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971.
Kim WS Kim MG Ahn JH Bae BS Park CB 《Langmuir : the ACS journal of surfaces and colloids》2007,23(9):4732-4736
Active protein micropatterns and microarrays made by selective localization are popular candidates for medical diagnostics, such as biosensors, bioMEMS, and basic protein studies. In this paper, we present a simple fabrication process of thick (approximately 20 microm) protein micropatterning using capillary force lithography with bifunctional sol-gel hybrid materials. Because bifunctional sol-gel hybrid material can have both an amine function for linking with protein and a methacryl function for photocuring, proteins such as streptavidin can be immobilized directly on thick bifunctional sol-gel hybrid micropatterns. Another advantage of the bifunctional sol-gel hybrid materials is the high selective stability of the amine group on bifunctional sol-gel hybrid patterns. Because amine function is regularly contained in each siloxane oligomers, immobilizing sites for streptavidin are widely distributed on the surface of thick hybrid micropatterns. The micropatterning processes of active proteins using efficient bifunctional sol-gel hybrid materials will be useful for the development of future bioengineered systems because they can save several processing steps and reduce costs. 相似文献
972.
Dixon MC Daniel TA Hieda M Smilgies DM Chan MH Allara DL 《Langmuir : the ACS journal of surfaces and colloids》2007,23(5):2414-2422
Thin nanoporous gold (np-Au) films, ranging in thickness from approximately 40 to 1600 nm, have been prepared by selective chemical etching of Ag from Ag/Au alloy films supported on planar substrates. A combination of scanning electron microscopy (SEM) imaging, synchrotron grazing incidence small angle X-ray scattering, and N2 adsorption surface area measurements shows the films to exhibit a porous structure with intertwined gold fibrils exhibiting a spectrum of feature sizes and spacings ranging from several to hundreds of nanometers. Spectroscopic ellipsometry measurements (300-800 nm) reveal the onset of surface plasmon types of features with increase of film thicknesses into the approximately 200 nm film thickness range. Raman scattering measurements for films functionalized with a self-assembled monolayer formed from 4-fluorobenzenethiol show significant enhancements which vary sharply with film thickness and etching times. The maximum enhancement factors reach approximately 10(4) for 632.8 nm excitation, peak sharply in the approximately 200 nm thickness range for films prepared at optimum etching times, and show high spot to spot reproducibility with approximately 1 microm laser spot sizes, an indication that these films could be useful as durable, highly reproducible surface-enhanced Raman substrates. 相似文献
973.
Chen CT Chan CY Huang CA Chen MT Peng KF 《Dalton transactions (Cambridge, England : 2003)》2007,(36):4073-4078
Three new anilido-oxazolines, ortho-C(6)H(4)(NHAr')(4,4-dimethyl-2-oxazoline) [Ar'=2,4,6-trimethylphenyl, HNPh(TriMe)Oxa (1); 2,6-diisopropylphenyl, HNPh(DiiPr)Oxa (2); 2-methoxyphenyl, HNPh(OMe)Oxa (3)], have been prepared. Reactions of 1 or 2 with one molar equivalent of ZnEt(2) in tetrahydrofuran or hexane solution give the zinc ethyl complexes (NPh(TriMe)Oxa)ZnEt (4) and (NPh(DiiPr)Oxa)ZnEt (5). The dinuclear zinc benzyloxide complexes, [(NAr'Oxa)Zn(mu-OBn)](2), [Ar'=2,4,6-trimethylphenyl, (6); 2-methoxyphenyl, (7)], were synthesized by the reaction of 4 with one molar equivalent of benzyl alcohol in tetrahydrofuran solution (for 6) or by treatment of with 3 one molar equivalent of ZnEt(2) in tetrahydrofuran solution followed by the addition of one molar equivalent of benzyl alcohol (for 7). The molecular structures are reported for compounds 6 and 7. Their catalytic activities toward the ring opening polymerization reactions are under investigation. 相似文献
974.
