• Title/Summary/Keyword: 가소성

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Study on the Rheological Properties of Acorn Starch(III) -Effect of sucrose on the Rheological Properties of Acorn Starch- (Acorn Starch의 유변학적 성질에 관한 연구(III) -Acorn Starch의 유변학적 성질에 미치는 Surcrose 효과를 중심으로-)

  • 김남희
    • The Korean Journal of Rheology
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    • v.10 no.1
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    • pp.7-13
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    • 1998
  • 중량 평균 분자량이 1.22$\times$106이고 다분산도가 8.90이며 수분과 아밀로오스 함량이 각각 9.35%, 27%인 도토리 전분에 sucrose를 첨가하여 동적 유변학적 특성에 대한 온도와 농도의존성을 고찰하였다. AS(acorn starch)-sucrose 계의 점도는 전단속도가 증가하면 감 소하는 전단담화 현상을 나타내며 sucrose 농도가 증가할수록 점도가 증가하였고, Casson 식에 의해 얻어진 항복치는 sucrose 농도가 증가하면 증가하였다. 저장영률과 손실영률은 sucrose 농도가 증가하면 단일하게 증가하였고 손실 탄성률은 온도가 증가하면 감소하였다. DSC 측정자료를 zipper model에 적용시켜 본 결과 sucrose 농도가 증가할수록 zipper의 수 와 junc-tion zone의 수는 증가했으며 크기는 감소하였다. Sucrose는 전분과 수소결합을 형 성하여 용액내에서 가소제처럼 거동함을 알수있었다.

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Response Characteristics of Ligand Free PVC Membranes (이온운반물을 사용치 않은 이온 선택성 막의 특성)

  • Kim, Young-Hak;Lee, Ji-Yeun;Jung, Moon-Mo;Kim, Eu-Jung;Hur, Moon-Hye;Ahn, Moon-Kyu
    • Analytical Science and Technology
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    • v.10 no.6
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    • pp.453-458
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    • 1997
  • Many polymeric poly(vinyl chloride) membrane electrodes have been developed for the determination of basic drugs. But relatively little has been roported concerning the behavior of ligand free PVC memebranes. In connection with the evaluation of various ionophores, we bave evaluated a near-Nernstian response and selectivity of these ligand-free PVC electrodes towards basic drugs such as alverine, chlorpromazine and promazine. The electrode membranes were constructed with only several plasticizer and poly (vinyl chloride) matrix. The plasticizer studied were dioctyl phenylphosphonate, 2-nitrophenyl octyl ether, isododecyl phenylphosphate and dioctyl maleate.

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Physiology of Forage Crops (사료작물 생리)

  • 이호진
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.12 no.3
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    • pp.70-73
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    • 1992
  • 사료작물 저온발아성(低溫發芽性)은 수수 $\times$ 수단그라스잡종들이 좋았고 옥수수와 수단그라스는 비교적 저조하였고 PGE에 종자침지처리가 이탈리안라이그라스의 저온발아에 효과적이었다. 간척지의 수수파종시 염해 방지에는 모래를 파종후 피복하여 제염(除鹽) 효과를 얻을수 있었다. 수수류의 토양수분조건에 대한 광합성 연구는 포장용수량의 $60\sim80%$의 조건에서 광합성이 가장 왕성하였고 건물수량도 동일한 결과를 나타내었다. 옥수수의 광이용과 초형과의 관계연구는 이삭상부 엽각의 직립화는 밀식 조건에서 광이용성이 증가되었고 건물 및 종실수량에서 종수가 있었다. 또 밀식화에 따라 직립화 경향이 현저하였으며 옥수수의 다수성초형의 육성이 요청되었다. 질소시비에 대한 청예류의 생장 반응 연구들은 수단그라스에서 10a당 40Kg까지는 건물수량생산을 증가시켰으나 80Kg/10a 사용시는 질산태질소함량이 중독위험치를 초과하였다. 이러한 질산태질소의 중독위험은 6엽기까지 존재하였고 청산중독의 위험농도는 4엽기 이전까지, 또 18/$8^{\circ}C$의 저온조건에서 나타났다. 옥수수의 적정재식 밀도는 10a당 16.600본까지 밀식할수록 증가되었으나 가소화수량과 종실수량은 5.500본과 10Kg/10a 에서 최고치를 나타내었고 질소 추비 효과는 대관령 같은 고산지대에서는 나타나지 않았다. 맥류의 총체(總體)사료 이용성은 호밀, 밀, 보리 순(順)으로 저하하였고 파종시기가 빠를수록 월동성이 향상되었으며 수확적기는 출수후 24일경이었다. 호밀의 청예이용에는 월동후 2회예취와 12cm높이가 건물수량과 TDN수량을 높힐 수 있었다. 수수$\times$ 수단잡종의 출수기 이전 예취는 고사 경비율을 줄일 수 있었고 년 2회 예취와 예취높이 10cm가 가장 좋았다. 유채는 생육기간이 길어질수록 수량은 증가하였고 소화율의 감소도 현저하지 않았다.

