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31.
Vincent J. Corcoran 《应用光谱学评论》2013,48(2):215-282
Abstract Until recently, infrared spectroscopy has been performed with spectrometers utilizing filtered broadband sources and gratings or prisms to spatially spread the energy spectrum of the source. These wavelength measuring spectrometers characteristically have large spectral tuning ranges with resolutions typically limited to 0.1–1 cm?1: In the far-infrared region where only small amounts of energy are available from broadband sources, two-beam interferometric techniques have been employed with computing techniques to perform Fourier transform spectroscopy. In this technique the entire spectrum to be analyzed is incident upon the detector from the two interfering beams to take advantage of all of the energy available and then computations are made to display the entire spectrum. 相似文献
32.
The stannylation of indole derivatives proceeds in good yields under palladium catalysis (5 mol %) without protection of the indolic nitrogen. The general utility of both PdCl(2)(PhCN)(2)/PCy(3) and Pd(2)dba(3)/PCy(3) as catalytic systems for the stannylation of three indole derivatives, with varying degrees of electron density, is presented. 相似文献
33.
Abouzaid E Arenton M Barker AR Bellantoni L Bellavance A Blucher E Bock GJ Cheu E Coleman R Corcoran MD Corti G Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hanagaki K Hsiung YB Huang H Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Niclasen R Ping H Qi XR Ramberg EJ Ray RE Ronquest M Santos E Shields J Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Velissaris C Wah YW Wang J White HB Whitmore J Wilking M Winstein B Winston R 《Physical review letters》2006,96(10):101801
Using the complete KTeV data set of 5,241 candidate K(L)--> pi(+) pi(-) e(+) e(-) decays (including an estimated background of 204 +/- 14 events), we have measured the coupling g(CR)= 0.163 +/- 0.0149(stat) +/- 0.023(syst) of the CP conserving charge radius process and from it determined a K(0) charge radius of = [-0.077 +/- 0.007(stat) +/- 0.011(syst)]fm(2). We have determined a first experimental upper limit of 0.04 (90% C.L.) /g(e1)/ / /g(M1)/ of the couplings for the E1 and M1 direct photon emission processes. We also report the measurement of /g(M1)/ including a vector form factor /g(M1)/(1 + (a(1)/a(2))/((M(2)(p)-(M(2)(k))= 2M(K)E(gamma*)), where vector /g(M1)/= 1.11+/- 0.12(stat) +/- 0.08(syst) and a(1)/a(2) = [-0.744 +/- 0.027(stat) +/- 0.032(syst)] GeV(2)/c(2). Finally, a CP-violating asymmetry of [13.6 +/- 1.4(stat) +/- 1.5(syst)]% in the CP and T odd angle phi between the decay planes of the e(+) e(-) and pi(+) pi(-) pairs in the K(L) center of mass is reported. 相似文献
34.
Abouzaid E Arenton M Barker AR Bellantoni L Blucher E Bock GJ Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hsiung YB Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nguyen H Niclasen R Phillips DG Ramberg EJ Ray RE Ronquest M Santos E Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Wah YW Wang J White HB Whitmore J Wilking MJ Winstein B Winston R Worcester ET Yamanaka T Zimmerman ED Zukanovich RF;KTeV Collaboration 《Physical review letters》2008,100(18):182001
We present a new determination of the parity of the neutral pion via the double Dalitz decay pi0-->e+e-e+e-. Our sample, which consists of 30,511 candidate decays, was collected from KL-->pi0pi0pi0 decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative pi0 parity and place a limit on scalar contributions to the pi0-->e+e-e+e- decay amplitude of less than 3.3% assuming CPT conservation. The pi0gamma*gamma* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be B(pi0-->e+e-e+e-)=(3.26+/-0.18)x10(-5). 相似文献
35.
M. J. Roeterink D. G. Kelly E. G. Dickson M. T. Andrews E. C. Corcoran 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):1131-1139
The composition of a second generation radio-opaque fabric and its performance relative to established characterised materials are described. The protection offered by this fabric has been examined using a wide range of discrete gamma photon energies. Data indicate improved attenuation in the range 50–300 keV relative to earlier lightweight personal protective materials and conventional personal protection fabrics. Statistically significant improvements were not observed for gamma photons possessing energies > 300 keV. Experimentally benchmarked models represent powerful tools for the investigation and optimisation of radio-opaque fabrics. In the present work, Monte Carlo simulations using the Monte Carlo N-Particle Transport Code, Version 5 software produced single layer fabric attenuation results for first and second generation fabrics within the uncertainties associated with the experimental data. This model was then used to assess secondary X-ray production and consider the attenuation performance of alternative fabric compositions. 相似文献
36.
