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41.
42.
Surface initiated‐atom transfer radical polymerization of a sugar methacrylate on gold nanoparticles
Kuk Ro Yoon Soo Min Lee B. Ramaraj Dong‐Pyo Kim 《Surface and interface analysis : SIA》2008,40(8):1139-1143
For development of surface‐functionalized gold nanoparticles (GNPs) as cellular probes, we report herein the synthesis of glycoconjugates of GNPs with cyclic sugar methacrylate, 2‐lactobionamidoethyl methacrylate (LAMA). The strategy involves the attachment of an initiator on the nanoparticle surface followed by surface initiated‐atom transfer radical polymerization (SI‐ATRP) of LAMA. SI‐ATRP of LAMA was achieved by reacting a mixture of copper (I) bromide (CuBr), 2,2′‐bipyridine (bpy) and initiator‐bound GNPs in methanol at 20 °C for 12 h. The resultant GNP glycoconjugates were characterized using Fourier‐transform infrared (FT‐IR) spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The FT‐IR spectra of GNP glycoconjugates show IR peaks characteristic of LAMA demonstrating the formation of a LAMA layer on the GNPs' surface. The XPS spectrum of glycoconjugates shows signals due to the presence of carbon (C1s, 288 eV) and oxygen (O1s, 536 eV) along with gold (Au 4f, 100 eV; Au 4p, 743 eV). The increase in diameter of GNPs from 13 to 25 nm measured by SEM further confirms the presence of a LAMA layer on the surface of the GNPs. Considering the biological importance of glycoconjugates, such as cell recognition, cell adhesion and cell growth regulation, the method described herein would be beneficial in many areas such as pathogen detection and biosensors. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
43.
Flow‐Assisted Synthesis of [10]Cycloparaphenylene through Serial Microreactions under Mild Conditions
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Dr. Heejin Kim Hyune‐Jea Lee Prof. Dr. Dong‐Pyo Kim 《Angewandte Chemie (International ed. in English)》2016,55(4):1422-1426
Cycloparaphenylene (CPP) has been recognized as an attractive template for the bottom‐up synthesis of carbon nanotubes with uniform diameter, and is important for the chemistry of graphitic as well as ring‐shaped macromolecules. However, the reported routes from halogenated benzenes have suffered from low yields even under time‐ and labor‐consuming multistep conditions. Herein we report a flow‐assisted synthesis of [10]CPP in four steps under mild conditions. For the synthesis, a selective nucleophilic addition of the unprotected diketone without the double‐added byproduct was achieved within 3 s in high yield. Subsequently, the obtained compound was reacted with dilithiated benzene at 25 °C to form a U‐shaped precursor for CPP in a separate microreactor, which was finally dimerized and aromatized to obtain [10]CPP by a two‐step in‐flask reaction. Precise control of time and flow facilitated by the flow‐assisted system enabled the development of an efficient synthetic route for [10]CPP. 相似文献
44.
??In this paper, we prove the existence and uniqueness of solutions
for reflected backward stochastic differential equations driven by a
Levy process, in which the reflecting barriers are just right
continuous with left limits whose jumps are arbitrary. To derive the
above results, the monotonic limit theorem of Backward SDE
associated with Levy process is established. 相似文献
45.
铀的高灵敏高选择性的光度法尚少见。最近有人合成过二溴苯基萤光酮(下简称Br-PF),但未见用于测定铀的报导。为此,本文研究了在吐温-60存在下用Br-PF测定铀的条件,结果表明,本法的灵敏度较高(ε=1.79×105),是迄今为止铀最灵敏的显色反应(见表1)。采用三辛胺(TOA)萃取分离铀,并用于岩矿中铀的测定。 相似文献
46.
Dongjin Pyo 《高等学校化学学报》1999,20(Z1):220
An analytical method is described for separating polyaromatic hydrocarbons using modified supercritical carbon dioxide and pure carbon dioxide. The effects of adding methanol in supercritical carbon dioxide mobile phase were studied. The modifier, methanol affected especially in the retentions of polyaromatic hydrocarbons. 相似文献
47.
We study the problem of the approximation in law of the Rosenblatt sheet. We prove the convergence in law of two families of process to the Rosenblatt sheet: the first one is constructed from a Poisson process in the plane and the second one is based on random walks. 相似文献
48.
McNamee CE Pyo N Tanaka S Kanda Y Higashitani K 《Colloids and surfaces. B, Biointerfaces》2006,47(1):85-89
Here, we propose a new method to improve the atomic force microscopy (AFM) image resolution of soft samples, such as cells, in liquid. Attaching a colloid probe to a cantilever was seen improve the image resolution of a living cell in a physiological buffer solution, obtained by the normal tapping mode, when compared to an image obtained using a regular cantilever tip. This may be due to the averaging out of the cantilever tip swinging caused by the visco-elasticity of the cell. The resolution was best, when silica spheres with a 3.3 microm diameter were attached. Although larger spheres gave a resolution better than a bare cantilever tip, their resolution was less than that obtained for the 3.3 microm diameter silica colloid. This dependency of the image resolution on the colloid probe size may be a result of the increased macroscopic van der Waals attraction between the cell and probe, the decreased repulsive force dependence on the cantilever probe radius, and the decrease in resolution due to the increased probe size. The size of the colloid probe, which should be attached to the cantilever to give the best image resolution, would be the one that optimises the combined result of these facts. 相似文献
49.
Sang‐Hoon Ji Wan Pyo Hong Seung Ho Ko Kee‐Jung Lee 《Journal of heterocyclic chemistry》2006,43(3):799-801
50.
Complete Convergence of Weighted Sums for Arrays of Rowwise $m$-Negatively Associated Random Variables
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In this paper, we discuss the complete convergence of weighted sums for
arrays of rowwise $m$-negatively associated random variables. By applying moment
inequality and truncation methods, the sufficient conditions of complete convergence
of weighted sums for arrays of rowwise $m$-negatively associated random variables are
established. These results generalize and complement some known conclusions. 相似文献