• 한국환경농학회지
• /
• 제29권1호
• /
• pp.61-65
• /
• 2010

Phytoextraction is a method of phytoremediation using plants to remediate metal-contaminated soils. Recently, various chelating agents were used in this method to increase the bioavailability of metals in soils. Even though phytoextraction is an economic and environment-friendly method, this cannot be applied in highly metal-contaminated areas because plants will not normally grow in such conditions. This research focuses on identifying chelating agents which are biodegradable and applicable to highly metal-contaminated areas. Lead (Pb) as a target metal and cysteine (Cys), histidine (His), citrate, malate, oxalate, succinate, and ethylenediamine (EDA) as biodegradable chelating agents were selected. Ethylenediamine tetraacetic acid (EDTA) was used as a comparative standard. Plants were grown on agar media containing various chelating agents with Pb to analyze the effect on root growth. Cys strongly increased the inhibitory effect of Pb on root growth of plants, while, His did not affect on it significantly. The inhibitory effect of oxalate is weak, and malate, citrate, and succinate did not show significant effects. Both EDTA and EDA diminished the inhibitory effect of Pb on root growth. The effect of EDA is correlated with decreased Pb uptake into the plants. In conclusion, as biodegradable chelating agents, EDA is a good candidate for highly Pb-contaminated area.

• 대한본초학회지
• /
• 제22권2호
• /
• pp.115-119
• /
• 2007

Objectives : A morphological classification among Sophora tonkinensis, Menispermum dauricum and Indigofera kirilowii was made through microscopic observation. Method : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Result : 1. The cross-sections of Sophora tonkinensis and Indigofera kirilowii have piths, but Menispermum dauricum does not have any. 2. The lateral parts of Sophora tonkinensis cortex include the square crystal of calcium oxalate, but Indigofera kirilowii does not. Conclusion : The number of piths and the presence of the square crystal of calcium oxalate can be used to distinguished Sophora tonkinensis from Indigofera kirilowii.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1991년도 추계학술대회 논문집
• /
• pp.33-36
• /
• 1991

For its outstanding magnetic property, preparations of MnZn ferrite were studied with various method. In this study, MnZn ferrite powders were prepared from ammonium oxalate and mixed metal sulfate by the controlled coprecipitation process. Considering to low dissolved each metal ion, high production yield and particle size, the established optimum reaction conditon by the statistical analysis of each results are that reaction temperature is $25^{\circ}C$, concentration of metal sulfate is 0.3M, molar ratio of ammonium oxalate/metal sulfate is 1.1:1. The effective experimental factor and characterization of the precipitated powder at optimum condition were studied.

• 분석과학
• /
• 제8권4호
• /
• pp.855-858
• /
• 1995

Vegetables contain more or less calcium. By the traditional method the total calcium in the vegetable was analyzed. A part or calcium in the vegetable is fixed as calcium oxalate and the calcium does not utilize for nutrition. In this investigation the free calcium was determined by extraction in boiling water, the combined calcium with oxalic acid was determined by extraction in 0.1 M hydrochloric aci and the other calcium combined with protein, amino acid etc. was estimated. The amount of calcium obtained from the difference between the total calcium and calcium exmtaining in calcium oxalate was estimated to be nutritious.

• 한국결정성장학회지
• /
• 제10권3호
• /
• pp.239-244
• /
• 2000

$LiMn_2$$O_4$Spine에 Li 과량 및 Mn 대신 Co를 일부 치환시킨 $_{1+x}$ Co$_{y}$ Mn$_{2-y}$ $O_4$(0$\leq$x$\leq$0.2,y=0,1/9,1/6) spinel에 대한 합성온도 결정, 상의 생성 등 고온 상평형에 대해 연구하였다. 고온 합성에 따른 제 2상의 생성을 방지하기 위해 저온합성이 가능한 습식화학적 합성법중 하나인 oxalate 침전법을 사용하여 $600^{\circ}C$ 이하에서 단일상의 spinel로 합성하였다. 이렇게 합성된 분말에 대해 TG-DTA분석 및 고온에서 급냉한 분말에 대한 XRD분석을 통해 질량(산소)의 증감에 연관된 가역적인 상전이 온도인 $T_1$, $T_2$및 $T_{2'}$ 들을 확인하였으며, 첨가된 Li의 양과 치환된 Co의 양에 따른 격자상수, 상전이 온도의 변화, 고온상의 안정성 등에 대해 연구하였다. 본 연구를 통해 Li$_{1+x}$ Co$_{y}$ Mn$_{2-y}$ $O_4$spinel의 합성온도 및 냉각속도 둥 합성과정 결정에 필요한 결과들을 얻을 수 있었다.

