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71.
This work deals with an analysis of biologically important compounds in complex matrices using preparative isotachophoresis (pITP) in column coupling configuration as a sample pretreatment technique followed by a direct infusion mass spectrometry with nano‐electrospray ionization (DI‐nESI‐MS). Busereline was chosen as a model analyte, and urine was chosen as an example of complex matrix. In pITP experiments, sodium cation (10 mmol/L concentration) was used as a leading ion and β‐alanine as terminating ion (20 mmol/L concentration). The fractions, obtained by pITP pre‐separation with the assistance of the mixture of discrete spacers, were finally analyzed by DI‐nESI‐MS. It was shown that pITP performed before DI‐nESI‐MS analysis can significantly simplify complex matrix, and, due to its concentration power, pITP can consequently decrease the concentration limit of detection. The concentration of buserelin in the urine samples analyzed by pITP‐DI‐nESI‐MS was 10 μg/L (reflecting at a 8.10?9 mol/L concentration) in our work but from the ion intensities obtained in MS as well as MS/MS analyses, it is clear that this concentration level could be several orders of magnitude lower for reliable detection and identification of buserelin in urine analyzed using pITP with DI‐nESI‐MS detection. 相似文献
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Zhang K Lam KF Albela B Xue T Khrouz L Hou QW Yuan EH He MY Bonneviot L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(50):14258-14266
Following the structural concept of copper-containing proteins in which dinuclear copper centers are connected by hydroxide bridging ligands, a bidentate copper(II) complex has been incorporated into nano-confined MCM-41 silica by a multistep sequential grafting technique. Characterization by a combination of EPR spectroscopy, X-ray photoelectron spectroscopy (XPS), UV/Vis spectroscopy, IR spectroscopy , and solid-state (13)C and (29)Si cross-polarization magic-angle spinning (CP-MAS) NMR suggests that dinuclear Cu complexes are bridged by hydroxide and other counterions (chloride or perchlorate ions), similar to the situation for EPR-undetectable [Cu(II)···Cu(II)] dimer analogues in biological systems. More importantly, a dynamic mononuclear-dinuclear equilibrium between different coordination modes of copper is observed, which strongly depends on the nature of the counterions (Cl(-) or ClO(4)(-)) in the copper precursor and the pore size of the silica matrix (the so-called confinement effect). A proton-transfer mechanism within the hydrogen-bonding network is suggested to explain the dynamic nature of the dinuclear copper complex supported on the MCM-41 silica. 相似文献
74.
Akhilesh K. Gaharwar Patrick J. Schexnailder Avinash Dundigalla James D. White Cristina R. Matos‐Prez Joshua L. Cloud Soenke Seifert Jonathan J. Wilker Gudrun Schmidt 《Macromolecular rapid communications》2011,32(1):50-57
Here, we show that a poly(ethylene oxide) polymer can be physically cross‐linked with silicate nanoparticles (Laponite) to yield highly extensible, bio‐nanocomposite fibers that, upon pulling, stretch to extreme lengths and crystallize polymer chains. We find that both, nanometer structures and mechanical properties of the fibers respond to mechanical deformation by exhibiting strain‐induced crystallization and high elongation. We explore the structural characteristics using X‐ray scattering and the mechanical properties of the dried fibers made from hydrogels in order to determine feasibility for eventual biomedical use and to map out directions for further materials development.
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Mia A. Levy John B. Freymann Justin S. Kirby Andriy Fedorov Fiona M. Fennessy Steven A. Eschrich Anders E. Berglund David A. Fenstermacher Yongqiang Tan Xiaotao Guo Thomas L. Casavant Bartley J. Brown Terry A. Braun Andre Dekker Erik Roelofs James M. Mountz Fernando Boada Charles Laymon Matt Oborski Daniel L. Rubin 《Magnetic resonance imaging》2012
Introduction
The National Cancer Institute Quantitative Research Network (QIN) is a collaborative research network whose goal is to share data, algorithms and research tools to accelerate quantitative imaging research. A challenge is the variability in tools and analysis platforms used in quantitative imaging. Our goal was to understand the extent of this variation and to develop an approach to enable sharing data and to promote reuse of quantitative imaging data in the community.Methods
We performed a survey of the current tools in use by the QIN member sites for representation and storage of their QIN research data including images, image meta-data and clinical data. We identified existing systems and standards for data sharing and their gaps for the QIN use case. We then proposed a system architecture to enable data sharing and collaborative experimentation within the QIN.Results
There are a variety of tools currently used by each QIN institution. We developed a general information system architecture to support the QIN goals. We also describe the remaining architecture gaps we are developing to enable members to share research images and image meta-data across the network.Conclusions
As a research network, the QIN will stimulate quantitative imaging research by pooling data, algorithms and research tools. However, there are gaps in current functional requirements that will need to be met by future informatics development. Special attention must be given to the technical requirements needed to translate these methods into the clinical research workflow to enable validation and qualification of these novel imaging biomarkers. 相似文献77.
Alaleh Dabbaghi Kourosh Kabiri Ali Ramazani Mohammad J. Zohuriaan‐Mehr Arash Jahandideh 《先进技术聚合物》2019,30(11):2894-2905
Recent researches focus on the synthesis of new cross‐linkers from natural resources. In the current work, functionalized tannic acid was employed as a replacement of petroleum‐based cross‐linkers because of its outstanding biochemical properties. Alkene‐ and epoxy‐functionalized tannic acids were synthesized as internal and external cross‐linkers, respectively. Cross‐linker structures were characterized with Ft‐IR and 1HNMR analysis. Different amounts, as well as different numbers of alkene functional group, were incorporated during the superabsorbent synthesis. Moreover, the internal cross‐linked superabsorbent was surface cross‐linked with different amounts of epoxy‐functionalized tannic acid and increased the absorbency under load about 10 g g?1. Free absorption properties in water and saline solution, absorbency under load, and rheological properties of superabsorbents were investigated. In addition, the antibacterial activity of the internal and external cross‐linked superabsorbent was studied against Escherichia coli and Staphylococcus aureus bacteria via different methods and compared with that of conventional superabsorbent. 相似文献
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Michael J. Landry Kaien Gu Stephanie N. Harris Laila Al‐Alwan Laura Gutsin Daniele De Biasio Bernie Jiang Diane S. Nakamura T. Christopher Corkery Timothy E. Kennedy Christopher J. Barrett 《Macromolecular bioscience》2019,19(5)
Poly‐d ‐lysine (PDL) and poly‐l ‐lysine are standard surfaces for culturing neural cells; however, both are relatively unstable, costly, and the coated surface typically must be prepared immediately before use. Here, polyelectrolyte multilayers (PEMs) are employed as highly stable, relatively inexpensive, alternative substrates to support primary neural cell culture. Initial findings identify specific silk‐based PEMs that significantly outperform the capacity of PDL to promote neuronal survival and process extension. Based on these results, a library of PEM variants, including commercial and bio‐sourced polyelectrolytes, is generated and three silk‐based PEMs that substantially outperform PDL as a substrate for primary neurons in cell culture are identified. Further, testing these PEM variants as substrates for primary oligodendrocyte progenitors demonstrates that one silk‐based PEM functions significantly better than PDL. These findings reveal specificity of cellular responses, indicating that PEMs may be tuned to optimally support different neural cell types. 相似文献
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Inside Back Cover: Programmed Photodegradation of Polymeric/Oligomeric Materials Derived from Renewable Bioresources (Angew. Chem. Int. Ed. 4/2015) 下载免费PDF全文