• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.824-831
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• 1992

Absorption spectra were observed for several Ho(III)-ligand systems in aqueous solution under the changes of ligand concentration and temperature. The intensity change of hypersensitive band $(^5I_8\;\to\;^5G_6)$ was quite remarkable with temperature and concentration, and was interpreted as the change of coordination environments. The transition intensities observed in these spectra were analyzed in terms of the Judd-Ofelt intensity parameters, $\Omega_\lambda$ ($\lambda$ = 2, 4, 6), for 4f $\to$ 4f electric dipole transitions. The $\Omega_2$ parameter was the most sensitive to the temperature and concentration. Using the changes of $\Omega_2$, $Cl^-$ and ${NO_3}^-$ ions were found to form inner sphere complexes in aqueous solution.

• Journal of the Korean Chemical Society
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• v.58 no.3
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• pp.283-288
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• 2014

A column solid phase extraction procedure based on modified polyurethane foam (PUF) by a newly synthesized Schiff base ionophore, named 2,2'-{iminobis[propane-3,1-diylnitrilo(1E)prop-1-yl-1-ylidene]}diphenol, was developed for preconcentration step of trace amounts determination of copper ions in water samples by atomic absorption flame spectroscopy. The influence of parameters on the adsorption process such as sample pH, amount of modified PUF packed in the column, type and volume of stripping reagent and its flow rate were investigated and optimized. Under optimum experimental conditions, the calibration graph was linear in a relatively wide range ($0.005-210{\mu}g/ml$) with a limit of detection $0.002{\mu}g/ml$ of copper. The proposed method allows achieving to a concentration factor of >133. The capacity of a column (1.6 cm i.d.) packed by 6 g of PUF modified by 12 mg of the Schiff base was found to be $247.7({\pm}2.1){\mu}g$ of copper. It was found that the adsorption process was highly selective towards copper ions with respect to some associated metal ions. The presented procedure was successfully applied for determination of copper in some water samples.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.273-279
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• 1990

For poly- $\beta$ -hydroxybutyrate (PHB) production, a pink-pigmented facultative methylotrophic bacterium (PPFM) P-10 was newly isolated from soils through methanol-enrichment culture. The optimal medium composition for cell growth was 1.0% (vlv) of methanol as carbon source and l.Og/l of ,TEX>$NH_4Cl$, equivalent to C/N ratio of 13.2 at pH 7.0 and $30^{\circ}C$. To investigate the optimal condition for YHB accumulation, two-stage culture technique was adopted; first stage for cell growth and second stage for accumulation of PHB providing unbalanced growth conditions. The optimal PHB accumulation was 1.0% (vIv) of methanol and 0.26gll of $NH_4Cl$, C/N of 50.8 at pH 6.0. To overcome methanol inhibition on cell growth, intermittent feeding fed-batch culture technique was employed, and the cell concentration as high as 14gll with 40% of PHB was achieved. The purified PHB was identified using IR and $1^H NMR$ as homopolymer of 8hydroxybutyric acid. The absorption spectrum of extracted pink colored microbial pigment was alsa investigated.

• YAKHAK HOEJI
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• v.37 no.3
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• pp.235-242
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• 1993

8-Fluorociprofloxacin(8-FCP) is an investigational quinolone derivative that is substituted with fluorine at the C-8 position of ciprofloxacin(CP). It was found that the in vitro activity of 8-FCP against Gram(+) bacteria was more potent that of CP, but the opposite against Gram(-) bacteria was true. However, 8-FCP showed better in vivo efficacy than CP against representative Gram(-) organisms, E. coli and K pneumoniae. In an attempt to seek for factors causing this discrepancy in the antibacterial activities, a comparative pharmacokinetic study of 8-FCP and CP was conducted in mice and rats treated either intravenously or orally at a single dose of 30 mg/kg. The pharmacokinetic parameters in mice were as follows; the mean peak serum concentrations(C$_{max}$) following i.v. and oral doses were 12.4 and 5.3 $\mu\textrm{g}$/ml for 8-FCP, and 9.5 and 2.5 $\mu\textrm{g}$/ml for CP, respectively. The terminal half-life(t$_{1/2\beta}$) was 72.9 min for 8-FCP, and 98.2 min for CP, and the oral bioavailability(F) was 89.9% for 8-FCP, and 50.5% for CP. In rats, the mean ($\pm$SD) $C_{max}$ after i.v. administration were 11.6$\pm$1.6 $\mu\textrm{g}$/ml for 8-FCP, and 10.2$\pm$1.3 $\mu\textrm{g}$/ml for CP, whereas oral administration produced $C_{max}$ of 5.9$\pm$1.8 $\mu\textrm{g}$/ml for 8-FCP and 1.1$\pm$0.9 $\mu\textrm{g}$/ml for CP, respectively. The t$_{1/2\beta}$ was 67.9$\pm$8.4 min for 8-FCP, and 76.4$\pm$7.2 min for CP. The F was 88.6$\pm$6.3% for 8-FCP, and 40.7$\pm$6.5% for CP. Marked differences were observed between the two quinolones in the $C_{max}$ and the area under the concentration-time curve obtained after oral administration in mice and rats. The extent of 8-FCP absorption in both mice and rats was approximately 2-fold higher than that of CP, suggesting that the fluorine atom attached to C-8 plays an important role in facilitating oral absorption from the gastrointestinal tract.

