• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.263-271
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• 1995

Chemical assessment of soil pollution with heavy metals was made by analyzing the changes in pH, ionic strength, cationic concentration and chemical species in the soil solution. Saturated pastes of the unpolluted soils were made by adding solutions containing Cu or Cd and the final Cu or Cd concentrations were in the range of 0 to 400 mg/kg. After equilibrating for 24 hours at $25^{\circ}C$, the soil solution was extracted from the saturated pastes by the vacuum extraction method and analyzed for pH, electrical conductivity, Cu, Cd, cations and inorganic ligands. Chemical species in soil solution were calculated by the GEOCHEM-PC program employing the input variables of pH, ionic strength(${\mu}$), molar concentrations of cations and ligands. Increasing Cu or Cd additions lowered pH of the soil solution but increased concentrations of Ca, Mg and K resulting in increases of ${\mu}$ of the soil solution. Effects of Cu on lowering pH and increasing ${\mu}$ were greater than those of Cd. Concentrations of Cu or Cd in soil solution were relatively very low as compared to those of additions, but increased linearly with increasing additions representing that concentrations of Cu were higher than those of Cd. At 400 mg/kg additions, concentrations of Cu were in the range of 0.51 to 11.70 mg/L but those of Cd were 34.4 to 88.5 mg/L. Major species of Ca, Mg and K were free ions and these species were equivalent to greater than 95 molar % of the existing respective molar concentrations. These cationic species were not changed by Cu or Cd additions. Major species of Cu in lower pH soils such as SiCL and SL were free $Cu^{2+}$ (>95 molar %), but those in LS having a higher pH were free $Cu^{2-}$ and Cu-hydroxide complex. At 100 mg Cu/kg treatment, $Cu^{2+}$ and Cu-hydroxide complex were equivalent to 73 and 22.4 molar %, respectively. These respective percentages were decreased and increased correspondingly with increasing Cu treatments. Major species of Cd in soil solution were free $Cd^{2+}$ and Cd-chloride complex, representing 79 to 85 molar % for $Cd^{2+}$ and 13 to 20% for Cd-chloride complex at 10 mg Cd/kg treatment. With increasing Cd additions to 400 mg/kg, $Cd^{2+}$ species decreased to $40{\sim}47%$ but Cd-chloride complexes increased to $53{\sim}60$ molar %. These results demonstrated that soil contamination with heavy metals caused an adverse effect on the plant nutritional aspects of soil solution by lowering pH, increasing cations temporarily, and increasing free metal concentrations and species enough to be phytotoxic.

• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.62-68
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• 2016

A chromium-free Ce-based conversion coating formed by immersion in a solution containing cerium chloride and nitric acid on AZ31 magnesium alloy has been studied. The effects of acid pickling on the morphology and the corrosion resistance of the cerium conversion coating were investigated. The corrosion resistance of the conversion coating prepared on AZ31 Mg alloy after organic acid pickling was better than that of inorganic acid pickling. The morphology of the conversion-coated layer was observed using optical microscope and SEM. Results show that the conversion coatings are relatively uniform and continuous, with thickness 1.0 to $1.1{\mu}m$. The main elements of the conversion coating of AZ31 Mg alloy are Mg, O, Al, Ce and Zn by EDS analysis. The electrochemical polarization results showed that the Ce-based conversion coating could reduce the corrosion activity of the AZ31 Mg alloy substrates in the presence of chloride ions.

• Tuberculosis and Respiratory Diseases
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• v.39 no.2
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• pp.131-140
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• 1992

