• The Korean Journal of Physiology and Pharmacology
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• 제24권1호
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• pp.69-79
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• 2020

Aging is one of the risk factors for the development of cardiovascular diseases. During the progression of cellular senescence, cells enter a state of irreversible growth arrest and display resistance to apoptosis. As a flavonoid, quercetin induces apoptosis in various cells. Accordingly, we investigated the relationship between quercetin-induced apoptosis and the inhibition of cellular senescence, and determined the mechanism of oxidative stress-induced vascular smooth muscle cell (VSMC) senescence. In cultured VSMCs, hydrogen peroxide (H₂O₂) dose-dependently induced senescence, which was associated with increased numbers of senescence-associated β-galactosidase-positive cells, decreased expression of SMP30, and activation of p53-p21 and p16 pathways. Along with senescence, expression of the anti-apoptotic protein Bcl-2 was observed to increase and the levels of proteins related to the apoptosis pathway were observed to decrease. Quercetin induced apoptosis through the activation of AMP-activated protein kinase. This action led to the alleviation of oxidative stress-induced VSMC senescence. Furthermore, the inhibition of AMPK activation with compound C and siRNA inhibited apoptosis and aggravated VSMC senescence by reversing p53-p21 and p16 pathways. These results suggest that senescent VSMCs are resistant to apoptosis and quercetin-induced apoptosis attenuated the oxidative stress-induced senescence through activation of AMPK. Therefore, induction of apoptosis by polyphenols such as quercetin may be worthy of attention for its anti-aging effects.

• 대한간호학회지
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• 제16권1호
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• pp.40-48
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• 1986

The purpose of this study was to identify the effect of the Stress Management Education Program (SMEP) on the nurses stress and stress management ability, and to identify the main factors affecting them. The subjects were 72 nurses who participated in the In-Service education program of the Jin-Ju District, Kyeong-Nam Branch of the Korean Nurses Association during the period from Oct. 1 to Nov. 30, 1985. The book of“The stress management education program”was developed by the investigators. With this book, we executed the 1st education through the lecture & showing an example, After 15 days from the 1st education, we mailed a reminding booklet to the individuals. (2nd education). Then, we mailed a questionnaire on 15th day from the 2nd education. Before and after the SMEP We measured the stress management ability & stress, and identified the affecting factors. Findings of this study are as follows ; 1. The 1st hypothesis that“the SMP will increase the. knowledge about the nurses' stress management”was supported (t= -6.60, p <.001) 2. The 2nd hypothesis that“the SMEP will increase the nurses' practice about the stress management”was rejected. 3. The 3rd hypothesis that“the SEMP will decrease the nurses' stress”was rejected. 4. The 4th hypothesis that“the higher the know-ledge about the stress management, the lower the nurses' stress”was rejected. 5. The 5th hypothesis that“the higher the degree of the practice about the stress management, the lower the nurses' stress”was supported. (r= - .2859, p<.05). 6. There were significant correlations between the knowledge about stress management and age (r= -.3717, p<.01), between the knowledge about stress management and the period of her work. (r= -.2897, p<0.5). There was significant difference in the knowledge about stress management between those who had married and those who had not. (t=2.82, p<.01) 7. There was significant difference in the practice about the stress management between those who had religion and those who had not. (t=2.7, p< .01) 8. There was significant difference in the stress according to the type or work. (t=6. 127, P <.05) There was significant correlation between the stress and supportive system. (r=-.2647, p<.05).

• 한국콘텐츠학회논문지
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• 제19권11호
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• pp.144-152
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• 2019

학습양식은 정보를 습득하고 처리하며 해석하고 조직화하는 도구를 의미한다. VARK(Visual Auditory Read Kinesthetic, VARK) 학습양식은 사용하는 감각양식에 따라 시각, 청각, 읽기/쓰기, 운동감각으로 구분된다. 국내 의과대학에서는 학습자 중심의 학습이 강조되지만 학습자의 VARK 학습양식에 대한 연구는 거의 없다. 본 연구에서는 국내 의과대학 학생을 대상으로 VARK 학습양식을 조사하여 각 학습유형과 성별, 학업성취 수준이 어떤 관계를 가지고 있는지 파악하고자 하였다. 본 연구의 대상은 전북지역 C의과대학·의학전문대학원에 재학 중인 394명의 학생이다. 학습양식검사는 VARK 웹 사이트에서 제공하는 Fleming이 개발한 VARK 검사지© 7.0 한국어버전, 총 16문항이다. 학업성취도는 표준화점수(t점수)로 변환하여 사용하였으며 학습유형에 대한 빈도분석과 집단별 비교를 위한 교차분석 및 분산분석(t-test, ANOVA)을 실시하였다. 연구 결과 학습선호 양식은 단일형이 87명(22.1%), 다중형이 307명(77.9%)이다. 남학생과 여학생 모두 4개 연합형인 VARK를 가장 선호하였다. 성별에 따른 전체 학습양식의 유의미한 차이는 없었다. 의학과 1학년은 단일형이 가장 낮고(8.8%), VARK 유형이 가장 높은 반면(47.8%), 의학과 4학년은 단일형이 가장 높고(30.7%), VARK 4개 연합유형(19.8%)과 3개 연합유형(19.8%)이 가장 낮았다. 모든 학습유형에서 학업성취도 차이는 확인되지 않았다(F=1.09, p=0.37). 의과대학 학생의 학습양식의 선호 결과는 추후 학습자 중심의 다양한 교수전략을 적용하는 기초 자료로서 의미가 있다.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.97-105
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• 2020

