• 한국어병학회지
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• 제6권2호
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• pp.197-204
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• 1993

Flounder culture has been developed mainly in the western parts of japan, and, to date, following six bacterial diseases have been reported. Bacterial white enteritis occurs in 16 to 30-day-old flounder larvae and often causes mass mortality in seed production. Bacterium named Vibrio sp. INFL invades and multiplies in the mucosae of posterier part of intestine, and causes desquamative enteritis. Gliding bacterial disease occurs mostly in juvenile stage and in spring to summer. Diseased signs are partial discoloration and erosion of skin and fins. Histologically, epidermis are removed, and the causative bacterium, Flexibacter maritimus, multiplies on the surface of demis and invades into the muscular tissue. Vibriosis caused by Vibrio anguillarum and related organisum is one of the well-known diseases among marine fish. Outbreaks of the disease in flounder culture are relatively few, but mass mortalities in fingerlings due to the disease were reported. An outbreak of nocardiosis in the autumn of 1984 has been reported, but since then the disease scarcely occurred. The disease is characterized by formation of abscesses under the skin and white nodes in the gill, heart, spleen and kidney. Streptococcicosis occurs frequently in recent years. Beta-hemolytic streptococcus is the causative bacterium, which possesses the same biochemical and serological characteristics as $\beta$-streptococci isolated from some marine and freshwater fish, and is seemed to related to Streptococcus iniae. Edwardsiellosis is the disease that causes most damage in flounder culture in Japan. Characteristic symptoms are swelling of abdomen and intestinal protrusion from the anus due to accumulation of ascites. Edwardsiella tarda, a well-known pathogen of freshwater fish, is the causative bacterium of the disease.

• Molecules and Cells
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• 제41권1호
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• pp.35-44
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• 2018

Mitochondria are responsible for supplying of most of the cell's energy via oxidative phosphorylation. However, mitochondria also can be deleterious for a cell because they are the primary source of reactive oxygen species, which are generated as a byproduct of respiration. Accumulation of mitochondrial and cellular oxidative damage leads to diverse pathologies. Thus, it is important to maintain a population of healthy and functional mitochondria for normal cellular metabolism. Eukaryotes have developed defense mechanisms to cope with aberrant mitochondria. Mitochondria autophagy (known as mitophagy) is thought to be one such process that selectively sequesters dysfunctional or excess mitochondria within double-membrane autophagosomes and carries them into lysosomes/vacuoles for degradation. The power of genetics and conservation of fundamental cellular processes among eukaryotes make yeast an excellent model for understanding the general mechanisms, regulation, and function of mitophagy. In budding yeast, a mitochondrial surface protein, Atg32, serves as a mitochondrial receptor for selective autophagy that interacts with Atg11, an adaptor protein for selective types of autophagy, and Atg8, a ubiquitin-like protein localized to the isolation membrane. Atg32 is regulated transcriptionally and post-translationally to control mitophagy. Moreover, because Atg32 is a mitophagy-specific protein, analysis of its deficient mutant enables investigation of the physiological roles of mitophagy. Here, we review recent progress in the understanding of the molecular mechanisms and functional importance of mitophagy in yeast at multiple levels.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2005년도 춘계 국제심포지엄 및 학술대회
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• pp.51-82
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• 2005

To compare the pulmonary toxicity between ultrafine colloidal silica particles (UFCSs) and fine colloidal silica particles (FCSs), mice were intratracheally instilled with 3 mg of 14-nm UFCSs and 230-nm FCSs and pathologically examined from 30 mill to 24 hr post-exposure. Histopathologically, lungs exposed to both sizes of particles showed bronchiolar degeneration and necrosis, neutrophilic inflammation in alveoli with alveolar type II cell proliferation and particle-laden alveolar macrophage accumulation. UFCSs, however, induced extensive alveolar hemorrhage compared to FCSs from 30 min onwards. UFCSs also caused more severe bronchiolar epithelial cell necrosis and neutrophil influx in alveoli than FCSs at 12 and 24 hr post-exposure. Laminin positive immunolabellings in basement membranes of bronchioles and alveoli of UFCSs treated animals was weaker than those of FCSs treated animals in all observation times. Electron microscopy demonstrated UFCSs and FCSs on bronchiolar and alveolar wall surface as well as in the cytoplasm of alveolar epithelial cells, alveolar macrophages and neutrophils. Type I alveolar epithelial cell erosion with basement membrane damage in UFCSs treated animals was more severe than those in FCSs treated animals. At 12 and 24 hr post-exposure, bronchiolar epithelia cells in UFCSs treated animals showed more intense vacuolation and necrosis compared to FCSs treated animals. These findings suggest that UFCSs has greater ability to induce lung inflammation and tissue damages than FCSs.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.98-101
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• 2022