• 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.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.88-94
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• 1998

This study was investigated the application of biofiltration using cometabolic process to remediate gaseous toluene that are highly recalcitrant to adsorption, absorption and biodegradation. The investigation was conducted using specially built steel columns packed with granular activated carbon for removal of toluene and G.A.C was also coated with Pseudomonas putida microorganisms by addition of KH$_{2}$PO$_{4}$. The biofilter unit was operated in the condition of dry and 27.5% moisture content at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C. equipped with F.I.D. detector. The removal efficiency of gaseous toluene was 85% at average inlet concentration of 970 ppm during dry operating condition. For gaseous toluene, 91% removal efficient was obtained at the filter material with moisture content and 97% removal efficiency was obtained with Pseudomonas putida microorganisms at gas loading rate of 12.5 l/min.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.236-243
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• 2018

A series of $Er^{3+}/Yb^{3+}$ co-doped fluorophosphate glasses with varying $YbF_3$ concentration were prepared by a high temperature melt quenching technique. Absorption and emission cross-sections were determined by using the McCumber theory. The larger emission cross-section ($9.86{\times}10^{-21}cm^2$) and longer fluorescence lifetime (12.37 ms) were obtained for the $^4I_{13/2}{\rightarrow}^4I_{15/2}$ transition of ABS3Er4Yb glass. The sensitivity and temperature of the maximum sensitivity were evaluated by the fluorescence intensity ratio method from the measured upconversion spectra. The results were discussed and compared to the other reported glasses.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.499-503
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• 2003

Because physiological changes that potentially alter pharmacokinetics occurs in diabetes mellitus patients, pharamacokinetics of drugs used in the treatment of hypertension was studied using acebutolol as a model anti-hypertensive drug. Thus, the pharmacokinetics of acebutolol was investigated after oral administration of acebutolol (15 mg/kg) to control rabbits and rabbits with acute or chronic diabetes mellitus induced by alloxan. Kidney and liver functions were documented for acute and chronic diabetes mellitus groups based on plasma chemistry data. After oral administration of acebutolol to acute and chronic groups, the plasma concentrations appeared higher; As a result, area under the plasma concentration-time curve from time zero to time infinity10575 and 8668 $\mu g\cdot$ h/mL for acute and chronic group, respectively. In comparison, the area was apparently smaller in the control group (i.e., 7132 $\mu g\cdot$ h/mL). The half-life in acute groups was significantly prolonged 8.45 h compared with the half-life in the control group (i.e., 6.30 h). Alteration in acebutolol pharmacokinetics was more pronounced in the acute group as evidenced by the significantly higher values the area under the plasma concentration time curve, absorption rate constant and maximum plasma concentration compared with chronic or control group. Therefore, these observations indicate that acebutolol pharmacokinetics may be affected in patients with diabetes mellitus, especially in the early stage of the disease.

• Advances in environmental research
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• v.5 no.1
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• pp.61-77
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• 2016

$NanoTiO_2$ was synthesized by ultrasonication assisted sol-gel process and subjected to iron doping and carbon-iron codoping. The synthesized catalysts were characterized by XRD, HR-SEM, EDX, UV-Vis absorption spectroscopy and BET specific surface area analysis. The average crystallite size of pure $TiO_2$ was in the range of 30 - 33 nm, and that of Fe-$TiO_2$ and C-Fe $TiO_2$ was in the range of 7 - 13 nm respectively. The specific surface area of the iron doped and carbon-iron codoped nanoparticles was around $105m^2/g$ and $91m^2/g$ respectively. The coupled semiconductor photo-Fenton's activity of the synthesized catalysts was evaluated by the degradation of a cationic dye (C.I. Basic blue 9) and an anionic dye (C.I. Acid orange 52) with concurrent investigation on the operating variables such as pH, catalyst dosage, oxidant concentration and initial pollutant concentration. The most efficient C-Fe codoped catalyst was found to effectively destruct synthetic dyes and potentially treat real textile effluent achieving 93.4% of COD removal under minimal solar intensity (35-40 kiloLUX). This reveals the practical applicability of the process for the treatment of real wastewater in both high and low insolation regimes.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1932-1940
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• 2024

The current work deals with investigation of the gamma ray shielding properties for various natural stones from Vietnam to be applied in the radiation shielding applications. The physical and chemical properties affecting the γ-ray shielding performance were examined. The MH-300A density meter was utilized to measure the density (ρ, g/cm³) of stone samples, as well as the chemical composition of Vietnamese natural stones was measured using the X-ray fluorescence analyzer (Olympus X-5000). The study shows that the increase in Fe + Ca concentrations within the stone samples increases their density (from 2.48 to 2.86 g/cm³) accompanied with a reduction in the porosity (Φ, %) (from 8.23 to 0.15%) and water absorption (K, %) (from 3.42 to 0.05%) factors. Additionally, the increase in Fe + Ca concentrations increases the linear attenuation coefficient (μ, cm^-1) of the studied stones, where the Vietnamese marble stone (M 3.1) with the highest Fe + Ca concentration (65.97 wt%) has the highest linear attenuation coefficient which varied between 3.781 and 0.155 cm^-1 with raising the gamma ray energy between 0.040 and 1.332 MeV.