• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.3
• /
• pp.189-195
• /
• 2013

Amyloid-${\beta}$ peptide ($A{\beta}$), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of $A{\beta}$ is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM $FeCl_2$, with 0.6 mM $FeCl_2$ treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM $FeCl_2$. APP-${\alpha}$-carboxyl terminal fragment (APP-${\alpha}$-CTF) associations with ADAM10 and APP-${\beta}$-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/ BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-${\alpha}/{\beta}$-CTF activation.

• Corrosion Science and Technology
• /
• v.9 no.2
• /
• pp.81-86
• /
• 2010

The mechanisms of selective oxidation of intercritically annealed CMnAl TRIP steels in a Continuous Galvanizing Line (GCL) were studied by cross-sectional observation of the surface and sub-surface regions by means of High Resolution Transmission Electron Microscopy (HR-TEM). The selective oxidation and nitriding of an intercritically annealed CMnAl TRIP steel in a controlled dew point 10%$H_2+N_2$ atmosphere resulted in the formation of c-xMnO.$MnO_2$ (1${\leq}$x<3) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) particles on the steel surface. Single crystal c-xMnO.$SiO_2$ ($2{\leq}x{\leq}4$) oxide particles were also observed on the surface. A thin film of crystalline c-xMnO.$SiO_2$ (2${\leq}$x<3) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) was present between these particles. In the sub-surface region, internal oxidation, nitriding and intermetallic compound formation were observed. In the first region, large crystalline c-xMnO.$SiO_2$ ($1{\geq}x{\geq}2$) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) oxides particles were present. In the second region, c-AlN particles were observed, and in a third region, small $MnAl_x$ (x>1) intermetallic compound particles were observed.

• Korean Journal of Materials Research
• /
• v.32 no.8
• /
• pp.354-360
• /
• 2022

In this study, an Co/Fe coated porcelain using a cobalt and ferrous sulfate was sintered at 1,250 ℃. The specimens were investigated by HR-XRD, FE-SEM (EDS), Dilatometer, and UV-vis spectrophotometer. The surface of the porcelain was uniformly fused with the pigment, and white ware and celadon body specimens were densely fused to a certain thickness from the surface. Other new compounds were produced by the chemical reaction of cobalt/ferrous sulfate with the porcelain body during the sintering process. These compounds were identified as cobalt ferrite spinel phases for white ware and white mixed ware, and an andradite phase for the celadon body, and the amorphous phase, respectively. As for the color of the specimens coated with cobalt and ferrous mixed pigments, it was found that the L^* value was greatly affected by the white ware, and the a^* and b^* values were significantly changed in the celadon body. The L^* values of the specimens fired with pure white ware, celadon body, and white mix ware were 72.1, 60.92, 82.34, respectively. The C7F3 pigment coated porcelain fired at 1,250 ℃ had L^* values of 39.91, 50.17, and 40.53 for the white ware, celadon body, and white mixed ware, respectively; with a^* values of -1.07, -2.04, and -0.19, and at b^* values of 0.46 and 6.01, it was found to be 4.03. As a new cobalt ferrite spinel phase was formed, it seemed to have had a great influence on the color change of the ceramic surface.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.823-830
• /
• 2022

The risk of project execution increases due to the enlargement and complexity of Engineering, Procurement, and Construction (EPC) plant projects. In the fourth industrial revolution era, there is an increasing need to utilize a large amount of data generated during project execution. The design is a key element for the success of the EPC plant project. Although the design cost is about 5% of the total EPC project cost, it is a critical process that affects the entire subsequent process, such as construction, installation, and operation & maintenance (O&M). This study aims to develop a system using machine-learning (ML) techniques to predict risks and support decision-making based on big data generated in an EPC project's design and construction stages. As a result, three main modules were developed: (M1) the design cost estimation module, (M2) the design error check module, and (M3) the change order forecasting module. M1 estimated design cost based on project data such as contract amount, construction period, total design cost, and man-hour (M/H). M2 and M3 are applications for predicting the severity of schedule delay and cost over-run due to design errors and change orders through unstructured text data extracted from engineering documents. A validation test was performed through a case study to verify the model applied to each module. It is expected to improve the risk response capability of EPC contractors in the design and construction stage through this study.

• Journal of Environmental Science International
• /
• v.18 no.7
• /
• pp.819-824
• /
• 2009

The objectives of this study were to evaluate the effects of chemical additives on total phosphorus (TP), soluble reactive phosphorus (SRP), and total volatile fatty acids (total VFAs) in hanwoo slurry. The treatments in this study were ferrous sulfate, alum, and aluminum chloride, and applied at the rate of 0, 0.5, and 1.0 g/25 g of hanwoo slurry. All of the chemical treatments significantly lowered TP (11 to 53% of the untreated control), SRP (41 to 99.9% of the untreated control), and total VFAs (22 to 48.5% of the untreated control) by reducing hanwoo slurry pH (3.42 to 6.86). Among these chemical amendments, addition of 0.5 g ferrous sulfate, alum, and aluminum chloride to hanwoo slurry were the best results evaluated on farms with respect to reducing negative environmental impacts. In conclusion, the results of this study indicate that the use of chemical amendments should be considered in the development of best management practices (BMPs) for the hanwoo industries.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.1
• /
• pp.35-42
• /
• 2000

