• Korean Journal of Materials Research
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• v.9 no.10
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• pp.956-961
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• 1999

When the 0-2 mol% of $\textrm{La}_{3+}$ were added to the nanocrystalline $BaTiO_3$ powders and sintered at $1200~1400^{\circ}C$, the nanocrystailine $BaTiO_3$ ceramics having the average grain size of 110-240 nm were obtained except for when no $\textrm{La}_{3+}$ was added and sintered at > $1350^{\circ}C$. As the average grain size decreased from 240 nm to 110 nm, the tetragonality (c/a) and volume fraction of the $90^{\circ}$ domain decreased, and all the properties such as relative dielectric constant at room temperature, maximum relative dielectric constant at the temperature of phase transformation $\textrm{T}_{c}$ and diffuseness of phase transformation at $\textrm{T}_{c}$ also decreased. The results were attributed to the internal stress induced by inhibition of the $90^{\circ}$ domain formation in the case of finer grain size.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.973-977
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• 2002

The pharmacokinetic of paclitaxel (1 mg/kg, i.v.) was investigated in rabbits with carbon tetrachloride-induced hepatic failure. The area under the plasma concentration-time curve (AUC) of paclitaxel was significantly (p<0.01) increased in severe carbon tetrachloride-induced hepatic failure rabbits ($1364.54{\pm}382.07$ ng/ml$\cdot$hr) compared to that of normal rabbits ($567.52{\pm}141.88$ ng/ml$\cdot$hr), but not significantly in moderate carbon tetrachloride-induced hepatic failure rabbits ($803.1{\pm}208.81$ ng/ml$\cdot$hr). The volume of distribution (Vd) (6.25$\pm$1.56 L) and the elimination rate constant($\beta$) ($0.09{\pm}0.025{\;}hr^{-1}$) of paclitaxel in severe carbon tetrachloride-induced hepatic failure rabbits were significantly (p<0.05) decreased compared to those of normal rabbits ($11.65<{\pm}2.91$L, $0.12{\pm}0.030{\;}hr^{-1}$), but not significantly in moderate carbon tetrachloride-induced hepatic failure rabbits ($9.46{\pm}2.37$ L, $0.10{\pm}0.026{\;}hr^{-1}$). Total body clearance ($CL_t$) of paclitaxel in severe carbon tetrachloride-induced hepatic failure rabbits ($0.733{\pm}0.183$ L/hr/kg) was significantly (p<0.01) decreased compared to that of normal rabbits ($1.762{\pm}0.440$ L/hr/kg), but not significantly in moderate carbon tetrachloride-induced hepatic failure rabbits ($1.245{\pm}0.311$ L/hr/kg). The half-life(t1/2) of paclitaxel in severe carbon tetrachloride-induced hepatic failure rabbits ($7.71{\pm}2.16$ hr) was significantly (p<0.05) increased compared to that of normal rabbits ($5.75{\pm}1.44$hr), but not significantly in moderate carbon tetrachloride-induced hepatic failure rabbits ($6.77{\pm}1.76$hr). This results could be due to inhibition of paclitaxel metabolism in liver disorder rabbits since paclitaxel is essentially metabolized in liver. The findings suggest that the dosage regimen of paclitaxel should be adjusted when the drug would be administered in patients with liver disorder in a clinical situation.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.149-158
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• 1998

Biomass of non-living brown seaweed Sargassun fluitans pretreated with NaOH is capable of taking up more than $10\%$ $(q_{max}$ : 3.85 mmol/g for Al and 1.48 mmol/g for Cu) of its dry weight in the Al and Cu at pH of 4.5. However, the maximum Al and Cu uptakes calculated from Langmuir isotherm were 1.58 mmol/g for Al and 1.35 mmol/g for Cu at pH 3.5. Equilibrium batch sorption study was performed using two-metal system containing Al and Cu. The mathematical model of the two-metal sorption system enabled quantitative estimation of one-metal biosorption inhibition due to the influence of a second metal. NaOH-treated S. fluitans contained 2.19 mmol $(43\;wt.\%)$ carboxyl groups per gram of biomass. A modified form of Langmuir, which assumes binding of Cu as $Cu^{2+}$ and Al as $Al(OH)_2^+,$ was used to model the experimental data. This result agrees with the one of mono-valent sorption for Al in single-metal system. The modified Langmuir model gives the following affinity correlated coefficients: 0.196 for Cu and 6.820 for Ah at pH 4.5, and 2.904 for Cu and 3.131 for Al at pH 3.5. The interference of Al in Cu biosorptive uptake was assessed by `cutting' the three dimensional uptake isotherm surfaces at constant second-metal final concentrations. Equimolar final equilibrium concentrations of Cu and Al of 1 mM at pH 4.5 give Cu and hi uptakes reduced by $82.5\%\;and\;5.4\%,$ respectively. However, these values at pH 3.5 were $55\%\;(Cu)\;and\;31\%$ (Al).

