• Journal of Plant Biology
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• 제28권1호
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• pp.21-28
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• 1985

The bipinnate-compound leaf of Parkia clappertoniana has prominent, long petiole with a pulvinal base. The pulvinus has wood, periderm, lenticels and extensive cortical layer. Its vascular bundles are elongated with alternating rays. The vascular bundles of the petiole, rachis and veins are oval, with conspicuous bundle caps. Stomatal complex is predominantly paracytic with occasional occurrence of anomocytic stomata near the midrib. The oval stomata have conspicuous stomatal ledges. Trichomes are unicellular, acicular and restricted to the rachis, petiole and pinnule mid-ribs and margin. Ecological and taxonomic significance of features is discussed.

• Asian-Australasian Journal of Animal Sciences
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• 제24권3호
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• pp.439-448
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• 2011

Oxalic acid is synthesized by a wide range of plants. A few of them are forage plants that can cause oxalate poisoning in ruminants under certain conditions. In this paper, the role of some agronomic, climatic and genetic factors in minimizing oxalate accumulation in forage plants has been discussed. Research indicates that the content of oxalate in forage can be controlled by fertilizer application. For example, nitrate application resulted in higher contents of soluble and insoluble oxalates than ammonium application. With an increased rate of potassium application, soluble oxalate content showed an increasing trend and insoluble oxalate content showed a decreasing trend. With an increased rate of calcium application, soluble oxalate content showed a decreasing trend and insoluble oxalate content showed a reverse trend. Other agronomic factors such as growing season, harvesting practices, plant maturity, plant species, plant variety and plant parts can also have a large effect on oxalate accumulation. However, the potential benefits of the above approaches for improving forage quality have not been fully exploited. In addition, there is still insufficient information to fully utilize means (e.g. plant nutrients, season and soil moisture) to minimize oxalate accumulation in forage plants. Therefore, more research is required for a better understanding of the interactions between oxalate and the above-mentioned factors in forage plants.

• 한국자원식물학회지
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• 제23권2호
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• pp.145-150
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• 2010

활성산소의 하나인 과산화수소(hydrogen peroxide, $H_2O_2$)에 대한 세포독성과 이에 대한 연꽃수술(Nelumbo nucifera stamen, NNS)추출물의 항산화효과 및 멜라닌화에 미치는 영향을 알아보기 위하여 세포부착율 (cell adhesion activity, CAA)을 비롯한 티로시나제활성저해능 및 총멜라닌합성량을 분석하였다. 본 실험 결과 hydrogen peroxide($H_2O_2$)는 배양 인체피부흑색종세포 (SK-MEL-3)의 CAA를 유의하게 감소시킴으로서 세포독성효과를 나타냈다. 이에 대하여 NNS추출물은 $H_2O_2$의 산화적 손상에 의하여 감소된 CAA를 유의하게 증가시킴으로서 항산화효과를 나타냈다. 한편, $H_2O_2$에 대한 NNS추출물의 멜라닌화에 대한 영향에 있어서 NNS추출물은 $H_2O_2$에 의하여 활성화된 티로시나제활성과 총멜라닌합성량을 감소시킴으로서 멜라닌화에 대하여 억제효과를 나타냈다. 이상의 결과로 부터 $H_2O_2$는 배양 인체피부흑색종세포에 고독성을 나타냈으며 NNS와 같은 식물추출물은 $H_2O_2$와 같은 활성산소에 의한 산화적 손상 및 멜라닌화를 방어하는데 효과적인 것으로 나타났다.

• 분석과학
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• 제25권3호
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• pp.159-163
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• 2012

A spectrofluorimetric method has been developed for the determination of free $CN^-$ in real samples with fluorescent safranine-O. When safranine-O interacts electrostatistically with $CN^-$, the fluorescent intensity of safranine-O is decreased. Several experimental conditions such as pH of the sample solution and the amount of safranine-O were optimized. $Ag^+$ interfered higher than any other ions. Interference of $Ag^+$ could be disregarded because $Ag^+$ was scarcely contained or mostly complexed with $CN^-$ in selected real samples. With this proposed method, the linear range of $CN^-$ was from 5.0 to 110 ng/mL and the detection limit of $CN^-$ was 2.9 ng/mL. For validating this technique, real samples (Cu, Ag, Au electroplating wastewater, and untreated wastewater in university and in sewage treatment plant) were used. Recovery yields of 91.5%~106.0% were obtained. Based on experimental results, it is proposed that this technique can be applied to the practical determination of free $CN^-$.

