• Plant Biotechnology Reports
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• 제4권4호
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• pp.311-319
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• 2010

Lettuce is an economically important leafy vegetable that accumulates a milk-like sap called latex in the laticifer. Previously, we conducted a large-scale lettuce latex proteomic analysis. However, the identified proteins were obtained only from lettuce ESTs and proteins deposited in NCBI databases. To extend the number of known latex proteins, we carried out an analysis identifying 302 additional proteins that were matched to the NCBI non-redundant protein database. Interestingly, the newly identified proteins were not recovered from lettuce EST and protein databases, indicating the usefulness of this hetero system in MudPIT analysis. Gene ontology studies revealed that the newly identified latex proteins are involved in many processes, including many metabolic pathways, binding functions, stress responses, developmental processes, protein metabolism, transport and signal transduction. Application of the non-redundant plant protein database led to the identification of an increased number of latex proteins. These newly identified latex proteins provide a rich source of information for laticifer research.

• Elastomers and Composites
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• 제37권1호
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• pp.31-38
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• 2002

카르복실화 스티렌-부타디엔 라텍스의 중합시간은 사용되는 부타디엔 모노머가 공액 이중결합을 가진 화학적 구조로 인하여 라디칼 중합시 홀 전파의 비편재화로 인해 아크릴 에멀젼의 제조시 보다 중합시간이 매우 길다. 또한 라텍스 자체가 고분자와 분산매의 분리 없이 사용되기 때문에 라텍스의 안정성은 대단히 중요하다. 물성의 저하없이 반응시간을 단축하기 위하여 기존에 사용하던 연쇄이동제인 사염화탄소 대신 tert-dodecylmercaptane 과 ${\alpha}$-methylstyrene dimer를 혼합 사용하여 반응시간을 14시간에서 12시간으로 줄일 수 있었다. 반응 성장단계에서 아크릴산의 투입량을 0.3 part로 제한하여 라텍스의 점도 상승을 막고 초기중합단계 직후에 아크릴아미드를 0.1 part 첨가하여 라텍스 입자의 내부영역과 외부영역의 고분자 사슬의 상호간확산을 막아 단단하면서도 접착력을 유지할 수 있는 라텍스의 합성 결과를 얻었다.

• 대한수의학회지
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• 제35권3호
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• pp.583-593
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• 1995

The present study was conducted to develop a toxoplasma latex agglutination test antigen(Test-MT) and evaluate the toxoplasma latex agglutination(LA) test using a newly-made "Test-MT kit" by comparing with the Toxo-MT kit(Eiken chemical co, Tokyo). Also, the specifity and sensitivity test were made by comparing with IFA test and IgG-ELISA. Tachyzoite suspensions of Toxoplasma gondii(RH strain) were ultracentrifuged for 30min at $60,000{\times}g(4^{\circ}C)$ and the supernatant was used as a water-lysate antigen. Polystyrene latex particles of $1.0{\mu}m$ in diameter(Polyscience co) were used for the preparation of sensitized latex-antigen supension(Test-MT). The frequency distribution of LA titers in Test-MT showed two peaks at <1:32 and 1:128. The borderline titer for positive test in Test-MT was determined to be 1:64. But the frequency distribution of LA tites in Toxo-MT showed two peaks at <1:16 and 1:64. The positive borderline was determined to be 1:32. Agreement of reactions between Test-MT and Toxo-MT kit by LA test was shown 92.5% in bovine sera and 97.0% in swine sera, respectively. From the results obtained here it was determined that the sensitized latex-antigen, Test-MT kit, for the microtiter agglutination test prepared as same as by the procedure described in the previous paper(Suh and Lee, 1993) was useful as a highly specific, sensitive and stable immunotiteration reagent for serodiagnosis of toxoplasma infection in animal sera.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.151-156
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• 2002

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. LMC and RSLMC were studied for field applications very actively in terms of strength and durability in Korea. However, there were no considerations in drying shrinkage. Therefore, the purpose of this study was to investigate the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a controlled environment of 60% of relative humidity and 2$0^{\circ}C$ of temperature. The drying shrinkage for specimens was measured with a digital dial gauge of Demec. The test results showed that the drying shrinkage of LMC and RSLMC were considerably lower than that of OPC and RSC, respectively. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation.

• 산업기술연구
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• 제33권A호
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• pp.93-99
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• 2013

Shotcrete has been referred to as gunite, pneumatically applied mortar or concrete, sprayed concrete or mortar. There are sound reasons why sprayed mortar is one of the best portland cement based material for repairing old concrete structures. However, it is difficult to find the research results on the latex-modified mortar nevertheless on the impact of air onto the fresh and hardened properties of latex-modified mortar. So, the main experimental program included strength test, slump test, rapid chloride permeability test, image analysis for air void system, and chemical attacks with the main experimental variables of latex content, fine aggregate content, water-cement ratio, and air foamer content.