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Non-Fickian Diffusion of Organic Solvents in Fluoropolymeys (불소고분자내 유기용매의 비-픽 확산)

  • 이상화
    • Polymer(Korea)
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    • v.28 no.1
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    • pp.24-34
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    • 2004
  • Transient sorption experiments were conducted among several combinations of fluoropolymers and various organic solvents. Fully fluorinated polymer tended to exhibit ideal sorption behavior, while partially fluorinated polymers showed anomalous sorption behaviors with a drastic acceleration at the final stage of uptake. Minimization of least-squares of the measured and predicted fractional uptake, which indicated the increasing degree of deviation from Fickian diffusion, gave values of 3.0${\times}$10$\^$-4/, 1.75${\times}$10$\^$-3/, 8.68${\times}$10/sup-3/, 1.75${\times}$10$\^$-2/, respectively, for perfluoroalkoxy copolymer, poly(ethylene-co-tetrafluoroethylene), poly(vinylidene fluoride), poly(ethylene-co-chlorotrifluoroethylene). From stress-strain tests, it was confirmed that non-Fickian diffusion is closely related to the significant variation of mechanical properties (such as modulus and tensile strength) of swollen polymer. Anomalous sorption behavior stemmed from non-Fickian diffusion caused by nonlinear disruption of polar inter-segmental bonds due to solvent-induced plasticization. Thus, it is imperative to investigate the diffusion behavior of swelling solvents in partially fluorinated polymers, especially for the application to barrier materials or perm-selective membranes.

Role of Tumor-associated Macrophage in Tumor Microenvironment (암미세환경에서 종양관련대식세포의 역할)

  • Min, Do Sik
    • Journal of Life Science
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    • v.28 no.8
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    • pp.992-998
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    • 2018
  • Cancer cells grow in an environment composed of various components that supports tumor growth. Major cell types in the tumor microenvironment are fibroblast, endothelial cells and immune cells. All of these cells communicate with cancer cells. Among infiltrating immune cells as an abundant component of solid tumors, macrophages are a major component of the tumor microenvironment and orchestrates various aspects of immunity. The complex balance between pro-tumoral and anti-tumoral effects of immune cell infiltration can create a chronic inflammatory microenvironment essential for tumor growth and progression. Macrophages express different functional programs in response to microenvironmental signals, defined as M1 and M2 polarization. Tumor-associated macrophages (TAM) secret many cytokines, chemokines and proteases, which also promote tumor angiogenesis, growth, metastasis and immunosuppression. TAM have multifaceted roles in the development of many tumor types. TAM also interact with cancer stem cells. This interaction leads to tumorigenesis, metastasis, and drug resistance. TAM obtain various immunosuppressive functions to maintain the tumor microenvironment. TAM are characterized by their heterogeneity and plasticity, as they can be functionally reprogrammed to polarized phenotypes by exposure to cancer-related factors, stromal factors, infections, or even drug interventions. Because TAMs produce tumor-specific chemokines by the stimulation of stromal factors, chemokines might serve as biomarkers that reflect disease activity. The evidence has shown that cancer tissues with high infiltration of TAM are associated with poor patient prognosis and resistance to therapies. Targeting of TAM in tumors is considered a promising therapeutic strategy for anti-cancer treatment.