• 한국세라믹학회지
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• 제43권12호
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• pp.764-767
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• 2006

Ni/YSZ $(Y_2O_3-stabilized\;ZrO_2)$ composite as an electrode component for High Temperature Electrolysis (HTE) was fabricated by mechanical alloying method using Ni and YSZ powders. Characterization of the synthesized composite was investigated with various analysis tools, including XRD, SEM and PSA, and a self-supporting planar unit cell prepared with the Ni/YSZ composite was prepared to study the electrochemical reactions for the production of hydrogen. The Ni/YSZ cermet is composed of crystalline Ni and YSZ, in a sub-micro scale, and has an even distribution without aggregated particles. In addition, under an electrochemical reaction, the unit cell showed an $H_2$ evolution rate from steam of 14 Nml/min and $600mA/cm^2$ of current density at the electrode.

• 대한환경공학회지
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• 제22권10호
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• pp.1881-1891
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• 2000

석탄화력 발전소에서 석탄이 연소되면서 생성된 석탄회 중 Cenosphere는 속이 비어 있거나 미세 입자들로 채워져 있고 입자의 크기가 큰 구형의 입자로 물에 부유할 정도로 비중이 작을뿐만 아니라 입자의 벽면에 유리질 성분이 많은 입자이다. 본 연구는 Cenosphere 입자에 대한 형성메카니즘을 분석하여 형태적, 물리적, 화학적 특성을 파악하였다. Cenosphere는 석탄이 연소하면서 입자의 내부에서 발생된 가스가 밖으로 방출되면서 형성되기 때문에 입자가 부풀어져 크게 되고 가스의 분출로 입자의 표변에 구멍이 발생하며 알루미노실리케이트 (Aluminosilicate) 성분에 의해 형성된 기포가 용융표면층에 부착되어 Cenosphere내부에 미세 입자들을 형성한다. 이와 같온 입자의 형성메카니즘 특성 때문에 분말성이 좋으면서 가볍고 큰 입자를 형성한다. Cenosphere의 입도분포는 $100{\sim}200{\mu}m$에 집중된 Single Modal로 질량중앙직경은 $123.11{\mu}m$이고 비중은 $0.67g/cm^3$, 분말도는 $1,135g/cm^3$으로 분석되었다. 또한 Cenosphere의 입자를 구성하는 성분 중 $SiO_2$는 59.17%, $Al_2O_3$는 30.16%로 전체의 89.33%를 차지하고 있고 있어 알루미노실리케이트 성분, 즉 유리질 성분이 높아 열절연성이 뛰어나다. 따라서 Cenosphere 입자를 실리카 바인더로 입자를 결합하면 다양한 온도에서 사용할 수 있는 우수한 열절연체를 만들 수 있어 재활용 원료로 활용이 가능하다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1599-1603
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• 2008

Sodium is involved in elevation of oxalate content in some plant species and this element is abundant in saline soils. Oxalate causes precipitation of insoluble calcium oxalate in the rumen and kidneys. The intention of this study was to evaluate the effect of soil salinity stress on dry matter yield and oxalate content in pot-grown napiergrass (Pennisetum purpureum Schumach). Plants were cut three times at 56, 118 and 179 d after transplanting to the pots. Five salinity treatments were used containing various concentrations of NaCl solution as follows: 0, 100, 300, 600 and 900 mM. At 28, 42, 84, 98, 146 and 160 d after transplanting, plants were irrigated with one liter of the particular treatment for each application. Dry matter yield of napiergrass was not affected (p>0.05) by salinity treatments. Plants treated with 100 mM NaCl exhibited a higher soluble oxalate content compared to other treatments, but the differences were not statistically significant (p>0.05). Although salinity treatments had significant (p<0.05) effects on insoluble and total oxalate contents in plant tissue between the 100 and 900 mM NaCl treatments, the differences were too small to be considered biologically important. The present study indicates that where the soil is high in NaCl, napiergrass will tend to grow well and be low in oxalate.

