• 원예과학기술지
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• 제18권3호
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• pp.387-390
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• 2000

포도나무의 수체관리와 수량이 과실품질과 내한성에 미치는 영향을 구명하기 위하여, 화성지역과 수원지역에서 '캠벨얼리' 품종을 이용하여 시험을 수행하였다. 동해 상습지역인 화성지역은 수원지역에 비해 동계 최저기온 극값이 낮았고, 재식거리가 좁아 과다결실을 하고 있었으며, 수확시기도 7일 가량 늦은 경향이었다. 또한 포도나무의 결과모지내 탄수화물 함량도 1.2~1.7% 정도 낮았으며, $-15^{\circ}C$의 저온처리에 의해 발아율도 현저히 낮았다. 수원지역에서 포도 착과량별 과실품질과 결과모지의 발아정도를 보면, 착과량이 많아질수록 과방 및 과립의 크기는 차이가 없었으나, 당도가 떨어지고, 착색이 나빠지는 것을 알 수 있었다. 착과량이 많아지면 결과모지의 탄수화물 함량이 적어지는 경향인데, 특히, $-15^{\circ}C$ 이하의 저온 처리에 의해 발아율이 현저히 낮아졌다. 과실품질을 고려한 적정 수량은 2.3~2.6MT/10a이 적합하였다.

• 동의생리병리학회지
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• 제25권4호
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• pp.628-634
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• 2011

The roots of Polygala tenuifolia Willd. is a well-known traditional medicine used as expectorant, tonic, tranquilizer in Asia including China and Korea. And also have been used to treat amnesia, neurasthenia, palpitation, insomnia, and disorientation. Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as Parkinson's disease, Alzheimer's disease, epilepsy and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a role in the pathogenesis of these diseases. NNMBS269, acid hydrolysis EtOAc fraction of the P. tenuifolia showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells while general EtOAc fraction of the P. tenuifolia (NNMBS268) not shown. NNMBS269 induced the expression of HO-1 protein that has been proposed to play an important cellular defense role against oxidant injury. In addition increased HO activity. In mouse hippocampal HT22 cells, NNMBS269 makes the nuclear accumulation of nuclear factor E2-related factor 2 (Nrf2). In conclusion, acid hydrolysis EtOAc fraction the P. enuifolia. (NNMBS269) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 translocation in mouse hippocampal HT22 cells.

• Toxicological Research
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• 제17권3호
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• pp.215-223
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• 2001

카드뮴의 주요한 표적장기이며 카드뮴이 만성 및 급성 폭로시 축적되는 가장 중요한 장기인 간의 세포독성을 Hepalclc7세포에서 caspases및 Bax단백질의 활성과 발현 그리고 미토콘드리아 세포막 전위 변화(MPT) 등을 조사하여 다음과 같은 결과를 얻었다. 1. 카드뮴은 농도의존적으로 간세포인 Hepalclc7 세포의 생존율을 감소시켰다. 2. 카드뮴을 농도별로 처리하였을 때 100 M 이상의 농도에서 세포사멸의 특징중의 하나인 DNA분절현상을 확인하였다. 3. 카드뮴 처리 후 caspase-3, caspase-8, caspase-9 의 활성변화를 조사한 결과 caspase-3,-9 pretease 활성이 시간이 경과함에 따라 증가하였다. 4. 카드뮴 처리 후 cytochrome c가 세포질내로 방출되었고 이는 caspase-9 proteas의 활성화를 유도하였다. 5. 카드뮴 처리 후 Bax가 세포질에서 미토콘드리아로 이동하여 cytochrome c의 세포질내로의 방출에 관여하였다. 6. 카드뮴 처리시 미토콘드리아 세포막 전위차의 감소를 JC-1 형광염색을 통하여 확인하였다. 이상의 결과는 카드뮴에 의한 Hepalclc7 세포사멸의 신호전달기전은 세포질내에 있는 Bax가 미토콘드리아로 이동, cytochrome c의 세포질내로의 방출, 그리고 caspase-3, 9 pretease 활성화를 의해서 매개되는 것으로 판단된다. 또한 Bax 단백질의 발현변화가 미토콘드리아의 기능변화에 기여하였으리라 사료된다.

