• Title/Summary/Keyword: Degree of Oxidation

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Effect of Na2SiO3 concentration on PEO film formation of Al6061 alloy (Al6061 합금의 PEO 피막 형성에 미치는 Na2SiO3 농도의 영향 )

  • Byung Geon Lee;Young Uk Han;Gibum Jang;Sung Youl Cho
    • Journal of Surface Science and Engineering
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    • v.57 no.2
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    • pp.86-91
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    • 2024
  • In this study, we investigated the effect of Na2SiO3 concentration on the Plasma Electrolytic Oxidation(PEO) film formation of Al6061 alloy. The morphology of the PEO films were examined by Optical Microscope(OM) and Scanning Electron Microscope(SEM). PEO film thickness increases as the Na2SiO3 concentration increases. The elemental analysis of PEO films was conducted using Dispersive X-ray Spectrometer(EDS). The cross-sectional elemental analysis result shows that the Si concentration tends to increase as the concentration of Na2SiO3 increases. X-Ray Diffraction(XRD) analysis was performed to confirm the degree of phase change according to Na2SiO3 concentration. In addition, Vickers hardness was measured to confirm the mechanical strength of the PEO film. As the concentration of Na2SiO3 increases, the hardness value also tends to increase.

Application of an Antimicrobial Protein Film in Beef Patties Packaging

  • Lee, Ji-Hyun;Song, Kyung Bin
    • Food Science of Animal Resources
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    • v.35 no.5
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    • pp.611-614
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    • 2015
  • This study was performed to apply a protein film containing a natural antimicrobial compound to meat packaging and determine quality change of meat during storage. Proteins obtained from the by-products of food processing have been utilized as biodegradable film sources. Porcine meat and bone meal (MBM) is obtained during meat processing, and proteins from the MBM can be extracted and used as a film base material. Previously, an antimicrobial MBM film containing coriander oil (CO) was prepared and its physical properties and antimicrobial activity were characterized. In this study, the antimicrobial MBM-CO film was applied to beef patties packaging, and the microbial population and the degree of lipid oxidation were determined during storage at 4℃ for 15 d. The population of inoculated E. coli O157:H7 in the samples wrapped with the MBM-CO film was 6.78 log colony forming unit (CFU)/g after 15 d of storage, whereas the control had 8.05 Log CFU/g, thus reducing the microbial population by 1.29 Log CFU/g. In addition, retardation of lipid oxidation in the patties was observed during storage for the samples packaged by the MBM-CO film, compared with the control samples. These results suggest that the MBM-CO film can be useful for enhancing the quality of beef patties during storage.

Lichen as Bioindicators: Assessing their Response to Heavy Metal Pollution in Their Native Ecosystem

  • Jiho Yang;Soon-Ok Oh;Jae-Seoun Hur
    • Mycobiology
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    • v.51 no.5
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    • pp.343-353
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    • 2023
  • Lichens play crucial roles in the ecosystems, contributing to soil formation and nutrient cycling, and being used in biomonitoring efforts to assess the sustainability of ecosystems including air quality. Previous studies on heavy metal accumulation in lichens have mostly relied on manipulated environments, such as transplanted lichens, leaving us with a dearth of research on how lichens physiologically respond to heavy metal exposure in their natural habitats. To fill this knowledge gap, we investigated lichens from two of South Korea's geographically distant regions, Gangwon Province and Jeju Island, and examined whether difference in ambient heavy metal concentrations could be detected through physiological variables, including chlorophyll damage, lipid oxidation, and protein content. The physiological variables of lichens in response to heavy metals differed according to the collection area: Arsenic exerted a significant impact on chlorophyll degradation and protein content. The degree of fatty acid oxidation in lichens was associated with increased Cu concentrations. Our research highlights the value of lichens as a bioindicator, as we found that even small variations in ambient heavy metal concentrations can be detected in natural lichens. Furthermore, our study sheds light on which physiology variables that can be used as indicators of specific heavy metals, underscoring the potential of lichens for future ecology studies.

