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101.
Lubomír Kubáček 《Mathematica Slovaca》2007,57(3):271-296
The aim of the paper is to present explicit formulae for parameter estimators and confidence regions in multivariate regression
model with different kind of constraints and to give some comments to it. The covariance matrix of observation is either totally
known, or some unknown parameters of it must be estimated, or the covariance matrix is totally unknown.
Supported by the Council of Czech Government J14/98: 153100011. 相似文献
102.
103.
Funston A Kirby JP Miller JR Pospísil L Fiedler J Hromadová M Gál M Pecka J Valásek M Zawada Z Rempala P Michl J 《The journal of physical chemistry. A》2005,109(48):10862-10869
One-electron reduction of the "extended viologen" dication 1 yields the red cation radical 2, characterized by strong near-IR absorption. It has been generated and studied by pulse radiolytic, electrochemical, redox titration, UV-visible, and electron paramagnetic resonance spectroscopic methods. All results are in agreement with a fully delocalized electronic structure for 2. 相似文献
104.
Density data for dilute aqueous solutions of phenylacetic acid, benzene-1, 2-dicarboxylic acid (phtalic acid), benzene-1,2,4-tricarboxylic acid and 1,2,3-trihydroxy- benzene (pyrogallol) are presented together with the partial molar volumes at infinite dilution calculated from the experimental data. The measurements were performed at temperatures from T=298.15 K up to T=373.15 K and at three pressures up to 30 MPa. The data were obtained using a high-temperature, high-pressure flow vibrating-tube densimeter. 相似文献
105.
Sexual attraction in the silkworm moth. Nature of binding of bombykol in pheromone binding protein--an ab initio study 总被引:1,自引:0,他引:1
An analysis of the crystal structure of [BmPBP...bombykol] complex identified nine amino acid residues involved in a variety of intermolecular interactions binding the ligand. Using simple model fragments as the representatives of the residues, the interaction energies of their complexes with bombykol were calculated using high-level ab initio methods. The results were discussed in terms of the method and basis set dependence and were further corrected to account for their pair nonadditivities. This enabled us to describe quantitatively the nature and origin of the binding forces in terms of contribution of the individual amino acids and individual types of interaction to the overall stability. All of these interactions are well defined and cannot be considered as nonspecific hydrophobic interactions, one of the major conclusions of this work. 相似文献
106.
Aleš Hrdlička Lubomír Prokeš Michaela Vašinová Galiová Karel Novotný Anna Vitešníková Tereza Helešicová Viktor Kanický 《Chemical Papers》2013,67(5):546-555
Double pulse laser induced breakdown spectroscopy in orthogonal configuration was used for the analysis of twelve samples of volcanic glass. Raw material and artifact samples originated from Czech, Slovak, German, Hungarian, Greek, Turkish, and Ukrainian sites. The primary 266 nm laser beam was focused onto a sample area of about 0.1 mm in diameter at the optimised energy of 10 mJ resulting in only very slight sample damage, almost unrecognizable even by a microscope. The secondary 1064 nm laser beam, positioned parallel to the sample surface and focused onto the intersection with the primary beam, induced a spark with enhanced radiation at the optimised energy of 100 mJ. Measurement of emission lines selected on basis of chemical composition, signal intensity, signal-to-background ratio, and minimum interference from the surrounding spectra: Si(I) 288.16 nm, Mg(II) 279.55 nm, 280.27 nm, Mg(I) 285.21 nm, Ca(II) 317.93 nm, Na(I) 589.59 nm, Al(I) 308.22 nm, Fe(II) 259.94 nm, Ti(II) 334.94 nm, Sr(II) 407.77 nm, Ba(II) 455.40 nm, K(I) 769.90 nm, provided experimental data sufficiently sensitive to differentiate the properties of the studied samples. Rare earth elements were not detected even though the double pulse technique is more sensitive than the single pulse variant. Visualisation methods of multidimensional statistical analyses such as radar chart, Chernoff faces, scatterplots, and the Spearman correlation matrix provided successful differentiation of the sample groups and/or particular samples by their origin. 相似文献
107.
The design of four new fluorinated biaryl fluorescent labels and their attachment to nucleosides and nucleoside triphosphates (dNTPs) by the aqueous cross-coupling reactions of biarylboronates is reported. The modified dNTPs were good substrates for KOD XL polymerase and were enzymatically incorporated into DNA probes. The photophysical properties of the biaryl-modified nucleosides, dNTPs, and DNA were studied systematically. The different substitution pattern of the biaryls was used for tuning of emission maxima in the broad range of 366-565 nm. Using methods of computational chemistry the emission maxima were reproduced with a satisfactory degree of accuracy, and it was shown that the large solvatochromic shifts observed for the studied probes are proportional to the differences in dipole moments of the ground (S(0)) and excited (S(1)) states that add on top of smaller shifts predicted already for these systems in vacuo. Thus, we present a set of compounds that may serve as multipurpose base-discriminating fluorophores for sensing of hairpins, deletions, and mismatches by the change of emission maxima and intensities of fluorescence and that can be also conviently studied by (19)F NMR spectroscopy. In addition, aminobenzoxazolyl-fluorophenyl-labeled nucleotides and DNA also exert dual pH-sensitive and solvatochromic fluorescence, which may imply diverse applications. 相似文献
108.
Novák Z Chlebek J Opletal L Jiros P Macáková K Kunes J Cahlíková L 《Natural product communications》2012,7(7):859-860
A new benzyldihydroisoquinoline alkaloid (1) was isolated from the tubers of Corydalis cava and named corylucinine. Additionally, 8-trichloromethyl-7,8-dihydropalmatine (2), an isolation artifact of tetrahydropalmatine, was obtained. The structures were established by spectroscopic (including 2D NMR and optical rotation) and HR-ESI-MS methods. Both compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. In comparison with the used standards, both compounds showed only moderate inhibitory activity against HuAChE (IC50,. HuAChE = 127.6 +/- 5.2 microM for 1, and IC50, HuAChE = 82.9 +/- 3.9 microM for 2) and none against HuBuChE. 相似文献
109.
Andrew M. Crawford Patrick Kurecka Tsz Kwan Yim Claire Kozemchak Aniruddha Deb Lubomír Dostál Cheng-Jun Sun Dale L. Brewe Raul Barrea James E. Penner-Hahn 《Journal of synchrotron radiation》2016,23(4):901-908
An X‐ray fluorescence flow cytometer that can determine the total metal content of single cells has been developed. Capillary action or pressure was used to load cells into hydrophilic or hydrophobic capillaries, respectively. Once loaded, the cells were transported at a fixed vertical velocity past a focused X‐ray beam. X‐ray fluorescence was then used to determine the mass of metal in each cell. By making single‐cell measurements, the population heterogeneity for metals in the µM to mM concentration range on fL sample volumes can be directly measured, a measurement that is difficult using most analytical methods. This approach has been used to determine the metal composition of 936 individual bovine red blood cells (bRBC), 31 individual 3T3 mouse fibroblasts (NIH3T3) and 18 Saccharomyces cerevisiae (yeast) cells with an average measurement frequency of ~4 cells min?1. These data show evidence for surprisingly broad metal distributions. Details of the device design, data analysis and opportunities for further sensitivity improvement are described. 相似文献
110.
Lubomír Kubáček 《Mathematica Slovaca》2010,60(5):739-749
In regular linear regression model with the type II constraints the unobservable parameters in the constraints can be estimated
by the BLUE of the observable parameters. The BLUE respects the constraints. If the estimator of the observable parameters
which is the BLUE in the model without constraints is used, then the estimator of the unobservable parameters is the same. 相似文献