In order to investigate the changes of hydroxyproline amount and pathologic finding in rat lung which were instilled the natural coal and free silica dust intratracheally, the subjects were divided into two groups as follows. The control group was only administered intratracheally 0.5 ml of normal saline, and the experimental groups were instilled at once the turbid solution containing 10 mg, 30 mg and 50 mg of natural coal and free silica dust each, subjects were sacrified at the 3rd and the 20th week each after the experiment. Hydroxyproline amount in the right upper lung was measured by Woessner method and HPLC (modified Dunphy) method, and the pathlogic finding of lung tissue were observed for hematoxylin-eosin staining, Bielschowski method and Masson's trichrome method. The results were as follows. 1) The wet lung weights of all experimental groups excluding in the groups instilled 10 mg and 30 mg of natural coal dust at 3rd week, were significantly increased (p<0.05) compared with control group. The weight in each free silica group was markedly increased (p<0.05) at 20th week compared with the same dose of natural coal dust group, while the weight in the same dose group of free silica dust was increased significantly at 20th week compared with at 3rd week. 2) The amount of hydroxyproline were significantly increased (p<0.05) in the natural coal and free silica groups at 20th week compared with the control groups, and in each experimental group instilled the same kind and dose of dust, its amount was markedly increased (p<0.05) at 20th week compared with at 3rd week. And also the hydroxyproline in 30 mg and 50 mg free silica groups increased markedly (p<0.05) at 20th week compared with the natural coal dust of the same dose. 3) The polymorphonuclear leukocytes, fibroblasts and macrophages in interstitium and alveolar space showed the increasing tendency in the free silica group more markedly than in the natural coal dust group. The exudate in alveolar space at 3rd week was disappeared at 20th week, and pneumoconiotic nodules observed microscopically in all experimental groups at 20th week, while the nodules apeared already at 3rd week in the 30 mg and 50 mg free silica dust groups. The significant increase of Hydroxyproline content in lung tissue and pneumoconiotic nodule formation in experimental groups found in this study indicate that the observation period, dust amount and kind of dust is important factors associated with pneumoconiosis. And these findings were generally more severe in free silica dust groups than in natural coal groups.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1543-1546
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• 2011

N-Bromosaccharin/$Mg(ClO_4)_2$ is an effective and regioselective system for ${\alpha}$-monobromination of 1,3-dicarbonyl compounds. A wide variety of ${\beta}$-keto esters and 1,3-diketones in reaction with this system afforded a regioselectively ${\alpha}$-monobrominated products. The bromination reaction can be conducted at 0-5 $^{\circ}C$ either in solution or under solvent-free conditions.

• Journal of Chest Surgery
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• v.31 no.5
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• pp.451-455
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• 1998

Bovine pericardial bioprosthesis treated with glutaraldehyde is one of the most popular prosthetic materials, but late calcific degeneration must be solved. According to the alleged hypothesis of this calcification mechanism the free aldehyde groups on the surface of the tissue treated with glutaraldehyde bind to the circulating free calcium and induce mineralization. For mitigating the calcific degeneration, I added MgCl2 into the 0.625% glutaraldehyde solution to compete with calcium for binding to free aldehyde from the glutaraldehyde. I prepared 60 pieces of square shaped bovine pericardia and fixed in the 0.625% glutaraldehyde solution as control group(group 1), and the other 60 pieces in the same glutaraldehyde solution with 4g/L MgCl2 6H2O as the other group(group 2). After fixation for 1 month these were implanted into the bellies of 60 Sprague-Dawley rats subdermally and extracted on 1 month, 2 months, 3 months and 6 months later. With atomic absorption spectophotometry I measured the deposited calcium amount with the following results; 1 month and 2 months after implantation I could not find any differences between two groups, but in the 3rd month calcium was 1.738 mg/g in group 1 and 0.786 mg/g in group 2 and in the 6th month calcium had risen to 3.102 mg/g in group 1 and 1.623 mg/g in group 2, which has statistical significance(p<0.05). This means magnesium shows meaningful calcium mitigation effects on subcutaneously implanted bovine pericardium in the rat models.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.317-321
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• 2013

This study was conducted to investigate the antimicrobial effect of freely available chlorine (FAC) on the vase life of cut rose 'Brut' (Rosa hybrida L.). Postharvest treatments to extend the vase life of cut roses were divided into holding solution treatment and pulsing solution treatment. In holding solution treatment, the cut roses were treated with the preservative solutions containing FAC (0, 10, 20, and $40mg{\cdot}L^{-1}$) and sucrose (0 and 2%, w/v). In pulsing solution treatment, cut roses were dipped into the FAC solutions of 100, 200, and $400mg{\cdot}L^{-1}$ for 10 seconds. The longest vase life of cut roses was observed in the holding solution with FAC $20mg{\cdot}L^{-1}$ as 12 days, followed by pulsing with $400mg{\cdot}L^{-1}$ as 11 days, which were four or five days longer than the control. In addition, relative fresh weight and water uptake were the highest in the holding solutions with FAC 20 and $40mg{\cdot}L^{-1}$. The antimicrobial effect of FAC in vase solution was lasted for eight days after treatment, which was offset by sucrose addition. FAC contents in the FAC holding solution mixed with sucrose were exhausted by 88% two days after treatment, whereas only 15% of FAC was reduced in the holding solution without sucrose. This study indicated that FAC can be applied to extension of the postharvest life of cut roses by antimicrobial activity.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.351-356
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• 2006