Photocatalytic Degradation of Mono-, Di-, Tri-chorophenols using continuous Flow Reactor (연속흐름식 반응기를 이용한 모노-, 디-, 트리 클로로페놀의 광촉매반응에 관한 연구)

  • Lee, Sang-Hyup;Park, Chung-Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.12 no.1
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    • pp.88-95
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    • 1998
  • The Electron/Hole Pair is generated when the Activation Energy produces by Ultraviolet Ray illumination to the Semiconductor. And $OH^-$ ion produces by Water Photo-Cleavage reacts with Positive Hole. As a result, OH Radical acting as strong oxidant is generated and then Photocatalytic Oxidation Reaction occurs. The Photocatalytic Oxidation can oxidize the chlorophenol to Chloride and Carbon Dioxide easier, safer and shorter than conventional Water Treatment Process With the same degree of chlorination, the $Cl^-$ ion at para (C4) position is most easily replaced by the OH radical. And then, the blocking effect of $OH^-$ ion between the $Cl^-$ ions and $Cl^-$ ions at symmetrical location is easily replaced by the OH radical. For mono-, di-, tri-chlorophenols, there is no obvious difference in decomposition rate, decomposition efficiency and completeness of the decomposition reaction except for 2,3-dichloropheno, 2,4,5-, 2,3,4-trichlorophenol. The decomposition efficiency is higher than 75% and completeness of the decomposition reaction is higher than 70%. Therefore, continuous flow photocatalytic reactor is promising process to remove the chlorinated aromatic compounds which is more toxic than non-chlorinated aromatic compound.

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The Korean Traditional Medicine Gyeongshingangjeehwan Reduces Lipid Accumulation in Skeletal Muscle and C2C12 Cells

  • Yoon, Mi-Chung
    • Biomedical Science Letters
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    • v.17 no.4
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    • pp.283-289
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    • 2011
  • Our previous study demonstrated that the Korean traditional medicine Gyeongshingangjeehwan (GGEx) activates AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor ${\alpha}$ ($PPAR{\alpha}$) critical for fatty acid oxidation in skeletal muscle and C2C12 skeletal muscle cells. Thus, we examined whether GGEx can reduce lipid accumulation in these cells and tissues. After obese and type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats were treated with GGEx, we studied the effects of GGEx on skeletal muscle lipid accumulation. The effects of GGEx and/or the AMPK inhibitor compound C on lipid accumulation and expression of AMPK and $PPAR{\alpha}$ were measured in C2C12 skeletal muscle cells. Compared with lean Long-Evans Tokushima Otsuka rats, obese OLETF rats had increased triglyceride droplets. However, administration of GGEx to OLETF rats for 8 weeks significantly decreased triglyceride droplets in skeletal muscle. Consistent with the $in$ $vivo$ data, GGEx inhibited lipid accumulation, the degree of which was comparable to Wy14,643, the potent activator of $PPAR{\alpha}$. GGEx also increased skeletal muscle mRNA levels of AMPK${\alpha}1$, AMPK${\alpha}2$, and $PPAR{\alpha}$. However, compound C inhibited these effects in C2C12 cells. These results suggest that GGEx suppresses skeletal muscle lipid accumulation and this process may be mediated by AMPK and $PPAR{\alpha}$ activation.

Mechanism of Formononetin-induced Stimulation of Adipocyte Fatty Acid Oxidation and Preadipocyte Differentiation

