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81.
J W Dolan L R Snyder R G Wolcott P Haber T Baczek R Kaliszan L C Sander 《Journal of chromatography. A》1999,857(1-2):41-68
Previous studies have shown that four experimental runs, where both temperature T and gradient time tG are varied, can be used for the reliable prediction of separation as a function of these two variables (two-dimensional optimization). Computer simulation (e.g., DryLab) can then be used to predict "optimized" conditions for maximum sample resolution using either isocratic or gradient elution. Samples that contain a large number of components (e.g., n>15-20) present a greater challenge. Resolution for these more complex samples is often quite sensitive to small changes in T or tG in turn requiring greater accuracy in predictions that result from computer simulation. In the present study of several samples, we have examined computer simulation errors that can arise from inexact expressions for retention time as a function of T, tG or isocratic %B. Resulting conclusions are applicable to both complex and simpler samples, in either one- or two-dimensional optimization. Means to anticipate and minimize the impact of these predictive errors are examined. 相似文献
82.
Mishra SR Auchincloss P Blair R Haber C Leung WC Ruiz M Oltman E Sciulli FJ Shaevitz MH Smith WH MacFarlane DB Purohit MV Coleman R Fisk HE Levinthal D Jovanovic DD Marsh W Rapidis PA White HB Garfinkle D Merritt FS Oreglia M Reutens P Bodek A Borcherding F Giokaris N Lang K Stockdale IE 《Physical review letters》1987,59(13):1397-1400
83.
K. Lang A. Bodek F. Borcherding N. Giokaris I. E. Stockdale P. Auchincloss R. Blair C. Haber S. Mishra E. Oltman M. Ruiz F. J. Sciulli M. Shaevitz W. H. Smith R. Zhu Y. K. Chu D. B. MacFarlane R. L. Messner D. B. Novikoff M. V. Purohit D. Garfinkle F. S. Merritt M. Oreglia P. Reutens R. Coleman H. E. Fisk Y. Fukushima O. Kerns B. Jin D. Levinthal T. Kondo W. Marsh P. A. Rapidis S. Segler R. Stefanski D. Theriot H. B. White D. Yovanovitch O. Fackler K. Jenkins 《Zeitschrift fur Physik C Particles and Fields》1987,33(4):483-503
Neutrino interactions with two muons in the final state have been studied using the Fermilab narrow band beam. A sample of 18v μ like sign dimuon events withP μ>9 GeV/c yields 6.6±4.8 events after backgroud subtraction and a prompt rate of (1.0±0.7)×10?4 per single muon event. The kinematics of these events are compared with those of the non-prompt sources. A total of 437v μ and 31 \(\bar v_\mu \) opposite sign dimuon events withP μ>4.3 GeV/c are used to measure the strange quark content of the nucleon: \(\kappa = {{2s} \mathord{\left/ {\vphantom {{2s} {\left( {\bar u + \bar d} \right) = 0.52_{ - 0.15}^{ + 0.17} \left( {or\eta _s \frac{{2s}}{{u + d}} = 0.075 \pm 0.019} \right) for 100< E_v< 230 GeV\left( {\left\langle {Q^2 } \right\rangle = {{23 GeV^2 } \mathord{\left/ {\vphantom {{23 GeV^2 } {c^2 }}} \right. \kern-0em} {c^2 }}} \right)}}} \right. \kern-0em} {\left( {\bar u + \bar d} \right) = 0.52_{ - 0.15}^{ + 0.17} \left( {or\eta _s \frac{{2s}}{{u + d}} = 0.075 \pm 0.019} \right) for 100< E_v< 230 GeV\left( {\left\langle {Q^2 } \right\rangle = {{23 GeV^2 } \mathord{\left/ {\vphantom {{23 GeV^2 } {c^2 }}} \right. \kern-0em} {c^2 }}} \right)}}\) using a charm semileptonic branching ratio of (10.9±1.4)% extracted from measurements ine + e ? collisions and neutrino emulsion data. 相似文献
84.
