• Korean Journal of Plant Tissue Culture
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• v.24 no.6
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• pp.361-367
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• 1997

This study was carried out to select cadmium resistant cell lines from leaf-derived calli of diploid and haploid of Nicotiana tabacum cv. BY4, for understanding adaptation mechanism of plants in cadmium contaminated environment. suspended cell clumps were plated onto selection medium containing 0 to 2,000 $\mu$M cadmium. Cadmium resistant colonies were formed on the selection medium after 3 or 4 weeks of culture. The minimum inhibition concentration (MIC) of cadmium on colony formation were 300 $\mu$M in diploid and 200 $\mu$M in haploid plants, respectively. In order to test the resistance to cadmium, selected cell line on MIC were transferred to medium containing high concentration of cadmium. The selected cell lines, especially haploid cell line, were resistant an the high concentration of cadmium. And dry weight, ash weight, and cadmium contents of cell were increased. These results indicated that the selected cell lines showed higher resistance of cadmium than control cells, and haploid plant is more resistant than diploid plant on medium with cadmium.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.391-400
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• 2018

Background: Atractylodes radix is a well-known medicinal crop having many physiological effects. This study was conducted to select useful Atractylodes japonica ${\times}$ Atractylodes macrocephala (AJM) cultivars by comparing anti-oxidative and anti-inflammatory efficacies. Methods and Results: Seven extracts from AJM cultivars were used to treat lipopolysacchride (LPS)-treated BV2 cells, and the effects on cell viability and inhibition on reactive oxygen species (ROS) and nitric oxide (NO) production were analyzed. In vitro scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and peroxynitrite ($NOO^-$) radicals were also investigated. Contents of total phenol, atractylenolide I, and atractylenolide III in the AJM extracts were measured using high performance liquid chromatography (HPLC) or spectrophotometry. The experiments show that none of the seven extracts was cytotoxic above 89.2% at $20-250{\mu}g/m{\ell}$. Extracts of Gowon, Dawon, Sangchul, and Huchul inhibited ROS generation in a dose-dependent manner, and Sangchul extract showed the highest inhibition on ROS production. All the AJM extracts showed effective inhibitory activity after on NO release in the LPS-treated BV2 cells, and Sangchul extract showed the highest activity. Sangchul extract had the most potent scavenging activities for $NOO^-$ and had some DPPH radical scavenging effect. Sangchul extract also had the highest content at total phenol and atractylenolide I content. Atractylenolide III was not detected in the AJM extracts. Conclusions: The results suggested that Sangchul was the most useful anti-oxidative and anti-inflammatory resource among the AJM cultivars.

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.14-21
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• 1992

Allanite crystals rich in rare-earth elements(REE) occur in soil developed on top of anorthositic rocks in the Jungsu-ri area of Okjong-myun, Hadong-run, where large Ti orebodies are embedded in the bed rock. In this study allanite is investigated mainly by transmitted light microscopy, electron microprobe analysis, atomic absoption spectrophotometry, X-ray diffraction, infrared spectrocopy. In addition, its specific gravity and micro=indentation hardness value are measured. Allanite occurs with max. dimension of $3cm{\times}6cm$ and coexists with quartz, epidote, zircon, biotite and muscovite. It shows nearly nonmetamict crystallinity, although ${\alpha}$-particles bombardment from the disintegration of the radioactive element Th is detected by an autoradiography. The allanite is particularly enriched in REE(19.88-23.99 wt.%), but is deficient in CaO(8.35-10.29wt.%). Genesis of the allanite in this area is not understood yet. It is, however, assumed to have been formed from magmatic fluid rich in REE and Ti, based on the facts that it ocexists with zircon and that it has high $TiO_2$(0.89-1.13 wt.%) whose concentration is significant in the country rocks.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1169-1174
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• 1999

2-Diazo-1-naphthoquinone-5-sulfonyl chloride(NQD-Cl) was synthesized from sodium 2-diazo-naphthoquinone-5-sulfonate by chlorination. NQD-Cl was esterified with hydroxybenzophenones to give several 1,2-naphthoquinone-(2)-diazide-5-sulfonic acid ester derivatives(NQD-esters). We have compared benzophenone derivatives with methoxy group to benzophenone derivatives with hydroxy group. Solubility of each NQD-ester was studied. Each of NQD-esters was formulated with novolac base resin and PS plates were manufactured. Photosensitivity, bleachability, compatible exposed time and relative sensitivity were determined by UV spectrophotometry, imaged by UV lithographic techniques, and the gray scale method. According to the number of substituted NQD group, it showed that relative sensitivity was different from gray scale method. NQD-esters with methoxy group showed a good solubility and higher sensitivity than commercial PS ones.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.484-495
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• 1989

