• Environmental Analysis Health and Toxicology
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• v.4 no.3_4
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• pp.1-6
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• 1989

The effects of his ($\beta$-amino-ethyl-oxo) oxalate and bis ($\alpha$-amino-methyl-oxo) oxalate on the toxicity of lead acetate in rast were examined. Rats were given intraperitoneally at the dose of lead acetate 45 mg/kg. The exposure of lead acetate showed the 70% decrease of ALAD ($\delta$-amino levulinic acid dehydratase) activity in red blood cell. In vivo 122 mg/kg administration of bis ($\beta$-amino-ethyl-oxo) oxalate and bis ($\alpha$-amino-methyl-oxo) oxalate showed the 50% increase of ALAD activity, whereas 149 mg/kg administeration of Ca-EDTA had no effect. In vitro, the same results were obtained. Both compounds had hemolytic activity at concentrations higher than that required for showing the 50% ALAD activity increase in vivo.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.177-182
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• 2010

To synthesize $Gd_2O_3:Eu^{3+}$ phosphor, gadolinium-europium oxalate precursors were prepared from oxalic acid, NaOH or aqueous ammonia via coprecipitation method. The obtained precursors were heat-treated and then characterized by XRD, SEM and PL. The kinds and amounts of coprecipitant (NaOH or aqueous ammonia) were found to affect the powder morphology and properties of gadolinium-europium oxalate precursors. Two crystalline precursors and one amorphous precursor were synthesized. The nanometer-sized amorphous gadolinium-europium oxalate precursor was first prepared using the oxalate coprecipitation technique. The calcined powders obtained from the amorphous precursor were nearly spherical in shape, and a narrow size distribution was obtained. The NaOH coprecipitant was more effective in the preparation of nanometer-sized spherical powders. A thermal decomposition process was conducted for the three kinds of precursors. The photoluminescence property was also measured as a function of europium content, and concentration quenching occurred for samples with europium concentrations of over 10 mol%.

• The Korean Journal of Zoology
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• v.10 no.2
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• pp.1-8
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• 1967

토끼의 골격근 homogenate에서 23,000$\times$G, 60 분간의 원심분리와 얻은 근 microsome의 ATPase 활성, 근수축에 대한 이완작용, 및 Ca 의 흡수작용을 여러 가지 조건에서 측정하였다. ATPase 활성은 Ca++ Mg++ 양 이온의 존재에 의하여 활성화되며 , 5 mM Mg++ 의 존재하에서는 Ca++ 의 최적농도는 0.1mM이다. Oxalate의 존재하에서는 1 mM 의 Ca++ 이 최적농도이므로 oxalate의 작용은 불용성 Ca-oxalate의 작용은 불용성 Ca-oxalate를 microsome vesicle so 및 medium 내에 침전시켜 유리 Ca++ 농도를 저하시키는 것이라고 생각된다. Microsome의 이완작용은 조제후 120 시간까지 시간에 따라 감소되어 가나, 그이 ATPase 활성은 거의 변화가 없는 것으로 보아 Ca++ + Mg++ -의존성 ATPase 는 이완작용에는 직접 관련이 없는 것으로 해석된다. Oxalatedmlwhswo는 microsome의 Ca++ 흡수량을 현저히 증대시키며 동시에 흡수포화에 도달하는 시간을 지연시킨다. Oxalate의 이러한 효과도 Ca-oxalate의 형성에 기인하는 것으로 해석된다. Microsome 내에 축적되는 Ca 의 량은 ATP 농도가 커질수록 많아진다. 그러나 축적된 Ca 의 량과 ATP 농도사이에 화학정량론적 관계는 없는 것같다.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1456-1458
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• 2002

A simple, sensitive and selective determination method of oxalate has been investigated based on the fluorescence enhancement of $Eu^{3+}$-TTA complex due to the formation of $Eu^{3+}$-TTA-oxalate ternary complex. An emission peak of $Eu^{3+}$-TTA, which is increased linearly with addition of oxalate, occurs at 610 nm in aqueous solution with excitation at 306 nm. The linear range of the calibration curve is 1 ${\times}$$10^{-6}$-8 ${\times}$$10^{-6}$ M and the detection limit is 1 ${\times}$$10^{-6}$ M. The effects of foreign ions were studied. The present method was applied to determine oxalate of two synthetic samples.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.395-401
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• 1989

The concentrations of Cu(II), Y(III) and Ba(II) ionic species in aqueous solution due to the formation of Cu2+-oxalate-complex have been theoretically calculated with respect to pH and their solubility diagrams could be obtained. It was verified from the calculation that the excess of Cu2+ and Ba2+ should be added in order to obtain oxalate coprecipitates with the molar ratio of Y : Ba : Cu=1 : 2 : 3. The exact amount of excess species has been calculated with respect to the initial concentrations of metal ions and pH.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.38-50
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• 2022

As a low-cost and high-efficiency electrocatalysts with high performance and stability become a key challenge in the development of the practical use of water electrolysis, there is an intense interest in transition-metal oxalate-based materials. Transition-metal oxalate-based catalysts with excellent electrochemical performances have been widely applied in water electrolysis due to its low-cost and ease of synthesis. This review provides a useful summary on the development of transition-metal oxalate as potential catalysts for water electrolysis with a focus on the structural and compositional alteration, role of oxalate anion, and enhanced electrochemical performances.