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.747-758
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• 2017

Chronic wounds, pressure sores, lesions, and infections of microbial origin in bedridden, paralyzed, or malnutrition patients remain the object of study of many researchers. A variety of factors behind the development of these disorders are related to the patient's immune system, making it unable to respond effectively to the treatment of the wound. These factors can be properly controlled, giving particular importance to the ethiology and stage of the wound, as well as the time periods corresponding to the replacement of the dressings. The present research reports a novel foam/soft material, ${{\small}L}$-Cys-g-PCL, with an application for decubitus/pressure ulcers, especially for wounds with a difficult healing process due to infections and constant oxidation of the soft tissues. During this work, the interactions between S. aureus and ${{\small}L}$-Cys-g-PCL foam were studied under conditions that simulate decubitus ulcers; namely, pH and exudate. The effects of duration of grafting (1 or 8 h) and pH (7.0 and 8.9) on wettability, surface energy, swelling, and porosity were also evaluated. Results showed an effective microbicidal activity exhibiting an inhibition ratio of 99.73% against S. aureus. This new ${{\small}L}$-Cys-g-PCL soft material showed saftey to contact skin, ability to be shaped to fill in sunken holes (craters) - pressure ulcers stage III - and to act as a smart material responsive to pH, which can be tailored to develop better swelling properties at alkaline pH where exudates are normally higher, so as to address exudate self-cleaning and prevention of desiccation.

• BMB Reports
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• v.29 no.3
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• pp.230-235
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• 1996

The interaction of ${\alpha}-ketoglutarate$ dehydrogenase complex (${\alpha}-KGDC$) with a hydrophobic fluorescent probe [1,1'-bi(4-aniline)naphthalene-5,5'-disulfonic acid] (bis-ANS) was studied. The punfied ${\alpha}-KGDC$ was potently inhibited by bis-ANS with an apparent half maximal inhibitory concentration ($IC_{50}$) of 9.8 ${\mu}m$ at pH 8.0. The catalytic activities of both the E1o and E2o subunits were predominantly inhibited while that of the E3 component was hardly affected. The binding of bis-ANS to the enzyme caused a marked enhancement and blue shift from 523 nm to 482 nm in the fluorescence emission spectrum. The dissociation constant ($K_d$) and the number of binding sites (n) were calculated to be 0.87 mM and 158, respectively. Allosteric regulators such as purine nucleotides and divalent cations further increased the fluorescence intensity of the $bis-ANS-{\alpha}-KGDC$ binary complex. These data suggest that the binding of these allosteric regulators to ${\alpha}-KGDC$ may cause the conformational changes in the enzyme and that bis-ANS could be used as a valuable probe to study the interaction of the multi-enzyme complex and its allosteric regulators.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1654-1659
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• 2010

In order to utilize squid liver by-products, which is normally discarded as industrial waste in the process of squid manufacturing, salt-fermented squid liver sauce was prepared experimentally and also tested for inhibitory activity against angiotensin converting enzyme (ACE). ACE inhibitory activity of squid liver sauce was increased with the elapse of fermentation days until 12 months, followed by a constant level of inhibitory activity thereafter. 15-month-old sauce ($IC_{50}=29.66\;{\mu}g$) was filtered through PM-10 membrane (M.W. cut-off 10,000 Da) to obtain the peptides fractions with ACE inhibition activity. Filtered fractions were applied to a Bio-gel P-2 column and three active fractions (A, B and C) were collected. Among them, fraction B applied to a SuperQ-Toyopearl 650S column chromatography lead to the isolation of active B-1 fraction. It has the ACE inhibitory activity ($IC_{50}=5.46\;{\mu}g$). The main composition of its amino acids is lysine, glycine and proline, which cover about 85% of the total amino acids.