Reactions of $(Et_4N)_2[MoOCl_5]$ with multidentate ligands containing nitrogen or/and oxygen donor atom (EDTA, DTPA, IDA, CyDTA, OX) produce a series of binuclear molybdate (V) complexes. The prepared Mo (V) complexes has been identified by Elemental Analysis, Infrared Spectra, Proton Magnetic Resonance Spectra, and Electronic Spectra. The electrochemical reduction mechanism has been studied by Cyclic voltammetry, Controlled Potential Coulometry, and Spectrophotometry in pH 3.571-10.375 acetate, borate, phosphate/sodium hydroxide, phosphate, ammonium/ammonia buffers. The cyclic voltammogram of the Mo-EDTA, DTPA, IDA, CyDTA complexes at pH < ca. 6.00 have shown two reduction waves. The first reduction wave shows two electron process and the second reduction wave shows two electron process. The cyclic voltammogram of the Mo-EDTA, DTPA, IDA, CyDTA complexes at pH < ca. 8.00 has shown one reduction wave. This reduction wave show four electron process. The cyclic voltammogram of the Mo-OX complex at pH < ca. 7.2 has shown one reduction wave. This reduction wave show four electron process.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.540-545
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• 1992

Kinetics and mechanism on the solvent extraction of nickel(Ⅱ) with 8-hydroxyquinoline (HOx) was studied spectrophotometrically. Absorbance variation was measured by changing the 8-hydroxyquinoline concentration in the chloroform organic phase and the pH values in the aquous phase. By analyzing absorbance data the reaction rate was found to be the first order for 8-hydroxyquinoline concentration and the inverse first one for [H$^+$]. Therefore the rate determining step of the extraction reaction is the formation of the one-to-one metal chelate NiOx$^+$ and the rate equation is as follows; -d[Ni$^{2+}$]/dt = k[Ni$^{2+}$][Ox$^-$] = k'[Ni$^{2+}$][HOx]$_0$/[H$^+$]. The value of k' was evaluated from the slope of plot of log [Ni$^{2+}$]$_0$/[Ni$^{2+}$]$_t$ versus time and the rate constant k was calculated according to the equation k' = k ${\times}$ K$_{HOx}$ / K$_{D,HOx}$. From the temperature dependence of the extraction rate, the activation energy E$_a$ = 6.26 kcal/mol is calculated, and activation parameters, ${\Delta}$G$^{\neq}_{298}$ = 6.59 kcal/mol, ${\Delta}$H$^{\neq}_{298}$ = 5.68 kcal/mol, ${\Delta}$S$^{\neq}_{298}$ = -3.09 eu/mol are estimated.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.667-675
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• 1994

The precipitate flotation using $La(OH)_3$ as a coprecipitant was studied for the simultaneous determination of trace three elements in a sea water. Several experimental conditions such as pH, coprecipitant and surfactant were investigated with an artificial sea water. To remove the influence of Cr(VI) the Cr(VI) was reduced to Cr(III) using $NaBH_4$ prior to the flotation. Trace amounts of Cu(II), Co(II) and total Cr in 1.0 l sea water was coprecipitated together with the precipitation of $La(OH)_3$ in the solution of pH 9.8 adjusted with 3.OM NaOH solution. The precipitate was floated by using a mixed surfactant (1 to 8 of each 0.5% ethanolic sodium oleate and sodium dodecylsulfate solution) by bubbling a nitrogen gas. The floats was separated and filtrated from the mother liquor by suction. The precipitate was dissolved in 7.0 M $HNO_3$ solution and then marked to 25.0 ml with a deionized water. These elements were determined by graphite fumace atomic absorption spectrophotometry. This method was applied to determine the elements in the sea water of the Eastern and Western coasts. And the recoveries were over 90.0% in the samples into which given amounts of the analyte elements were spiked.

• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.298-306
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• 2006

A rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of neomycin and streptomycin either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C), and methylene blue (method D), in the same acid medium at a suitable lmax=521, 485, 610 and 664 nm, respectively. Beers law is obeyed in the concentration range of 5-10 and 2-7 mg mL-1 for neomycin and streptomycin, respectively. The apparent molar absorptivity and sandell sensitivity values are in the range 5.47-6.20104, 2.35-2.91105 L mol-1 cm-1 and 7.57-8.59, 5.01-6.2 ng cm-2 for neomycin and streptomycin, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods.