• 동아시아식생활학회지
• /
• 제5권2호
• /
• pp.63-71
• /
• 1995

Defatted sesame flour is the by-products obtained after oil extracting process. Although this flour has high quality and quantity of protein its use is limited only for animal feed and fertilization. Sesame seeds contain antinutrients such as oxalate, phytate and phenol compounds and these compounds lower their nutritive value. recently, ultrafiltration(UF) has been used to concentrate protein from various food sources. This study was carried out to examine the effects of UF with different membrane pore size on the components of sesame protein concentrates including antinutrients and to compare with that of conventional acid-precipitated sesame protein isolate. The protein contents of sesame protein concentrates prepared by JF using 10K, 30K, 100K were 84.2%, 82.7%, 76.4% and the protein yields were 36.44%, 34.69, 31.43% and the protein contents was 88.7% Alkali extraction process at pH 9.0 followed by UF technique reduced oxalate and phytate content. There were 85% and 94% reduction of oxalate and phytate content by UF with membrane pore size of 100K daltons, respectively. However, the content of total phenol compounds was not reduced by this method. About 99% of calcium and 50% of zinc were removed by UF with membrane of 100K daltons. total essential amino acid contents of sesame protein concentrates prepared by UF were decreased slightly when compared with acid-precipitated sesame protein concentrate.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권11호
• /
• pp.6257-6260
• /
• 2013

Gallstone disease is a major surgical problem in many populations; it is probably related to diet, especially excessive consumption of meat. The objective of this study was to determine the chemical composition of gallstones and their association with neoplastic changes including cholangiocarcinomas in cholecystectomised patients. The chemical composition of gallstones from 40 patients (8 males and 32 females) was analyzed. This is a prospective study performed in Baquba teaching hospital in the period from 1/10/2012 to 1/1/2013 in which we collected the gallstones for the patients who underwent cholecystectomy, whether open or laparoscopic. The stones were classified according to their chemical composition as a mixed stones (MS), and examined using a stone analysis set (chemical qualitative method) for calcium, magnesium, phosphate, uric acid and oxalate which was used reagent for qualitative determination of main individual components of stones. The results of this study showed the highest incidence of gallstones in the age group 40-49 was 13 cases followed by 11, 8 and 4 cases for age groups 30-39, 50-59, 20-29 and 60 and above, respectively. The chemical analysis showed the majority of gallstones were mixed, 38 containing calcium followed by 37 cases with uric acid, 28 with magnesium, and 25 and 22 stones with oxalate and phosphate, respectively. Microscopically, we confirmed neoplastic changes (17.5%) as cholangiocarcinomas (CCCs) (7.55%) and dysplastic cells of carcinoma in situ in 4 (10%), 31 (77.5%) cases were chronic cholecystitis and 2 (5%) cases were acute cholecystitis with empyema out of bile duct disorders patients. In conclusion, majority of cases had mixed gallstones that involved five and four of inorganic chemicals of calcium, magnesium and phosphate, the highest incidence of gallstones in age group 40-49 years old was 13 cases, and neoplastic changes were confirmed (17.5%) including CCCs, (7.5%) and dysplastic cells of carcinoma in situ (10%), while 31 (77.5%) cases were chronic cholecystitis.

• 대한본초학회지
• /
• 제20권2호
• /
• pp.77-82
• /
• 2005

Objectives : A morphological classification among Achyranthes japonica Nakai (produced in Korea), A. bidentata Blume (imported from China), and Cyathula officinalis Kuan (used in China exclusively) was made through microscopic observation. Method : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Result : 1. Korean A. japonica Nakai has slim roots, whose diameter is $1{\sim}5\;mm$. 1) Most of its intersection is stele, which includes a lot of vascular bundles. The inside of vascular bundles shows the arrangement of $2{\sim}4$ cycles, the innermost wheel of which is divided into two parts. 2) Parts of parenchymatous cell include Crystal sand of calcium oxalate. 2. The diameter of the roots of Chinese A. bidentata Blume is $0.4{\sim}1\;cm$. 1) The xylem in the vascular bundle in the middle of its intersection is rather big, around which the inner parts of the vascular bundles are arranged in the shape of $2{\sim}4$ cycles around. The most outside part of it is small, and the middle part is gathered into $2{\sim}3$ groups. 2) Parts of parenchymatous cells include Crystal sand of calcium oxalate. 3. The roots of Chinese C. officinalis Kuan is thick, whose diameter is $0.5{\sim}3\;cm$. 1) Vascular bundle of its intersection is spotted, arranged in the shape of $4{\sim}11$ concentric circles, whose center is divided into $2{\sim}9$ groups. 2) Parenchymatous cells include crystal sand and square crystal of calcium oxalate. Conclusion : It is concluded that Achyranthes japonica Nakai, A. bidentata Blume, and C. officinalis Kuan have different shapes in both external forms and internal intersections, so that they can be easily distinguished from one another through microscopic observation.