In this study, we investigated the effect of adding a 1, 3, or 5% solution of germinated brown rice concentrate (GBRC) to fermented kimchi. During fermentation, the concentration of free amino acids and essential amino acids increased with increasing concentrations of GBRC. In particular, higher levels of free amino acids were associated with a sweet taste compared with controls. The ${\gamma}$-aminobutyric acid (GABA) content of kimchi containing the 5% GBRC solution was 3 times higher than that of controls. The total phenolic compound content (130 mg%) did not change significantly in the control group, but increased in 10 mg% increments as the GBRC concentration rose from 1 to 3 to 5%. 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity and superoxide radical scavenging activity also increased with the GBRC concentration, with maximum activity during the ripe stage with GBRC measured at 79 to 82% compared with controls (30 to 71 %). The nitrite scavenging activity was 10% higher with GBRC compared with controls and was highest when the pH was 1.2. These results showed that the addition of GBRC is effective in improving the function of kimchi.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.5
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• pp.229-238
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• 2015

The effects of Sn addition and solution treatment on corrosion behavior were studied in AZ91 magnesium casting alloy. The addition of 5%Sn contributed to the introduction of $Mg_2Sn$ phase, to the reduction in dendritic cell size and to the increase in the amount of secondary phases. After the solution treatment, trace amount of $Al_8Mn_5$ particles were observed in the ${\alpha}$-(Mg) matrix for the AZ91 alloy, while $Mg_2Sn$ phase with high thermal stability was additionally found in the AZ91-5%Sn alloy. Before the solution treatment, the AZ91-5%Sn alloy had better corrosion resistance than the Sn-free alloy, which is caused by the enhanced barrier effect of the (${\beta}+Mg_2Sn$) phases formed more continuously along the dendritic cell boundaries. It is interesting to note that after the solution treatment, the corrosion rate of both alloys became increased, but the Sn-added alloy showed higher corrosion rate than the Sn-free alloy. The microstructural examination on the corroded surfaces revealed that the remaining $Mg_2Sn$ particles in the solution-treated AZ91-5%Sn alloy play a role in accelerating corrosion by galvanic coupling with the ${\alpha}$-(Mg) matrix.

• Journal of Pharmacopuncture
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• v.10 no.3
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• pp.53-62
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• 2007

Objective The objective of this study was to investigate the antioxidative effects of Puerariae Radix extract. Method Total antioxidant capacity (TAC), Total antioxidant response (TAR), Total phenolic content, Reactive oxygen species (ROS), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities, lipid peroxidation were examined. Result Total antioxidant status was examined by total antioxidant capacity(TAC) and total antioxidant response(TAR) against potent free radical reactions. TAC and TAR of Puerariae Radix extract at the concentration of 5 mg/ml were 2.02 and 1.50 mM Trolox equivalents, respectively. Total phenolic content of Puerariae Radix extract at the concentration of 5 mg/ml was 2.29 mM gallic acid equivalent. Concentration of Puerariae Radix extract at which DPPH radical scavenging activity was inhibited by 50% was 5.91 mg/ml as compared to 100% by pyrogallol solution as a reference. The inhibitory effect of the extract on lipid peroxidation was examined using rat liver mitochondria induced by FeSO4/ascorbic acid. Puerariae Radix extract at the concentration of 1 mg/ml slightly but significantly decreased TBARS concentration. The extract further prevented lipid peroxidation in a dose-dependent manner. The effect of Puerariae Radix extract on reactive oxygen species (ROS) generation was examined using cell-free system induced by hydrogen peroxide/FeSO4. Addition of 1 mg/ml of Puerariae Radix extract significantly reduced dichloroflurescein (DCF) fluorescence. The extract caused concentration-dependent attenuation of the increase in DCF fluorescence, indicating that the extract significantly prevented ROS generation in vitro. Thus antioxidant effects of Puerariae Radix extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation, followed by inhibition of lipid peroxidation. Conclusion As a result, Puerariae Radix seems to have antioxitative effect and antioxidant compount.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.380-385
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• 1988

The urease adsorption on zeolite and the various properties of adsorbed urease were investigated to find out the influence of zeolite on activity and properies of urease. Free urease in solution was adsorbed on zeolite untill the max. adsorption, and the amount of max. adsorption was 11.3mg urease/100mg zeolite at pH 7.0. It is apparent that free urease was adsorbed on the outer surface of zeolite by cation exchange reaction, and more than 70% of urease adsorption was adsorbed within 30 min. The activity of adsorbed urease was decreased by 89.6%, whereas Km value was increased to 34.4mM, which is higher than that of free urease. The optimum pH of adsorbed urease was widened 6.5 to 7.0, compared to that of free urease 7.0. The resistance of urease to protease became weaker by adsorption, however substrate specificity and thermal stability were not affected.