• 한국토양비료학회지
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• 제43권2호
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• pp.166-173
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• 2010

게르마늄 토양처리시 게르마늄 종류가 벼의 생육특성 및 부위별 게르마늄 흡수에 미치는 영향을 조사하기 위해 무기게르마늄 ($GeO_2$)과 수도작용 액상게르마늄으로 시비를 달리하여 게르마늄 종류에 따른 벼의 생육특성, 게르마늄 종류에 따른 부위별 게르마늄 흡수 특성을 각각 조사한 결과 수도작용 액상게르마늄 처리구와 무처리구의 경우 벼에 게르마늄에 의한 독성이 거의 나타나지 않은 반면에 $GeO_2$ 처리구에서는 일부 벼에서 게르마늄의 독성이 나타났다. 게르마늄 종류에 따른 잎의 게르마늄 흡수량은 $GeO_2$ 처리구에서 평균 177.0 ${\mu}g\;m^{-2}$로 수도작용 액상게르마늄 처리구보다 약 6배 높았으나, 줄기와 뿌리의 게르마늄 흡수량은 게르마늄 종류에 따라 전반적으로 큰 차이는 없었다. 게르마늄 종류에 따른 쌀겨 중 게르마늄 함량은 $GeO_2$ 처리구 및 수도작용 액상 게르마늄 처리구 모두 별 차이 없이 비슷한 경향이었고, 현미 중 게르마늄 함량은 $GeO_2$ 처리구에서 평균 40.9 mg $kg^{-1}$으로 수도작용 액상게르마늄 처리구의 평균 31.1 mg $kg^{-1}$보다 유의성 있게 높았다. 하지만 백미 중 게르마늄 함량은 $GeO_2$ 처리구에서 평균 7.9 mg $kg^{-1}$으로 수도작용 액상게르마늄 처리구의 평균 14.3 mg $kg^{-1}$보다 유의성 있게 낮았다. 게르마늄 종류에 따른 벼 부위별 게르마늄 흡수율은 전반적으로 잎 > 쌀겨 > 현미(백미) > 줄기 > 뿌리 순으로 잎에서 가장 높았다. 쌀의 미질은 전반적으로 게르마늄 종류에 따라 별 차이 없었으나 무처리구에 비해 약간 낮은 경향을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1154-1163
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• 2024

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4'-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4',7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4',5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.

• 한국산학기술학회논문지
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• 제12권9호
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• pp.4274-4282
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• 2011

본 연구는 염색폐수 처리시설에서 생물학적공정(2차) 처리를 거처 배출되고 있는 방류수 중에 미처리되어 잔존하고 있는 난분해성 유기물(COD) 성분을 제거하기 위하여, 고도처리공법으로서 Fenton 산화공정을 적용하여, 공법의 적용 가능성과 최적의 운전조건을 얻고자, 실험실 실험과 Pilot Plant 현장 운전을 실시하였다. 본 Fenton 산화실험의 원수로 사용된 생물학적(2차) 처리수의 수질은 실험기간동안 $COD_{Mn}$ 30~50mg/L으로 측정되었다. Fenton 산화반응 실험 결과, 최적의 반응조건은 pH 3~3.5, 반응시간 2~2.5시간, 약품 주입량비($FeCl_2$(33%)/$H_2O_2$(35%)) 3 : 1 로 나타났다. 약품 주입량 비가 적정조건일 때, 슬러지 발생량($SV_{2hr}$)은 전체 양의 21~28% 범위인 것으로 측정되었다. Pilot Plant 실험 결과, 산화반응조의 체류시간 변화에 따라 처리효율이 크게 영향을 받고 있었으며, 적정 체류시간은 2.0시간 이었다. 현장에 Pilot Plant($2m^3/d$)를 설치하여 연속운전을 실시한 결과, COD 농도가 제거효율 면에서 60~70%를 나타내었고, 처리수질은 20mg/L 이하로 측정되어, 대체로 안정적이고 양호한 처리효율을 나타내고 있었다.