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81.
Microfluidic device embedding electrodes realizes cell manipulation with the help of dielectrophoresis. Cell manipulation is an important technology for cell sorting and cell population purification. Till now, the theory of dielectrophoresis has been greatly developed. Microfluidic devices with various arrangements of electrodes have been reported from the beginning of the single non‐uniform electric field to the later multiple physical fields. This paper reviews the research status of microfluidic device embedding electrodes for cell manipulation based on dielectrophoresis. Firstly, the working principle of dielectrophoresis is explained. Next, cell manipulation approaches based on dielectrophoresis are introduced. Then, different types of electrode arrangements in the microfluidic device for cell manipulation are discussed, including planar, multilayered and microarray dot electrodes. Finally, the future development trend of the dielectrophoresis with the help of microfluidic devices is prospected. With the rapid development of microfluidic technology, in the near future, high precision, high throughput, high efficiency, multifunctional, portable, economical and practical microfluidic dielectrophoresis will be widely used in the fields of biology, medicine, agriculture and so on. 相似文献
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84.
A series of aluminum-containing kanemite (Al-kanemite) samples with several Si/Al molar ratios were synthesized. The Al-kanemite samples were pillared with silica. X-ray diffractograms showed that the layered structure of the Al-kanemite samples was maintained at Si/Al= infinity approximately 10 but was broken at Si/Al = 5, 2.5, and 1. 29Si MAS NMR spectra of the Al-kanemite samples, except for that of Si/Al = 1, mainly showed peaks of Q(3) sites, which were attributed to Si(OSi)(3)(OH) groups, although peaks assigned to Si(OAl)(OSi)(2)(OH) were also seen. The 27Al MAS NMR spectra indicated that the Al-kanemite samples had only four-coordinate aluminum atoms. The FTIR spectra of pyridine adsorbed on the pillared Al-kanemite derivatives revealed Lewis acid sites on the surface. The nitrogen adsorption isotherms of the derivatives were classified as type I (Langmuir) absorption isotherms. Using the alpha(s) method, the specific surface areas of the derivatives were 572-756 m(2)g(-1), and the pore sizes were calculated as 1.25-1.83 nm. The pillared Al-kanemite derivatives had slit-shaped micropore structures. 相似文献
85.
Yusuke SugiyamaTaku Matsumoto Hiroshi YamamotoMiki Nishikawa Masashi KinoshitaTohru Takei Wasuke MoriYoshito Takeuchi 《Tetrahedron》2003,59(44):8689-8696
A series of tris[(2-methoxymethyl)phenyl]germanes with a substituent on germanium was prepared and their solid-state and solution structures were investigated by means of X-ray crystallography and NMR spectroscopy to elucidate the effect of the substituent on the hypercoordination of the germanium atom in triarylgermanes. It was shown that when the substituent is a halogen, the triarylgermanes tend to be pentacoordinated trigonal bipyramidal while the triarylgermane is tetrahedral with no coordination when the substituent is a phenyl group. The methyl derivative is a monocapped tetrahedron. 相似文献
86.
Katsuraya K Imoto Y Okuyama K Hashimoto K Takei H Aono R Hatanaka K 《Carbohydrate letters》2001,4(2):131-136
A simple method for the synthesis of alternate heteropolysaccharide was investigated. Two types of modified glucose were combined into a cellobiose-type disaccharide monomer having only acetyl groups except a free hydroxyl group at C-3'. Polycondensation of this monomer, using stannic tetrachloride as catalyst, easily gave a novel copolysaccharide having regularly alternating 1,3-beta and 1,4-beta linkages. 相似文献
87.
Acid-catalyzed polymerization of a sugar oxazoline monomer 1b having two free hydroxy groups was carried out to produce a branched aminopolysaccharide 2b. The reaction proceeded via the stereoregular glycosylation through oxazoline ring-opening process, giving rise to 2b consisting of β-glycosidic linkages. The structure of 2b was determined by the 1H NMR, 13C NMR, and IR spectra. The molecular weights determined by GPC measurements were 4200-6100. The degrees of branching were estimated by the 1H NMR spectra of the products by the reaction of 2b with 3,5-dinitrobenzoyl chloride. Deprotection of 2b was carried out by the catalytic hydrogenation in the presence of 10% Pd-C to produce a free branched aminopolysaccharide. 相似文献
88.