• Journal of Ginseng Research
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• v.26 no.4
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• pp.213-218
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• 2002

Crystalline calcium oxalate occur throughout near)y all plants species in five major forms; styloids, druses, raphids, prisms and sands. These crystals are known to be distributed in specific tissue such as cortex, xylem, phloem, cambium and epidermis. This research was undertaken to identify the occurrence, type, location and ultrastructure of druse crystals in Panax ginseng. In situ visualization, conventional light microscopy, histochemistry and scanning electron microscopy were applied for these purposes. Druse crystals in ginseng were identified as calcium oxalate by silver nitraterubeanic acid histochemistry. Calcium oxalate crystals are observed in nearly all plant organs such as leaf, petiole, peduncle, stem, rhizome, tap root and lateral root except fine root. Most frequent observation of crystals in the leaf and rhizomes were noticed. Three different types of calcium of oxalate druse crystals were identified by scanning electron microscopy.

• Journal of the Korean Ceramic Society
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• v.32 no.4
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• pp.455-461
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• 1995

To investigate the synthesis of $\beta$-Al2O3 and its crystallization behavior by oxalate coprecipitation method, the optimum pH range for oxalate coprecipitates has been theoretically calculated from the solubility products and the equilibrium constans of each metal ionic species and their solubility diagram wa obtained. The optimum pH range for oxalate coprecipitates at room temperature was estimated as <4. In experiment, we found that the optimum condition for oxalate coprecipitates was pH<1, which was not doped with pH controller. The Na+ ions were easily exchanged for the NH4+ ions of NH4OH which was used as pH controller, and those NH4+ ions were supposed to affect the crystallization behavior of $\beta$-Al2O3. The thermal decomposition of all complexes was almost complete below 40$0^{\circ}C$. The primary product of the decomposition process was m-Al2O3, which transformed to $\beta$"- or $\beta$-Al2O3 at temperature higher than 100$0^{\circ}C$. We found that the powder prepared at 120$0^{\circ}C$ had only $\beta$"- and $\beta$-Al2O3.EX>-Al2O3.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.986-991
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• 2010

This study was conducted to investigate the changes of mineral, oxalate and phytate during tofu processing with Korean recommended soybean cultivars. Fourteen cultivars were selected by distribution of calcium, oxalate and phytate contents. Tofu was manufactured and analyzed for quality characteristics, mineral, oxalate and phytate contents. The yield and moisture contents of tofu ranged from 137.77% in Anpyeongkong to 201.91% of Geomjeongkong 4, and 74.42 (Bongeuikong)~80.01% (Hojangkong), respectively. The lightness (L-value), redness (a-value) and yellowness (b-value) ranged from 53.05 (Dawonkong) to 86.16 (Jipumkong 2), -2.04~5.85, and from 3.28 in Geomjeongkong 4 to 16.17 of Cheongjakong, respectively. The hardness of tofu with selected soybean cultivar ranged from 537.36 g (Dongpuktae) to 1696.05 g (Jinpumkong 2). The highest calcium content was 1.488 mg/g in Dawonkong, oxalate and phytate in tofu were high at 0.40 mg/g in Geomjeongkong 4 and 0.41 mg/g in Dawonkong, respectively. The transfer ratios of oxalate and phytate from soybean to tofu were ranged from 0.31~19.70 and 0.41~19.70%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.214-219
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• 2008

An experiment was conducted to evaluate the effects of nitrogen (N) level on the dry matter (DM) yield, N concentration and oxalate content of some tropical grasses, namely Rhodesgrass (Chloris gayana), Guineagrass (Panicum maximum) and Sudangrass (Sorghum vulgare). Three levels of N as urea were applied (Standard- 260, $Standard{\times}2$- 540 and$Standard{\times}4$- 1,060 kg N/ha for Rhodesgrass; Standard- 380, $Standard{\times}2$- 770 and $Standard{\times}4$- 1,570 kg N/ha for Guineagrass and Sudangrass) in a completely randomized design and grasses were harvested twice at approximately two-month intervals. Dry matter yield tended to be higher with increased rate of N fertilizer in all species, while further additional N ($Standard{\times}2$ or $Standard{\times}4$) did not significantly (p>0.05) further increase DM yield, when compared with the Standard level of N fertilizer application. There was also a trend towards higher N concentration in plants as N fertilization increased in all species and it was increased significantly in Rhodesgrass and Sudangrass (p<0.05 or p<0.01, respectively). Further additional N ($Standard{\times}2$ or $Standard{\times}4$) application showed no significant (p>0.05) differences on oxalate content in plant tissue within species, when compared with the Standard level of N. The Rhodesgrass contained 0.11, 0.13 and 0.15% soluble oxalate and 0.23, 0.25 and 0.27% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively. The Guineagrass contained 0.54, 0.50 and 0.42% soluble oxalate and 1.60, 1.56 and 1.45% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively. The Sudangrass contained 0.06, 0.15 and 0.12% soluble oxalate and 0.22, 0.22 and 0.21% total oxalate with Standard, $Standard{\times}2$ and $Standard{\times}4$ level of N application, respectively The results from this study suggest that these grasses do not use further addition of N fertilizer ($Standard{\times}2$ or $Standard{\times}4$) to form high content of oxalate salts, when compared with the Standard level of N. In addition, the levels of oxalate present with these grasses are quite low as far as toxicity to animals is concerned.