• YAKHAK HOEJI
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• v.53 no.4
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• pp.179-183
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• 2009

We explored the role of reactive oxygen species (ROS) in LPS-induced bone loss. LPS was shown to increase the concentration of ROS in osteoclast precursors. The antioxidant decreased osteoclast formation by LPS. Furthermore, the antioxidant decreased NFATc1 expression by LPS, suggesting that ROS mediates NFATc1 expression in the regulation of LPS-induced osteoclast formation. Finally, the antioxidant decreased LPS-induced RANKL mRNA expression in osteoblasts. Taken together, these data indicate that LPS mediates ROS to induce bone loss.

• Korean Journal of Organic Agriculture
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• v.8 no.2
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• pp.89-96
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• 2000

To reduce loss of nitrogen and generation of ammonia gas during composting, poultry manure and sawdust were mixed at the equivalent ratio and calcium chloride, fused superphosphate and vermiculite were added. Ammonia and sulfurous gas during composting, and NH4-N and NO3-N contents of composts were periodically measured. With the treatments of 0.5∼3% calcium chloride and 3% fused superphosphate, ammonia and sulfurous gas during composting significantly decreased, and especially generation of gases sharply reduced and a increase of calcium chlorde. Extractable NH4-N content in composts treasted with calcium chloride and fused superphosphate were high but extractable NO3-N markedly decreased. In conclusion, the results suggest that it is necessary the additon of 1∼3% calcium chloride or 3% fused superphosphate to reduce loss of nirogen and generation of offensive odor during composting of poultry manure mixed with sawdust.

• The Journal of Internal Korean Medicine
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• v.40 no.1
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• pp.58-69
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• 2019

Objective: This study investigated the effects of Hansu-Daebowon (HDW) on bone resorption in vitro and bone loss in vivo. Methods: Osteoclast differentiation was measured by counting TRAP (+) MNC formed from RAW 264.7 in the presence of RANKL. Bone pit formation was determined in an artificial bone slice loaded with RANKL-stimulated osteoclasts. To elucidate the mechanisms of the inhibitory effects of HDW on bone resorption and osteoclast differentiation, osteoclastogenic genes (i.e. TRAP, MMP-9, NFATc1, c-Fos, and Cathepsin K) were measured using real time PCR. Furthermore, bone loss was observed using micro-CT in an LPS-treated mammal model. Results: HDW inhibited the bone pit formation in vitro and inhibited bone loss in vivo. Moreover, HDW decreased the number of TRAP (+) MNCs in the presence of RANKL, and HDW inhibited the expressions of cathepsin K, MMP-9, TRAP, NFATc1, and c-Fos in the osteoclasts. Conclusion: HDW exerts inhibitory effects on bone loss and bone resorption resulting from the inhibitions of osteoclast differentiation and osteoclastogenic gene expression.

• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.42-49
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• 2016

Step-drawdown pumping tests for identifying the improvement of groundwater well performance after rehabilitation treatments were conducted in three longstanding wells. Three selective mechanical treatment methods including power bubble, high-voltage electric pulse, and air surging were applied to these wells and the applicability of these methods to secure additional groundwater resources were evaluated quantitatively. Commonly, drawdown at final stage of stepdrawdown pumping tests after rehabilitation decreased by as much as 0.61~0.70 meters compared to those before rehabilitation. In addition, final specific drawdown values of three wells increased from 9% to 14% after rehabilitation. Formation loss coefficient and well loss coefficient decreased to 6.1% and 60.6%, respectively, indicating some clogging materials by precipitation/corrosion/microbe within pores of aquifer materials, gravel packs, and screens were effectively removed by applied methods. Decrease of formation loss coefficient was higher in the well applied by the power bubble method meanwhile high-voltage electric pulse method demonstrated the higher decrease of well loss coefficient. Additionally secured groundwater amounts after rehabilitation ranged from 23.3 to 32.1 m³/day, which account for 8~16% of initially developed pumping rates of the wells. From the results of this study, the effective selection of rehabilitation treatments considering aquifer characteristics are expected to contribute to secure groundwater resources for irrigation as well as to plan systematic management program for groundwater resources in rural area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1465-1472
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• 2009

The effect of heat loss rate on NOx formation of $CH_4/air$premixed flame were examined numerically in a perfectly stirred reactor. The following conclusions were drawn. Under the adiabatic wall condition, an increase in the residence time causes a remarkable increases in NOx emission. Under the heat loss conditions, however, NOx decreases significantly as the heat transfer coefficient and residence time increase. As the heat loss rate increases, Thermal NO mechanism and Re-burning NO mechanism play an important role in the NOx reduction, but Prompt NO mechanism and $N_2O$-intermediate NO mechanism lead to the increase in NOx production. Although the NOx formation is actually related to complex NOx mechanism with the changes in the heat transfer coefficient and residence time, it was found that NOx concentration can be represented by independent Thermal NO mechanism. From these results, new NOx correlation combined with the heat loss rate and residence time was suggested for predicting the NOx concentration in a practical $CH_4/air$premixed combustor.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.225-232
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• 2009

