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81.
Kang‐Yu Peng Shiu‐Wei Wang Ren‐Shen Lee 《Journal of polymer science. Part A, Polymer chemistry》2013,51(13):2769-2781
Amphiphilic diblock copolymers with various block compositions were synthesized on poly(2‐ethyl‐2‐oxazoline) (PEtOz) as a hydrophilic block and poly(4‐methyl‐ε‐caprolactone) (PMCL) or poly(4‐phenyl‐ε‐caprolactone) (PBCL) as a hydrophobic block. These PEtOz‐b‐PMCL and PEtOz‐b‐PBCL copolymers consisting of soft domains of amorphous PEtOz and PM(B)CL had no melting endothermal peaks but displayed Tg. The lower critical solution temperature (LCST) values for the PEtOz‐b‐PMCL, and the PEtOz‐b‐PBCL aqueous solution were observed to shift to lower temperature than PEtOz homopolymers. Their aqueous solutions were characterized using fluorescence techniques and dynamic light scattering (DLS). The block copolymers formed micelles with critical micelle concentrations (CMCs) in the range 0.6–11.1 mg L?1 in an aqueous phase. As the length of the hydrophobic PMCL or PBCL blocks elongated, lower CMC values were generated. The mean diameters of the micelles were between 127 and 318 nm, with PDI in the range of 0.06–0.21, suggesting nearly monodisperse size distributions. The drug entrapment efficiency and drug‐loading content of micelles depend on block polymer compositions. In vitro cell viability assay showed that PEtOz‐b‐PMCL has low cytotoxicity. Doxorubicin hydrochloride (DOX)‐loaded micelles facilitated human cervical cancer (HeLa) cell uptake of DOX; uptake was completed within 2 h, and DOX was able to reach intracellular compartments and enter the nuclei by endocytosis. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2769–2781 相似文献
82.
A general equation is derived for the shift in half wave potential, ΔE
, for ligand reduction on complexation with a metal. The formation of several complexes with differing stoichiometry and protonation states is considered explicitly. The dependence of ΔE
on metal ion concentration, holding the ligand concentration constant, can be used to determine stability constants or their ratios. The meaning of ΔE
depends on the stoichiometric changes following ligand oxidation state change, in a manner analogous to the case where the metal is the redox site. 相似文献
83.
84.
This study investigates plasmonic Bloch oscillations (PBOs) in cylindrical metal-dielectric waveguide arrays (MDWAs) by performing numerical simulations and theoretical analyses. Optical conformal mapping is used to transform cylindrical MDWAs into equivalent chirped structures with permittivity and permeability gradients across the waveguide arrays, which is caused by the curvature of the cylindrical waveguide. The PBOs are attributed to the transformed structure. The period of oscillation increases with the wavelength of the incident Gaussian beam. However, the amplitude of oscillation is almost independent of wavelength. 相似文献
85.
W. Sierpiski showed that each x in 0<x1 has a representation1/a1...ak is an increasing sequence of positive integers. Weshow that the subset of numbers x for which(ak) is strictlyincreasing is a Cantor set. 相似文献
86.
87.
Deng‐Shiu Yang Ming‐Kuang Wang Chia‐Ming Chang Hwo‐Shuenn Sheu Bing‐Joe Hwang 《中国化学会会志》2003,50(5):985-990
Lithiophorite consists of alternatively stacked MnO6 octahedral sheets and LiAl2(OH)6 octahedral sheets. Its applications in laboratories and industries have been hindered by sophisticated operation procedures, long reaction time, or impurities existing in the final product. We proposed a fast and simple method, mixing birnessite, aluminate and lithium hydroxide together (designated it as the BAL method) in high alkaline conditions (pH > 13), and treating it hydrothermally at 423 K for 6 hours to prepare pure lithiophorite. A specific reaction between lithium cations and aluminate anions plays as a key role in the BAL method. Due to this specific reaction, LixAln(OH)m+z complexed cations can form and penetrate into interlayers of birnessite to replace sodium cations. In high alkaline conditions (pH > 12), LixAln(OH)m+z complexed cations become smaller and are soluble. Thus, the higher alkaline LixAln(OH)m+z complexed cations can penetrate into interlayers of birnessite at a higher rate. Furthermore, impurities, such as lithium intercalated gibbsite (LIG), aluminum oxyhydroxides and aluminum hydroxides are not stable in high alkaline conditions. Consequently, pure lithiophorite can be easily obtained within 6 hours in high alkaline conditions. 相似文献
88.
Lou JL Shiu HW Chang LY Wu CP Soo YL Chen CH 《Langmuir : the ACS journal of surfaces and colloids》2011,27(7):3436-3441
We have grown 1-dodecandthiol (DDT) monolayer on a bare Si(111) surface through ultraviolet-assisted photochemical reaction. The resulting monolayer was investigated by means of water contact angle measurement, synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy, and polarization-dependent near-edge X-ray absorption fine structure spectroscopy. These combined probes for characterization reveal a hydrophobic ambient surface; the DDT was directly attached to Si through a Si-S bond, and the molecules formed an ordered monolayer with an average tilt angle of 57° of the alkyl chains relative to the substrate surface. 相似文献
89.
Electron-transfer properties of different carbon nanotube materials,and their use in glucose biosensors 总被引:1,自引:0,他引:1
Different types of carbon nanotube material (single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs)
of different internal diameter) have been used for preparation of CNT-modified glassy-carbon electrodes. Redox reactions involving
ferricyanide and hydrogen peroxide were examined at the CNT-modified electrodes. Electrodes modified with SWCNTs usually had
better electron-transfer properties than MWCNT-modified electrodes. Glucose biosensors were also prepared with electropolymerized
polyphenylenediamine films, CNT materials, and glucose oxidase. Amperometric behavior in glucose determination was examined.
SWCNT-modified glucose biosensors usually had a wider dynamic range (from 0.1 to 5.5 mmol L−1) and greater sensitivity in glucose determination. The detection limit was estimated to be 0.05 mmol L−1. 相似文献
90.
Glucose oxidase showed direct electrochemical transfer at glassy carbon electrodes immobilized with carbon nanotube‐gold colloid (CNT‐Au) composites with poly(diallydimethylammonium chloride) (PDDA) coatings. The modified electrode (GC/CNT/Au/PDDA‐GOD) was employed for the amperometric determination of glucose. Under optimal conditions, the biosensor displayed linear response to glucose from 0.5 to 5 mM with a sensitivity of 2.50 mA M?1 at an applied potential of ?0.3 V (vs. Ag|AgCl reference). 相似文献