• Clean Technology
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• v.19 no.4
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• pp.401-409
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• 2013

BBiodegradable polymers have attracted great attention because of the increased environmental pollution by waste plastics. In this study, PLA (polylactic acid)/Clay-20 (Cloisite 20) and PLA (polylactic acid)/PBS (poly(butylene succinate)/Clay-20 (Cloisite 20) nanocomposites were manufactured in a twin-screw extruder. Specimens for mechanical properties of PLA/Clay-20 and PLA/PBS (90/10)/Clay-20 nanocomposites were prepared by injection molding. Thermal, mechanical, morphological and raman spectral properties of two nanocomposites were investigated by differential scanning calorimetry (DSC), tensile tester, scanning electron microscopy (SEM) and raman-microscope spectrophotometer, respectively. In addition, hydrolytic degradation properties of two nanocomposites were investigated by hydrolytic degradation test. It was confirmed that the crystallinity of PLA/Clay-20 and PLA/PBS/Clay-20 nanocomposite was increased with increasing Clay-20 content and the Clay-20 is miscible with PLA and PLA/PBS resin from DSC and SEM results. Tensile strength of two nanocomposites was decreased, but thier elongation, impact strength, tensile modulus and flexural modulus were increased with an increase of Clay-20 content. The impact strength of PLA/Clay-20 and PLA/PBS/Clay-20 nanocomposites with 5 wt% of Clay-20 content was increased above twice than that of pure PLA and PLA/PBS (90/10). The hydrolytic degradation rate of PLA/Clay-20 nanocomposite with 3 wt% of Clay-20 content was accelerated about twice than that of pure PLA. The reason is that degradation may occur in the PLA and Clay-20 interface easily because of hydrophilic property of organic Clay-20. It was confirmed that a proper amount of Clay-20 can improve the mechanical properties of PLA and can control biodegradable property of PLA.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.29-42
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• 1998

$Mg^{2+}$ is one of the most abundant divalent cations in mammalian body(0.2~1.0mM) and the important physiological roles are : first, the cofactor of many enzyme activities, second, the regulator of glycolysis and DNA synthesis, third, the important role of bioenergetics by regulating of phosphorylation, fourth, the influence of cardiac metabolism and function. In this work we have investigated the regulation of the $Mg^{2+}$ induced by ${\alpha}_1-adrenoceptor$ stimulation in perfused guinea pig hearts and isolated myocytes. The $Mg^{2+}$ content of the perfusate or the supernatant was measured by atomic absorbance spectrophotometry. The elimination of $Mg^{2+}$ in the medium increased the force of contraction of right ventricular papillary muscles, and the left ventricular pressure. Phenylephrine also enhanced the force of contraction in the presence of $Mg^{2+}-free$ medium. ${\alpha}_1-Agonists$ such as phenylephrine and methoxamine were found to induce $Mg^{2+}$ efflux in both perfused hearts and myocytes. These effects were blocked by prazosin, an ${\alpha}_1-adrenoceptor$ antagonist. The $Mg^{2+}$ influx could also be induced by phenylephrine and R59022, a diacylglycerol kinase inhibitor. In the presence of protein kinase C(PKC) inhibitors, phenylephrine produced an increase in $Mg^{2+}$ efflux from perfused hearts. Furthermore, $Mg^{2+}$ efflux by phenylephrine was amplified by phorbol 12-myristate 13-acetate(PMA). This enhancement of $Mg^{2+}$ efflux by PMA was blocked by prazosin in perfused hearts. By contrast, the $Mg^{2+}$ influx could be induced by verapamil, nifedipine, ryanodine in perfused hearts, but not in myocytes. $W^7$, a $Ca^{2+}$/calmodulin antagonist, completely blocked the phenylephrine-induced $Mg^{2+}$ efflux in perfused hearts. In conclusion, $Mg^{2+}$ is responsible for the cardiac activity associated with ${\alpha}_1-adrenoceptor$ stimulation. The mobilization of $Mg^{2+}$ is decreased or increased by ${\alpha}_1-adrenoceptor$ stimulation in guinea pig hearts. These responses may be related specifically to the respective pathways of signal transduction. A decrease in $Mg^{2+}$ efflux by ${\alpha}_1-adrenoceptor$ stimulation in hearts can be through PKC dependent and intracellular $Ca^{2+}$ levels.