• Korea-Australia Rheology Journal
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• 제21권3호
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• pp.185-191
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• 2009

Polystyrene/multi-walled carbon nanotube (PS/MWCNT) composites were prepared by the use of latex technology. The monodisperse PS latex was synthesized by an emulsifier-free emulsion polymerization from styrene/potassium persulfate/water system in the presence of ethanol. The MWCNTs were first treated with acid mixture to eliminate impurities, dispersed in deionized water driven by ultrasonicator, and then mixed with the PS latex. From these mixtures, PS/MWCNT composites were prepared by freeze-drying and subsequent compression molding. In the small-amplitude oscillatory shear experiments, both complex viscosity and storage modulus increased with increasing MWCNT content. A pronounced effect of MWCNT content was observed, resulting in larger storage modulus and stronger yield behavior at low frequencies when compared to unmodified PS. It showed a transition from viscous to elastic behavior with increasing MWCNT content. Over the MWCNT content of 3 wt%, the storage modulus was higher than the loss modulus across all frequencies.

• 펄프종이기술
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• 제30권3호
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• pp.63-72
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• 1998

This research was intended to evaluate the effect of carboxymethylcellulose(CMC) on the coating structure and surface strength of coated paper prepared with amphoteric latex based coating color. Printability and optical properties of coated papers were compared. The influence of the consolidation behavior of coating color on the coating structure and the surface strength of coated paper was investigated. Compared with the conventional anionic latex, amphoteric latex formed bulkyer, smoother and more porous coating layer, which in turn, restricted binder migration in the coating layers, and facilitated immobilization of coating colors. However, dry pick strength of coated paper was decreased. The addition of CMC to these systems had strongly influenced on. the consolidation behavior and porosity in the dry state, through forming the network structure of coating layers by the interaction with amphoteric latex particles. Thus, printability and optical properties of coated papers were improved. Results indicated that amphoteric latex could be practically applied to the paper coating to improve printability and optical properties of coated papers.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.240-248
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• 2010

The blending effects of surfactants on the polystyrene emulsion polymerization were studied. The blending of Triton X-100 and SDS affects to the interfacial properties of the styrene monomer and water phases, and finally, the properties of the polystyrene latex particles. As the blending ratio of SDS/Triton X-100 increases, the interfacial tension and CMC of the blended surfactants were decreased and results in a reducing the size of the latex particles. It was found that the interfacial tension was reduced when the surfactant were blended. By increasing the SDS content, the interfacial tension was reduced, and, at a certain condition, the interfacial tension was reached to an extremely low value to form micro-emulsion and the nano-sized latex particles (80~110 nm).

• 한국구조물진단유지관리공학회 논문집
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• 제10권5호
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• pp.147-156
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• 2006

본 연구는 재생굵은골재를 이용한 콘크리트의 성능을 개선하기 위하여 SBR 라텍스를 활용하여 재생골재 콘크리트를 제조하고, 유동성과 역학적 성능 및 건조수축에 대하여 검토하였다. 실험결과 SBR 라텍스를 6%정도 혼입하면 재료분리에 저항하는 유동성을 확보할 수 있고, 압축강도 증진 및 휨강도 개선에 큰 효과가 있는 것을 알 수 있었다. 또한 건조수축의 감소에 우수한 재생골재 콘크리트를 제조할 수 있을 것으로 판단된다.

• 한국연초학회지
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• 제1권1호
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• pp.33-38
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• 1979

低濃度의 바이러스 조건하에서도 반응의 민감도가 높은 바이러스病의 血淸學的 診斷法을 개발하고자 담배모자이크 바이러스(Tobacco mosaic virus), 보리줄무늬 모자이크 바이러스( Barleys-tripe mosaic virus) 및 大豆모자이크 바이러스(Soybean mosaic virus)의 抗血淸으로부터 電氣泳動에 의해 추출된 Immunoglobulin을 Latex(0.8l$\mu$, Difco)粒子에 흡착시켜 梢子毛細管(1 $\times$ 100mm)내에서 各 罹病組織의 汁液과 반응시킨 결과 寒天沈降法이나 微量沈降法보다 민감도가 매우 높았다. 이 방법은 작업과정이 간편하고 빠른 시간내에 다량의 시료를 檢定할 수 있으며 陽性反應과 陰性反應을 쉽게 구별할 수 있었다.