• Title/Summary/Keyword: resistant capacity

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Combination of oxaliplatin and β-carotene suppresses colorectal cancer by regulating cell cycle, apoptosis, and cancer stemness in vitro

  • Junghyeun Lee;Seung Chul Heo;Yuri Kim
    • Nutrition Research and Practice
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    • v.18 no.1
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    • pp.62-77
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    • 2024
  • BACKGROUND/OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer worldwide with a high recurrence rate. Oxaliplatin (OXA) resistance is one of the major reasons hindering CRC therapy. β-Carotene (BC) is a provitamin A and is known to have antioxidant and anticancer effects. However, the combined effect of OXA and BC has not been investigated. Therefore, this study investigated the anticancer effects and mechanism of the combination of OXA and BC on CRC. MATERIALS/METHODS: In the present study, the effects of the combination of OXA and BC on cell viability, cell cycle arrest, and cancer stemness were investigated using HCT116, HT29, OXA-resistant cells, and human CRC organoids. RESULTS: The combination of OXA and BC enhanced apoptosis, G2/M phase cell cycle arrest, and inhibited cancer cell survival in human CRC resistant cells and CRC organoids without toxicity in normal organoids. Cancer stem cell marker expression and self-replicating capacity were suppressed by combined treatment with OXA and BC. Moreover, this combined treatment upregulated apoptosis and the stem cell-related JAK/STAT signaling pathway. CONCLUSIONS: Our results suggest a novel potential role of BC in reducing resistance to OXA, thereby enhances the anticancer effects of OXA. This enhancement is achieved through the regulation of cell cycle, apoptosis, and stemness in CRC.

A Study on Relations between Shape Factor and Temperature History of Steel of Composit Beam in Standard Fire under Same Thickness Condition of Spray-type Fire Resistant Materials (동일 내화뿜칠 피복조건에서 표준화재에 노출된 합성보의 강재 온도이력 및 단면형상계수와의 관계)

  • Yeo, In-Hwan;Cho, Kyung-Suk;Cho, Bum-Yean
    • Fire Science and Engineering
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    • v.26 no.6
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    • pp.72-77
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    • 2012
  • When the concrete and steel combined composite beam is exposed to high temperature, concrete could delay temperature rising of steel by covering or increase heat capacity of structural member. For becoming of structural reinforcing by unification between materials, fire resistance rate of composite beam would be higher than simple steel beam. The temperature rising of exposed steel of composite beam is directly related with section shape and exposure length of steel. In this study, fire resistant tests were carried out for composite beams and steel beam with same thickness of spray-type fire resistant materials in standard fire, and after that, temperature histories were analysed and compared with shape factor. The correlation between steel temperature and shape factor was showed very high. This result suggests that if it can be predict the comparative advantage of member by factor which cause the performance enhancement, it could be conclude that an Standard Accreditation method can be adjust to members without indivisual certifiicate of accreditation.

Earthquake Resistant Performance of a High-rise Shear Wall Apartment Based on Nonlinear Time History Response Analysis (동적 탄소성 지진응답해석에 의한 고층 벽식 아파트의 내진성능 검토)

  • 박성수
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.1
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    • pp.1-8
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    • 1999
  • Dynamic elastoplastic LPM (lumped parameter mass) analyses are carried out in order to investigate the seismic resistant performance of a typical high-rise shear wall apartment subjected to several earthquakes. Three-dimensional nonlinear pushover analysis is adopted to estimate initial elastic stiffness, yielding strength and post-yielding stiffness of each story for the time history analysis of LPM shear model. For the hysteresis of each story, Clough and bilinear models are used with the input of four recorded earthquake ground motions of EI Centro 1940 NS, Taft 1952 EW, Hachinohe 1968 NS and Kobe 1995 NS, of which the amplitudes are scaled down to have the same maximum ground velocity of 12 kine. The result shows that yieldings take place in most storys of the building, i.e. the earthquake resistant capacity of this high-rise shear wall apartment is not sufficient at the event of earthquake M=5~6.

