• Archives of Pharmacal Research
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• v.13 no.1
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• pp.33-37
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• 1990

The effects of pH values, temperature and some elements on the amylolytic activity and stability of the purified S. aureofacienc 77 amylase were studied in this investigation. The purified enzyme showed its maximum activity at pH 6 within 8 min incubation at $40^{\circ}C$. None of the tested 6 metals showed on stimulatory effect on the enzymatic activity, $Fe^{+++}$, $Cu^{++}$ and $Hg^{++}$ at high dose inhibited the enzyme activity to great extent as compared with $Zn^{++}$, $Mn^{++}$ and $Fe^{++}$ whih gave less effect in this respect. The enzyme liquor was found to be thermolabile, since it lost completely its activity after 4 days incubation under room temperature and showed maximum activity during this period as a result of additions of $Ca^{++}$and NaCl, Gradual reduction was however recorded until activity reached 30% after 60 days of incubation.

• Archives of Pharmacal Research
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• v.20 no.2
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• pp.171-175
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• 1997

The stability of ondansetron and fluconazole in 5% dextrose injection and normal saline during simulated Y-site injection at room temperature was studied. Ondansetron 0.03, 0.1 and 0.3 mg/ml were admixed 1:1 with fluconazole 2 mg/ml. The solutions were stored at room temperature and samples were retrieved at time 0, 1, 2, 4 and 12 hr for immediate assay. At the time of the assay and before any dilution, each sample was visually inspected for clarity, color, precipitation, and the pH was determined. Drug concentrations were measured by a stability-indicating high performance liquid chromatograph. Ondansetron 0.03, 0.1 and 0.3 mg/ml were stable when mixed with concentration of fluconazole 2 mg/ml. There were no change in clarity and color and no precipitates in any admixture for 12 hr of inspection. The pH measurements did not have a particular trend in any direction over time.

• Journal of Marine Bioscience and Biotechnology
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• v.11 no.2
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• pp.89-93
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• 2019

In this study, the stability of the extracted natural pigments against light, temperature, pH, metal ions, and antimicrobial activity were evaluated in marine bacteria Zooshikella sp. 17TA. The pigment of the strain used in the study was red with maximum absorption at a wavelength of 541 nm. The stability of the pigment was evaluated by measuring the absorbance while preserving for 15 days and examining the retention rate. After 15 days of irradiation, the pigment of this bacterium showed 98% retention in the dark and 91% retention in the temperature range of -20℃ ~ 30℃. When the pH was in the range 4-7, the retention was about 80%, and the retention rate was higher than 85% for all kinds of metal ions except for CuCl₂, ZnCl₂, and KCl. The bacterial pigments showed high stability under the given irradiated pH, temperature, and metal ion conditions and had shown activity against gram-positive strains. These results suggest that this highly conserved microbial pigment can be applied to the food industry.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.4
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• pp.468-473
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• 2006

This study was conducted to develop pigment of flowers as a food material and the red rose(Rosa hybrida L.) was used for this study. To check the possibility of using the rose pigment as a food additive we have extracted the pigment from rose and examined all the factors (pH, temperature, free sugars, organic acids, metal ions) for stability. The results obtained are as follows: In examining the stability of the pigment, the residue of the pigment noticeably decreased with the increase of the pH and the temperature, and among free sugars (fructose, glucose, sucrose) the addition of fructose made the residue the lowest. With the addition of organic acids the samples exhibited the hyperchromic effect throughout the period of the storage. The pigment residue decreased when the amount of the metal ions increased and especially the Cu$^{2+}$ ion was most destructive.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.9-15
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• 2010

Extraction Efficiency of colorants from sorghum and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. The extraction at pH 4 extract was most efficient among the various pH conditions. In the juice extractor system, the amount of extracted colorant was more in distilled water pre-treatment than pH 5, but it was more in pH 5 in the long time pre-treatment above 20 hour. The color of extract solutions changed through variation of the pH. Its color changed from light yellow to heavy yellow finally red ton by pH increasing. The Methionine addition gave an effect on the storage stability of colorant solution and then had better storage stability. And so it delayed the color change up to storge period 18th day and the stabilizing effect was revealed in order of Methionine 10mmol-addition>20mmol-addtion>non-addtion.