• BMB Reports
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• v.33 no.4
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• pp.317-320
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• 2000

The succinic semialdehyde dehydrogenase from bovine brain was inactivated by treatment with phenylglyoxal, a reagent that specifically modifies arginine residues. The inhibition at various phenylglyoxal concentrations shows pseudo-first-order kinetics with an apparent secondorder rate constant of 30 $M^{-1}min^{-1}$ for inactivation. Partial protection against inactivation was provided by the coenzyme $NAD^+$, but not by the substrate succinic semialdehyde. Spectrophotometric studies indicated that complete inactivation of the enzyme resulted from the binding of 2 mol phenylglyoxal per mol of enzyme. These results suggest that essential arginine residues, located at or near the coenzyme-binding site, are connected with the catalytic activity of brain succinic semialdehyde dehydrogenase.

• Journal of Soil and Groundwater Environment
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• v.21 no.5
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• pp.8-15
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• 2016

Bioremediation, which uses microbes to degrade most organic pollutants in soil and groundwater, can be used in solving environmental issues in various polluted sites. In this research, a wind-driven bioventing system is built to degrade about 20,000 mg/kg of high concentration diesel pollutants in soil-pollution mode. The wind-driven bioventing test was proceeded by the bioaugmentation method, and the indigenous microbes used were Bacillus cereus, Achromobacter xylosoxidans, and Pseudomonas putida. The phenomenon of two-stage diesel degradation of different rates was noted in the test. In order to interpret the results of the mode test, three microbes were used to degrade diesel pollutants of same high concentration in separated aerated batch-mixing vessels. The data derived thereof was input into the Haldane equation and calculated by non-linear regression analysis and trial-and-error methods to establish the kinetic parameters of these three microbes in bioventing diesel degradation. The results show that in the derivation of μ_m (maximum specific growth rate) in biodegradation kinetics parameters, K_s (half-saturation constant) for diesel substance affinity, and K_i (inhibition coefficient) for the adaptability of high concentration diesel degradation. The K_s is the lowest in the trend of the first stage degradation of Bacillus cereus in a high diesel concentration, whereas K_i is the highest, denoting that Bacillus cereus has the best adaptability in a high diesel concentration and is the most efficient in diesel substance affinity. All three microbes have a degradation rate of over 50% with regards to Pristane and Phytane, which are branched alkanes and the most important biological markers.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.571-578
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• 1999

This study evaluated the effects of PKC activation using phorbol 12-myristate 13-acetate (PMA) and PKC inhibition using the isoquinoline sulfomide derivative H-7 on hemodynamics and glucoregulation in the isolated perfused rat liver. Livers were isolated from fed male Holtzman rats and perfused with Krebs Ringer bicarbonate solution under a constant flow of 50 ml/min at $35^{\circ}C.$ Portal vein pressure, glucose and lactate concentrations in the medium and oxygen consumption rates were continuously monitored by a Grass polygraph, YSI glucose and lactate monitors, and a YSI oxygen monitor, respectively. PMA at concentration of 2 to 200 nM increased the portal vein pressure, glucose and lactate production, but decreased oxygen consumption rate in a dose-dependent fashion. H-7 $(200\;{\mu}M)$ attenuated PMA (50 nM)-induced vasoconstriction $(15.1{\pm}1.36\;vs\;10.56{\pm}1.17\;mmHg),$ glucose production rate $(91.3{\pm}6.15\;vs\;71.8{\pm}2.50\;{\mu}moles/g/hr),$ lactate production rate $(72.4{\pm}6.82\;vs\;53.6{\pm}4.82\;{\mu}moles/g/hr)$ and oxygen consumption rate $(33.7{\pm}1.41\;vs\;27.9{\pm}1.75\;{\mu}l/g/min).$ The effects of PMA were blocked either by addition of verapamil $(9\;{\mu}M)$ or perfusion with $Ca^{2+}-free$ KRB. These results suggest that the hemodynamic and glucoregulatory changes in the perfused rat liver are mediated by protein kinase C activation and require $Ca^{2+}$ influx from the extracellular fluid.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.614-618
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• 1992

The batch and fed-batch cultivations of Brevibacteriurn CHI were carried out for the production of nitrile hydratase. In batch culture, with pH control the cell mass and the specific activity increased more 20% and 30%. respectively. The maximum growth rate was obtained at a glucose concentration of $20g/{\ell}$ because of substrate inhibition. The fed-batch culture of Brevibacteriurn CHI with constant substrate feeding gave a cell density of up to $68g/{\ell}$ and nitrile hydratase activity was maintained at above 6.1units/mg. The cell growth yield on carbon .source was ca. 0,68 g/g glucose consumed. The total nitrile hydratase activity in this fed-batch mode increased up to 414.8 units/m${\ell}$, which amounted to 4.4 times that of the batch culture.