• 한국식품영양과학회지
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• 제28권3호
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• pp.638-645
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• 1999

This study was done to investigate effects of ${\gamma}$ irradiated beef feeding on the formation of gluta thione S transferase placental form positive(GST P+) foci, lipid peroxidation, cytochrome P450 system and microsomal glucose 6 phosphate activity in diethylnitrosamine(DEN) initiated rat hepatocarci nogenesis. Weaning Sprague Dawley male rats were fed the diet containing ${\gamma}$ irradiatied ground beef at the dose of 0, 3, 5kGy as a 20% of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN(50mg/kg BW). As a promoter, 0.05% phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, rats were sacrificed and hepatic GST P+ foci, microsomal malondialdehyde(MDA) and conjugated diene contents were determined. In addition, cytochrome P450 content and the activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase were also measured. There was no significant effect by gamma irradiation on microsomal MDA content, conjugated diene, cytochrome P450 content and activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase. However with DEN treatment, microsomal MDA content and conjugated diene contents were significantly changed. Cytochrome P450 content was also significantly increased while microsomal glucose 6 phophatase activity was significantly decreased with DEN treatment. However activity of NADPH cytochrome P450 reductase was not affected. An interesting finding in this study was that the number and area of hepatic GST P+ foci of the rats fed gamma irradiated beef were significantly(p<0.05) lower than those of the control. Such a lowering effect on GST P+ foci formation was highest at the dose of 3kGy than others. Overall results suggest that the consumption of low dose of gamma irradiated beef does not affect the formation of lipid peroxide, cytochrome P450 system and membrane stability.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.149-159
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• 2005

A full nonlinear finite element P185/70Rl4 passenger car radial-ply tire model was developed and run on a 1.7-meter-diameter spinning test drum/cleat model at a constant speed of 50 km/h in order to investigate the tire transient response characteristics, i.e. the tire in-plane free vibration modes transmissibility. The virtual tire/drum finite element model was constructed and tested using the nonlinear finite element analysis software, PAM-SHOCK, a nonlinear finite element analysis code. The tire model was constructed in extreme detail with three-dimensional solid, layered membrane, and beam finite elements, incorporating over 18,000 nodes and 24 different types of materials. The reaction forces of the tire axle in vertical (Z axis) and longitudinal (X axis) directions were recorded when the tire rolled over a cleat on the drum, and then the FFT algorithm was applied to examine the transient response information in the frequency domain. The result showed that this PI 85/70Rl4 tire has clear peaks of 84 and 45 Hz transmissibility in the vertical and longitudinal directions. This result was validated against more than 10 previous studies by either theoretical or experimental approaches and showed excellent agreement. The tire's post-impact response was also investigated to verify the numerical convergence and computational stability of this FEA tire model and simulation strategy, the extraordinarily stable scenario was confirmed. The tire in-plane free vibration modes transmissibility was successfully detected. This approach was never before attempted in investigations of tire in-plane free vibration modes transmission phenomena; this work is believed to be the first of its kind.

• 폴리머
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• 제33권1호
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• pp.19-25
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• 2009

내수성 감습막으로 사용하기 위하여 이온넨을 포함하는 광경화성 반응성 올리고머(PIDM)로부터 새로운 종류의 전해질 고분자를 제조하였다. PIDM, hexamethylene dimethacrylate(HDM), pentaerythritol triacrylate dimer(SP1013) 및 광개시제를 혼합하여 전극에 광개시 라디칼 중합과 동시에 도포하였다. 또한, 센서의 내수성 그리고 고온/고습에서의 안정성을 증진시키기 위하여 전극 기판에 비닐기를 가지는 실란 카플링제를 사용하여 전처리 하였다. 가교화된 이온넨으로 이루어진 습도센서의 상대습도에 대한 저항을 측정하였을 때, 저항은 20%$\sim$90%RH 상대습도 영역에서 $10^3$의 값이 변화하였으며 이것은 대기의 습도를 측정하는데 요구되는 특성을 만족시키고 있다. 그 밖에 온도의존성, 히스테리시스 응답 및 회복속도, 내수성 그리고 고온/고습에서 장기 안정성을 측정하여 습도센서로서 특성을 평가하였다.

• 동의생리병리학회지
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• 제21권3호
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• pp.709-713
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• 2007

Basement membranes (BMs) are extracellular matrices associated with epithelia, endothelia, muscle, fat and peripheral nerve. They are involved in cell survival, migration, differentiation. BMs functions also include tissue formation and provide mechanical stability as a selective barriers. Laminins are heterotrimeric glycoproteins found in BMs and have a crucial role in cell adhesion and signalling. Madin-Darby canine kidney (MDCK) cells are the best established mammalian model for studying epithelial cell biology The cells form an epithelial monolayer, with tight junctions separating an apical surface from a basolateral membrane facing the filter support and neighboring cells. In this study, using MDCK cells, the synthesis of the BM protein such as laminin with or without methanol extract of Chrysanthemum morifolium (CM) stimulation was analyzed by immunoblotting and CM showed significant increased cell density and enhanced synthesis of laminin.