• YAKHAK HOEJI
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• v.34 no.6
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• pp.415-421
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• 1990

The effects of temperature, pH, light and concentration on the degradation of trimebutine maleate in aqueous solution were investigated on the basis of accelerated stability analysis, and the stabilization of the solution was attempted by addition of several additives. The decomposition of trimebutine maleate in solution followed first-order reaction the was not only accelerated by temperature elevation but also the lower the concentratin the more speeded up the reaction. The decomposition mechanism of trimebtine could be confirmed by hydrolysis of ester bond in the structure. It was assumed trimebutine maleate is so photosensitive that the solution of the drug underwent accelerated decomposition under UV rays. What is more, the degradation of trimebutine solution was supposed to catalyzed by specific acid-base catalysis considered the pH dependence for the hydrolysis of ester, and the solution was most stable over the range of pH 2-2.8 in solution. The additives, citric acid, asparitc acid and glutamic acid, inhibited considerably the decomposition of the drug solution, and these additives might be used as stabilizers in trimebutine maleate solution.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.176-183
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• 1992

The stabilizing effects of $\alpha$-$\beta$-$\gamma$- and dimethyl-$\beta$-cyclodextrins $(\alpha$-, $\beta$-, $\gamma$- and DM-$\beta-$-CyDs) on the degradation of hydrocortisone 17-butyrate (HC-17B) in aqueous solution was investigated. Hc-17B underwent a facile hydroxide ion-catalyzed rearrangement to the less active 21-butyrate ester by the apparent first-order kinetics, and maximum stability of HC-17B was obtained at around pH 4.0. The stability of HC-17B was increased by inclusion complexation with $\alpha$-, $\gamma$- and DM-$\beta$-CyD in the pH range of 2.0-8.0 examined, whereas $\beta$-CyD accelerated the degradation of HC-17B at the pH higher than 5.0. The effects of ionic strength, solvent, temperature and CyD concentration were also investigated. Stability constants and apparent degradation rate constants of HC-17B-$\gamma$-CyD and HC-17B-DM-$\beta$-CyD complexes were determined kinetically on the basis of 1:1 complexation. The results suggested that the inclusion complexation with $\gamma$-CyD or DM-$\beta$-CyD was most useful means to enhance the stability of the steroid.

• BMB Reports
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• v.44 no.10
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• pp.665-668
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• 2011

In order to clarify the impact of Ca-binding sites (Ca1 and 2) on the conformational stability of neutral proteases (NPs), we have analyzed the thermal, pH and organic solvent stability of a NP variant, V189P/A195E/G203D/A268E (Q-mutant), from Salinovibrio proteolyticus. This mutant has shown to bind calcium more tightly than the wild-type (WT) at Ca1 and to possess Ca2. Q-mutant was resisted against autolysis, thermoinactivation and pH denaturation in a Ca-dependent manner and exhibited better activity in organic solvents compared to the WT enzyme. These results imply that Ca1 and Ca2 are important for the conformational stability of NPs.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.167-171
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• 2003

CMP(Chemical Mechanical Planarization) slurry for STI process is made by mechanically synthesized$CeO_2$as abrasive. The abrasive can be stabilized by electrostatic or steric stabilization in aqueous slurry and steric stabilization is more effective for long-term stability. Blanket-type$SiO_2$and $Si_3N_4$ wafers are polished with CMP slurry containing$CeO_2$synthesized in 50$0^{\circ}C$ or $700^{\circ}C$. Removal rate and surface uniformity of$SiO_2$and$Si_3N_4$wafer and selectivity are influenced by synthetic condition of abrasive, suspension stability and pH of slurries.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.31-38
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• 2010

Extraction efficiency of colorants from red bean and black bean seed coat and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. pH 4 extracting was most efficient among the various pH conditions. The absorbance values of extracted colorant from red bean were increased with increasing extract time and temperature, when the extraction process was kept at $30^{\circ}C$ and $50^{\circ}C$, but it were decreased with increasing extract time at $70^{\circ}C$. In the case of black bean, it were also increased with increasing extract time and temperature. pH 5 extract was most efficient among the various pH conditions. In juice extractor system from red bean, the pH 5 of the pre-treatment was more efficient than the distilled water of pre-treatment. In black beans of the short-term pre-treatment with distilled water, the colorant was extracted better than at pH 5, but above 4 hours pre-treatment was decrease in pH 5. The Methionine added as a stabilizer gave the more effect to the stability of colorant from red bean the more Methionine addition. In the case of black bean 10mmol addition of methionine was more efficient than 20mmol.