Chan TS Liu RS Yang CC Li WH Lien YH Huang CY Lee JF 《The journal of physical chemistry. B》2007,111(9):2262-2267
The effect of isovalent chemical substitution of Eu3+ into the Tb3+ sites on the magnetic and electrical properties of (Tb1-xEux)MnO3 (0 = x = 1.0) system has been investigated. The orthorhombic structure with space group Pbnm is observed in this series of materials. An increase in Mn-O bond distance with increasing Eu content leads to improvement in the overlap between the Mn 3d and O 2p orbital thereby causing a decrease in activation energy and resistivity. Moreover, as the Eu content increases, the effective moments (mueff) are reduced linearly and an exchange coupling is observed in Tb-Tb, Tb-Eu, and Eu-Eu complexes for x = 0.1 and 0.3 samples. Both these features can be related to the substitution of bigger Eu3+ ions replacing the original Tb-Tb coupling. 相似文献
975.
Striolo A McCabe C Cummings PT Chan ER Glotzer SC 《The journal of physical chemistry. B》2007,111(42):12248-12256
Polyhedral oligomeric silsesquioxanes (POSS) are multifunctional molecules that can be employed as building blocks to develop nanocomposite materials whose mechanical properties often improve upon those of traditional polymeric materials. We report here molecular simulation results for the effective potential of mean force between octamethyl POSS monomers and between POSS monomers in which one methyl group has been substituted by a linear alkane chain of nine carbon atoms in liquid normal hexane at 300 and 400 K. The results are discussed and compared to available data for the effective interactions between octamethyl POSS monomers in normal hexadecane. Our results show that the effective short-ranged POSS-POSS attraction is significantly weaker in hexane than it is in hexadecane, perhaps explaining why normal hexane is often the solvent of choice for the preparation of POSS-containing materials. Additionally, we provide results for the radial distribution functions between selected sites in the POSS monomers that can be used both to understand the association between POSS monomers in solution and to parametrize coarse-grained simulation models. Such models will be used to study the formation of POSS-containing supramolecular structures such as lamellae or micelles that are currently not accessible by atomistic simulation and can be compared to experimental observations. 相似文献
976.
A novel two-step synthesis of substituted 2-formylpyrroles is described. Aldol adducts of ketones and 4-formyloxazole undergo a dehydration/oxazole hydrolysis/cyclization cascade on sequential treatment with MsCl/Et3N and aqueous NaOH to yield 5-substituted and 4,5-disubstituted 2-formylpyrroles. The methodology was extended to an N-benzyl thiazolium salt. 相似文献
977.
Vector generalized linear and additive extreme value models 总被引:2,自引:0,他引:2
Over recent years parametric and nonparametric regression has slowly been adopted into extreme value data analysis. Its introduction has been characterized by piecemeal additions and embellishments, which has had a negative effect on software development and usage. The purpose of this article is to convey the classes of vector generalized linear and additive models (VGLMs and VGAMs) as offering significant advantages for extreme value data analysis, providing flexible smoothing within a unifying framework. In particular, VGLMs and VGAMs allow all parameters of extreme value distributions to be modelled as linear or smooth functions of covariates. We implement new auxiliary methodology by incorporating a quasi-Newton update for the working weight matrices within an iteratively reweighted least squares (IRLS) algorithm. A software implementation by the first author, called the vgam package for , is used to illustrate the potential of VGLMs and VGAMs. 相似文献
978.
979.
圆锥形血管中的振荡发展流动 总被引:5,自引:2,他引:3
本文在小锥度角的假设下,研究了圆锥形血管的非定常振荡的发展流动问题.导得了相应的速度分布公式.分析表明,所有收缩的圆锥形血管的流动都是发展流动,而且锥度角对发展流动的影响随着锥度角的增大而增大. 相似文献
980.
J. C. Sun & Tony F. Chan 《计算数学(英文版)》1995,13(4):325-336
1.IntroductionWeconsiderthefollowingsecondorderellipticboundaryvalueproblem:Lu=f,infl,(1)u=o,onOfl,(2)whereLisaselfadjointpositiveoperatorandflCnd(15dS3)isapolyhedraldomain.Aweaksolutionhasthefollowingform:FinduEHf(fl)suchthat:LetVh:=M=Span{rki},where{ghi}couldbenodalbasisconsistingofpiece-wiselinearfunctionsorothersplinefunctions-Substitutingthefollowingsolutionuh=Zui4iintotheaboveweakformleadstoadiscreteequationAu=f,(3)whereA=(crij),oij=A(ofi,rkj).(4)Itiswellknownthatthec0efficientmat… 相似文献