Liquid-based Triboelectric nanogenerator (L-TENG) is one of the alternatives to solid-based Triboelectric nanogenerator (S-TENG) because of the absence of surface damage which can decrease the durability of the generator. However, the L-TENG also has an obvious drawback of significantly lower output than that of S-TENG. This article produces water-sloshing-based electricity generating device (W-ED) with a new design of L-TENG that improves electrical output in portable form. The dual-electrode system, consisting of closed-loop circuit and inner electrode which enables water to contact directly in the bottle, can generate the open-circuit voltage and the short-circuit current of up to 348 V and 5.1 mA, respectively. By investigating the motion of water for each frequency, we propose that W-ED is suitable device for a variety of human motions. We expect that W-ED can be applied in small electrical devices or sensors in daily-use items.

• 한국구조물진단유지관리공학회 논문집
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• 제27권5호
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• pp.16-22
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• 2023

이 연구는 원전 콘크리트 배합설계를 모사한 콘크리트 시험체에 대하여 염수침지 실험을 수행하였으며, 시험체 깊이에 따른 염화물량과 XRF 성분의 상관관계를 분석하였다. 원전 콘크리트의 표면부의 염화물량은 염수 침지기간이 증가함에 따라 소폭 증가하였으나, 깊이 5.5 mm 이상의 콘크리트 시험체 내부 염화물량은 염수 침지기간이 증가함에 증가하는 경향이 뚜렷하게 나타났다. 콘크리트의 염화물량과 XRF 성분의 상관관계 분석결과, OPC 배합과 비교하여 FA가 20% 치환된 배합은 XRF 성분분석을 통한 Cl 이온의 구성비율과 염해저항성 평가결과의 상관관계가 매우 높게 나타났다. 이에 따라 FA가 20% 치환된 원전 콘크리트 배합에서는 반복적인 데이터 누적을 통해 XRF 성분분석을 통하여 염소이온분석 및 염해저항성능 평가가 가능함을 확인하였다.

• 대한지리학회지
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• 제30권3호
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• pp.230-241
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• 1995

제주도에서 때때로 밭생하는 동해(凍害) 는 감귤 농사에 많은 영향을 준다. 특히 한 라산 북사면의 감귤 과수원에서는 대규모의 동해 뿐만 아니라 소규모 냉기류의 정체로 인하 여 품질과 생산성이 낮아지는 경우가 빈번하다. 본 연구는 감귤 과수원지역의 동해나 한해 (寒害)로 인한 피해 방지를 모색하기 위한 연구의 일환으로서 1989-1990년 겨울에 동해 피 해가 컸던 북제주군 와산리 일대를 사례로 택한 1995년 1월 관측 결과를 중심으로 기온 분 포의 특성을 분석하였다. 기상조건에 따라서 고지대(해발 200m 이상의 지역)와 저지대(해발 200m미만의 지역)의 최저기온 분포가 다르게 나타났다. 흐리고 바람이 강한 날과 강수현상 이 있는 날에는 고지대의 기온이 낮은데, 저지대와의 차이는 전자의 경우 2.4$^{\circ}C$, 후자의 경 우 0.2$^{\circ}C$ 정도이다. 반면 바람이 없고 맑은 날 야간에는 저지대보다 고지대의 기온이 높은데 최대 차이는 4.8$^{\circ}C$에 달하였다. 방풍 시설에 의하여 밀폐된 곳이나 지형적으로 함몰된 와지 에서는 냉기류가 정체되면서 소규모의 냉기호가 형성되었다. 그리고 최대 강도 3.1$^{\circ}C$ 에 이 르는 지표면의 복사냉각에 의한 기온 역전 현상이 발생하는데, 방풍시설로 완전히 밀폐된 고도인 90cm까지 뚜렷하게 저온현상이 나타났다. 방풍림과 방풍담으로 밀폐된 곳에서는 방 풍 시설의 전면과 후면의 기온차가 2.O$^{\circ}C$에 이르고 있다. 저지대에 냉기호가 형성되었을 경 우, 인공적으로 소규모의 대류현상을 일으켜 냉기호 내의 기온을 상승시키는대 큰효과를 얻 을 수 있었다. 본 연구의 결과는 실측에 의한 상습 냉해지역의 파악과 냉해 방지를 위한 합 리적인 방풍시설의 설계의 방요성이 시급함을 보여준다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.477-477
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• 2008