• 한국재료학회지
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• 제10권2호
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• pp.155-159
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• 2000

고주기 피로조건에서 응력진폭은 항복점이하의 응력이므로 변형은 일반적으로 탄성적이다. 만약 변형이 완전히 탄성적이라면 피로는 생겨나지 않을 것이다. 그러나 이는 항복점의 개념과 항복점 아래에서의 순수탄성변형의 가정을 과도하게 단순화한 것이다. 인장실험 시 시편 전체가 파괴 절차를 따르는 반면, 고주기 피로실험에서는 국부적 영구 슬립띠가 파괴절차를 따른다. 그러나 두 경우에서 파괴 전변형영역의 단위체적 당 변형의 축적은 두 재료가 동일하기 때문에 국부적으로 동일하다. 미소 소성변형이나 Luders band, 탄성영역에서의 인장실험곡선의 기울기변화는 재료속에 포함된 경도가 높은 침입형 또는 침탄형 원자의 구름에 기인한다. 이들이 구름운동(Rolling movement)을 일으켜 다음 격자로 이동하면 소성변형이 발생되는 반면, 완전히 구르지 못하고 제자리로 되돌아오는 운동을 반복하는 경우가 바로 피로한계인다.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.251-257
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• 2017

Purpose: A chisel mounted on working implement, such as agricultural machinery used in irregular farming conditions, is subjected to highly variable fatigue loading during work. To ensure the safety of the chisel on a working implement for the duration of its service life, fatigue testing must be performed with the proper fatigue test load conditions. In this study, working loads for a chisel were developed by reconstructing loads from strain gage data collected during field tests and used to conduct fatigue tests on the chisel component. Methods: FE analysis with nCode software was utilized to select the proper quantity and locations of strain gages for load measurements. A fatigue test was performed to experimentally verify the fatigue strength of the chisel and to evaluate the validity of the load history developed with the load reconstruction technique. Results: A strain history for the chisel was obtained from data collected during field tests. The data was filtered for the 14-16 km/h speed range, connected, and merged. The chisel load history was developed using the load reconstruction technique. The resulting load history was expressed as a load spectrum using the rain-flow counting method. Conclusions: A fatigue test was conducted on a chisel under a constant load condition with an equivalent load amplitude and number of cycles, as calculated by Miner's Rule for linear damage accumulation. During the fatigue test, there were no cracks at any position. It is concluded that the fatigue test method proposed in this study can be utilized successfully as a durability evaluation method for the chisel.

• 원예과학기술지
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• 제32권5호
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• pp.584-589
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• 2014

Jeffersonia dubia is a spring-flowering perennial found in rich forests in Korea and Northern China and has potential as an ornamental or medicinal plant. However, illegal picking and land use change have decreased the number of populations and overall population size of this plant in its natural habitat. Although J. dubia has been reported to be a shade-preferring plant, no study has determined the optimum light intensity for its growth. The objectives of this work were to observe the effects of various shading levels on the physiological responses of J. dubia and to determine the proper shading level for cultivation. Treatments consisted of four shading levels (0%, 50%, 75%, and 95% shade) imposed using black mesh cloth. The number of leaves and dry weight increased with decreased shading. The shoot-to-root ratio increased with increased shading, mainly due to decreased root dry weight under shading. Plants showed low net $CO_2$ assimilation rates and $F_v/F_m$ values combined with low dry matter levels when grown under 0% shade (full sunlight). These results indicate that J. dubia plants experience excessive irradiance without shading, resulting in damage to the photosynthetic apparatus. By contrast, the net photosynthesis rate increased as the shading level increased. $F_v/F_m$, the potential efficiency of PSII, was 0.8 under 95% shade, indicating that J. dubia is well-adapted under heavy shading. However, the low dry matter of plants in the 95% shade treatment indicated that the low light intensity under 95% shade led to a decline in plant growth. Thus, moderate light (50% shading) is recommended for cultivating J. dubia without physiological defects.

• 한국식품영양과학회지
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• 제12권2호
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• pp.84-92
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• 1983

자동 산화유가 mouse의 간장 효소에 미치는 영향을 구명하기 위하여 autoxidized methyl linoleate의 일정량을 mouse에게 1일 1회 20일 동안 경구 투여하여 간에서의 효소 활성을 조직화학적 및 생화학적 방법으로 검토한 결과는 다음과 같다. 실험군의 간에서의 POV, COV 및 TBA값은 정상군에 비해 크게 증가하여 AOML이 많이 흡수되어 있음을 알 수 있었다. 실험군의 간에서의 phospholipid, triglyceride 및 total cholesterol의 양은 정상군에 비해 증가하였다. 실험군의 간에서의 acid phosphatase, alkaline phosphatase의 활성은 정상군에 비해 증가하였으며, ATPase의 활성은 감소하였다. 실험군의 간에서의 형태학적 변화는 정상군에 비해 핵산의 감소, 지질의 축적 및 간 세포의 손상이 있었다. 이상의 결과로부터 mouse에 경구 투여한 자동 산화 methyl linoleate는 간에서의 효소 활성과 간의 형태학적 변화에 크게 영향을 주고 있음을 알 수 있었다.

