• 한국정밀공학회지
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• 제31권8호
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• pp.737-742
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• 2014

This paper reports a customized silver ink and its inkjet printing process on a cellulose electro-active paper (EAPap). To synthesize a silver ink, silver nanoparticle is synthesized from silver nitrate, polyvinylpyrrolidone and ethylene glycol, followed by adding a viscosifier, hydroxyethyl-cellulose solution, and a surfactant, diethylene glycol. The silver ink is used in an inkjet printer (Fujifilm Dimatix DMP-2800 series) to print silver electrodes on cellulose EAPap. After printing, the electrodes are heat treated at $200^{\circ}C$. The sintered electrodes show that the thickness of the electrodes linearly increases as the number of printing layers increases. The electrical resistivity of the printed electrodes is $23.5{\mu}{\Omega}-cm$. This customized ink can be used in inkjet printer to print complex electrode patterns on cellulose EAPap to fabricate flexible smart actuators, flexible electronics and sensors.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.977-982
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• 2013

다양한 종류의 지방산 아실 체인으로 치환된 Cellulose mixed esters(CME)는 재생 가능한 bio-based 폴리머이다. 셀룰로오스 에스터는 생분해성 고분자로써, 분해되지 않는 석유계 플라스틱을 대체할 미래 고분자 소재이다. 본 연구에서는 개질 실험에 앞서 alpha 셀룰로오스를 $40^{\circ}C$의 증류수에 2시간동안 activation하였다. Water-activated 셀룰로오스와, 다양한 불포화 지방산, 무수 아세트산을 $120^{\circ}C$의 lithium chloride/N,N-dimethylacetamide (LiCl/DMAc)용매에서 5시간동안 반응시켜 CME를 합성했다. 세척과 감압을 반복한 후, TGA, FT-IR, 1H-NMR과 FE-SEM를 통해 특성을 관찰하였고, water activation이 셀룰로오스의 수산기 치환에 미치는 영향에 대하여 조사하였다.

• 한국초지조사료학회지
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• 제5권2호
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• pp.127-135
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• 1985

옥수수 및 sorghum 식물(植物)에 있어서 생육시기(生育時期)와 환경온도(環境溫度)가 cell-wall constituents의 합성(合成) 및 축적형태(蓄積形態)에 미치는 영향(影響)을 구명(究明)하기 위하여 옥수수의 Blizzard와 sorghum의 Sioux 및 Pioneer 931 품종(品種)을 공시재료(供試材料)로 하여 포장(圃場) 및 Phytotron 시험(試驗)을 실시(實施)하였다. Phytotron의 주(晝)/야간(夜間) 실내온도(室內溫度)는 30/25, 25/20, 28/18 및 $18/8^{\circ}C$로 하였으며 일조(日照)는 30,000-35,000Lux로 13시간(時間) 조사(照謝)하였다. 1979-81년간(年間) 얻어진 결과(結果)를 요약(要約)하면 다음과 같다. 1. 옥수수 및 sorghum의 cell wall constituents는 유수형성기(幼穗形成期)에서 지엽(止葉)이 출현(出現)되는 시기(時期)에 최대(最大)의 합성능력(合成能力)을 갖는다. Neutral Detergence Fiber 및 Acid Detergence Fiber 농도(濃度)는 동화엽면적(同化葉面積)이 최대(最大)인 출수기전후(出穗期前后)에 각각(各各) NDF 52-55% (옥수수) 및 64-68%(Sorghum)와 ADF 30%(옥수수) 및 45% (Sorghum)로 가장 높은 수준(水準)을 나타낸다. 2 Cellulose 및 Hemicellulose는 세포구조막(細胞救造膜)을 형성(形成)하고 있는 structural carbohydrates로 Cellulose가 주(主)로 경조직(莖組織)의 cell wall을 구성(構成)하고 있는데 비해 Hemicellulose는 엽(葉)과 곡실부위(穀實部位)의 세포막구성물질(細胞膜構成物質)로서 중요(重要)한 역할(役割)을 한다. 3. Cell wall constituents의 합성(合成)은 환경온도(環境溫度)가 상승(上昇)됨에 따라 비례적(比例的)으로 증가(增加)한다. 그러나 fructosan, mono- 및 disaccharose 등 non-structural carbohydrates축적(蓄積)은 $30/25^{\circ}C$이상(以上)의 고온(高溫)에서 감소(減少)된다. 고온(高溫)에서의 세포구조막물질(細胞構造膜物質) 증가(增加)는 cell wall을 구성(構成)하고 있는 물질중(物質中) 特(特)히 Cellulose가 급증(急增)된데 기인(其因)된 것으로 온도상승(溫度上昇)에 따른 Cellulose의 합성능력(合成能力)은 Hemicellulose 및 Lignin에 비해 현저(顯著)한 증가(增加)를 보인다. 4 세포구조막물질(細胞構造膜物質)의 증가(增加)는 소화율(消化率) 및 net energy 축적(蓄積)을 크게 저해(沮害)한다. cell wall constituents 중(中) phenol 성분(成分)의 Lignin과 in vitro 소화율간(消化率間)에는 높은 부(負)의 상관(相關)이 있다($P{\leqq}0.1%$). Cellulose 및 Hemicellulose는 sorghum식물(植物)의 경우 소화율(消化率)과 NEL 축적(蓄積)을 크게 악화(惡化)시키나($P{\leqq}0.1%$) 옥수수에 있어서는 이같은 부(負)의 상관관계(相關關係)가 sorghum에서와 같이 크게 나타나지 않는다.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1160-1164
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• 2013

The solid super acid catalyst $SO{_4}^{2-}$/$ZrO_2$ was prepared by impregnation method using $ZrO_2$ as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). $Al_2O_3$ and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and $NH_3$-TPD. In this paper, the effects of concentration of $H_2SO_4$ impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that $SO{_4}^{2-}/ZrO_2$ successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L $H_2SO_4$ and calcined at $500^{\circ}C$. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at $50^{\circ}C$ for 8 h.