Reaction characteristics of 4-methylcatechol 2,3-dioxygenase (4MC230) purified from Pseudomonas putida SU10 with a higher activity toward 4-methylcatechol than catechol or 3-cethylcatechol were studied by altering their physical and chemical properties. The enzyme exhibited a maximum activity at pH 7.5 and approximately 40% at pH 6.0 for 4-methylcatechol hydrolysis. The optimum temperature for the enzyme was around $35^{\circ}C$, since the enzyme was unstable at higher temperature. Acetone(10%) stabilized the 4MC230. The effects of solvent and other chemicals (inactivator or reactivator) for the reactivation of the 4MC230 were also investigated. Silver nitrate and hydrogen peroxid severely deactivated the enzyme and the deactivation by hydrogen peroxide severely deactivated the enzyme and the deactivation by hydrogen peroxide was mainly due to the oxidation of ferrous ion to ferric ion. Some solvents acted as an activator and protector for the enzyme from deactivation by hydrogen peroxide. Ascorbate, cysteine, or ferrous ion reactivated the deactivated enzyme by hydrogen peroxide. The addition of ferrous ion together with a reducing agent fully recovered the enzyme activity and increased its activity abut 2 times.

• Resources Recycling
• /
• v.27 no.5
• /
• pp.54-60
• /
• 2018

The quality of steel produced from scrap can be adversely affected because of the buildup of tramp elements in recycled scrap. The tramp element of greatest concern is copper because of its effect on steel quality, even in small percentage quantities. In this study, possibility of removal of copper from ferrous scrap by using $Cl_2$ gas is experimentally examined in a small size experimental apparatus. Synthetic ferrous scraps containing copper were reacted with $Cl_2$ gas in various atmosphere. The copper was chloridized and evaporated, whereas iron was oxidized and was not reacted with Cl2 and oxygen mixture gas.

• Journal of Environmental Science International
• /
• v.23 no.12
• /
• pp.2129-2134
• /
• 2014

The antioxidant activities and total phenolics of four Rosaceae species Pourthiaea villosa (Thunb.) Decne, Sorbus commixta Hedlund, Sorbaria sorbifolia var. stellipila Maxim and Pyrus pyrifolia (Burm.f.) Nakai were determined. Phenolic content (polyphenol and flavonoid), radical scavenging activities [2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylnezthiazoline-6-sulfoic acid) (ABTS)] and ferrous ion chelating effect were evaluated. Total polyphenol and flavonoid contents were highest in Pourthiaea villosa (Thunb.) Decne and lowest in Pyrus pyrifolia (Burm.f.) Nakai. Phenolic contents of Pourthiaea villosa (Thunb.) Decne was $331.45{\pm}7.78$ and $90.4{\pm}3.5mg{\cdot}g^{-1}$. DPPH and ABTS radical scavenging activities were found to be lowest in Sorbus commixta Hedlund whereas Sorbaria sorbifolia var. stellipila Maxim and Pourthiaea villosa (Thunb.) Decne showed relatively good DPPH and ABTS radical scavenging activities. Ferrous ion chelating effect was highest in Pyrus pyrifolia (Burm.f.) Nakai ($1.05{\pm}0.04mg{\cdot}ml^{-1}$) and lowest in Sorbus commixta Hundlund ($4.22{\pm}0.71mg{\cdot}ml^{-1}$).

• Journal of Powder Materials
• /
• v.8 no.3
• /
• pp.157-162
• /
• 2001

An optimum route to fabricate the ferrous alloy dispersed $Al_2O_3$ nanocomposites such as $Al_2O_3$/Fe-Ni and $Al_2O_3$/Fe-Co with sound microstructure and desired properties was investigated. The composites were fabricated by the sintering of powder mixtures of $Al_2O_3$ and nano-sized ferrous alloy, in which the alloy was prepared by solution-chemistry routes using metal nitrates powders and a subsequent hydorgen reduction process. Microstructural observation of reduced powder mixture revealed that the Fe-Ni or Fe-Co alloy particles of about 20 nm in size homogeneously surrounded $Al_2O_3$, forming nanocomposite powder. The sintered $Al_2O_3$/Fe-Ni composite showed the formation of Fe$Al_2O_4$ phase, while the reaction phases were not observed in $Al_2O_3$/Fe-Co composite. Hot-pressed $Al_2O_3$/Fe-Ni composite showed improved mechanical properties and magnetic response. The properties are discussed in terms of microstructural characteristics such as the distribution and size of alloy particles.

• Tribology and Lubricants
• /
• v.32 no.6
• /
• pp.189-194
• /
• 2016

Wear debris in lubricating oil can be indicative of potential damage to mechanical parts in rotating and reciprocating machinery. Therefore, on-line or in-line monitoring of lubricating components in machinery is of great importance. This work presents a device based on inductive measurement of lubricating oil to detect magnetic wear particles in a tested volume. The circuit in the device consists of Maxwell Bridge and LVDT to measure inductance differences between pure and contaminated oil. The device detects the passage of ferrous particles by monitoring inductance change in a coil. The sensing principle is initially demonstrated at the microscale using a solenoid. The device is then tested using iron particles ranging from $50{\mu}m$ to $100{\mu}m$, which are often found in severely worn mechanical components. The test results show that the device is capable of detecting and distinguishing ferrous particles in lubricating oil. The design concept demonstrated here can be extended to an in-line monitoring device for real-time monitoring of ferrous debris particles. A simulation using the CST code is performed to better understand the inductive response in the presence of magnetic bodies in the oil. The CST simulation further verifies the effectiveness of inductance measurement for monitoring magnetic particles within a tube.