness during bridge exercise with contraction of the hip adductor muscles(p<.05). CONCLUSION: The results from this study showed that contraction of the hip adductor muscles during bridge exercise increased change in the transversus abdominis muscle thickness. These results can be a good source to prevent low back pain due to hip adductor weakness. Therefore, inducing activation of hip adductor with abdominal stabilizing exercise is more effective in patients with low back pain.

• 대한금속재료학회지
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• 제50권1호
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• pp.52-58
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• 2012

Hydrogen-delayed fracture (HDF) was analyzed from the deposited weld metals of 600-MPa and 800-MPa flux-cored arc (FCA) welding wires, and then from the diffusible hydrogen behavior of the weld zone. Two types of deposited weld metal, that is, rutile weld metal and alkali weld metal, were used for each strength level. Constant loading test (CLT) and thermal desorption spectrometry (TDS) analysis were conducted on the hydrogen pre-charged specimens electrochemically for 72 h. The effects of microstructures such as acicular ferrite, grain-boundary ferrite, and low-temperature-transformation phase on the time-to-failure and amount of diffusible hydrogen were analyzed. The fracture time for hydrogen-purged specimens in the constant loading tests decreased as the grain size of acicular ferrite decreased. The major trapping site for diffusible hydrogen was the grain boundary, as determined by calculating the activation energies for hydrogen detrapping. As the strength was increased and alkali weld metal was used, the resistance to HDF decreased.

• 대한한방내과학회지
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• 제40권3호
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• pp.425-442
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• 2019

Objectives: This study aimed to reveal the pharmacological properties of the newly prescribed herbal mixture, Chenmadansamgamibokhap-tang(CDBT), against hypoxia-induced neuronal cell injury (especially mouse hippocampal neuronal cell line, HT-22 cells) and their corresponding mechanisms. Methods: A cell-based in vitro experiment, in which a hypoxia condition induced neuronal cell death, was performed. Various concentrations of the CDBT were pre-treated to the HT-22 cells for 4 h before 18 h in the hypoxia chamber. The glial cell BV-2 cells were stimulated with $IFN{\gamma}$ and LSP to produce inflammatory cytokines and reactive oxygen species. When the neuronal HT-22 cells were treated with this culture solution, the drug efficacy against neuronal cell death was examined. Results: CDBT showed cytotoxicity in the normal condition of HT-22 cells at a dose of $125{\mu}g/mL$ and showed a protective effect against hypoxia-induced neuronal cell death at a dose of $31.3{\mu}g/mL$. CDBT prevented hypoxia-induced neuronal cell death in a dose-dependent manner in the HT-22 cells by regulating $HIF1{\alpha}$ and cell death signaling. CDBT prevented neuronal cell death signals and DNA fragmentation due to the hypoxia condition. CDBT significantly reduced cellular oxidation, cell death signals, and caspase-3 activities due to microglial cell activations. Moreover, CDBT significantly ameliorated LPS-induced BV-2 cell activation and evoked cellular oxidation through the recovery of redox homeostasis. Conclusions: CDBT cam be considered as a vital therapeutic agent against neuronal cell deaths. Further studies are required to reveal the other functions of CDBT in vivo or in the clinical field.

• 대한한의학방제학회지
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• 제27권1호
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• pp.45-52
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• 2019

Objectives : Hyperthermia is a widely used therapeutic tool for cancer therapy and a well-known inducer of apoptosis. Although the Cinnamomi cortex (CC) is a potent anticancer agent for several human carcinomas, it is less potent in the human U937 cell line. To explore any enhancing effects of CC with hyperthermia induced apoptosis, this study investigated the combined effects and apoptotic mechanisms of hyperthermia and CC in U937 cells. Methods : U937 cells were heat treated at $43^{\circ}C$ for 30 min with or without pre-treatment for 1h with CC and then incubated at $37^{\circ}C$ with 5% $CO_2$. Cell viability was analyzed by MTT assay and Trypan blue assay. Morphological changes reflecting apoptosis were visualized under microscope. Synergy effect of CC combined with hyperthermia were calculated by Compusyn software. The expression of proteins related to apoptosis and signaling pathways was determined by western blotting. Results : Hyperthermia with CC reduced cell viability and induced apoptosis. Combined hyperthermia and CC treatment markedly augmented apoptosis by upregulating proapoptotic proteins and suppressing antiapoptotic proteins, culminating in caspase-3 activation. Furthermore, the combined treatment, decreased the expression of in Bcl-2 family, cyclin D1, VEGF, MMP2 and MMP9 expression. Conclusion : This study provides compelling evidence that hyperthermia, in combination with CC, is a promising therapeutic strategy for enhancement of apoptosis and suggests a promising therapeutic approach for cancer.

• 실천공학교육논문지
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• 제9권1호
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• pp.31-39
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• 2017

단기 현장실습 위주의 양적 성장과 대학 간 과다 경쟁으로 현장실습의 내실화가 요구되며 학생의 실무능력 향상과 현장실습을 통한 채용연계성을 높이기 위한 방안으로 장기현장실습 모형의 필요성이 높아지고 정부와 대학의 참여도 증가하는 추세이다. 금오공대와 3개 참여대학은 2015년부터 중소 중견기업의 R&D 인력 부족현상과 취업을 앞둔 대학생들의 고민을 해결하기 위한 방안으로 중소 중견기업 R&D 관련부서에서 6개월동안 장기현장실습을 통해 R&D 실무능력을 향상하고 취업역량을 강화하기 위해 R&D 장기현장실습 프로그램인 산업인턴을 실시하고 있다. 본 논문에서는 2015년과 2016년 산업인턴 운영사례에 대한 비교 분석을 통해 사전준비 단계부터 종료시점까지 장기현장실습을 통한 효과적인 연계취업 활성화 방안을 제안하였으며 취업률 비교와 만족도 조사 비교를 통해 그 결과를 확인하였다.