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171.
A unique flow field pattern in a bio-functional microchannel is utilized to significantly enhance the performance of a microsystem developed for selectively isolating circulating tumor cells from cell suspensions. For high performance of such systems, disposal of maximum non-target species is just as important as retention of maximum target species; unfortunately, most studies ignore or fail to report this aspect. Therefore, sensitivity and specificity are introduced as quantitative criteria to evaluate the system performance enabling a direct comparison among systems employing different techniques. The newly proposed fluidic scheme combines a slow flow field, for maximum target-cell attachment, followed by a faster flow field, for maximum detachment of non-target cells. Suspensions of homogeneous or binary mixtures of circulating breast tumor cells, with varying relative concentrations, were driven through antibody-functionalized microchannels. Either EpCAM or cadherin-11 transmembrane receptors were targeted to selectively capture target cells from the suspensions. Cadherin-11-expressing MDA-MB-231 cancer cells were used as target cells, while BT-20 cells were used as non-target cells as they do not express cadherin-11. The attachment and detachment of these two cell lines are characterized, and a two-step attachment/detachment flow field pattern is implemented to enhance the system performance in capturing target cells from binary mixtures. While the system sensitivity remains high, above 0.95, the specificity increases from about 0.85 to 0.95 solely due to the second detachment step even for a 1 : 1000 relative concentration of the target cells. 相似文献
172.
173.
An efficient one-pot method to access 2-amino-1,3,4-oxadiazoles from isoselenocyanates and hydrazides or dihydrazides was developed via cyclodeselenization. Without any harsh reagents, various 2-amino-1,3,4-oxadiazoles were obtained in considerably high yields (82%-97%) and purities (>99%) directly with simple crystallization in ethanol. And the formed precipitated Se powder during the reaction could be recycled for preparation of isoselenocyanates efficiently. A plausible mechanism is proposed for the formation of the target products. 相似文献
174.
A set of all-electron scalar relativistic calculations on Au
n
Cu (n = 1–12) clusters has been performed using density functional theory with the generalized gradient approximation at PW91 level.
The lowest energy geometries of Au
n
Cu clusters may be considered as assemblies of triangular Au3 moieties substituted with one Cu atom at the highest coordinated site. All these lowest energy geometries of the Au
n
Cu clusters are slightly distorted but retain the planar structures of the Au
n+1 clusters due to the strong scalar relativistic effects. The Au–Cu bonds are stronger, and a few Au–Au bonds far from the
Cu atom are weaker, than the corresponding Au–Au bonds in pure Au
n+1 clusters. After doping with a Cu atom, the thermodynamic stability and chemical reactivity are enhanced to some extent. The
odd-numbered Au
n
Cu clusters with even numbers of valence electrons are more stable than the neighboring even-numbered Au
n
Cu clusters with odd numbers of valence electrons. Odd–even alternations of magnetic moments and electronic configurations
for the Au
n
Cu clusters can be observed clearly and may be understood in terms of the electron pairing effect. 相似文献
175.
This article proves the existence and uniqueness of solution to two-parameter stochastic Volterra equation with non-Lipschitz coefficients and driven by Brownian sheet, where the main tool is Bihari's inequality in the plane. Moreover, we also discuss the time regularity property of the solution by Kolmogorov's continuity criterion. 相似文献
176.
Xing Gao Songqi Gu Qian Gao Yang Zou Zheng Jiang Shuo Zhang Xiangjun Wei Haisheng Yu Guodong Sheng Peiquan Duan Yuying Huang 《X射线光谱测定》2013,42(6):502-507
A high‐resolution X‐ray fluorescence spectrometer based on Rowland circle geometry was developed and installed at BL14W1 XAFS beamline of Shanghai Synchrotron Radiation Facility. The spectrometer mainly consists of three parts: a sample holder, a spherically curved Si crystal, and an avalanche photodiode detector. The simplicity of the spectrometer makes it easily assembled on the general purpose X‐ray absorption beamline. X‐ray emission spectroscopy and high‐resolution X‐ray absorption near edge spectroscopy can be carried out by using this spectrometer. X‐ray emission preliminary results with high‐resolution about 3 eV of Mn compounds were obtained, which confirmed the feasibility of the spectrometer. The application about Eu (III) retention on manganese dioxide was also studied using this spectrometer. Compared with conventional X‐ray absorption fine structure spectroscopy technique, the fluorescence peak of probed element [Eu (III) Lα] and matrix constituents (Mn Kα) were discriminated using this technique, indicating its superiority in fluorescence detection. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
177.
Abstract
This paper describes a practical synthetic approach to preparation of an immunosuppressant, FTY720. The key steps involve an iron-catalyzed cross-coupling reaction and a Wittig reaction. The advantages of this synthesis include readily available starting materials, inexpensive reagents, simple operations and good yields. 相似文献178.
A characterization of orthodox transversals is given and the maximum idempotent-separating congruence concerned with quasi-ideal orthodox transversals is explored. The well-known results about orthodox semigroups are generalized and enriched. 相似文献
179.
Qiong Huang Zhi Geng Tao Chen Xiangjun Cheng Haitao Gu Qingguo Li Dianfu Li Rui Liu 《Electrophoresis》2019,40(14):1848-1854
Congenital heart disease is one of the largest class of birth defects. Eight subjects with ventricular septal defect (VSD, a kind of congenital heart disease) and 11 health children were enrolled in tandem mass tags label‐based quantitative proteomic analysis to compare plasma proteins differentially abundance. A total of 66 proteins were significantly upregulated or downregulated in VSD patients compared with healthy children. These proteins were involved in pathways linked to platelet activation, fructose and mannose metabolism, complement and coagulation cascades, glycolysis/gluconeogenesis, regulation of actin cytoskeleton, and carbon metabolism. The amount of ten proteins changed significantly (p < 0.05) in newly recruited 30 VSD compared with 15 control children, which were validated by ELISA. The areas under the receiver operating characteristic curve values of fructose‐bisphosphate aldolase B (ALDOB) and thymosin beta‐4 (Tβ4) were higher than those of other candidate proteins. ALDOB and Tβ4 might be potential biomarkers applied for identifying VSD in the further works. 相似文献
180.
A novel scheme of time-stacked optical code label based on optical code division multiple (OCDM) technique for optical packet switching network is proposed, in which two-dimensional wavelength-time OCDM code is used as the optical label. Packet loss rate and system characteristic based on the proposed scheme are studied. Results show that less packet loss rate of proposed scheme can be achieved as compared with that of one-dimension time-stacked optical code label system. 相似文献