최근 초고속 이더넷(ethernet)의 데이터 및 동작주파수 속도가 증가하고 있으며, 이에 따라 EMI(electromagnetic interference)가 증가하고 있다. 이러한 EMI의 발생은 주변 전자기기들에 영향을 미쳐 오동작 원인이 될 가능성이 높다. 본 연구에서는 고속 이더넷 스위치 EMI 발생의 주요 원인인 DC-DC SMPS (switching mode power supply)에서 발생하는 EMI 저감을 위해 EMI 필터를 적용하였다. EMI 필터소자는 소형화, 양산화에 장점을 가지며, 내전압(dielectric voltage) 특성이 우수한 MLCC (multi-layer ceramic capacitor)를 사용하였다. MLCC 필터는 X-커패시터 및 X, Y-커패시터로 구성되어 있다. X-커패시터는 10 nF 및 100 nF 용량의 2개의 MLCC와 1개의 마일러 콘덴서(mylar capacitor)로 구성하였다. Y-커패시터는 용량 27 nF의 6개의 MLCC를 사용하여 구성하였다. X-커패시터만을 EMI 필터로 적용한 경우, 전도성(conductive) EMI는 150 kHz ~ 30 MHz의 주파수 대역에서 EMI 전계강도가 허용 한계치를 초과함을 알 수 있었다. 또한 방사성(radiative) EMI도 특정 주파수에서 EMI 전계 강도가 높고, 허용 마진폭도 매우 적음을 알 수 있었다. 반면 X, Y-커패시터를 적용하였을 경우, 전 주파수 대역에서 전도성 EMI가 크게 감소하였으며, 방사선 EMI도 충분한 마진이 확보됨을 알 수 있었다. 또한 X, Y-커패시터의 전기적인 신뢰성을 평가하기 위하여 절연 저항(insulation resistance) 및 내전압 성능을 측정하였으며, 절연 저항 및 내저항 성능이 모두 전기적 신뢰성 기준을 만족함을 알 수 있었다. 결론적으로 MLCC 필터를 X, Y-커패시터로 사용하여 전도성 및 방사성 EMI 노이즈가 효과적으로 감소되었고, 우수한 전기적인 신뢰성도 확보됨을 알 수 있었다.

• Applied Biological Chemistry
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• 제30권4호
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• pp.364-370
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• 1987

본연구의 근간이 되는 기본적 가정은, (1) 식물냉해기작에서 2차과정은 반응성이 강한 $O_2^-$의 체내 축적이다. (2) $O_2^-$는 식물체가 저온(低溫)처리를 받고 있는 도중이 아니라 상온(常溫)으로 환원된 뒤에 축적되기 시작한다. (3) $O_2^-$의 축적은 미토콘드리아 막의 상전이가 야기한 세포대사(細胞代謝)$(glycolysis{\rightarrow}TCA\;cycle{\rightarrow}respiratory\;electron\;transport)$의 균형파괴에 기인 한다. 이와 같은 가정을 뒷받침할 수 있는 중요한 연구 결과는 다음과 같다. 먼저 $O_2^-$의 상대적(相對的) 수준(水準)을 측정하는 방법을 확립하였다. 저온처리를 받은 벼 유묘는 처리하지 않은 유묘보다 그 조직 추출액중의 $O_2^-$수준이 높게 나타났다. 48시간의 저온처리중에는 $O_2^-$의 축적이 거의 일어나지 않았으나, 상온(常溫)으로 환원시킨 후 축적되기 시작하여 약 8시간후에 최고치에 도달하였다. Model system을 이용한 연구 결과, 호흡기질을 공급했을 때 미토콘드리아 membrane(SMP)에서 $O_2^-$의 생성이 증가하였다. 효소적으로 발생시킨 $O_2^-$가 존재하는 조건하에서 미토콘드리아막의 전자전달 활성이 저해를 받았다. $O_2^-$의 축적이 최고치에 도달한 후 급격히 감소되는 사실이 관찰되었으며, 이는 Superoxide dismutase(SOD)에 의한 $O_2^-$의 dismutation 결과로 해석되었다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1656-1664
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• 2009

Bioaugmentation of bioreactors focuses on the removal of numerous organics, with little attention typically paid to the maintenance of high and stable nitrite accumulation in partial nitrification. In this study, a bioaugmented membrane bioreactor (MBR) inoculated with enriched ammonia-oxidizing bacteria (AOB) was developed, and the effects of dissolved oxygen (DO) and temperature on the stability of partial nitrification and microbial community structure, in particular on the nitrifying community, were evaluated. The results showed that DO and temperature played the most important roles in the stability of partial nitrification in the bioaugmented MBR. The optimal operation conditions were found at 2-3 mgDO/l and $30^{\circ}C$, achieving 95% ammonia oxidization efficiency and nitrite ratio ($NO_2^-/{NO_x}^-$) of 0.95. High DO (5-6 mg/l) and low temperature ($20^{\circ}C$) had negative impacts on nitrite accumulation, leading to nitrite ratio drop to 0.6. However, the nitrite ratio achieved in the bioaugmented MBR was higher than that in most previous literatures. Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) were used to provide an insight into the microbial community. It showed that Nitrosomonas-like species as the only detected AOB remained predominant in the bioaugmented MBR all the time, and coexisted with numerous heterotrophic bacteria. The heterotrophic bacteria responsible for mineralizing soluble microbial products (SMP) produced by nitrifiers belonged to the Cytophaga-Flavobacterium-Bacteroides (CFB) group, and $\alpha$-, $\beta$-, and $\gamma$- Proteobacteria. The fraction of AOB ranging from 77% to 54% was much higher than that of nitrite-oxidizing bacteria (0.4-0.9%), which might be the primary cause for the high and stable nitrite accumulation in the bioaugmented MBR.

• 한국기후변화학회지
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• 제8권1호
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.