The leaf essential oils of Zanthoxylum rhoifolium and Zanthoxylum setulosum (Rutaceae) from Monteverde, Costa Rica have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The principal constituents of Z. rhoifolium leaf oil were germacrene D (14.6%), limonene (12.5%), trans-2-hexenal (11.3%), beta-elemene (9.2%), 2-undecanone (9.2%), myrcene (7.9%), bicyclogermacrene (7.5%), and germacrene A (5.2%). The leaf oil of Z. setulosum was composed largely of beta-phellandrene (37.5%), beta-caryophyllene (13.7%), alpha-pinene (11.9%), germacrene D (10.9%), myrcene (5.9%), and nerolidol (5.4%). The essential oils were screened for in-vitro cytotoxic activity against Hep G2, MCF-7, and PC-3 human tumor cell lines; antibacterial activity against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli; and for Artemia salina (brine shrimp) lethality. Neither Z. rhoifolium nor Z. setulosum leaf oils exhibited cytotoxicity or antibacterial activity. Both oils showed activity against A. salina. 相似文献
85.
Addition of gold nanoparticles to real-time PCR: effect on PCR profile and SYBR Green I fluorescence
Haber AL Griffiths KR Jamting AK Emslie KR 《Analytical and bioanalytical chemistry》2008,392(5):887-896
Real-time quantitative polymerase chain reaction (qPCR) is the industry standard technique for the quantitative analysis of
nucleic acids due to its unmatched sensitivity and specificity. Optimisation and improvements of this fundamental technique
over the past decade have largely consisted of attempts to allow faster and more accurate ramping between critical temperatures
by improving assay reagents and the thermal geometry of the PCR chamber. Small gold nanoparticles (Au-NPs) have been reported
to improve PCR yield under fast cycling conditions. In this study, we investigated the effect of Au-NPs on optimised real-time
qPCR assays by amplifying DNA sequences from genetically modified canola in the presence and absence of 0.9 nM Au-NPs of diameter
12 ± 2nm. Contrary to expectations, we found that Au-NPs altered the PCR amplification profile when using a SYBR Green I detection
system due to fluorescence quenching; furthermore, high-resolution melt (HRM) analysis demonstrated that Au-NPs destabilised
the double-stranded PCR product. The results indicate that effects on the assay detection system must be carefully evaluated
before Au-NPs are included in any qPCR assay.
Figure Raw amplification profiles in the presence and absence of gold nanoparticles 相似文献
86.
Itai Benjamini Simi Haber Michael Krivelevich Eyal Lubetzky 《Random Structures and Algorithms》2008,32(1):101-114
The isoperimetric constant of a graph G on n vertices, i(G), is the minimum of , taken over all nonempty subsets S ⊂ V (G) of size at most n/2, where ∂S denotes the set of edges with precisely one end in S. A random graph process on n vertices, , is a sequence of graphs, where is the edgeless graph on n vertices, and is the result of adding an edge to , uniformly distributed over all the missing edges. The authors show that in almost every graph process equals the minimal degree of as long as the minimal degree is o(log n). Furthermore, it is shown that this result is essentially best possible, by demonstrating that along the period in which the minimum degree is typically Θ(log n), the ratio between the isoperimetric constant and the minimum degree falls from 1 to , its final value. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008 相似文献
87.
Leaf essential oil composition of five Zanthoxylum species from Monteverde, Costa Rica 总被引:1,自引:0,他引:1
The leaf essential oils from five species of Zanthoxylum (Rutaceae) from Monteverde, Costa Rica, have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The species examined include Z. fagara, Z. acuminatum, Z. melanostictum, Z. monophyllum, and an undescribed species. The most abundant classes of compounds found in Zanthoxylum leaf oils are acyclic and menthane monoterpenoids as well as simple alcohols, aldehydes, and ketones. In terms of molecular diversity, menthane and acyclic monoterpenoids, cadinane and mesocyclic sesquiterpenoids, and simple alcohols, aldehydes, and ketones dominate the essential oils of Zanthoxylum species. Monoterpenoids make up the majority of the mass of the leaf oils of Z. monophyllum, Z. acuminatum, Z. fagara, and Zanthoxylum sp. nov. Linalool, 4-terpineol, -terpineol, and trans-2-hexenol, are found in all of the Zanthoxylum species examined in this study. 相似文献
88.
W. E. Garner C. A. Waters H. Lüers C. W. G. Hetterschy Aristides Kanitz F. Liebert A. Uhl W. Kestranek J. M. Kolthoff B. D. Hartong J. Pinkhof E. Biilmann A. Klit F. Haber Z. Klemensiewicz W. S. Hughes A. L. v. Steiger W. E. L. Brown Phyllis M. T. Kerridge Th. Arnd W. Siemers K. H. Goode W. D. Treadwell J. W. Williams Th. A. Whitenack U. Ehrhardt E. Linde 《Analytical and bioanalytical chemistry》1930,80(5-6):203-213
89.
90.