37.
Bravar A Adams DL Akchurin N Belikov NI Bonner BE Bystricky J Corcoran MD Cossairt JD Cranshaw J Derevschikov AA En'yo H Funahashi H Goto Y Grachov OA Grosnick DP Hill DA Iijima T Imai K Itow Y Iwatani K Krueger K Kuroda K Laghai M Langland JL Lehar F de Lesquen A Lopiano D Luehring FC Maki T Makino S Masaike A Matulenko YA Meschanin AP Michalowicz A Miller DH Miyake K Nagamine T Nessi-Tedaldi F Nessi M Nguyen C Nurushev SB Ohashi Y Onel Y Patalakha DI Pauletta G Penzo A Rappazzo GF Read AL 《Physical review letters》1995,75(17):3073-3077
38.
The use of microbial cultures as a complementary model for mammalian drug metabolism has been well established previously. Here is a preliminary investigation into the potential of 19F NMR spectroscopy as a rapid screening tool to quantify the biotransformations of fluorine-containing model drugs. Biotransformations of three model drugs in 48 taxonomically diverse organisms were measured by acquiring 19F NMR spectra at 376 MHz. The presence of fluorine in the molecules allowed rapid, simultaneous detection of over 20 biotransformation products without sample pretreatment, chromatography, mass spectrometric techniques or the use of radiolabelled substrates. The detection limit at 376 MHz using 5 mm NMR tubes was ca. 0.3 microg ml(-1) using a typical analysis time of 20 min per sample. With the recent advent of flow injection NMR technology, analysis time of 5 min could be achieved with less sample. This approach may be used to develop fast small-scale microbial screens for the biosynthesis of metabolite standards and production of novel drug analogues, whilst also having a role in reducing animal experiments needed to identify animal and human metabolites of fluorinated xenobiotics. 相似文献
39.
Coghlan MP Culbert AA Cross DA Corcoran SL Yates JW Pearce NJ Rausch OL Murphy GJ Carter PS Roxbee Cox L Mills D Brown MJ Haigh D Ward RW Smith DG Murray KJ Reith AD Holder JC 《Chemistry & biology》2000,7(10):793-803
BACKGROUND: Glycogen synthase kinase-3 (GSK-3) is a serine/threonine protein kinase, the activity of which is inhibited by a variety of extracellular stimuli including insulin, growth factors, cell specification factors and cell adhesion. Consequently, inhibition of GSK-3 activity has been proposed to play a role in the regulation of numerous signalling pathways that elicit pleiotropic cellular responses. This report describes the identification and characterisation of potent and selective small molecule inhibitors of GSK-3. RESULTS: SB-216763 and SB-415286 are structurally distinct maleimides that inhibit GSK-3alpha in vitro, with K(i)s of 9 nM and 31 nM respectively, in an ATP competitive manner. These compounds inhibited GSK-3beta with similar potency. However, neither compound significantly inhibited any member of a panel of 24 other protein kinases. Furthermore, treatment of cells with either compound stimulated responses characteristic of extracellular stimuli that are known to inhibit GSK-3 activity. Thus, SB-216763 and SB-415286 stimulated glycogen synthesis in human liver cells and induced expression of a beta-catenin-LEF/TCF regulated reporter gene in HEK293 cells. In both cases, compound treatment was demonstrated to inhibit cellular GSK-3 activity as assessed by activation of glycogen synthase, which is a direct target of this kinase. CONCLUSIONS: SB-216763 and SB-415286 are novel, potent and selective cell permeable inhibitors of GSK-3. Therefore, these compounds represent valuable pharmacological tools with which the role of GSK-3 in cellular signalling can be further elucidated. Furthermore, development of similar compounds may be of use therapeutically in disease states associated with elevated GSK-3 activity such as non-insulin dependent diabetes mellitus and neurodegenerative disease. 相似文献
40.
Bonner BE Buchanan JA Carey DC Clement JM Coleman RN Corcoran MD Cossairt JD Derevshchikov AA Grosnick DP Hill DA Imai K Lehar F de Lesquen A Lopiano D Luehring FC Kruk JW Kuroda K Maki T Makino S Masaike A Matulenko YA Meshchanin AP Michalowicz A Miettinen HE Miller DH Miyake K Mohammadzadeh AH Mutchler GS Nagamine T Nessi-Tedaldi F Nessi M Nurushev SB Nguyen C Ohashi Y Pauletta G Penzo A Phillips GC Read AL Roberts JB van Rossum L Salvato G Schiavon P Shima T Solovyanov VL Spinka HM 《Physical review letters》1988,61(17):1918-1921