• 생명과학회지
• /
• 제20권7호
• /
• pp.1041-1046
• /
• 2010

Phytoextraction은 식물을 이용하여 환경 정화하는 한 기술로서 금속으로 오염된 토양을 정화하는 것이다. 토양에 존재하는 금속의 추출을 용이 하기 위해서 현재 다양한 킬레이트가 사용되고 있다. Phytoextraction이 경제적이고 친환경적인 장점이 있지만 고농도로 오염된 지역에서는 적용이 어려운데 이는 식물이 이러한 지역에서 살아남기 어렵기 때문이며 이러한 문제점을 해결하는 것이 본 연구의 목적이다. 연구 대상의 금속으로서 알루미늄을 선택하였고, 킬레이트는 아미노산인 시스테인과 히스티딘, 작은 크기의 유기산으로서 citric acid, malic acid, succinic acid, oxalic acid, 그리고 ethylenediamine (EDA)를 선택하였으며, EDTA는 비교 대상으로 본 연구에 사용되었다. 다양한 농도의 알루미늄를 포함하는 배지에 식물을 키우면서 여러 킬레이트가 식물의 뿌리 성장에 미치는 영향을 분석하였다. 알루미늄에 의한 식물의 성장 억제는 히스티딘에 의해서 약간 완화되었으며 시스테인, citrate, malate, oxalate, 그리고 succinate는 별 다른 영향이 없었다. EDTA와 EDA는 알루미늄에 의한 식물성장 억제를 강력하게 억제하였으며 이는 알루미늄의 식물 내 흡수를 억제에 의한 것이다. 따라서 알루미늄의 식물성장억제를 강력하게 완화시켜주는 EDA는 고농도의 알루미늄으로 오염된 지역에 식물의 성장이 가능하도록 유용하게 사용될 수 있을 것이다.

• 전기화학회지
• /
• 제10권4호
• /
• pp.288-294
• /
• 2007

Modified oxalate method에 의해 합성한 중온형 Solid Oxide Fuel Cell 용 LSCF cathoded의 pH 변화에 따른 분말특성 및 여러 종류의 전해질에 따른 전극특성에 대해 연구하였다. LSCF를 합성하기 위한 출발물질로는 La, Sr, Co 및 Fe의 염화물과 oxalic acid, ethanol 및 $NH_4OH$를 사용하여, $80^{\circ}C$ 에서 pH 2, 6, 7, 8, 9 및 10에서 합성하였다. 합성한 LSCF 분말은 pH $2{\sim}9$까지는 단일상의 LSCF 결정상을 생성하였다. 그러나, PH 10에서는 LSCF결정상 외에 이차상인 $La_2O_3$ 결정상이 나타났으며, 또한 $800^{\circ}C$에서 4시간 하소한 경우 50 nm정도의 작은 크기를 나타내었다. 합성한 LSCF cathode 분말의 전기전도도는 pH 7에서 합성한 LSCF 분말의 경우 $600^{\circ}C$부터 $900^{\circ}C$까지 측정하였을 때 약 950 S/cm의 높은 값을 나타내었다. 또한 분극저항의 경우 같은 합성 조건에서 합성한 LSCF 분말이라도 하소조건에 따라 다른 결과를 나타내었는데, $800^{\circ}C$에서 하소한 분말의 경우 $1200^{\circ}C$에서 하소한 분말 보다 낮은 분극저항을 나타내었다. 특히 $800^{\circ}C$에서 4시간 하소하여 합성한 LSCF 분말은 $600^{\circ}C$에서 Scandia Stabilized Zirconia (ScSZ), yttria (8mol.%)-stabilized zirconia(8Y-YSZ) 및 Gadolinium Doped Ceria(GDC) 전해질을 사용하였을 때, 전극면적이 $0.5\;cm^2$일 때 각각 2.52, 1.54 및 $2.58\;{\Omega}$을 나타내었다.