The ratio of saccharification and formation of furans during the acid hydrolysis of agar with oxalic acid and sulfuric acid were examined base on the contents of the agar and acids. The ratio of saccharification in oxalic acid appeared to be 51~59% somewhat higher than 49~61% of sulfuric acid. Formation of the furans during the acid hydrolysis increased proportional to the contents of agar and acid. The relative formation ratio was high 10~47% for furfural (FUR) and 15~29% for hydroxy-methyl furfural (HMF) in 0.5~1.25% sulfuric acid rather than those of oxalic acid. When comparing the removal efficiency of the furans using an alkali treatment, steam stripping and hydrophobic resins, FUR was eliminated 60% by the alkali treatment, 62~90% by steam stripping and 71~75% by Amberlite XAD4 and 7HP, while HMF was removed to low levels of 10.5%, 4~17% and 13~25%, respectively. The loss of reducing sugar was also observed in process of the removal of furans, and the loss rate was the level of 2~4% in alkali treatment, 11~16% in steam stripping and 7~9% in Amberlite resins.

• Journal of the Korean Applied Science and Technology
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• v.19 no.2
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• pp.131-136
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• 2002

As model waterborne acrylic coatings, mono-dispersed poly(butyl acrylate-methyl methacrylate) copolymer latexes of random copolymer and core/shell type graft copolymer were prepared by seeded multi-staged emulsion polymerization with particle size of $180{\sim}200$ nm using semi-batch type process. Sodium lauryl sulfate and potassium persulfate were used as an emulsifier and an initiator, respectively. The effect of particle texture including core/shell phase ratio, glass transition temperature and crosslinking density, and film forming temperature on the film formation and final properties of film was investigated using SEM, AFM, and UV in this study. The film formation behavior of model latex was traced simultaneously by the weight loss measurement and by the change of tensile properties and UV transmittance during the entire course of film formation. It was found that the increased glass transition temperature and higher crosslinking degree of latex resulted in the delay of the onset of coalescence of particles by interdiffusion during film forming process. This can be explained qualitatively in terms of diffusion rate of polymer chains. However, the change of weight loss during film formation was insensitive to discern each film forming stages-I, II and III.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3377-3382
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• 2007

In proton exchange membrane fuel cell, the heat is generated at the catalyst layer as result of exothermic electrochemical reaction. This heat increases temperature of gas diffusion layer and membrane whose conductivity is very sensitive to humidity, function of temperature. So it is very important to analysis heat transfer through fuel cell to maintain temperature at specified range. In this paper numerical simulation was done including reversible, irreversible, ionic resistance, water formation loss to source term of energy equation. Results show that irreversible and water formation loss contributes mainly to energy source term and as current density increases, all of energy source terms become increased and Nusselt number is increased as results of more heat generation. Particularly irreversible loss is found to be predominant among the all energy source and water formation at cathode channel influences the temperature distribution of fuel cell greatly.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4098-4102
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• 2012

The potential energy surface (PES) for the loss of HCN from the pyrimidine molecular ion has been explored using quantum chemical calculations. Possible reaction pathways to form five $C_3H_3N^{+{\bullet}}$ isomers have been obtained with Gaussian 4 model calculations. The rate constant for the HCN loss and the product branching ratio have been calculated using the Rice-Ramsperger-Kassel-Marcus theory on the basis of the obtained PES. The resultant rate constant agrees with the previous experimental result. By a kinetic analysis, it is proposed that the formation of $CH=CHC{\equiv}NH^{+{\bullet}}$ is favored near the dissociation threshold, while the formation of $CH=CHN{\equiv}CH^{+{\bullet}}$ is favored at high energies.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.7
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• pp.486-494
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• 2009

One-dimensional modeling of $CH_4$/air premixed flame was conducted to validate the heat loss model and investigate NOx formation characteristics in the postflame region. The predicted temperature and NO concentration were compared to experimental data and previous heat loss model results using a constant gradient of temperature (100 K/cm). The following conclusions were drawn. In the heat loss model using steady-state heat transfer equation, the numerical results using the effective heat loss coefficient ($h_{eff}$) of $1.0\;W/m^2K$ were in very good agreement with the experiments in terms of temperature and NO concentration. On the other hand, the calculated values using the constant gradient of temperature (100 K/cm) were lower than that in the experiments. Although the effects of heat loss suppress NO production near the flame region, a significant difference in NO concentration was not found compared to that under adiabatic conditions. In the postflame region, however, there were considerable differences in NO emission index as well as the contribution of NO formation mechanisms. In particular, in the range of ${\phi}\;{\geq}\;0.8$, the prompt NO mechanism plays an important role in the NO reduction under the adiabatic condition. On the other hand, the mechanism contributes to the NO production under the heat loss conditions.