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The Roofing System of High wind-Resistant Performance using Thermoplastic polyolefin and Electromagnetic Induction Technology (TPO 시트재와 유도가열공법을 적용한 고내풍성 지붕마감 공법)

  • Choi, Hee-Bok;Shin, Yoon-Seok;Choi, Jin-Cheol;Lee, Bo-Hyeong;Kang, Kyung-In
    • Journal of the Korea Institute of Building Construction
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    • v.9 no.1
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    • pp.103-109
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    • 2009
  • Strong winds according to global warming cause the increase of the frequency and the repair cost of damaged roofs. In the United States, Factory Mutual Insurance Company(FMIC) promotes the roofing design that resists heavy wind-load, as the means of strict criteria. This fact reveals that more durable roofing system will be also required in Korea. Therefore, this study aims at developing such a system with high wind-resistance performance using Thermoplastic polyolefin(TPO) and Electromagnetic induction technology(EIT) than the previous systems. The system presented in this study consists of 4 main devices as follow; 1) a disc to fix sheets for TPO & EIT method, which can conduct structural design according to site condition, such as region, building height, and wind load. 2) a nail to have about 30% stronger lifting-up capacity than that of the previous nail. 3) a disc to fix sheets, which has triangle protuberance not to damage sheets in the repeatable wind load, and 4) a electromagnetic induction device to combine a disc and a sheet by heating uniformly and quickly adhesive agent on the disc. The results of mock-up test illustrate that the system provides wind-resistant performance to achieve satisfactorily the structural design criteria of FMIC. In addition, the system is faster, chipper, and easier than the existing system, and is expected that this roofing system can be applied to the rehabilitations of an existing as well as a new building.

Development of the High-quality Coating System for the Steam Pipe of Ship (선박 스팀파이프용의 고내구성 도장 사양 개발 연구)

  • Lee, Sung-Kyun;Baek, Kwang-Ki;Hwang, Dong-Un;Song, Eun-Ha
    • Special Issue of the Society of Naval Architects of Korea
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    • 2006.09a
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    • pp.46-52
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    • 2006
  • For ships, heat resistant coating is applied on the aluminized steel pipe systems dealing with high temperature steam over $200^{\circ}C$. The coatings on these steam pipes should retain both heat resistance and anti-corrosion properties to provide long-term resistance against coating defects (rust, delamination and crack) under the harsh outdoor environment including repeated seawater wetting and condensation. Thus, it is important to improve the coating qualities and to reduce maintenance works for these steam pipe systems. In this study, five different commercial heat resistant coatings (A, B, C, D, E) were selected for evaluation. Various physical properties of these coatings were evaluated on the coatings applied on the aluminized steam pipes. FT-IR analysis was also employed to identify the factors contributing the degree of heat resistance and durability of each coating material. The results indicated that the heat resistance capacity of coatings increased with the increase of silicon content as well as the decrease of substituent content. Both products C and D showed the best coating qualifies, which can be standard coating systems for future steam pipe areas.

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Buckling resistance behavior of WGJ420 fire-resistant weathering steel columns under fire

  • Yiran Wu;Xianglin Yu;Yongjiu Shi;Yonglei Xu;Huiyong Ban
    • Steel and Composite Structures
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    • v.47 no.2
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    • pp.269-287
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    • 2023
  • The WGJ420 fire-resistant weathering (FRW) steel is developed and manufactured with standard yield strength of 420 MPa at room temperature, which is expected to significantly enhance the performance of steel structures with excellent fire and corrosion resistances, strong seismic capacity, high strength and ductility, good resilience and robustness. In this paper, the mechanical properties of FRW steel plates and buckling behavior of columns are investigated through tests at elevated temperatures. The stress-strain curves, mechanical properties of FRW steel such as modulus of elasticity, proof strength, tensile strength, as well as corresponding reduction factors are obtained and discussed. The recommended constitutive model based on the Ramberg-Osgood relationship, as well as the relevant formulas for mechanical properties are proposed, which provide fundamental mechanical parameters and references. A total of 12 FRW steel welded I-section columns with different slenderness ratios and buckling load ratios are tested under standard fire to understand the global buckling behavior in-depth. The influences of boundary conditions on the buckling failure modes as well as the critical temperatures are also investigated. In addition, the temperature distributions at different sections/locations of the columns are obtained. It is found that the buckling deformation curve can be divided into four stages: initial expansion stage, stable stage, compression stage and failure stage. The fire test results concluded that the residual buckling capacities of FRW steel columns are substantially higher than the conventional steel columns at elevated temperatures. Furthermore, the numerical results show good agreement with the fire test results in terms of the critical temperature and maximum axial elongation. Finally, the critical temperatures between the numerical results and various code/standard curves (GB 51249, Eurocode 3, AS 4100, BS 5950 and AISC) are compared and verified both in the buckling resistance domain and in the temperature domain. It is demonstrated that the FRW steel columns have sufficient safety redundancy for fire resistance when they are designed according to current codes or standards.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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Isolation of copper-resistant bacteria with plant growth promoting capability (식물 생장을 촉진할 수 있는 구리 내성 세균의 분리)

