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991.
Z‐Hun Kim Hwa Yeon Oh Younghoon Choi Hanwool Park Daewoo Jung Jong‐Min Kim Yang Ho Na Sang‐Min Lim Choul‐Gyun Lee Jin‐Kyun Lee 《Journal of polymer science. Part A, Polymer chemistry》2016,54(1):108-114
In this article, we demonstrate that hydrogel‐based composite membranes are used as semipermeable materials for the construction of photobioreactors (PBRs). PBRs are developed to culture microalgae using nutrients dissolved in seawater, and thus they need to be fabricated with membranes possessing sufficient material‐transport properties. While hydrogels are characterized by their highly swelling nature in water and therefore have desirable transport of dissolved matter, they lack the mechanical strength to be cast into thin structures of large surface area. This issue motivated us to design a new concept, i.e., fabric‐hydrogel composite membranes ( FHCM s). A cotton fabric inside the hydrogel matrix endows the composite with tensile strength, which enables casting of FHCM s into thin membranes. Several FHCM s were prepared with 2‐hydroxyethyl methacrylate ( HEMA ), cross‐linking poly(ethylene glycol) dimethacrylate ( PEGDMA ) and a sheet of gauze by controlling the composition of the monomers and water. In the permeability measurement of nitrate ions, a key ingredient for the growth of microalgae, the permeability coefficient reached as high as 1.2 x 10?8 m2 min?1, which is roughly three times higher than that of a commercially available semipermeable membrane (3.3 x 10?9 m2 min?1). In the following evaluation of microalgal culture, a PBR constructed with a FHCM was able to maintain sufficient ion concentration and pH of the culture broth, supporting microalgal growth. These results suggest that the composite membranes with hydrogel and fabric have potential in the application of microalgal culture for bio‐diesel production in a marine environment. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 108–114 相似文献
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Hyo-Young Mun Hong-Gyu Park Hae-Chang Jeong Ju Hwan Lee Byeong-Yun Oh 《Liquid crystals》2017,44(3):538-543
Doping with cerium (IV) oxide (CeO2) nanoparticles can significantly enhance the thermal stability and electro-optical (EO) properties of nematic liquid crystal (NLC) systems. Thermal stability was improved without aggregation and reduction of transmittance by adding CeO2 nanoparticles in a liquid crystal medium. In particular, the EO properties greatly improved in CeO2-dispersed NLC cells. The threshold voltage reduced from 3.027 to 2.279 V and the response time decreased from 13.097 to 9.970 ms with increased CeO2 nanoparticles in the NLC cells. The improved properties of liquid crystals doped with CeO2 nanoparticles depend on the anchoring energy and the electric field of the CeO2-dispersed liquid crystal displays. 相似文献
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Inside Cover: Identification of Endocrine Disrupting Chemicals using a Virus‐Based Colorimetric Sensor (Chem. Asian J. 21/2016) 下载免费PDF全文
996.
Aitha Vishwa Prasad Algin Oh Biying Woo Yuan Ling Ludger Paul Stubbs Yinghuai Zhu 《Journal of polymer science. Part A, Polymer chemistry》2013,51(19):4167-4174
We report on the application of biodegradable cyclic poly(L ‐lactide) (PLLA) as new stabilizer; synthesis and application of a cyclic PLLA‐clay hybrid material as recyclable catalyst support. Cyclic PLLAs were used to stabilize palladium nanoparticles synthesized by a wet chemical method. It was found that the palladium particles were smaller with cyclic PLLA stabilizer (~5–10 nm) than the particles obtained from linear PLLA. The cyclic PLLA‐clay hybrid was prepared by a zwitterionic ring‐opening polymerization catalyzed by in situ‐generated N‐heterocyclic carbene catalyst. Palladium (0) nanoparticles were supported and well dispersed on the cyclic PLLA‐clay hybrid to form a new nanocomposite. The nanocomposite was found to be a highly efficient and recyclable catalyst for the aminocarbonylation reactions of aryl halides with various amines. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4167–4174 相似文献
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Yeon‐Ji Oh Goeun Choi Prof. Young Bin Choy Dr. Je Won Park Jung Hyun Park Prof. Hwa Jeong Lee Prof. Yeo Joon Yoon Hee Chul Chang Prof. Jin‐Ho Choy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4869-4875
Poor aqueous solubility and the unpleasant taste of aripiprazole (APZ) have been recurring problems, owing to its low bioavailability and low patient tolerance, respectively. Herein, we prepared a nanohybrid system that was based on a bentonite clay material, montmorillonite (MMT), which could both mask the taste and enhance the solubility of APZ (i.e., APZ‐MMT). To further improve the efficacy of this taste masking and drug solubility, APZ‐MMT was also coated with a cationic polymer, polyvinylacetal diethylamino acetate (AEA). In vitro dissolution tests at neutral pH showed that the amount of drug that was released from the AEA‐coated APZ‐MMT was greatly suppressed (<1 %) for the first 3 min, thus suggesting that AEA‐coated APZ‐MMT has strong potential for the taste masking of APZ. Notably, in simulated gastric juice at pH 1.2, the total percentage of APZ that was released within the first 2 h increased up to 95 % for AEA‐coated APZ‐MMT. Furthermore, this in vitro release profile was also similar to that of Abilify®, a commercially available medication. In vivo experiments by using Sprague–Dawley rats were also performed to compare the pharmacokinetics of AEA‐coated APZ‐MMT and Abilify®. AEA‐coated APZ‐MMT exhibited about 20 % higher systemic exposure of APZ and its metabolite, dehydro‐APZ, compared with Abilify®. Therefore, a new MMT‐based nanovehicle, which is coated with a cationic polymer, can act as a promising delivery system for both taste masking and for enhancing the bioavailability of APZ. 相似文献
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Sungho Ahn Joo Yeon Hong Moo Ki Hong Young Pyo Jang Myung Sook Oh Jee H. Jung Jongki Hong 《Rapid communications in mass spectrometry : RCM》2009,23(19):3158-3166
Sildenafil and its analogues, which are used as illegal additives in several dietary supplements, were isolated by liquid‐liquid extraction and column chromatography and analyzed by fast‐atom bombardment mass spectrometry (FAB‐MS). Structures of sildenafil and its derivatives were elucidated by FAB‐tandem mass spectrometry (MS/MS) with exact mass measurement in the positive‐ion mode. To find structurally diagnostic ions for the sildenafil analogues, authentic sildenafil was preferentially analyzed by high‐energy collision‐induced dissociation (CID)‐MS/MS. The CID‐MS/MS spectra of [M+H]+ precursor ions resulted in the formation of numerous characteristic ions via a series of dissociative processes. The product ions formed by CID provided important information on the modification of the piperazine ring, the phenylsulfonyl group and the pyrazolopyrimidine moiety of sildenafil. By interpreting their MS/MS spectra, the chemical structures of sildenafil analogues isolated from dietary supplements could be elucidated and fragmentation patterns were proposed. To clearly identify the sidenafil derivatives in dietary supplements, some of the derivatives such as acetildenafil, homosildenafil and hydroxyhomosildenafil which are not commercially available were synthesized and compared with their MS/MS spectra. In addition, high‐resolution mass measurements were conducted to obtain the elemental compositions of sildenafil and its analogues. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献