Preparation of Makgeolli Residue Protein Film Containing Wasabi Extract and Its Application (고추냉이 추출물을 함유한 막걸리박 단백질 필름 제조 및 응용)

  • Lee, Ji-Hyeon;Lee, Ji-Hyun;Yang, Hyunju;Song, Kyung Bin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.2
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    • pp.268-274
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    • 2015
  • Makgeolli residue protein (MRP) was extracted from byproduct of makgeolli processing, and MRP films containing various plasticizers were prepared. Among the plasticizers used in this study, MRP film containing glycerol-sorbitol (1:2) showed the most desirable mechanical properties. In addition, MRP films containing wasabi extract (WE) were prepared by incorporating different amounts (0, 0.8, 1.0, and 1.2%) of WE into film-forming solution. Tensile strength, elongation at break, and moisture content of MRP films decreased with addition of WE as compared with the control. However, MRP films containing WE showed antimicrobial activities against Escherichia coli O157:H7 and Listeria monocytogenes. Application of MRP film containing 1.0% WE to beef packaging decreased populations of E. coli O157:H7 and L. monocytogenes after storage at $4^{\circ}C$ for 8 days by 1.1 and 0.41 log CFU/g, respectively, compared with those of the control. In addition, the peroxide value and 2-thiobarbituric acid reactive substance value decreased by 53 and 56%, respectively, compared to the control. Therefore, these results suggest that MRP film containing WE can be used to improve the quality of beef during storage.

Migration of di-(ethylhexyl)phthalate from PVC food packaging materials detected plasticizer into flood simulanting solvent (가소제가 검출된 PCV 식품용기에서의 식품유사침출 용매에 따른 디에틸헥실프탈레이트 용출에 관한 연구)

  • 김일영;유인실;이정미;김성단;정소영;한상운
    • Proceedings of the Korean Society of Food Hygiene and Safety Conference
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    • 2002.05a
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    • pp.127-131
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    • 2002
  • Migration of di-(ethylhexyl)phthalate (DEHF) from PVC food packaging materials detected plasticizer into food simulanting solvents(4% Acetic acid, 8% Ethanol, 50% Ethanol, 95% Ethanol, Heptane) were studied. For executing this study ,2 PVC food packaging materials detected DEHP were used. Analysis was by GC-FID and GC-MSD(selected ion monitoring) for DEHP, and optimized for quantification of plasticizer. The recovery of DEHP into food simulanting solvents were min. 87.4${\pm}$ 3.6 ∼ max. 109.9 ${\pm}$ 10.7% respectively. Following exposure to food simulants 95% Ethanol for 24hours at 60$^{\circ}C$ the migration results of 1020.90 ${\pm}$ 10.15$\mu\textrm{g}$/g, 563.54 ${\pm}$ 5.60$\mu\textrm{g}$/dm$^2$and 73.51 ${\pm}$ 5.09$\mu\textrm{g}$/g 149.22 ${\pm}$ 10.34$\mu\textrm{g}$/dm$^2$were detected from the container for lunch and for stock fish respectively.