For more than three decades, the gate dielectrics in CMOS devices are $SiO_2$ because of its blocking properties of current in insulated gate FET channels. As the dimensions of feature size have been scaled down (width and the thickness is reduced down to 50 urn and 2 urn or less), gate leakage current is increased and reliability of $SiO_2$ is reduced. Many metal oxides such as $TiO_2$, $Ta_2O_4$, $SrTiO_3$, $Al_2O_3$, $HfO_2$ and $ZrO_2$ have been challenged for memory devices. These materials posses relatively high dielectric constant, but $HfO_2$ and $Al_2O_3$ did not provide sufficient advantages over $SiO_2$ or $Si_3N_4$ because of reaction with Si substrate. Recently, $HfO_2$ have been attracted attention because Hf forms the most stable oxide with the highest heat of formation. In addition, Hf can reduce the native oxide layer by creating $HfO_2$. However, new gate oxide candidates must satisfy a standard CMOS process. In order to fabricate high density memories with small feature size, the plasma etch process should be developed by well understanding and optimizing plasma behaviors. Therefore, it is necessary that the etch behavior of $HfO_2$ and plasma parameters are systematically investigated as functions of process parameters including gas mixing ratio, rf power, pressure and temperature to determine the mechanism of plasma induced damage. However, there is few studies on the the etch mechanism and the surface reactions in $BCl_3$ based plasma to etch $HfO_2$ thin films. In this work, the samples of $HfO_2$ were prepared on Si wafer with using atomic layer deposition. In our previous work, the maximum etch rate of $BCl_3$/Ar were obtained 20% $BCl_3$/ 80% Ar. Over 20% $BCl_3$ addition, the etch rate of $HfO_2$ decreased. The etching rate of $HfO_2$ and selectivity of $HfO_2$ to Si were investigated with using in inductively coupled plasma etching system (ICP) and $BCl_3/Cl_2$/Ar plasma. The change of volume densities of radical and atoms were monitored with using optical emission spectroscopy analysis (OES). The variations of components of etched surfaces for $HfO_2$ was investigated with using x-ray photo electron spectroscopy (XPS). In order to investigate the accumulation of etch by products during etch process, the exposed surface of $HfO_2$ in $BCl_3/Cl_2$/Ar plasma was compared with surface of as-doped $HfO_2$ and all the surfaces of samples were examined with field emission scanning electron microscopy and atomic force microscope (AFM).

• 한국융합학회논문지
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• 제4권2호
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• pp.21-27
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• 2013

점용접은 자동차 산업에서 많이 사용되어지는데 조립공정의 자동화로 인하여 경제성과 차체 중량을 높이지 않아 자동차 연비 개선효과가 있다. 그러나 차량 주행시 노면으로부터 불규칙적인 하중전달 및 진동으로 인하여 점 용접부에 응력집중이 발생하고 피로파괴가 종종 발생한다. 이에 대하여 강성변화를 고려한 점용접부의 피로수명 평가는 필수적이다. 본 논문에서는 선형정적해석을 수행하여 취약부위를 파악하였다. 점용접부의 피로특성을 획득하였고, 시간영역에서 3단계의 하중이력을 도출하여, 준정적 피로해석에 조건으로 설정하여 수행하였다. 또한 점용접부에 대한 피로수명예측 방법은 기존 방법과 피로누적으로 인한 손상방법을 적용하여 나타낸 결과를 가지고 비교분석하였다.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.197-205
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• 2017