  • Kim, Min-Ju;Song, Hong-Gyu
    • Korean Journal of Microbiology
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    • v.53 no.4
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    • pp.251-256
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    • 2017
  • Some rhizobacteria were isolated, that have copper resistance and can confer copper resistance to plants allowing growth under copper stress. Isolated strains Pseudomonas veronii MS1 and P. migulae MS2 produced 0.13 and 0.26 mmol/ml of siderophore, that is a metal-chelating agent, and also showed 64.6 and 77.9% of biosorption ability for Cu in 20 mg/L Cu solution, respectively. Copper can catalyze a formation of harmful free radicals, which may cause oxidative stress in organisms. Removal activity of 1,1-diphenyl-2-picryl hydrazyl radical and antioxidant capacity of strains MS1 and MS2 increased up to 82.6 and 78.1%, respectively compared to those of control at 24 h of incubation. They exhibited 7.10 and $6.42{\mu}mol$ ${\alpha}$-ketobutyrate mg/h of 1-aminocyclopropane-1-carboxylic acid deaminase activity, respectively, which reduced levels of stress hormone, ethylene in plants, and also produced indole-3-acetic acid and salicyclic acid that can help plant growth under abiotic stress. All these results indicated that these copper-resistant rhizobacteria could confer copper resistance and growth promotion to plants.

New High Recovery Membrane Modules for Desalination

  • Fujiwara, Nobuya
    • Proceedings of the Membrane Society of Korea Conference
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    • 2002.07a
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    • pp.1-12
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    • 2002
  • Desalination by reverse osmosis (RO), which first entered commercial use in the 1970s, was initially mainly used for treating brackish water. Technological progress led to the development of an RO membrane enabling single-pass seawater desalination. Toyobo succeeded in developing a single-pass seawater desalination RO module composed of hollow fiber type membranes made of cellulose triacetate in 1978, and then in 1979 began production of the first commercially available double-element module. This double-element module has many advantages suitable for seawater desalination. It has high chlorine tolerance and high salt rejection, derived from the properties of the membrane material, and it is highly resistant to fouling and scaling matters due to the unique flow pattern and fiber bundle configuration. These advantages help to explain why the Toyobo double-element module has been used so successfully at the many seawater desalination plants around the world. Since the 1980s, large plants capable of desalinating several tens of thousands of cubic meters a day have sprung up around the Mediterranean and In the Middle East. The Jeddah RO Phase I Plant, which has a capacity of 56, 800m$^3$/day, went into operation in 1989. In 1994, the same sized Phase II Plant came on stream, giving the plant a huge total capacity of 113, 600m$^3$/day. The plant constructor Mitsubishi Heavy Industries, Ltd. (MHI), and the RO membrane manufacturer Toyobo Co., Ltd. In 1998, the world's largest RO seawater desalination plant in operation, which has a capacity of 128, 000m$^3$/day and is run by Saudi Arabia's Saline Water Conversion Corporation (SWCC), went into operation at Yanbu. RO seawater desalination technology has thus already reached the stage of full-scale commercial use. In order to encourage its wider use, however, RO desalination needs to be made more economical by lowering construction and water treatment costs. Toyobo has therefore developed a new economical RO desalination system by a recovery ratio of 60% using a high-pressure module with a high product flow rate. In 2000, Toyobo high recovery membrane module was selected for the largest seawater desalination plant in Japan, which has a capacity of 50, 000m$^3$/day.

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Parameters for Evaluating the Sink Capacity of Broad Leaves Trees for the Gas Phase Air Pollutants (가스상 대기오염물질에 대한 활엽수의 정화능력 평가인자)

  • Kim, Jeong-Gyu;Koh, Kang-Suk
    • Korean Journal of Environmental Agriculture
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    • v.15 no.4
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    • pp.472-478
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    • 1996
  • It was conducted to compare the availabilities of parameters for evaluating the sink capacity of the broad leaves trees such as Acer saccharium, Ailanthus altissima, Ginkgo biloba, Platanus occidentalis and Salix pseudolasiogyne. These trees, repoted as resistant species to air pollutants, were exposed to $SO_2$, $NO_2$ and CO within a phytotron at $25^{\circ}C$ with 70% of relative humidity. Since the amount of ad- or absorbed gas does not always agree with the amount of accumlated pollutants in leaves and with the stomatal density, it is assumed that the amount of ad- or absorbed gas is the most basal index to evaluate the sink capacity of trees. The stomatal diffusive resistance, which has a good agreement with the amount of ad- or absorbed gas, is also available for evaluating the sink capacity of broad leaves trees.

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