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111.
Soo Kyung Bae Min‐Jung Kim Eon‐Jeong Shim Doo‐Yeoun Cho Ji‐Hong Shon Kwang‐Hyeon Liu Eun‐Young Kim Jae‐Gook Shin 《Biomedical chromatography : BMC》2009,23(6):568-572
A simple and rapid HPLC method using fluorescence detection was developed for determination of irbesartan in human plasma. Sample preparation was accomplished through a simple deproteinization procedure with 0.4 mL of acetonitrile containing 800 ng/mL of losartan (internal standard), and to a 0.1 mL plasma sample. Chromatographic separation was performed on a Zorbax Xclipse XDB C18 column (150 × 4.6 mm, i.d., 5 µm) at 40°C. An isocratic mobile phase, acetonitrile:0.1% formic acid (37:63, v/v), was run at a flow‐rate of 1.0 mL/min, and the column eluent was monitored using a fluorescence detector set at excitation and emission wavelengths of 250 and 370 nm, respectively. The retention times of irbesartan and losartan were 4.4 and 5.9 min, respectively. This assay was linear over a concentration range of 10–5000 ng/mL with a lower limit of quantification of 10 ng/mL. The coefficient of variation for this assay precision was less than 8.48%, and the accuracy exceeded 94.4%. The mean relative recoveries of irbesartan and losartan were 98.4 and 99.1%, respectively. This method was successfully applied for pharmacokinetic study after oral administration of irbesartan (300 mg) to 23 Korean healthy male volunteers. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
112.
Lacie V. Brownell Jihoon Shin Chulsung Bae 《Journal of polymer science. Part A, Polymer chemistry》2009,47(23):6655-6667
A combination of iridium‐catalyzed C H activation/borylation and atom transfer radical polymerization (ATRP) was used to generate polar graft copolymers of syndiotactic polystyrene (sPS). The borylation at aromatic C H bonds of sPS and subsequent oxidation of boronate ester proceeded without negatively affecting the molecular weight properties and the tacticity of sPS. A macroinitiator suitable for ATRP could be synthesized by the esterification of 2‐bromo‐2‐methylpropionyl bromide and hydroxy‐functionalized sPS. The graft polymerizations of methyl methacrylate and tert‐butyl acrylate from the macroinitiator using ATRP afforded polar block grafted sPS materials, syndiotactic polystyrene‐graft‐poly(methyl methacrylate) (sPS‐g‐PMMA) and syndiotactic polystyrene‐graft‐poly(tert‐butyl acrylate) (sPS‐g‐PtBA). The latter was hydrolyzed to yield an amphiphilic graft copolymer, syndiotactic polystyrene‐graft‐poly(acrylic acid) (sPS‐g‐PAA). The structures of the copolymers were characterized by NMR and FTIR spectroscopies. Size exclusion chromatography and 1H NMR spectroscopy were used to study any changes in the molecular weight properties from the parent polymer. A decrease in the hydrophobicity of the graft copolymers was confirmed by water contact angle measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6655–6667, 2009 相似文献
113.
Tae Soo Jo Meilong Yang Lacie V. Brownell Chulsung Bae 《Journal of polymer science. Part A, Polymer chemistry》2009,47(18):4519-4531
A TEMPO‐functionalized isotactic poly(1‐butene) macroinitiator was synthesized via rhodium‐catalyzed activation of the alkane C? H bonds in polyolefin side chain using a boron reagent and subsequent transformations of the boronate ester group in the polymer. These functionalization processes did not induce cross‐linking or degradation of the polymer chains. Nitroxide mediated radical polymerization of dipropyl(4‐vinylphenyl)amine with the macroinitiator produced high‐molecular weight amine‐grafted copolymers of the polyolefin. Adjusting the ratio of polar monomer concentration to macroinitiator concentration controlled the concentrations of amine blocks in the graft copolymers up to 10 mol %. Quaternization of the amine‐grafted copolymers with methyl triflate generated ammonium ion blocks along the side chain of the graft copolymers. A systematic decrease of contact angle in a series of ammonium ion‐grafted copolymers was observed through water contact angle measurements, suggesting that the graft polymerization and the quaternization led to increased hydrophilicity in the polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4519–4531, 2009 相似文献
114.
Sulfated choline ionic liquid (SCIL) has been found to be an efficient solid acid IL catalyst for the protection of amine groups with acetic anhydride under solvent-free grindstone conditions. The attractive features of this new catalytic methodology include its sustainability, facile work-up procedure, economic viability, and biodegradability. The SCIL catalyst was characterized using infrared spectroscopy, wide-angle X-ray scattering analysis, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The catalyst could be reused six times without significant loss in activity. Furthermore, no chromatographic separations were needed to obtain the desired products. 相似文献
115.
