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1.
The use of narrow bore LC capillaries operated at ultralow flow rates coupled with mass spectrometry provides a desirable convergence of figures of merit to support high-performance LC-MS/MS analysis. This configuration provides a viable means to achieve in-depth protein sequence coverage while maintaining a high rate of data production. Here we explore potential performance improvements afforded by use of 25 μm × 100 cm columns fabricated with 5 μm diameter reversed phase particles and integrated electrospray emitter tips. These columns achieve a separation peak capacity of ≈750 in a 600-min gradient, with average chromatographic peak widths of less than 1 min. At room temperature, a pressure drop of only ≈1500 psi is sufficient to maintain an effluent flow rate of ≤10 nL/min. Using mouse embryonic stem cells as a model for complex mammalian proteomes, we reproducibly identify over 4000 proteins across duplicate 600 min LC-MS/MS analyses. 相似文献
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CK Combs DE Johnson SB Cannady TM Lehman GE Landreth 《Canadian Metallurgical Quarterly》1999,19(3):928-939
Microglial interaction with amyloid fibrils in the brains of Alzheimer's and prion disease patients results in the inflammatory activation of these cells. We observed that primary microglial cultures and the THP-1 monocytic cell line are stimulated by fibrillar beta-amyloid and prion peptides to activate identical tyrosine kinase-dependent inflammatory signal transduction cascades. The tyrosine kinases Lyn and Syk are activated by the fibrillar peptides and initiate a signaling cascade resulting in a transient release of intracellular calcium that results in the activation of classical PKC and the recently described calcium-sensitive tyrosine kinase PYK2. Activation of the MAP kinases ERK1 and ERK2 follows as a subsequent downstream signaling event. We demonstrate that PYK2 is positioned downstream of Lyn, Syk, and PKC. PKC is a necessary intermediate required for ERK activation. Importantly, the signaling response elicited by beta-amyloid and prion fibrils leads to the production of neurotoxic products. We have demonstrated in a tissue culture model that conditioned media from beta-amyloid- and prion-stimulated microglia or from THP-1 monocytes are neurotoxic to mouse cortical neurons. This toxicity can be ameliorated by treating THP-1 cells with specific enzyme inhibitors that target various components of the signal transduction pathway linked to the inflammatory responses. 相似文献
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Maria M Velencoso Agustin SB Gonzalez Joaquin C García‐Martínez Maria J Ramos Antonio De Lucas Juan F Rodriguez 《Polymer International》2013,62(5):783-790
A simple strategy for the synthesis and functionalization of polyurethanes is described. Anionic ring‐opening polymerization was combined with ‘click’ chemistry to synthesize polyols with fluorescent properties. This route allows the incorporation of a wide range of functionalities in the polyols with an easy, clean and highly selective process compatible with several types of functional groups. The proposed strategy opens the way to the production, in a cost‐effective way, of ‘smart’ polyurethanes with non‐conventional properties like fire retardancy, antimite properties, antibacterial properties, etc. Alkynyl groups were introduced into the polyol chains by the controlled addition of glycidyl propargyl ether as co‐monomer during a conventional anionic ring‐opening copolymerization with propylene oxide. Subsequently 4‐azidomethyl‐7‐methoxycoumarin molecules were introduced onto the alkynyl‐polyether polyols by copper‐catalysed cycloaddition reactions to produce end‐functionalized polyols. The chemical structure of the novel polyols was characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography with triple detection and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy. These characterization techniques confirmed the presence of a considerable amount of functional groups in the structure of the polyols. Finally, various fluorescent rigid foams, based on the functionalized polyols, were synthesized. Copyright © 2012 Society of Chemical Industry 相似文献
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HY Song SI Park HY Jung SB Kim JH Kim SJ Huh TH Kim YK Kim S Park HK Yoon KB Sung YI Min 《Canadian Metallurgical Quarterly》1997,203(3):747-752
PURPOSE: To evaluate the clinical effectiveness of a polyurethane-covered, retrievable, self-expandable metallic stent and hook catheter in the treatment of esophageal strictures. MATERIALS AND METHODS: Stents were constructed of 0.4-mm stainless steel wire in a cylindric zig-zag configuration of six to nine bends. Four to eight stents were connected in tandem by dipping in a polyurethane solution. A nylon loop was hooked inside to each bend of the proximal portion of the stent and strung with a thread. Under fluoroscopic guidance, 22 stents were placed in 16 patients with a malignant stricture and five patients with a benign stricture. The stent was removed with a hook catheter 2 months after placement in patients with a benign stricture and when complications occurred in patients with a malignant stricture. All patients had dysphagia with ingestion of soft foods or liquids. RESULTS: Stent placement was technically successful and well tolerated in 20 patients. In one patient, the stent was misplaced but relocated successfully. After stent placement, all patients were able to ingest solid and/or soft foods without dysphagia. After stent removal, strictures showed improvement but recurred in two patients. CONCLUSION: Use of polyurethane-covered, retrievable expandable stents seems to be a feasible and effective method of treatment of benign and malignant esophageal strictures. 相似文献