• Genes and Genomics
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• 제40권11호
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• pp.1237-1248
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• 2018

Introduction Cellulose microfibril is a major cell wall polymer that plays an important role in the growth and development of plants. The gene cellulose synthase A (CesA), encoding cellulose synthases, is involved in the synthesis of cellulose microfibrils. However, the regulatory mechanism of CesA gene expression is not well understood, especially during the early developmental stages. Objective To identify factor(s) that regulate the expression of CesA genes and ultimately control seedling growth and development. Methods The presence of cis-elements in the promoter region of the eight CesA genes identified in flax (Linum usitatissimum L. 'Nike') seedlings was verified, and three kinds of ethylene-responsive cis-elements were identified in the promoters. Therefore, the effect of ethylene on the expression of four selected CesA genes classified into Clades 1 and 6 after treatment with $10^{-4}$ and $10^{-3}M$ 1-aminocyclopropane-1-carboxylic acid (ACC) was examined in the hypocotyl of 4-6-day-old flax seedlings. Results ACC-induced ethylene either up- or down-regulated the expression of the CesA genes depending on the clade to which these genes belonged, age of seedlings, part of the hypocotyl, and concentration of ACC. Conclusion Ethylene might be one of the factors regulating the expression of CesA genes in flax seedlings.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권1호
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• pp.1-8
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• 2005

Bacterial cellulose (BC), which is produced by some bacteria, has unique structural, functional, physical and chemical properties. Thus, the mass production of BC for industrial application has recently attracted considerable attention. To enhance BC production, two aspects have been considered, namely, the engineering and genetic viewpoints. The former includes the reactor design, nutrient selection, process control and optimization; and the latter the cloning of the BC synthesis gene, and the genetic modification of the speculated genes for higher BC production. In this review, recent advances in BC production from the two viewpoints mentioned above are described, mainly using the bacterium Gluconacetobacter xylinus.

• 공업화학
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• 제9권4호
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• pp.603-607
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• 1998

Cellulose를 출발물질로 하여 ethylene oxide와 hydroxyethylcellulose를 합성하였다. Epichlorohydrin과 triakylamine을 치환반응시켜 제4급 암모늄염을 만든후, 산을 첨가하여 3-chloro-2-hydroxypropyltrialkylammonium chloride를 얻었다. Hydroxyethylcellulose와 glycidylalkylammonium chloride 또는 3-chloro-2-hydroxypropyltrialkylammonium chloride를 coupling하여 지금까지 알려져 있지 않은 화합물 hydroxyethylcellulose-2-hydroxypropylammonium chloride ether와 hydroxyethyl-cellulose-2-hydroxypropyltriethylammonium chloride ether를 각각 73.9%, 74.2%의 수율로 합성하였다.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4122-4126
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• 2012

Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1366-1372
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• 2021

Bacterial nanocellulose (BNC) is a biocompatible material with a lot of potential. To make BNC commercially feasible, improvements in its production and surface qualities must be made. Here, we investigated the in situ fermentation and generation of BNC by addition of different cellulosic substrates such as Avicel and carboxymethylcellulose (CMC) and using Komagataeibacter sp. SFCB22-18. The addition of cellulosic substrates improved BNC production by a maximum of about 5 times and slightly modified its structural properties. The morphological and structural properties of BNC were investigated by using Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy and X-ray diffraction. Furthermore, a type-A cellulose-binding protein derived from Clostridium thermocellum, CtCBD3, was used in a novel biological analytic approach to measure the surface crystallinity of the BNC. Because Avicel and CMC may adhere to microfibrils during BNC synthesis or crystallization, cellulose-binding protein could be a useful tool for identifying the crystalline properties of BNC with high sensitivity.

• Journal of Biosystems Engineering
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• 제40권4호
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• pp.373-393
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• 2015

Background: Cellulose is a ubiquitous, renewable and environmentally friendly biopolymer, which has high promise to fulfil the rising demand for sustainable and biocompatible materials. Particularly, the recent progress in the synthesis of highly crystalline cellulose-based nanoscale biomaterials, namely cellulose nanocrystals (CNCs), draws significant attention from many research communities, ranging from bioresource engineering, to materials science and engineering, to biological and biomedical engineering to bionanotechnology. The feasibility of harnessing CNCs' unique biophysicochemical properties has inspired their basic and applied research, offering much promise for new biomaterials with diverse advanced functionalities. Purpose: This review focuses on vital issues and topics on the recent advances in CNC-based biomaterials with potential, in particular, for bionanotechnology and biological and biomedical engineering. The challenges and limitations of CNC technology are discussed as well as potential strategies to overcome them, providing an essential source of information in the exploration of possible and futuristic applications of the CNC-based functional "green" nanomaterials. Conclusion: CNCs offer exciting possibilities for advanced "green" nanomaterials, driving innovative research and development in a wide range of fields, including biological and biomedical engineering.