• Food Science and Biotechnology
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• 제14권3호
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• pp.317-322
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• 2005

A simple and convenient method of immobilizing dextransucrase via an affinity interaction is described, along with the use of this system to synthesize leucrose. Dextransucrase was produced in sucrose-free medium by fermenting a constitutive mutant of Leuconostoc mesenteroides NRRL B-512F and was separated using an ultrafiltration membrane. The purified enzyme was free of dextran polymer, which previously was always found with the sucrose-induced enzyme. Therefore, it was possible to immobilize the enzyme on dextran-based resins using an affinity interaction. Sephadex G-200 was the best resin for immobilizing the dextransucrase and gave a fast flow rate through the packed column. The immobilized dextransucrase retained more than 80% of its specific activity after immobilization ($K_m\;=\;18.1\;mM$ and $k_{cat}\;=\;450\;sec^{-1}$ vs. 13.1 mM and $640\;sec^{-1}$, respectively, for the free enzyme). The immobilized dextransucrase showed improved stability over a pH range of 4.0 to 6.5 and at moderately high temperatures over $40^{\circ}C$. When immobilized dextransucrase was used to synthesize leucrose via the transfer reaction with sucrose and fructose, about 74% of the sucrose was converted into leucrose after one day, and the half-life of the enzyme activity was 15 days. Regeneration of the resin by supplementation with dextransucrase enabled the recovery of the initial activity of the system, but both the reaction and the flow rate were lower, probably owing to the accumulation of dextran inside the resin.

• 세라미스트
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• 제21권4호
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• pp.388-405
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• 2018

In this paper, we review about current development of electrode materials for Li-ion batteries and catalysts for fuel cells. We scrutinized various electrode materials for cathode and anode in Li-ion batteries, which include the materials currently being used in the industry and candidates with high energy density. While layered, spinel, olivine, and rock-salt type inorganic electrode materials were introduced as the cathode materials, the Li metal, graphite, Li-alloying metal, and oxide compound have been discussed for the application to the anode materials. In the development of fuel cell catalysts, the catalyst structures classified according to the catalyst composition and surface structure, such as Pt-based metal nanoparticles, non-Pt catalysts, and carbon-based materials, were discussed in detail. Moreover, various support materials used to maximize the active surface area of fuel cell catalysts were explained. New electrode materials and catalysts with both high electrochemical performance and stability can be developed based on the thorough understanding of earlier studied electrode materials and catalysts.

• Genes and Genomics
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• 제40권12호
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• pp.1383-1388
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• 2018

The development of therapeutic bacteriophages will provide several benefits based on an understanding the basic physiological dynamics of phage and bacteria interactions for therapeutic use in light of the results of antibiotic abuse. However, studies on bacteriophage therapeutics against microbes are very limited, because of lack of phage stability and an incomplete understanding of the physiological intracellular mechanisms of phage. The major objective of this investigation was to provide opportunity for development of a novel therapeutic treatment to control respiratory diseases in swine. The cytokine array system was used to identify the secreted cytokines/chemokines after Bordetella bronchiseptica infection into swine nasal turbinate cells (PT-K75). We also performed the real-time quantitative PCR method to investigate the gene expression regulated by B. bronchiseptica infection or bacteriophage treatment. We found that B. bronchiseptica infection of PT-K75 induces secretion of many cytokines/chemokines to regulate airway inflammation. Of them, secretion and expression of IL-$1{\beta}$ and IL-6 are increased in a dose-dependent manner. Interestingly, membrane-bound mucin production via expression of the Muc1 gene is increased in B. bronchiseptica-infected PT-K75 cells. However, cytokine production and Muc1 gene expression are dramatically inhibited by treatment with a specific B. bronchiseptica bacteriophage (Bor-BRP-1). The regulation of cytokine profiles in B. bronchiseptica-induced inflammation by B. bronchiseptica bacteriophage is essential for avoiding inappropriate inflammatory responses. The ability of bacteriophages to downregulate the immune response by inhibiting bacterial infection emphasizes the possibility of bacteriophage-based therapies as a novel anti-inflammatory therapeutic strategy in swine respiratory tracts.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.406-414
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• 2021

Electrochemical devices are constructed for continuous syngas (CO + H₂) production with controlled selectivity between CO₂ and proton reduction reactions. The ratio of CO to H₂, or the faradaic efficiency toward CO generation, was mechanically manipulated by adjusting the space volume between the cathode and the polymer gas separator in the device. In particular, the area added between the cathode and the ion-conducting polymer using 0.5 M KHCO₃ catholyte regulated the solution acidity and proton reduction kinetics in the flow cell. The faradaic efficiency of CO production was controlled as a function of the distance between the polymer separator and cathode in addition to that manipulated by the electrode potential. Further, the electrochemical CO₂ reduction device using Au NPs presented a stable operation for more than 23 h at different H₂:CO production levels, demonstrating the functional stability of the flow cell utilizing the mechanical variable as an important operational factor.

• Journal of Veterinary Science
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• 제23권3호
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• pp.41.1-41.15
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• 2022

Background: Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium. Objectives: This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue. Methods: We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis. Results: The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × 10⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses. Conclusions: This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.

• 한국해양바이오학회지
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• 제14권2호
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• pp.133-142
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• 2022

The increased production and consumption of polyethylene terephthalate (PET)-based products over the past several decades has resulted in the discharge of countless tons of PET waste into the marine environment. PET microparticles resulting from the physical erosion of general PET wastes end up in the ocean and pose a threat to the marine biosphere and human health, necessitating the development of new technologies for recycling and upcycling. Notably, enzyme-mediated PET degradation is an appealing option due to its eco-friendly and energy-saving characteristics. PETase, a PET-hydrolyzing enzyme originating from Ideonella sakaiensis, is one of the most thoroughly researched biological catalysts. However, the industrial application of PETase-mediated PET recycling is limited due to the low stability and poor reusability of the enzyme. Here we developed the whole-cell catalyst (WCC) in which functional PETase is attached to the outer membrane of Escherichia coli. Immunoassays are used to identify the surface-expressed PETase, and we demonstrated that the WCC degraded PET microparticles most efficiently at 30℃ and pH 9 without agitation. Furthermore, the WCC increased the PET-degrading activity in a concentration-dependent manner, surpassing the limited activity of soluble PETase above 100 nM. Finally, we demonstrated that the WCC could be recycled up to three times.