Probes reception

Based upon a piezoelectric 1-3-composite material, air-bome ultrasonic probes for frequencies up to 2 MHz were developped. These probes are characterized by a bandwidth larger than 50 % as well as a signal-to-noise ratio higher than 100 dB. Applications are the thickness measurement of thin powder layers, the inspection of sandwich structures, the detection of surface near cracks in metals or ceramics by generation/reception of Rayleigh waves and the inspection of plates by Lamb waves. 

Fluorescent labels, by contrast, can provide tremendous sensitivity due to their property of discrete emission of light upon excitation. Proteins, nucleic acids, and other molecules can be labeled with fluorescent probes to provide highly receptive reagents for numerous in vitro assay procedures. For instance, fluorescently tagged antibodies can be used to probe cells and tissues for the presence of particular antigens, and then detected through the use of fluorescence microscopy techniques. Since each probe has its own fluorescence emission character, more... 

While NMR spectra possess a high information content, this confers a level of complexity that can be obstructive if a quick and simple answer is required. The use of NMR flow probes has reduced the time taken to acquire a spectrum to 2-3 min and flow NMR has consequently found considerable application in robot synthesis, multiple parallel synthesis (MPS) or combinatorial chemistry. Since H possesses 5600 times the receptivity of it is inevitable that it will continue to be the nucleus of choice in this area, complicating the analysis. Unless automatic analysis is able to transcend the aid to interpretation role and into the confirm or refute the structure role, the higher information content of the NMR spectrum constitutes a threat rather than an opportunity. 

This means that we use (a) P-31 NMR both qualitatively, for information on the orientation of the tertiary phosphine ligands, and analytically to determine the number of complexes in solution (this is a very receptive nucleus and 1-2% of impurities often are detected readily) (b) Sn-119 (I = i, natural abundance = 8.6%) NMR as a probe for the identity of the trichlorostannate moiety and (c) Pt-195 (I = i, natural abundance = 33.7%) NMR for multiplicity data concerned with the number of coordinated phosphines (and NMR spins in general). The value of H-l NMR in metal hydride chemistry is so well established (18) that no further justification is required here. 

Baxter DF, Kirk M, Garcia AF et al. (2002) A novel membrane potential-sensitive fluorescent dye improves cell-based assays for ion channels. J Biomol Screen 7(1) 79—85 Epps DE, Wolfe ML, Groppi V (1994) Characterization of the steady-state and dynamic fluorescence properties of the potential-sensitive dye bis-(l,3-dibutylbarbituric acid)trimethine oxonol (BiBAC4(3)) in model systems and cells. Chem Phys Lipids 69(2) 137—150 Gonzalez JE, Maher MP (2002) Cellular fluorescent indicators and voltage/ion probe reader (VIPR(TM)) tools for ion channel and receptor drug discovery. Recept Channels 8(5—6) 283—295... 

Y. Todoroki N. Hirai, Abscisic Analogs for Probing the Mechanism of Abscisic Acid Reception and Inactivation. In Studies in Natural Product Chemistry Ed. Atta-ur-Rahman, Ed. Elsevier Amsterdam, 2002 Vol. 27, pp 321-360. 

Abscisic acid analogs for probing the mechanism of abscisic acid reception and inactivation... 

ABSCISIC ACID ANALOGS FOR PROBING THE MECHANISM OF ABSCISIC ACID RECEPTION AND... 

It should be mentioned that in cases where one of the heteronuclei is F, D or Li. the use of designated triple-resonance probe heads for "X, Y correlations can be avoided, and standard equipment may be used. The resonance frequency of F is far outside the range of other heteronuclei, but close to the H frequency, so that F, "X correlations can frequently be performed by detuning the proton coil of a standard multinuclear probe head. Even if this procedure may result in longer pulses and some loss of sensitivity for experiments with F detection, many experiments are still practicable due to the high receptivity of fluorine. Of course, experiments with this set-up... 

Iodine-127 SSNMR data and references are summarized in Tables 18-20. Although I has a good NMR receptivity, its applicability as an NMR probe is limited due to its large Q value and the resulting broad line shapes when symmetry at the... 

More than 100 ABA analogs have been synthesized in an effort to find compounds with strong ABA activity, to clarify structure-activity relationships, or for use as tools for investigating the molecular mechanism of ABA action [1,4,14]. ABA and its analogs can be useful tools for probing the mechanism of ABA action, especially ABA reception and catabolic inactivation, since ABA itself binds directly to a receptor and catabolic enzyme. The structures and activities of the analogs that are referred in this review are summarized in Table 1. 

Dead-207 NMR spectroscopy does not provide the details of electronic structure that can be gleaned from PES or atomic transitions, but can—at least in theory—provide complementary information about the Pb(II) coordination environment in solution. Dead-207 NMR spectroscopy is an excellent probe for the lead coordination environment due to the characteristics of the ° Pb isotope (I = j) Excellent receptivity (11.7 times greater than that of C), high natural abundance (22.6%), and large chemical shift range (>16,000 ppm) (172, 173). Although ° Pb NMR spectroscopy has been used extensively to characterize alkyl Pb(IV) derivatives and solid-state Pb(II) compounds, relatively few studies have been conducted of soluble Pb(ll) coordination compounds (171-183). Nonetheless, those studies that have been conducted to date on Pb(II) coordination compounds in solution reveal that the ° Pb chemical shift is particularly... 

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