• YAKHAK HOEJI
• /
• v.19 no.4
• /
• pp.219-226
• /
• 1975

Physical and chemical properties on the aging inhibition mechanism of hydrous aluminum oxide were studied by means of dehydration velocity, activation energy, DTA, TGA, IR spectra, X-ray diffraction and TMA. During aging, changes may occur in the hydrous aluminum oxide structure which results in a loss of acid reactivity and in crystal formation to the hydrated hydrous alumina. The results obtained from the X-ray diffraction pattern and DTA, TGA thermogram studies showed that the aging product stabilized with either sorbitol or mannitol was hydrous aluminum oxide ($Al_{2}O_{3}{\cdot}xH_{2}O$) but the aging product not stabilized with either sorbitol or mannitol product not stabilized was hydrated hydrous aluminum oxide $Al_{2}O_{3}{\cdot}xH_{2}O{\cdot}yH_{2}O$. The activation energy of dehydration of the hydrous almina was about 17 Kcal. mol$^{1}$ deg$^{-1}$ which was observed a little less than that of 22 kcal.mol.$^{-1}$ deg.$^{-1}$ of or mannitol, the inhibition mechanism in the aging process from oxide is assumed to prevent the formation of the hydrated hydrous aluminum oxide and the aging process is thought of as analogous to the polymorphic transformations which occur as a system converts to its most stable state.

• Korean Journal of Medicinal Crop Science
• /
• v.23 no.2
• /
• pp.155-160
• /
• 2015

This research evaluate antioxidant and skin-whitening effect of Abeliophyllum distichum Nakai by extraction processes. First, antioxidant effects were follows: EE (70% ethanol extract) showed higher DPPH scavenging activity of 69.66% than WE (hot water exract) 59.13% at $0.3mg/m{\ell}$, also UE's (70% ethanol extract by sonication process) higher than EE. Reducing power was that also EE showed higher than WE, and it was the highest value with UE's because of ultrasonic pretreatment. Next, the whitening effect tyrosinase inhibition activity was measured that EE was 23.88%, WE's was 16.69%, and UE was 23.34%. Ultrasonic pretreatment did not influence to tyrosinase inhibition activity. Cell viability showed low cell toxicity in all groups. UE's inhibited melanin synthesis, 55.1%, that is higher than EE and WE, 52.7% and 39.5%, respectively. As a result, we confirmed that antioxidant activities and skin-whitening effect by extraction process. Also, this results confirmed that the Abeliophyllum distichum Nakai extracts worth as cosmetic materials.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.63-67
• /
• 2002

The induced chemical and salt solution in water or admixture are originated to the corrosion process of the steeo rebar. These liquids penetrate into concrete as the accompanied by the chemical reaction and cause to attack the steel rebar in concrete. Concrete surfaces which it exposed to deicing, water and sea water is allowed to enter the chlorides in the structures. To prevent from the source of corrosion and deterioration Is subjected to put an end to corrode or reduce to contaminate on the steel rebar. As this reason the MCI 2022 products are applied to the surface of concrete and steel rebar. The concrete samples were made of to the kind of four, i.e. RF, MR, MS, and MM. Corrosion inhibitor is applied to coat on the surface of concrete after it had been cured for 28days. Specimen were immersed in a 3.5％ sodium chloride solution. Concrete specimen were tested to determine the changes of the resistance polarization, Rp, over a 22 weeks period. MCI 2022 is significantly shown the corrosion inhibition of steel rebar in 3.5% NaCl solution. In the each different concrete sample, MS and MM is seemed to be better than others. The results are proofed that MCI 2022 is promised to maintain the inhibition of corrosion with high resistance polarization of the steel rebar in concrete.

• BMB Reports
• /
• v.40 no.4
• /
• pp.494-500
• /
• 2007

The endophytic bruchid pest Callosobruchus maculatus causes severe damage to storage cowpea seeds, leading to economical losses. For this reason the use of $\alpha$-amylase inhibitors to interfere with the pest digestion process has been an interesting alternative to control bruchids. With this aim, $\alpha$-amylase inhibitors from baru seeds (Dipteryx alata) were isolated by affinity chromatographic procedures, causing enhanced inhibition of C. maculatus and Anthonomus grandis $\alpha$-amylases. To attempt further purification, this fraction was applied onto a reversed-phase HPLC column, generating four peaks with remarkable inhibition toward C. maculatus $\alpha$-amylases. SDS-PAGE and MALDI-ToF analysis identified major proteins of approximately 5.0, 11.0, 20.0 and 55 kDa that showed $\alpha$-amylase inhibition. Results of in vivo bioassays using artificial seeds containing 1.0% (w/w) of baru crude extract revealed 40% cowpea weevil larvae mortality. These results provide evidence that several $\alpha$-amylase inhibitors classes, with biotechnological potential, can be isolated from a single plant species.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.1
• /
• pp.155-160
• /
• 2017

