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1.
V ? R,T deactivation of the ν4 (243 cm?1) level in BCl3 by HCl has been measured over the range 220–340 K, with an infrared double resonance technique. The deactivation probabilities show an inverse temperature dependence below room temperature, indicating that long-range attractive forces are important in the resonant transfer process. The results are compared with the theory of Sharma and Brau. 相似文献
2.
An N2O laser is used to pump the ground vibrational state (8,7) inversion doublet of 14NH3 while simultaneously monitoring other ground state doublets. Time-resolved rotational energy transfer signals are observed in accordance with known selection values. Absolute rates of rotational energy transfer processes are estimated. 相似文献
3.
Alexander Scheeline Bernita Williams Eric Williksen Jeffrey Steinfeld Brian McEnroe 《Spectrochimica Acta Part B: Atomic Spectroscopy》1998,53(14):1855-1861
This article is an electronic publication in Spectrochimica Acta Electronica (SAE), a section of Spectrochimica Acta, Part B (SAB). The hardcopy text is accompanied by an electronic archive, stored on the SAE homepage at http://www.elsevier.nl/locate/sabe. The archive contains data, index and program files. The main article discusses the bibliographical purpose of the program and data files. A collective index for Spectrochimica Acta for volumes since it was split into Parts A and B, and continuing through 1991 for SAA and 1997 for SAB, is presented in DBF format, along with rudimentary data entry and access software. 相似文献
4.
Weixun Wang Bernard K. Choi Wenyu Li Zhege Lao Anita Y. H. Lee Sandra C. Souza Nathan A. Yates Timothy Kowalski Alessandro Pocai Lucinda H. Cohen 《Journal of the American Society for Mass Spectrometry》2014,25(4):614-625
Stromal cell-derived factor 1α (SDF-1α) or CXCL12 is a small pro-inflammatory chemoattractant cytokine and a substrate of dipeptidyl peptidase IV (DPP-IV). Proteolytic cleavage by DPP-IV inactivates SDF-1α and attenuates its interaction with CXCR4, its cell surface receptor. To enable investigation of suppression of such inactivation with pharmacologic inhibition of DPP-IV, we developed quantitative mass spectrometric methods that differentiate intact SDF-1α from its inactive form. Using top-down strategy in quantification, we demonstrated the unique advantage of keeping SDF-1α’s two disulfide bridges intact in the analysis. To achieve the optimal sensitivity required for quantification of intact and truncated SDF-1α at endogenous levels in blood, we coupled nano-flow tandem mass spectrometry with antibody-based affinity enrichment. The assay has a quantitative range of 20 pmol/L to 20 nmol/L in human plasma as well as in rhesus monkey plasma. With only slight modification, the same assay can be used to quantify SDF-1α in mice. Using two in vivo animal studies as examples, we demonstrated that it was critical to differentiate intact SDF-1α from its truncated form in the analysis of biomarkers for pharmacologic inhibition of DPP-IV activity. These novel methods enable translational research on suppression of SDF-1 inactivation with DPP-IV inhibition and can be applied to relevant clinical samples in the future to yield new insights on change of SDF-1α levels in disease settings and in response to therapeutic interventions. Figure
? 相似文献
5.
M.W. Todd R.A. Provencal T.G. Owano B.A. Paldus A. Kachanov K.L. Vodopyanov M. Hunter S.L. Coy J.I. Steinfeld J.T. Arnold 《Applied physics. B, Lasers and optics》2002,75(2-3):367-376
A novel instrument, based on cavity-ringdown spectroscopy (CRDS), has been developed for trace gas detection. The new instrument
utilizes a widely tunable optical parametric oscillator (OPO), which incorporates a zinc–germanium–phosphide (ZGP) crystal
that is pumped at 2.8 μm by a 25-Hz Er,Cr:YSGG laser. The resultant mid-IR beam profile is nearly Gaussian, with energies
exceeding 200 μJ/pulse between 6 and 8 μm, corresponding to a quantum conversion efficiency of approximately 35%. Vapor-phase
mid-infrared spectra of common explosives (TNT, TATP, RDX, PETN and Tetryl) were acquired using the CRDS technique. Parts-per-billion
concentration levels were readily detected with no sample preconcentration. A collection/flash-heating sequence was implemented
in order to enhance detection limits for ambient air sampling. Detection limits as low as 75 ppt for TNT are expected, with
similar concentration levels for the other explosives.
Received: 1 April 2002 / Revised version: 13 June 2002 / Published online: 12 September 2002
RID="*"
ID="*"Corresponding author. Fax: +1-408/524-0551, E-mail: mtodd@picarro.com 相似文献
6.
7.
8.
David A. Keire Hongping Ye Michael L. Trehy Wei Ye Richard E. Kolinski Benjamin J. Westenberger Lucinda F. Buhse Moheb Nasr Ali Al-Hakim 《Analytical and bioanalytical chemistry》2011,399(2):581-591
During the 2007–2008 heparin crisis, it was found that the United States Pharmacopeia (USP) testing monograph for unfractionated
heparin sodium (UFH) did not detect the presence of the contaminant, oversulfated chondroitin sulfate (OSCS) in heparin. In
response to this concern, new tests and specifications were developed by the Food and Drug Administration (FDA) and USP and
put in place to not only detect the contaminant OSCS but also to improve assurance of quality and purity of the drug product.
Additional tests were also developed to monitor the heparin supply chain for other possible economically motivated additives
or impurities. In 2009, a new USP monograph was put in place that includes 500 MHz 1H NMR, SAX-HPLC, %galactosamine in total hexosamine, and anticoagulation time assays with purified factor IIa or factor Xa.
These tests represent orthogonal approaches for UFH identification, measurement of bioactivity, and for detection of process
impurities or contaminants in UFH. The FDA has applied these analytical approaches to the study of UFH active pharmaceutical
ingredients in the marketplace. Here, we describe results from a comprehensive survey of UFH collected from seven different
sources after the 2009 monograph revision and compare these data with results obtained on other heparin samples collected
during the 2007–2008 crisis. 相似文献
9.
O. Steinfeld 《Acta Mathematica Hungarica》1968,19(3-4):243-261
Ohne Zusammenfassung
Vorgelegt von
L. Rédei 相似文献
10.
O. Steinfeld 《Periodica Mathematica Hungarica》1973,4(2-3):169-181
Ohne Zusammenfassung
Dem Andenken von Professor
A. G. Kurosch
gewidmet 相似文献