Silica/perfluoroalkyl methacrylate polymer (PHDFDMA) particles were prepared using various types of silica by polymerization
in supercritical carbon dioxide. There are three steps in the fabrication of inorganic/organic hybrid composites: silane treatment,
polymerization, and soxhlet extraction. After these steps, we observed the morphology of silica/PHDFDMA particles using field
emission scanning electron microscope and transmission electron microscope. From these analyses, we can confirm that the silica/PHDFDMA
core/shell particles were obtained when we used Ludox and silica gel as a silica template. On the other hand, core/shell particles
were not formed when using fused silica and precipitated silica. In addition, to confirm the amount of polymer on silica,
we performed an analysis using thermogravimetric analysis and electron probe micro-analyzer. In this case, PHDFDMA was approximately
20 wt.% on the silica gel and 40 wt.% on the Ludox, respectively. When using fused silica and precipitated silica as a template,
amount of PHDFDMA on silica was maximum 5 wt.% and over 40 wt.%, respectively. From these results, to obtain enough PHDFDMA
encapsulated silica particle, colloidal silica, Ludox is the best template in four different types of silica. 相似文献
116.
We propose a new Helmholtz energy of mixing equation following the original Flory–Huggins (F–H) closed-packed lattice model. Also, to overcome F–H mean-field approximation, we introduce new universal constants to consider chain length dependence of polymer in solvent and consider specific interactions to describe strongly interacting polymer systems. Our proposed model successfully describes liquid–liquid equilibria (LLE) for binary polymer–solvent systems using identical interaction parameters which do not depend on the polymer molecular weight. We also describe vapor–liquid equilibria (VLE) for polymer/solvent systems and swelling equilibria of thermosensitive hydrogel systems using the same energy parameters obtained from LLE calculations. 相似文献
117.
Joon-Soo Kim SeungCheol Yang Byeong-Soo Bae 《Journal of Sol-Gel Science and Technology》2010,53(2):434-440
Methacrylate oligosiloxane-based hybrid materials (methacrylate hybrimers) were fabricated by curing the methacrylate oligosiloxane
resins synthesized by sol–gel condensation reaction of 3-(trimethoxysilyl)propyl methacrylate (MPTS) and diphenylsilanediol
(DPSD) for the LED encapsulant application. The fabricated hybrimers are optically transparent and have a high refractive
index up to 1.565 depending on the precursor composition. The lower DPSD content hybrimer, which is the more polymerized and
heated in a vacuum to remove the non-polymerized methacrylate groups, produces higher optical transmittance and thermal stability.
This behavior is interpreted by thermal degradation of methacylate groups in the hybrimers. 相似文献
118.
119.
B. J. Park J. K. Yeon W. S. Lim S. K. Kang J. W. Bae G. Y. Yeom M. S. Jhon S. H. Shin K. S. Chang J. I. Song Y. T. Lee J. H. Jang 《Plasma Chemistry and Plasma Processing》2010,30(5):633-640
Highly selective and low damage etching of the GaAs cap layer on AlGaAs is essential in fabricating GaAs/AlGaAs high electron mobility transistors. The GaAs on AlGaAs was etched using a low energy Cl2/O2 neutral beam and the Schottky device characteristics fabricated on the exposed AlGaAs were compared with those fabricated after the etching using wet etching and a Cl2/O2 ion beam. Using a low energy Cl2/O2 ion beam or a Cl2/O2 neutral beam, highly selective etching of the GaAs cap layer to AlGaAs similar to wet etching could be achieved through the formation of Al2O3 on the exposed AlGaAs during the etching. When the electrical characteristics of the Schottky devices were compared, the devices fabricated after the etching using the neutral beam showed the best electrical characteristics such as electrical stability, low leakage current, higher barrier height, etc. by showing low damage to the exposed AlGaAs surface. 相似文献
120.
Electrospinning fabrication and characterization of poly(vinyl alcohol)/montmorillonite/silver hybrid nanofibers for antibacterial applications 总被引:1,自引:0,他引:1
Jae Hyeung Park Mohammad Rezaul Karim In Kyo Kim In Woo Cheong Jong Won Kim Do Gyu Bae Jin Won Cho Jeong Hyun Yeum 《Colloid and polymer science》2010,288(1):115-121
Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT)/silver (Ag) nanoparticles have been electrospun for fabricating PVA/MMT/Ag
nanofiber in aqueous solutions. Since PVA is a water-soluble and biocompatible polymer, it is one of the best materials for
preparation of antibacterial nanofiber. MMT has been used as an inorganic filler to enhance properties of homopolymeric nanofiber.
The PVA/MMT/Ag nanofiber diameter increases with increasing contents of MMT clay and Ag nanoparticles. In preservation test,
the PVA/MMT/Ag nanofiber confirms an excellent antibacterial performance, elucidating for practical uses as a new preservative.
Moreover, the PVA/MMT/Ag nanofiber shows improved thermal properties. 相似文献