  • Seok-Yeong Yu;Youngmin Choi;Young-In Kwon;Ok-Hwan Lee;Young-Cheul Kim
    • Journal of Food and Nutrition Research
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    • v.9 no.3
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    • pp.163-169
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    • 2021
  • Decreased adipocyte fatty acid oxidation (FAO) and impaired preadipocyte differentiation characterize hypertrophic expansion of adipose tissue (AT) from obese and insulin resistant humans and are recognized as potential mechanisms for obesity-mediated dyslipidemia. Supplementation of formononetin (FMN), one of the principal isoflavones extracted from red clover or Huangqi (Astragalus roots), has been shown to have beneficial effects on obesity-related hyperlipidemia, a well-established cardiovascular risk factor. However, a target tissue and underlying mechanism(s) through which FMN acts have been under-investigated. Thus, we investigated whether FMN promotes adipocyte FAO and preadipocyte differentiation using 3T3-L1 preadipocytes to provide potential mechanisms of FMN action. We further extended this to the culture of 10T1/2 mesenchymal stem cells (MSCs) as well as mouse AT explants to reflect in vivo effects of FMN. In fully differentiated 3T3-L1 adipocytes, FMN-treatment significantly increased the expression levels of FAO-related proteins such as pAMPK, pACC, and CPT1, all of which were consistently upregulated in AT explant cultures treated with 10 μM FMN. In addition, FMN significantly enhanced the degree of differentiation of both 3T3-L1 preadipocytes and 10T1/2 MSCs into adipocytes as evidenced by Oil Red O staining of cellular lipids. This observation correlated with increased expression levels of key adipogenic transcription factors (PPARγ and C/EBPα) and their down-stream target proteins (FABP4, Glut4 and adiponectin). Moreover, FMN failed to exert its stimulatory effects on preadipocyte differentiation in both cell types in the presence of a PPARγ antagonist, suggesting a PPARγ-dependent effect of FMN. Collectively, these data provide possible mechanisms of action of FMN on lipid metabolism and further support the favorable in vivo effects of FMN in diet and obesity-induced dyslipidemia.

Qualitative attributes of meat from Teramana goat kids, an Italian native breed of the Abruzzo region

  • Ianni, Andrea;Bennato, Francesca;Martino, Camillo;Luca, Alessio Di;Martino, Giuseppe
    • Animal Bioscience
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    • v.35 no.7
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    • pp.1091-1099
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    • 2022
  • Objective: The aim of this work was the characterization of the qualitative aspects of meat obtained from Teramana goats, an Italian indigenous breed of the Abruzzo region. Specifically, the study included a comparison with meat samples deriving from Saanen goat kids reared in the same environment and applying the same feeding protocol. Methods: Upon reaching about 7 months of age the animals were slaughtered and samples of muscle tissue were collected to be analyzed. Specifically, meat samples were subjected to evaluations of the physical parameters, including color and the meat ability to retain water, in addition to chemical evaluations that were focused to the determination of the total lipids amount, fatty acids composition, lipid oxidation, and volatile profile. Results: The meat samples obtained from the indigenous breed showed a less intense reddish color and no significant variations for the muscle tissue tendency to retain water, both regarding fresh and cooked meat. Several differences were instead observed in the fatty acid profile. The Teramana samples were richer in saturated fatty acids (p<0.01) and interestingly showed higher concentrations of rumenic acid (p<0.05), a conjugate of linoleic acid that has been associated with important health benefits for the consumers. Another important finding for these meat samples was the marked resistance to oxidative events, as evidenced by the thiobarbituric acid reactive substances-test (p<0.05) and by the characterization of the volatile profile that highlighted a strong reduction in the relative percentage of hexanal (p<0.05), commonly associated to lipid oxidation and the development of unpleasant aromatic notes. Conclusion: The collected data, therefore appeared useful for the valorization of the food product derived from the Teramana goat, although no sensory information has been collected to define the degree of acceptability by the consumers.

