• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.71-82
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• 2020

The existing transportation system, which is based on internal combustion engines, is rapidly being converted to electrification. Thus, eco-friendly public transportation with high transportation efficiency will continue to spread throughout the market in the near future. The purpose of this study is to compare and analyze the cognitive characteristics of passengers redgarding the technical and social factors of various public transportation means to help a successful introduction of eco-friendly public transit. Through a survey questionnaire (N=485), seven factors of seven transportation modes were evaluated and analyzed using principal component analysis. As a result, it is confirmed that potential passengers have high expectations for the eco-friendliness and city image of the eco-friendly buses. Also, it is confirmed that eco-friendly buses are superior in cleanliness and ride comfort than diesel buses. Given the study's results, this study identifies the cognitive characteristics of passengers regarding eco-friendly public transportation. We hope that these results will be used as basic information for image positioning and improved service with the use of eco-friendly transportation.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.357-365
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• 1989

The positional parameters of framework atoms, cations, and water molecules in hydrated and dehydrated $Mg_4Na_4-A$, $Ca_6-A$, $Zn_5Na_2-A$ and $Co_4Na_4-A$ were determined by the optimization technique using some potential energy functions and VAIOA optimization program. Upon dehydration, cations in hydrated states move toward the framework oxygens of 6 rings. Frameworks of fully dehydrated zeolite A are more stable than those of fully dehydrated divalent cation exchanged Zeolite A. There are three different kinds of water molecules in divalent cation exchanged Zeolite A; W(III) (water molecules having hydrogen bonds), W(II) (water molecules associated with $Na^+$ ions), and W(I) (water molecules associated with divalent cations). Three different DTA endothermic peaks were observed corresponding to the dehydration of three different kinds of water molecules in divalent cation exchanged Zeolite A.

• Journal of Life Science
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• v.27 no.11
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• pp.1349-1356
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• 2017

Potassium channel openers (KCOs) produce physiological and pharmacological defense mechanisms against cell injuries caused by oxidative stress of diverse origins. Openings of mitochondrial and plasmalemmal $K^+$ channels are involved in the defense mechanisms. This study tested whether NS 1619, an opener of large-conductance BK channels, has a similar beneficial influence on the pigment epithelial cells of retinas. The human retinal pigment epithelial cell line ARPE-19 was exposed to $H_2O_2$-induced oxidative stress in the absence and presence of NS 1619. The degrees of the cells' injuries were assessed by analyzing the cells' trypan-blue exclusion abilities and TUNEL staining. NS 1619 produced remarkable protections against cell injuries caused by $H_2O_2$. It prevented apoptotic and necrotic cell deaths. The protective effect of NS 1619 was significantly diminished when the cells were treated with NS 1619 in combination with the BK channel-blocker paxilline. NS 1619 significantly ameliorated cellular ATP deprivations in $H_2O_2$-treated cells. It helped mitochondria preserve their functional integrity, which was estimated by their MTT reduction abilities and mitochondrial membrane potential. In conclusion, it was suggested that NS 1619 had a beneficial effect on mitochondria in regards to preserving their functional integrity under oxidative stress, and it produces defense mechanisms against oxidant-induced cell injuries in ARPE-19 cells.

• Membrane Journal
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• v.15 no.3
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• pp.247-254
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• 2005

Chitosan film has potential applications in agriculture, food, and pharmacy. However, films made only from chitosan lack gas barrier and have poor mechanical properties. For enhanced gas barrier and mechanical properties, chitosan/clay nanocomposites have been prepared with montmorillonite (MMT) which is a layered structure of clays and chitosan. The cationic biopolymer, chitosan is intercalated into $Na^+-montmorillonite$ through cationic exchange and hydrogen bonding process. Diluted acetic acid is used as solvent f3r dissolving and dispersing chitosan. Chitosan was intercalated or exfoliated in MMT and it was confirmed by X-ray diffraction method. D-spacing of the characteristic peak from MMT plate in chitosan/clay nanocomposites was moved and diminished. The thermal stability and the mechanical properties of the nanocomposites are measured by TGA and Universal Testing Machine. Gas permeability through the chitosan/clay nanocomposites films decreased due to increased tortuosity made by intercalation of clay in chitosan.

• Food Science and Preservation
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• v.31 no.3
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• pp.444-451
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• 2024

This study aimed to investigate the characteristics of protein hydrolysates derived from defatted egg yolk using various proteolytic enzymes and compare the antioxidant activity of the resulting hydrolysates. The defatted egg yolk powder was subjected to enzymatic hydrolysis using four different proteases (alcalase, bromelain, flavourzyme and neutrase), and the resulting hydrolysates were evaluated for their antioxidant properties. Through analysis of available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was observed that the defatted egg yolk powder treated with alcalase, flavourzyme, and neutrase for 12 h exhibited a high degree of hydrolysis value. Based on the RC₅₀ values obtained from two different antioxidant analyses, all hydrolysates showed comparable antioxidant activity, except for the alcalase hydrolysate, which demonstrated notably higher scavenging activity against hydrogen peroxide than the other hydrolysates. These findings suggest the potential of protein hydrolysates from defatted egg yolk, a by-product of lecithin extraction, as natural antioxidants.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.13-24
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• 2004