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Properties of Polymer Electrolytes based on PEO-LiClO$_4$ Matrix Fabricated by Sol-Gel Process (솔-젤 법으로 만든 PEO-LiClO$_4$에 기초한 고분자 전해질의 물성)

  • 박영욱;이동성
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.265-270
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    • 2003
  • In spite of high ionic conductivity, the polymer gels have poor mechanical properties and high reactivity with lithium metal anode. To solve these problems, the dry solid systems and polymer composites have been intensively studied, due to their good mechanical, thermal, chemical, and electrochemical stability. The objectives of this experiment were to improve ionic conductivity and mechanical properties of the solid polymer electrolytes based on PEO-LiClO$_4$. To obtain higher ionic conductivity and better mechanical properties, ceramic or rubber phase was added in the PEO-LiClO$_4$(8:1) matrix. The results showed that ionic conductivity and mechanical properties were improved. The ionic conductivity of the samples was as high as 10$\^$-5/ S cm$\^$-1/. This value is similar to the best ionic conductivity ever reported in the solid drying system. To obtain better results, we used PEO with various molecular weights (600∼8000) and changed the salt contents. By using DSC, we found that the addition of salt reduced the crystallinity of PEO. The mobility of polymer dependence on salt contents was examined by FT-IR.

Characterization of a Corn Fiber Protein Film Containing Green Tea Extract (녹차 추출물을 함유한 옥피 단백질 필름의 특성)

  • Yang, Hyun-Ju;Lee, Ji-Hyun;Lee, Ji-Hyeon;Song, Kyung Bin
    • Journal of Applied Biological Chemistry
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    • v.58 no.2
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    • pp.145-151
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    • 2015
  • Corn fiber protein (CFP) was extracted from corn wet-milling by-product, corn fiber. CFP films containing various plasticizers and cross-linking agents were prepared and their mechanical properties were determined. Among the plasticizers and cross-linking agents used in this study, the CFP film containing 2 g fructose and 0.03% cinnamaldehyde had the most appropriate physical property. In addition, the CFP films containing green tea extract (GTE) were prepared by incorporating different amounts (0, 0.5, 1.0, 1.5%) of GTE into the film-forming solution. Tensile strength, film solubility, and opacity of the CFP films increased with the addition of GTE, whereas elongation and water vapor permeability of the CFP/GTE films decreased compared to those of the control. The antioxidant activity of the CFP/GTE film was determined in terms of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. As a result, antioxidant activity of the films increased with increasing GTE concentration. Furthermore, antimicrobial activity against Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus increased with increasing GTE concentration. These results indicate that the incorporation of GTE could enhance antioxidant and antimicrobial activities of the CFP films.

Nutrient Utilization of Broiler Litter and Bakery By-product Ration in Sheep (육계분-제과부산물 발효 완전혼합사료(TMR)의 면양 체내에서의 영양소 이용성 평가)

  • Kwak, W.S.;Yoon, J.S.;Jung, K.K.
    • Journal of Animal Science and Technology
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    • v.45 no.4
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    • pp.607-616
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    • 2003
  • This study was conducted to determine the effect of feeding a total mixed ration(TMR) of broiler litter(BL) and bakery by-product(BB) with additional BL or rice straw incorporated at 10% of dietary DM as a roughage source on behavior pattern, nutrient intake, digestibility, digestible nutrient intake, ruminal and blood parameters, and N balance of sheep. All the treatment diets were formulated to be isoenergetic[total digestible nutrients(TDN) 66.9%]. Compared with the conventional formulated feed - rice straw feeding system(control), feeding TMR with BL(T1) or rice straw(T2) at 10% of dietary DM resulted in reduced eating, ruminating and total chewing time(P<0.05), similar DM intake, low(P<0.05) digestible DM, OM, fiber and total nutrients intake, low(P<0.05) nutrients digestibilities except EE, similar ruminal characteristics(pH, VFA concentrations and ratios, efficiency of carbohydrate fermentation, NH3-N), and favorable N digestion and retention. There were no differences in the above parameters between T1 and T2 with the exception of increased(P<0.05) eating, ruminating and total chewing time for T2. These results suggested that a TMR of BL and BB with or without rice straw may replace the conventional formulated feed and rice straw in ruminant diets successfully and furthermore feeding the TMR with rice straw made sheep behavior pattern more favorable.