The dye decolorization rate in a cell-free culture broth of the white-rot fungus Trametes versicolor CBR43 was studied, including the effects of inhibitors of NaCl, Zn(II), and Cd(II) on dye decolorization activity. The maximum rates of dye decolorization in cell-free culture broth were 1,410, 44.7, 41.2, and $0.19{\mu}mol{\cdot}l^{-1}{\cdot}min^{-1}$ for Acid Blue 62, Acid Black 175, Reactive Blue 4, and Acid Red 114, respectively. The inhibition effects of NaCl, Zn(II), and Cd(II) on dye decolorization were quantitatively compared using the half maximal inhibition concentration ($IC_{50}$), which indicates the concentration of an inhibitor required for 50% inhibition. Based on $IC_{50}$ values, dye decolorization in the cell-free culture broth of CBR43 was most potently inhibited by Cd(II), whereas the inhibitory effect of NaCl was relatively low. The dye decolorization rates and $IC_{50}$ data can be used in the design and development of a dye-wastewater treatment process using T. versicolor CBR43 and its operating factors.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.5
• /
• pp.293-296
• /
• 2012

Memory reconsolidation is ubiquitous across species and various memory tasks. It is a dynamic process in which memory is modified and/or updated. In experimental conditions, memory reconsolidation is usually characterized by the fact that the consolidated memory is disrupted by a combination of memory reactivation and inhibition of protein synthesis. However, under some experimental conditions, the reactivated memory is not disrupted by inhibition of protein synthesis. This so called "boundary condition" of reconsolidation may be related to memory strength. In Pavlovian fear conditioning, the intensity of unconditional stimulus (US) determines the strength of the fear memory. In this study, we examined the effect of the intensity of US on the reconsolidation of contextual fear memory. Strong contextual fear memory, which is conditioned with strong US, is not disrupted by inhibition of protein synthesis after its reactivation; however, a weak fear memory is often disrupted. This suggests that a US of strong intensity can inhibit reconsolidation of contextual fear memory.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.23 no.2
• /
• pp.7-22
• /
• 1997

Inhibitory effects of 200 medicinal plants on elastase activity were screened. Among the 200 plants, six plant extracts exhibited more than 65% of inhibition on elastase activity by their total methanol extracts at 1, 000$\mu\textrm{g}$/$m\ell$ as a final concentration. For six active plants including Areca catechu, Cinnamonum cassia, Myristica frograns, Curcumma longa, Alponia katsumadai, and Dryopteris crassirrhizoma, the inhibitory effects of their comsituents were examined on the activity of human leukocyte elastase, hyaluronidase and lipid peroxidation. In lipid peroxidation assay using TBA method, three of the 6 plants including Curcumma longa, Areca Catechu and Alponia katsumadai exhibited more than 70% of inhibition at the concentration of 1, 000$\mu\textrm{g}$/$m\ell$, but only one plant, Areca Ctechu showed high inhibitory effect on hyaluronidase activity. The results suggest that medicinal plants showing several biological activities may be potent inhibitors of anti-aging process on skin and that might be useful for application in cosmetics.

• Journal of Electrochemical Science and Technology
• /
• v.8 no.3
• /
• pp.222-235
• /
• 2017

First, in this study, the inhibition efficiencies of metal complexes with Cu(II), Ni(II) and Zn(II) of STSC ligand for corrosion control of mild steel in oilfield formation water were investigated. The IEs for a mixture of 500 ppm STSC and 5 ppm metal ion ($Cu^{+2}$, $Ni^{+2}$, $Zn^{+2}$) were found to be 88.77, 87.96 and 85.13 %, respectively. The results were obtained from the electrochemical techniques such as open circuit potential, linear and tafel polarization methods. The polarization studies have showed that all used Schiff base metal complexes are anodic inhibitors. The protective film has been analyzed by FTIR technique. Also, to detect the presence of the iron-inhibitor complex, UV-Visible spectral analysis technique was used. The inhibitive effect was attributed to the formation of insoluble complex adsorbed on the mild steel surface and the adsorption process follows Langmuir adsorption isotherm. The surface morphology has been analyzed by SEM. Secondly, the computational studies of the ligand and its metal complexes were performed using DFT (B3LYP) method with the $6-311G^{{\ast}{\ast}}$ basis set. Finally, it is found that the experimental results were closely related to theoretical ones.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.268-278
• /
• 2011

Corrosion of aluminum in 0.1 M HCl solution in the absence and presence of ${\beta}$-blocker inhibitors (atenolol, propranolol, timolol and nadolol) was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency increased with inhibitor concentration and decreased with rise of temperature. Potentiodynamic polarization curves revealed that they acted as cathodic inhibitors. Some thermodynamic parameters were calculated and discussed. All inhibitors were adsorbed on Al surface obeying Frumkin isotherm. All EIS tests exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The inhibition efficiencies of all test methods were in good agreement.

• Journal of the Korean Chemical Society
• /
• v.57 no.1
• /
• pp.25-34
• /
• 2013

The efficiency of three complex surfactants based on sunflower oil and nitrogen containing compounds as corrosion inhibitors for mild steel in $CO_2$-saturated 1% NaCl solution, has been determined by weight loss and LPR corrosion rate measurements. These compounds inhibit corrosion even at very low concentrations. The inhibition process was attributed to the formation of an adsorbed film on the metal surface that protects the metal against corrosive media. The inhibition efficiency increases with increasing the concentration of the studied inhibitors. Maximum inhibition efficiency of the surfactants is observed at concentrations around its critical micellar concentration (CMC). Adsorption of complex surfactants on the mild steel surface is in agreement with the Langmuir adsorption isotherm model, and the calculated Gibbs free energy values confirm the chemical nature of the adsorption. Energy dispersive X-ray fluorescence microscopy (EDRF) observations of the electrode surface confirmed the existence of such an adsorbed film.