• 한국토양비료학회지
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• 제49권3호
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• pp.265-270
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• 2016

Accumulated Phosphate can be released by ligand exchange reaction of organic acids. The objective of this study was to evaluate effects of the organic acids on the availability of phosphate and the growth of crop in phosphate and salts accumulated soil. Soil samples were collected from farmer's plastic film house. Available phosphate and electrical conductivity of soil were $3,005mg\;kg^{-1}$ and $16.63mg\;kg^{-1}$ which were 6 and 8 times higher than the optimum range of soil for crop growth, respectively. Corns were cultivated in pots for 2 months. Treatments were no treatment (control), phosphate fertilizer (P), citric acid (CA) 1, 5, 10 mM, and oxalic acid (OA) 1, 5, 10 mM. Water soluble phosphorus, available phosphate, corn growth and uptake were determined after cultivation. Results showed that organic acids increased water soluble phosphorus and available phosphate. For the level of 10 mM, the order of effectiveness of organic acids for water soluble P was citric acid (44%) > oxalic acid (32%). Height and dry weight of corns were increased significantly by the treatment of citric acid 1 and 5 mM. Also, corn absorbed more phosphorus, nitrogen, potassium, calcium and magnesium in the treatment of citric acid 1 mM than these of other treatments. Even though phosphate availability of soil was enhanced by addition of citric acid 10 mM, the growth of corns decreased because high concentration of citric acid caused salt damage by increasement of electrical conductivity. Thus, the citric acid of 1 mM has the potential to improve the availability of phosphate and the healthy growth of corns.

• Smart Structures and Systems
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• 제17권1호
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• pp.149-165
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• 2016

Floods have been known to be one of the main causes of bridge collapse. Contrary to earthquakes, flood events tend to occur repeatedly and more frequently in rainfall areas; flood-induced damage and collapse account for a significant portion of disasters in many countries. Nevertheless, in contrast to extensive research on the seismic fragility analysis for civil infrastructure, relatively little attention has been devoted to the flood-related fragility. The present study proposes a novel methodology for deriving flood fragility curves for bridges. Fragility curves are generally derived by means of structural reliability analysis, and structural failure modes are defined as excessive demands of the displacement ductility of a bridge under increased water pressure resulting from debris accumulation and structural deterioration, which are known to be the primary causes of bridge failures during flood events. Since these bridge failure modes need to be analyzed through sophisticated structural analysis, flood fragility curve derivation that would require repeated finite element analyses may take a long time. To calculate the probability of flood-induced failure of bridges efficiently, in the proposed framework, the first order reliability method (FORM) is employed for reducing the required number of finite element analyses. In addition, two software packages specialized for reliability analysis and finite element analysis, FERUM (Finite Element Reliability Using MATLAB) and ABAQUS, are coupled so that they can exchange their inputs and outputs during structural reliability analysis, and a Python-based interface for FERUM and ABAQUS is newly developed to effectively coordinate the fragility analysis. The proposed framework of flood fragility analysis is applied to an actual reinforced concrete bridge in South Korea to demonstrate the detailed procedure of the approach.

• Journal of Ginseng Research
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• 제41권3호
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• pp.316-325
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• 2017

Background: Ginseng essence (GE) is a formulation comprising four medicinal and edible herbs including ginseng (Panax ginseng), American ginseng (Panax quinquefolius), lotus seed (Nelumbo nucifera), and lily bulb (Lilium longiflorum). This study was aimed at investigating the hepatoprotective effect of GE against carbon tetrachloride ($CCl_4$)-induced liver injury in rats. Methods: We treated Wistar rats daily with low, medium, and high [0.625 g/kg body weight (bw), 1.25 g/kg bw, and 3.125 g/kg bw, respectively] doses of GE for 9 wk. After the 1st wk of treatment, rats were administered 20% $CCl_4$ (1.5 mL/kg bw) two times a week to induce liver damage until the treatment ended. Results: Serum biochemical analysis indicated that GE ameliorated the elevation of aspartate aminotransferase and alanine aminotransferase and albumin decline in $CCl_4$-treated rats. Moreover, $CCl_4$-induced accumulation of hepatic total cholesterol and triglyceride was inhibited. The hepatoprotective effects of GE involved enhancing the hepatic antioxidant defense system including glutathione, glutathione peroxidase, glutathione reductase, glutathione S-transferase, superoxide dismutase, and catalase. In addition, histological analysis using hematoxylin and eosin and Masson's trichrome staining showed that GE inhibited $CCl_4$-induced hepatic inflammation and fibrosis. Furthermore, immunohistochemical staining of alpha-smooth muscle actin indicated that $CCl_4$-triggered activation of hepatic stellate cells was reduced. Conclusion: These findings demonstrate that GE improves $CCl_4$-induced liver inflammation and fibrosis by attenuating oxidative stress. Therefore, GE could be a promising hepatoprotective herbal formulation for future development of phytotherapy.