Exposure of Jurkat T cell clone (J/Neo cells) to acacetin (5,7-dihydroxy-4'-methoxyflavone), which is present in barnyard millet (Echinochloa esculenta (A. Braun)) grains, caused cytotoxicity, enhancement of apoptotic $sub-G_1$ rate, Bak activation, loss of mitochondrial membrane potential (${\Delta}{\Psi}m$), activation of caspase-9 and caspase-3, degradation of poly(ADP-ribose) polymerase, and FITC-Annexin V-stainable phosphatidylserine exposure on the external surface of the cytoplasmic membrane without accompanying necrosis. These apoptotic responses were abrogated in Jurkat T cell clone (J/Bcl-xL) overexpressing Bcl-xL. Under the same conditions, cellular autophagic responses, including suppression of the Akt-mTOR pathway and p62/SQSTM1 down-regulation, were commonly detected in J/Neo and J/Bcl-xL cells; however, formation of acridine orange-stainable acidic vascular organelles, LC3-I/II conversion, and Beclin-1 phosphorylation (Ser-15) were detected only in J/Neo cells. Correspondingly, concomitant treatment with the autophagy inhibitor (3-methyladenine or LY294002) appeared to enhance acacetin-induced apoptotic responses, such as Bak activation, ${\Delta}{\Psi}m$ loss, activation of caspase-9 and caspase-3, and apoptotic $sub-G_1$ accumulation. This indicated that acacetin could induce apoptosis and cytoprotective autophagy in Jurkat T cells simultaneously. Together, these results demonstrate that acacetin induces not only apoptotic cell death via activation of Bak, loss of ${\Delta}{\Psi}m$, and activation of the mitochondrial caspase cascade, but also cytoprotective autophagy resulting from suppression of the Akt-mTOR pathway. Furthermore, pharmacologic inhibition of the autophagy pathway augments the activation of Bak and resultant mitochondrial damage-mediated apoptosis in Jurkat T cells.

• 한국작물학회지
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• 제52권2호
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• pp.213-219
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• 2007

본 연구는 알루미늄 스트레스가 녹두에 미치는 영향을 보기 위해 뿌리의 생장, 알루미늄 함량, 뿌리 표면의 pH 변화, 원형질막의 $H^+-ATPase$ 활성과 단백질 양의 변화를 조사하여 분석하였다. 1. 처리된 알루미늄의 농도는 10, 25, 50, $100{\mu}M$이었으며, 알루미늄에 의한 뿌리생장의 억제는 $25{\mu}M$ 이상의 농도 처리구에서 12시간부터 현저히 나타났고, 50과 $100{\mu}M$ 처리구에서는 뿌리의 생장이 거의 중단되었다. 2. 0.2% Hematoxlin으로 염색 시 알루미늄이 처리된 근단부에서 주로 염색되었으며, $50{\mu}M$ 농도로 처리된 뿌리의 경우 12시간째보다는 24시간째에 근단부 전체가 염색되어 그 피해가 심각함을 보여 주었다. 또 근단 부위가 대조구와 비교하여 어두운 갈색을 나타내고, 표면이 가로 쪽으로 갈라졌다. 3. 처리 농도별 근단부(1 cm)와 근단부를 제외한 부위의 뿌리로 나누어 24시간 처리를 한 후 알루미늄 함량을 측정한 결과, $10{\mu}M$ 처리구에서는 차이가 없었다. 그러나 알루미늄 처리 농도가 높을수록 즉, $25{\mu}M$ 이상 알루미늄 처리구에서는 근단부에서 2.5배 이상 높았다. 4. pH 지시약과 agarose plate technique를 이용하여 뿌리표면의 $H^+-flux$의 차이를 본 결과 녹두의 근단부 표면의 알카리화가 대조구에서는 12시간 정도부터 노란색(pH 4.5)에서 보라색(pH 6.0 이상)으로 변하는 것을 관찰하였으나 알루미늄 처리구에서는 색깔의 변화를 볼 수 없었다. 5. 24시간 동안 $50{\mu}M$ 알루미늄을 처리한 뿌리 원형질막 $H^+-ATPase$ 활성은 대조구에 비해 56%가 억제 되었다. $H^+-ATPase$ 단백질의 발현을 조사한 Western blotting 결과는 효소 활성의 감소와 유사하게 알루미늄이 처리된 뿌리에서 현저하게 줄어들었음을 확인할 수 있었다.