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51.
Summary The purity of the investigational antibacterial Abbott-086719.1 (I) which is 8[(3S)-3-amino-1-pyrrolidinyl]-1-cyclopropyl-7-fluoro-9-methyl-4-oxo-4H-quinolizine-3-carboxylic
acid hydrochloride is determined using gradient elution HPLC. The chromatographic separation was optimized and the chromatographic
parameters critical to separation are discussed in detail. Most acceptable separations were achieved using an Alltima C18
column (5 μm) measuring 4.6 mm I.D. × 15 cm with 0.01M–0.03M citrate eluents which were modified with acetonitrile or with mixtures of acetonitrile and methanol. Related substances in
I were determinable to 0.05 %. Repeatability (RSD values) for determining related substances at levels of 0.50 to 0.06 % ranged
from ±1.9 to ±10 %. Determinations of I in 5 % dextrose in water and in hydroxypropyl methylcellulose were made using the
same column and a simple isocratic system. The determination of I was stability indicating with precision (RSD values) of
±0.5 % to ±2.0 % and good agreement with theory for formulations containing I at 1.0 to 95 mg/mL concentrations. Recoveries
of I from the vehicles were quantitative and linearity of the detector response of I was demonstrated to at least 0.10 mg/mL. 相似文献
52.
F. E. J. Linton 《Semigroup Forum》1984,29(1):247-250
53.
Armstrong DR Clegg W Davies RP Liddle ST Linton DJ Raithby PR Snaith R Wheatley AE 《Angewandte Chemie (International ed. in English)》1999,38(22):3367-3370
Lithium cages containing hydride: The reaction of tBuLi with Me(2)AlN(2-Pyr)Ph in toluene gave [Li(8)(H){N(2-Pyr)Ph}(6)](+)[Li(Me(2)AltBu(2))(2)](-), whose cation is the first molecular main group metal species to contain interstitial hydride (the cluster core is shown in the picture). Treatment of the reaction mixture with THF gave the neutral hydride Li(7)(H)[N(2-Pyr)Ph](6), which has a capped octahedral (Li(+))(7) cluster core. 2-Pyr=2-pyridyl. 相似文献
54.
A formula for the effective wavenumber in a dilute random array of identical scatterers in two dimensions is derived, based on Lax's quasicrystalline approximation. This formula replaces a widely-used expression due to Twersky, which is shown to be based on an inappropriate choice of pair-correlation function. 相似文献
55.
F. E. J. Linton 《Annali di Matematica Pura ed Applicata》1970,86(1):1-13
Summary In questo lavoro presentiamo due teoremi di rappresentazione funtoriale, l'uno(2.1) contravariante, l'altro(3.1) covariante. Questi due teoremi risultono, ambe due, d'una forma primitiva(1.7) del teorema fundamentale di caratterizzazione di Jon Beck nella semantica funtoriale.
Si ritrova, come caso speciale del primo, la dualità di Stone trà gli anneli di Boole e gli spazii compatti0-dimensionali; di modo analogo, si ritrova dall'altro un teorema di tipo ? risoluzione spettrale ? per una classa di spazii
vettoriali reticolati, annunciata senza dimostrazione in un articolo anteriore[11] dell'autore.
Dedicated to the sixtieth birthday of Prof. Edgar R. Lorch
Research supported by an NAS-NRC Postdoctoral Research Fellowship, stimulated by the 1966–7 E.T.H. Triples Seminar, Zürich,
and recorded at Παλαιоℵχστρiτσα, 8 April, 1967. 相似文献
56.
B R Linton M S Goodman E Fan S A van Arman A D Hamilton 《The Journal of organic chemistry》2001,66(22):7313-7319
Recognition of dicarboxylates by bis-functional hydrogen-bonding receptors displays divergent thermodynamics in different solvent systems. NMR titration and isothermal titration calorimetry indicated that neutral bis-urea and bis-thiourea receptors form exothermic complexes with dicarboxylates in DMSO, with a near zero entropic contribution to binding. The increased binding strength of bis-guanidinium receptors precluded quantitative measurement of binding constants in DMSO, but titration calorimetry offered a qualitative picture of the association. Formation of these 1:1 complexes was also exothermic, but additional endothermic events occurred at both lower and higher host-guest ratios. These events indicated multiple binding equilibria but did not always occur at a discrete 2:1 or 1:2 host-guest molar ratio, suggesting higher aggregates. With increasing amounts of methanol as solvent, bis-guanidinium receptors form more endothermic complexes with dicarboxylates, with a favorable entropy of association. This switch from association driven by enthalpy to one driven by entropy may reflect a change from complexation involving the formation of hydrogen bonds to that promoted by solvent liberation from binding sites. 相似文献
57.
Michael H. Albert Steve Linton Nik Ruškuc Vincent Vatter Steve Waton 《Discrete Mathematics》2011,311(8-9):715-722
A selection of points drawn from a convex polygon, no two with the same vertical or horizontal coordinate, yields a permutation in a canonical fashion. We characterise and enumerate those permutations which arise in this manner and exhibit some interesting structural properties of the permutation class they form. We conclude with a permutation analogue of the celebrated Happy Ending Problem. 相似文献
58.
The P(5) branch features of the A (3)Φ(4)←X (3)Φ(4) (1,0) band near 628.2 nm of a molecular beam of iridium monofluoride, (193)IrF, were recorded field free and in the presence of a static electric field. The (193)Ir (I(1)=3/2) and (19)F (I(2)=1/2) hyperfine interactions in the A (3)Φ(4) (υ=1) and X (3)Φ(4) (υ=0) states were analyzed. The permanent electric dipole moments, μ(el), for the A (3)Φ(4) (υ=1) and X (3)Φ(4) (υ=0) states were determined to be 1.88(5) and 2.82(6) D, respectively, from the analysis of the observed Stark shifts. A comparison of the electric dipole moments for IrC, IrN, and CoF is presented. 相似文献
59.
60.