Corrosion Behavior of Ti-6Al-4V Alloy after Plasma Electrolytic Oxidation in Solutions Containing Ca, P and Zn

  • Hwang, In-Jo;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.120-120
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    • 2016
  • Ti-6Al-4V alloy have been used for dental implant because of its excellent biocompatibility, corrosion resistance, and mechanical properties. However, the integration of such implant in bone was not in good condition to achieve improved osseointergraiton. For solving this problem, calcium phosphate (CaP) has been applied as coating materials on Ti alloy implants for hard tissue applications because its chemical similarity to the inorganic component of human bone, capability of conducting bone formation and strong affinity to the surrounding bone tissue. Various metallic elements, such as strontium (Sr), magnesium (Mg), zinc (Zn), sodium (Na), silicon (Si), silver (Ag), and yttrium (Y) are known to play an important role in the bone formation and also affect bone mineral characteristics, such as crystallinity, degradation behavior, and mechanical properties. Especially, Zn is essential for the growth of the human and Zn coating has a major impact on the improvement of corrosion resistance. Plasma electrolytic oxidation (PEO) is a promising technology to produce porous and firmly adherent inorganic Zn containing $TiO_2(Zn-TiO_2)$coatings on Ti surface, and the a mount of Zn introduced in to the coatings can be optimized by altering the electrolyte composition. In this study, corrosion behavior of Ti-6Al-4V alloy after plasma electrolytic oxidation in solutions containing Ca, P and Zn were studied by scanning electron microscopy (SEM), AC impedance, and potentiodynamic polarization test. A series of $Zn-TiO_2$ coatings are produced on Ti dental implant using PEO, with the substitution degree, respectively, at 0, 5, 10 and 20%. The potentiodynamic polarization and AC impedance tests for corrosion behaviors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to +2000mV. Also, AC impedance was performed at frequencies ranging from 10MHz to 100kHz for corrosion resistance.

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Effect of Anodized Carbon Fiber Surfaces on Interfacial Adhesion of Carbon Fiber-reinforced Composites (양극산화된 탄소섬유가 복합재료의 계면결합력에 미치는 영향)

  • 박수진;김문한;최선웅;이재락
    • Polymer(Korea)
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    • v.24 no.4
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    • pp.499-504
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    • 2000
  • The effect of anodic oxidation on high strength PAN-based carbon fibers has been studied in terms of surface functionality and surface energetics of the fiber surfaces, resulting in improving the mechanical properties of composites. According to FT-IR and XPS measurements, it reveals that the oxygen functional groups on fiber surfaces induced by an anodic oxidation largely influence the surface energetics of fibers or the mechanical interfacial properties of composites, such as the interlaminar shear strength (ILSS) of composites. According to the contact angle measurements based on the wicking rate of a test liquid, it is observed that anodic oxidation does lead to an increase in surface free energy of the carbon fibers, mainly due to the increase of its specific (or polar) component. From the surface energetic point of view, it is found that good wetting plays an important role in improving the degree of adhesion at interfaces between fiber and epoxy resin matrix of the resulting composites. Also, a direct linear relationship is shown between 01s/01s ratio and ILSS or between specific component and ILSS of the composites for this system.

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The Removal of Algae by Pre-oxidation (전산화 공정을 이용한 조류제거)

  • Son, Hee-Jong;Jung, Chul-Woo;Bae, Sang-Dae;Choi, Young-Ik;Kang, Lim-Seok
    • Journal of Environmental Science International
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    • v.18 no.3
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    • pp.289-298
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    • 2009
  • The blue-green algae which caused odor problem in the tap water are difficult to precipitate in sedimentation basin and clogged the filter void rapidly. The studies of this paper were not only oxidation, coagulation and sedimentation processes for effectively removing blue-green algae but yellow clay and polyamine for verification as coagulants aids. The results of this research are summarized as follows: Higher ozone dose(C) and longer contact time(T) were needed for a high degree of removing blue-green algae efficiency. the removal rate of blue-green algae was proportional to the $C\times T$ value. The removal percent of chlorophyll-a by sedimentation and filter without pre-ozonation was about 75% but 1 mg/L pre-ozonation could increase the removal percent of chlorophyll-a to 99% and more pre-ozonation could remove completely. Though the removal efficiency of turbidity could increased by high dose of chlorination, the dissolved organic carbon was increased. More chlorine dose from 4 to 10 mg/L dissolved organic carbon was decreased. Using yellow clay as coagulant aids increased density of floc so the settling velocity of floc become rising but polyamine could not increase settling velocity of floc though it could formated large floc.