Izuru Takei Yoshiaki Nishibayashi Yasushi Mizobe Masanobu Hidai 《Journal of organometallic chemistry》2003,679(1):32-42
Treatment of 1-trimethylsilyloxy-1-cyclohexene (1a) in the presence of a catalytic amount of the acidic dihydrogen complex [RuCl(η2-H2)(dppe)2]OTf (4a) [dppe=1,2-bis(diphenylphosphino)ethane, OTf=OSO2CF3] (10 mol.%) under 1 atm of H2 in anhydrous ClCD2CD2Cl at 50 °C for 8 h afforded cyclohexanone (3a) and Me3SiH in quantitative NMR yields. Silyl enol ethers such as 1-triethylsilyloxy-1-cyclohexene (1b), 1-t-butyldimethylsilyloxy-1-cyclohexene (1c), and other trimethylsilylethers (1d, 1e, and 1f) reacted similarly with H2 to afford the corresponding ketones and trialkylsilanes. The direct proton transfer from H2 to the trimethylsilyl enol ethers (1a and 1d-1f) was confirmed by the experiments employing D2 gas, where α-monodeuterated ketones (3a′ and 3d′-3f′) were obtained in high yields. The enantioselective protonation of prochiral silyl enol ethers with 1 atm of H2 by employing [RuCl(η2-H2)((S)-BINAP)2]OTf (4e) [BINAP=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl] and [RuCl(η2-H2)((R, R)-CHIRAPHOS)2]OTf (4f) [CHIRAPHOS=2,3-bis(diphenylphosphino)butane] showed that no enantioselectivity was observed in either catalytic or stoichiometric protonation reactions under various reaction conditions. The reaction of [RuHCl(dppe)2] (5a) with one equivalent of Me3SiOTf under 1 atm of H2 produced rapidly 4a, concurrent with the formation of Me3SiH. Based on these studies, the mechanism for this novel hydrogenolysis of silyl enol ethers is proposed which involves heterolytic cleavage of the coordinated H2 on the ruthenium atom caused by the nucleophilic attack of the oxygen atom of enol ethers to give ketones and Me3SiOTf, and the subsequent reaction of the resultant complex 5a with Me3SiOTf under 1 atm of H2 to regenerate the original dihydrogen complex 4a. On the other hand, the stoichiometric reaction of a lithium enolate 6e with one equivalent of 4e at −78 °C in CH2Cl2 under 1 atm of H2 afforded 2-methyl-1-tetralone (3e) with 75% ee (S) in >95% yield, together with the formation of [RuHCl((S)-BINAP)2] (5e). 相似文献
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90.
Prasad GK Takei T Yonesaki Y Kumada N Kinomura N 《Journal of colloid and interface science》2005,288(1):200-204
A novel nanocomposite based on poly(N-octadecyl-2-ethynylpyridinium bromide) (PNOEtPyBr) and Mg(0.04)Nb(1.66)O5 nanosheets is synthesized by the method of exfoliation-reflocculation. The XRD data of the nanocomposite indicates the formation of Mg(0.04)Nb(1.66)O5 nanosheets/PNOEtPyBr nanostructure with an interlayer expansion of 4.6 nm along a direction perpendicular to the Mg(0.04)Nb(1.66)O5 nanosheets. Formation of this nanocomposite is further supported by the results obtained by FT-IR spectroscopy and thermogravimetry. This nanocomposite exhibits interesting dielectric properties with a dielectric constant of 18.7 F/m at 1000 Hz and 25 degrees C, which are also compared to the properties of HMg(0.34)Nb(1.66)O5 and PNOEtPyBr. 相似文献