• Tuberculosis and Respiratory Diseases
• /
• v.43 no.6
• /
• pp.936-944
• /
• 1996

Background: Neutrophils or monocytes separated in vitro by the adherence to plastic surface are known to be activated by surface adherence itself and subsequent experimental data might be altered by surface adherence. Adhesion molecules and gene transcription of the inflammatory mediators are known to be associated in this process. To evaluate whether adhesion molecule and transcriptional activation of the inflammatory substances are also involved in the activation of human alveolar macrophage by the adherence procedure, we designed this experiment. Method : Bronchoalveolar lavage was performed in the person whose lung of either side was confirmed to be nonnal by chest cr and alveolar macrophage was harvested. To measure the expression of Interleukin-8(IL-8) mRNA, manganese superoxide dismutase(SOD) mRNA and CD11/CD18 mRNA in human alveolar macrophage of both adherence state and suspension state, Northern blot analysis was done at 0, 2, 4, 8 and 24hrs after the adherence to plastic surface and during suspension state. Then, phorbol myristate acetate(pMA) and N-formyl-methionyl-leucyl-phenylalanine(fMLP) were added respectively in the same experimental condition. Result : 1) Human alveolar macrophages in the adherent state induced IL-8 mRNA and SOD mRNA expression which was maximal at 8 hours after the adherence to plastic surface. But we could not observe the upregulation of CD18 mRNA by surface adherence. 2) PMA induced these mRNA expression both in the adherent cell and the nonadherem cells, but the induction of mRNA expression by fMLP occurred only in the adherent cells. Conclusion: These results suggest that adherence of huamn alveolar macropahge is an important cell-activating event that may play a critical role in the modulation of lung inflammatory respones.

• Korean Journal of Cognitive Science
• /
• v.12 no.4
• /
• pp.49-56
• /
• 2001

When multiple features are presented in the image the computational models for stereopsis select the most activated matches through the excitatory and inhibitory interactions among all possible matches. Using the random-dot stereogram with two surfaces. we investigate whether human binocular mechanism selects the most activated matches. The dots consisting a surface lying in a fixation plane were selected randomly while each of the dots consisting the other surface was paired with each of the original dots in the following manner. After finding the position of each dots in the original random pattern we placed an additional dot to the left and to the right of the original position in each of the left and right image of a stereogram respectively. The luminance of additional dots was varied while that of the original random dots was fixed so that the hypothetical matches presumably could be activated differently. Across the luminance condition the depth of each surface was measured to examine whether matches to be selected were changed depending on the activation level of possible matches. When the luminance of two patterns was within 30% of one another observers perceived an opaque surface. Beyond this value two transparent surfaces were seen with the magnitude of perceived depth varying with relative luminance of two patterns. When original pattern was brighter one additional surface was perceived at the depth corresponding to the disparity of original pattern. When original dot was dimmer. however the depth of an additional surface corresponded to the disparity of newly introduced pattern. These results suggest that there are dynamic interactions within the matching process whereby highly activated matches inhibit weaker one.

• Resources Recycling
• /
• v.17 no.6
• /
• pp.68-78
• /
• 2008

Using a Pinus koraiensis and Pinus rigida which are normally being discarded in South Korea, optimal conditions of producing activated carbons have been studied to recycle as a higher value-added product. This study consists of two processes, the production process of charcoals from waste timbers by low temperature pyrolysis and the production process of activated carbons from the charcoals by chemical activation reaction. This paper deals with the production process of activated carbons from the charcoals by chemical activation reaction. As an alkali has been generally used as an activating agent, KOH and NaOH which react well with a carbon were used in this study. As a result of the experiments, it is confirmed that activated carbons made with KOH treatment had superior values in physicochemical properties to NaOH, showing that there was no remain of KOH at the surface of the charcoals while there was $3{\sim}4%$ of NaOH remaining after the experiments. Thus, it is concluded that KOH reacted more actively with a charcoal than NaOH. Moreover, it was also found that values in physicochemical properties when using a Pinus koraiensis are superior to the ones when using a Pinus rigida. The optimal mixing ratio of an activating agent to a charcoal was 400 wt.%. To improve the physicochemical properties, activated carbons were washed out by distilled water after neutralization with SM hydrochloric acid solution. When activated carbons were produced from a Pinus koraiensis in this optimal conditions, value of BET surface area was found to be approx. $2400\;m^2/g$.

• Korean Chemical Engineering Research
• /
• v.52 no.6
• /
• pp.807-813
• /
• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of Life Science
• /
• v.25 no.10
• /
• pp.1103-1109
• /
• 2015

Cholinergic innervation of the hippocampus is known to be correlated with learning and memory. The cholinergic agonist carbachol (CCh) modulate synaptic plasticity and produced long-term synaptic depression (LTD) in the hippocampus. However, the exact mechanisms by which the cholinergic system modifies synaptic functions in the hippocampus have yet to be determined. This study introduces an acetylcholine receptor-mediated LTD that requires internalization of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors on the postsynaptic surface and their intracellular mechanism in the hippocampus. In the present study, we showed that the application of the cholinergic agonist CCh reduced the surface expression of GluA2 on synapses and that this reduction was prevented by the M1 muscarinic acetylcholine receptor antagonist pirenzepine in primary hippocampal neurons. The interaction between GluA2 and the glutamate receptor-interacting protein 1 (GRIP1) was disrupted in a hippocampal slice from a rat upon CCh simulation. Under the same conditions, the binding of GluA2 to adaptin-α, a protein involved in clathrin-mediated endocytosis, was enhanced. The current data suggest that the activation of LTD, mediated by the acetylcholine receptor, requires the internalization of the GluA2 subunits of AMPA receptors and that this may be controlled by the disruption of GRIP1 in the PDZ ligand domain of GluA2. Therefore, we can hypothesize that one mechanism underlying the LTD mediated by the M1 mAChR is the internalization of the GluA2 AMPAR subunits from the plasma membrane in the hippocampal cholinergic system.