This study was carried out to plan the prevention of the generation and discharge of Acid Rock Drainage (ARD). The Acid Base Accounting(ABA) test was performed for geological materials such as pit wall, waste rock and stream sediments near the Imgi abandoned pyrophyllite mine in Busan, Korea. In addition, hydraulic characteristics were tested with the disk tension infiltrometer around the waste rock dump. Maximum Potential Acidity(MPA) of geological materials near the Imgi mine was 246.942kg $H_2SO_4/t$, and maximum Acid Neutralising Capacity(ANC) was 8.7kg $H_2SO_4/t$. These results indicate the pit wall and waste rock, except most of stream sediments are acid generating geological materials. These have salt and free hydrogen ion which resulted from oxidation of sulfides. Hence they could be convert rain water to acid rock drainage. Although the waste rock dump of the Imgi mine have very low infiltration rate, slopes of the waste rock dump have many "V" type erosion gullies and multi-layers. These gullies and multi-layers have coarse clastic particle layers which have very large hydraulic conductivity. Through this coarse clastic particle layer a large part of rain flow into ground. And also this layer could function as aeration path which induced oxidation of sulfide minerals and generation of ARD continuously.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.405-413
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• 2000

This study was conducted to develop an on-line monitoring system for a forest hydrological environment and its meteorological condition, such as temperature, wind direction and speed, rainfall and water level on V-notch, electrical conductivity(EC), potential of hydrogen(PH) by the motor drive sensor unit and measurement with a single-chip microprocessor as controller. These results are summarized as follows ; 1. The monitoring system consists of a signal process unit, motor drive sensor unit, radio modem unit and power supply. 2. The motor drive sensor unit protects the sensor from swift current or freezing and can constantly maintain fixed water level during measurements. 3. This monitoring system can transfer the data by radio modem. Additionally, this system can monitor hydrological conditions in real time. 4. The hardware was made of several modules with an independent CPU. They can be mounted, removed, repaired and added to. Their function can be changed and expanded. 5. These are the result of an accuracy test, the values of temperature, EC and pH measured within an error range of ${\pm}0.2^{\circ}C$, ${\pm}1{\mu}S$ and ${\pm}0.1pH$ respectively. 6. This monitoring system proved to be able to measure various factors for a forest hydrological environment in various experimental stations.

• Analytical Science and Technology
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• v.19 no.6
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• pp.482-489
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• 2006

Two electrode-based lactate biosensor was prepared by immobilizing lactate oxidase (LOD) obtained from pediococcus species in a poly(vinyl alcohol). Hydrogen peroxide ($H_2O_2$) produced by the reaction of lactate and LOD was detected on the Pt-black that was electrochemically deposited on the Au electrode. Sensors fabricated with Pt-black deposited Au electrode provided a high current of $H_2O_2$ oxidation at a substantially lowered applied potential (+300 mV vs. Ag/AgCl), resulting in reduced interferences from easily oxidizable species such as ascorbic acid, acetaminophen, and uric acid. An outer membrane is formulated by adjusting water uptake of hydrophilic polyurethane (HPU). The sensor performance was evaluated in vitro with both flow-through arrangement and static mode. The sensor showed a linear range from 0.1 mM to about 9.0 mM in 0.05 M phosphate buffer (pH 7.6) containing 0.05 M NaCl. Storing the sensors prepared in this work at $4^{\circ}C$ buffer solution while not in use, they provided same electrochemical performance for more than 25 days.

• Food Science and Preservation
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• v.30 no.5
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• pp.885-895
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• 2023

This study aims to investigate the production and characteristics of protein hydrolysates derived from tuna byproducts (TP) using various proteolytic enzymes and to compare the antioxidant activity of the resulting hydrolysates. The TP were subjected to enzymatic hydrolysis using five different proteases: alcalase, bromelain, flavourzyme, neutrase, and papain, and the antioxidant activities of the hydrolysates were evaluated. Subsequent analysis of the available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns indicated a high degree of hydrolysis in TP after treatment with all the enzymes, except for papain. Based on the RC₅₀ values obtained from four different antioxidant analyses, all the hydrolysates exhibited similar antioxidant activity, except for the flavourzyme hydrolysate, which showed significantly higher scavenging activity against ABTS radicals and hydrogen peroxide than the other hydrolysates. These findings suggest that protein hydrolysates derived from TP hold promise as potential sources of natural antioxidants.

• Journal of Life Science
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• v.27 no.7
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• pp.783-789
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• 2017

Malus melliana (Hand.-Mazz.) Rehder (M. melliana) is a Chinese plant that belongs to the Rosaceae family. There have been no previous reports regarding its bioactivity. In this study, the anti-oxidative and anti-inflammatory activities of M. melliana ethanol extract (MMEE) were evaluated using a 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity assay, reactive oxygen species (ROS) scavenging activity assay, nitric oxide (NO) inhibitory activity assay, and the analysis of related protein expressions through Western blot hybridization. MMEE showed potent scavenging activity against DPPH, similar to ascorbic acid, a well-known anti-oxidative agent, which was used as a positive control. MMEE also inhibited hydrogen peroxide-induced ROS in RAW 264.7 cells. Moreover, MMEE induced the expression of an anti-oxidative enzyme, heme oxygenase 1, and its upstream transcription factor, nuclear factor E2-related factor-2, in a dose-dependent manner. On the other hand, MMEE was associated with a reduction in NO production, which was induced by the lipopolysaccharide treatment of RAW 264.7 cells. The expression of inducible nitric oxide synthase, which is the upstream regulator of NO production, was also inhibited. Taken together, these results suggest that MMEE has anti-oxidative and anti-inflammatory properties, thus appearing to be a potential anti-oxidant and anti-inflammatory agent. The further identification of active compounds that confer the biological activities of MMEE may be necessary.