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51.
52.
Gao J Strässler C Tahmassebi D Kool ET 《Journal of the American Chemical Society》2002,124(39):11590-11591
We report on a new class of water-soluble fluorescent molecules (polyfluors) that are composed of multiple individual fluorophores assembled on a DNA-like backbone. Four fluorophore deoxyribosides were synthesized, and these individual molecules were assembled into oligofluor strings on a DNA synthesizer. A library of 256 tetrafluors was generated by split and pool methods on polystyrene beads. Images of the library under a fluorescence microscope revealed at least 40-50 different hues and intensities. Selected tetrafluors were resynthesized in pure form in solution and displayed properties, such as large Stokes shifts, that individual fluorophores do not have. 相似文献
53.
Superior laryngeal nerve paresis and paralysis 总被引:1,自引:0,他引:1
Gürsel Dursun Robert Thayer Sataloff Joseph R. Spiegel Steven Mandel Reinhardt J. Heuer Deborah Caputo Rosen 《Journal of voice》1996,10(2):206-211
Superior laryngeal nerve paresis and paralysis are relatively common but often difficult to diagnose with certainty. They are most commonly caused by viral infections, though other etiologies must be considered. A thorough history and physical examination, including strobovideolaryngoscopy and laryngeal electromyography, are needed for definitive diagnosis. It is essential to establish the diagnosis accurately to differentiate an apparent superior laryngeal nerve paresis from other conditions, such as myasthenia gravis. Laryngeal electromyography is used to confirm clinical impressions, as a guide for therapy, and as one measure of recovery. In our experience, accurate and early diagnosis assure the best phonatory outcome by directing therapy that will prevent or eliminate compensatory vocal abuses, which may themselves lead to even more serious vocal injury. 相似文献
54.
Youval Shvo Yigal Blum Deborah Reshef Marit Menzin 《Journal of organometallic chemistry》1982,226(1):C21-C24
Ru3(CO)12 acts as a homogeneous catalyst precursor for the transformation of αω-diols to polyesters and lactones. 相似文献
55.
Lateral diffusion measurements, most commonly accomplished through Fluorescence Photobleaching Recovery (FPR or FRAP), provide
important information on cell membrane molecules' size, environment and participation in intermolecular interactions. However,
serious difficulties arise when these techniques are applied to weakly expressed proteins of either of two types: fusions
of membrane receptors with visible fluorescent proteins or membrane molecules on autofluorescent cells. To achieve adequate
sensitivity in these cases, techniques such as interference fringe FPR are needed. However, in such measurements, cytoplasmic
species contribute to the fluorescence recovery signal and thus yield diffusion parameters not properly representing the small
number of surface molecules. A new method helps eliminate these difficulties. High Probe Intensity (HPI)-FPR measurements
retain the intrinsic confocality of spot measurements to eliminate interference from fluorescent cytoplasmic species. However,
HPI-FPR methods lift the previous requirement that FPR procedures be performed at probe beam intensities low enough to not
induce bleaching in samples during measurements. The high probe intensities now employed provide much larger fluorescence
signals and thus more information on molecular diffusion from each measurement. We report successful measurement of membrane
dynamics by this technique. 相似文献
56.
57.
Parker KJ Taylor LS Gracewski S Rubens DJ 《The Journal of the Acoustical Society of America》2005,117(5):2705-2712
A number of different approaches have been developed to estimate and image the elastic properties of tissue. The biomechanical properties of tissues are vitally linked to function and pathology, but cannot be directly assessed by conventional ultrasound, MRI, CT, or nuclear imaging. Research developments have introduced new approaches, using either MRI or ultrasound to image the tissue response to some stimulus. A wide range of stimuli has been evaluated, including heat, water jets, vibration shear waves, compression, and quasistatic compression, using single or multiple steps or low-frequency (<10 Hz) cyclic excitation. These may seem to be greatly dissimilar, and appear to produce distinctly different types of information and images. However, our purpose in this tutorial is to review the major classes of excitation stimuli, and then to demonstrate that they produce responses that fall within a common spectrum of elastic behavior. Within this spectrum, the major classes of excitation include step compression, cyclic quasistatic compression, harmonic shear wave excitation, and transient shear wave excitation. The information they reveal about the unknown elastic distribution within an imaging region of interest are shown to be fundamentally related because the tissue responses are governed by the same equation. Examples use simple geometry to emphasize the common nature of the approaches. 相似文献
58.
Nicolaou KC Snyder SA Nalbandian AZ Longbottom DA 《Journal of the American Chemical Society》2004,126(20):6234-6235
Although glycosylamines constitute an important group of carbohydrates from the standpoint of biology and medicine, methods for their synthesis typically lack substrate generality and/or result in variable stereoselectivity, especially in complex contexts. In this communication, we report an operationally simple method for the synthesis of both alpha- and beta-glycosylamines using the Burgess reagent that overcomes many of these limitations in a bare minimum of synthetic steps. 相似文献
59.
Silvestri MA Miles D Rothwell AP Wood KV Cushman M 《Rapid communications in mass spectrometry : RCM》2003,17(15):1703-1708
Electrospray ionization (ESI) mass spectrometry was employed to obtain both molecular weight confirmation and structural information for a series of novel alkenyldiarylmethane (ADAM) analogs. The mass spectral data were intended for use during the structure elucidation of ester hydrolysis products formed during an in vitro metabolism study of a series of novel ADAM analogs. The data on the precursor molecules show the presence of the molecular ion peak, [M+H](+), as well as a peak consistent with the hydrolysis product of the original ester ([MH-ROH+H(2)O](+)). However, chemical ionization mass spectrometry, elemental analysis and (1)H NMR data indicated the presence of only the intact diester compounds, suggesting that the formation of the hydrolysis product was an instrumental artifact, i.e., in-beam hydrolysis during ESI or a result of longer ion residence times of the ion trap mass analyzer. 相似文献
60.