• The Journal of Advanced Prosthodontics
• /
• v.8 no.2
• /
• pp.94-100
• /
• 2016

PURPOSE. To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS. The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at $80^{\circ}C$ after hydrogen peroxide etching. After storage of the specimens in distilled water at $37^{\circ}C$ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (${\alpha}=0.05$). RESULTS. Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P<.05). Heat drying after silanization also significantly increased the bond strength (Group 3 and 4) (P<.05). However, no effect was determined for hydrogen peroxide etching before applying silane agent (Group 2 and 3) (P>.05). CONCLUSION. Fiber post silanization and subsequent heat treatment ($80^{\circ}C$) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.3
• /
• pp.144-149
• /
• 2016

The metal-impregnated activated carbon was produced from bamboo activated carbon by soaking method of metal nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use as de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20^{\circ}C{\sim}850^{\circ}C$) and NO gas partial pressure (0.1 kPa~1.8 kPa). As results, the specific volume and surface area of bamboo activated carbon impregnated with copper were decreased with increasing Cu amounts of activated carbon. In NO reaction, the reaction rate of Cu impregnated bamboo activated carbon[BA(Cu)] was promoted to compare with that of bamboo activated carbon[BA]. But the reaction rate of Ag impregnated bamboo activated carbon[BA(Ag)] was retarded. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.92[BA(Cu)], and 80.5 kJ/mol[BA], 48.5 kJ/mol[BA(Cu)], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.5
• /
• pp.713-721
• /
• 2012

In many instances phosphorus is a limiting factor for eutrophication in streams, and lakes. Because wastewater treatment plant itself may be the main phosphorus source in a natural water body, removal of phosphorus in final effluent of wastewater treatment processes is required. Amongst various technologies for phosphorus removal in wastewater, adsorption technology was investigated using activated Ca-loess complex. Ca was added in loess to enhance adsorption capacity and intensity of phosphorus. Ca added loess was activated at a high temperature of $400^{\circ}C$ which turned out to be the optimum temperature. Activated Ca-loess complex below $400^{\circ}C$ had not enough strength to be applied as an activated Ca-loess pallet column in wastewater treatment process. Ca-loess complex which activated above $400^{\circ}C$ lost its adsorption capacity as the loess surface was glassified when the activation temperature reached above $400^{\circ}C$20. Even if adsorption capacity of activated Ca-loess was not very high due to the lack of abundant pores on its surface, adsorption intensity was still high because it was activated with added Ca in loess. Activated loess was made by pallets. The activated loess pallets were filled in a column, and were applied in wastewater treatment process. Using an activated Ca-loess pallet column, total phosphorus (T-P) was reduced from about 0.5 mg/l to lower than 0.1 mg/l in wastewater treatment, and ionic phosphorus (phosphate) was completely removed for the four months of pilot plant operation.

• Polymer(Korea)
• /
• v.24 no.1
• /
• pp.82-89
• /
• 2000

The blood compatibilities of PU/PVA polymer blends with different mixing ratios were evaluated using various methods, such as fibrinogen adsorption, plasma recalcification time, platelet adhesion, whole blood clotting time, and complement activation. In addition, PVA on the surface of the polymer blends was crosslinked by glutaraldehyde to restrain the mobility of PVA molecules for characterizing the effect of PVA in the polymer blends on blood compatibility. The fibrinogen adsorption on the polymer blends decreased with the increase of PVA amount in the polymer blends. The plasma recalcification times of the polymer blends with 10-50 wt% PVA were longer than those of PU, PVA, and polymer blends with higher amount of PVA. The morphological changes and adhesion of platelets on the polymer blends with 30-50 wt% PVA were less than those on the other materials. The blood clotting times and complement activation on the polymer blends with 30-50 wt% PVA were reduced, compared to the other materials. On the other hand, the blood compatibility of the crosslinked polymer blends was relatively decreased, compared to the non-crosslinked ones. According to these experimental results, the blood compatibility of the polymer blends with 30-50 wt% PVA was better than that of the other materials and such a blood compatibility of the polymer blends might be related to the mobility of PVA molecules on the surface.

• Korean Chemical Engineering Research
• /
• v.52 no.1
• /
• pp.133-140
• /
• 2014

The experiment was designed to compare the char combustion kinetics of pulverized Indonesia coals commonly utilized in Korea power plants. The reaction rate of coal char has been formulated using the external and internal effectiveness factors to describe the diffusion effect quantitatively. The Random Pore Model (RPM) was used for applying internal specific surface area as a function of carbon conversion ratio. Reaction rate was obtained from reaction time using the Wire Heating Reactor (WHR) which can heat and measure the char particle temperature at the same time. BET and TGA were used to obtain physical properties such as internal specific surface area and structural parameter. Three kinds of Indonesia Sub-bituminous coals "BARAMULTI, ENERGYMAN, AGM" were used in order to derive the activation energy and pre-exponential factor. The results of this study showed that the effect of internal diffusion than that of external diffusion is the dominant as comparison of kinetics was reflected in external and internal effectiveness factors. For three kinds of coal char, finally, activation energy of intrinsic kinetics indicates 110~118 kJ/mol.