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81.
82.
We have converted an ultracold Fermi gas of 6Li atoms into an ultracold gas of 6Li2 molecules by adiabatic passage through a Feshbach resonance. Approximately 1.5 x 10(5) molecules in the least-bound, v=38, vibrational level of the X1Sigma(+)(g) singlet state are produced with an efficiency of 50%. The molecules remain confined in an optical trap for times of up to 1 s before we dissociate them by a reverse adiabatic sweep. 相似文献
83.
Alex Andrus Beverly Partridge James V. Heck B.G. Christensen 《Tetrahedron letters》1984,25(9):911-914
A series of N-(tetrazol-5-yl)azetidin-2-ones have been prepared from serine and threonine and evaluated as antibiotics against a range of bacteria. 相似文献
84.
Wilmes LJ Pallavicini MG Fleming LM Gibbs J Wang D Li KL Partridge SC Henry RG Shalinsky DR Hu-Lowe D Park JW McShane TM Lu Y Brasch RC Hylton NM 《Magnetic resonance imaging》2007,25(3):319-327
Dynamic contrast-enhanced MRI (DCE-MRI) was used to noninvasively evaluate the effects of AG-03736, a novel inhibitor of vascular endothelial growth factor (VEGF) receptor tyrosine kinases, on tumor microvasculature in a breast cancer model. First, a dose response study was undertaken to determine the responsiveness of the BT474 human breast cancer xenograft to AG-013736. Then, DCE-MRI was used to study the effects of a 7-day treatment regimen on tumor growth and microvasculature. Two DCE-MRI protocols were evaluated: (1) a high molecular weight (MW) contrast agent (albumin-(GdDTPA)(30)) with pharmacokinetic analysis of the contrast uptake curve and (2) a low MW contrast agent (GdDTPA) with a clinically utilized empirical parametric analysis of the contrast uptake curve, the signal enhancement ratio (SER). AG-013736 significantly inhibited growth of breast tumors in vivo at all doses studied (10-100 mg/kg) and disrupted tumor microvasculature as assessed by DCE-MRI. Tumor endothelial transfer constant (K(ps)) measured with albumin-(GdDTPA)(30) decreased from 0.034+/-0.005 to 0.003+/-0.001 ml min(-1) 100 ml(-1) tissue (P<.0022) posttreatment. No treatment-related change in tumor fractional plasma volume (fPV) was detected. Similarly, in the group of mice studied with GdDTPA DCE-MRI, AG-013736-induced decreases in tumor SER measures were observed. Additionally, our data suggest that 3D MRI-based volume measurements are more sensitive than caliper measurements for detecting small changes in tumor volume. Histological staining revealed decreases in tumor cellularity and microvessel density with treatment. These data demonstrate that both high and low MW DCE-MRI protocols can detect AG-013736-induced changes in tumor microvasculature. Furthermore, the correlative relationship between microvasculature changes and tumor growth inhibition supports DCE-MRI methods as a biomarker of VEGF receptor target inhibition with potential clinical utility. 相似文献
85.
Partridge Ashton Harris Paul Hirotsu Toshihiro Kurosawa Shigeru 《Plasmas and Polymers》2000,5(3-4):191-200
The paper describes attempts to apply plasma polymers to the development of chemical sensors. The plasma polymers were used as membranes to coat conventional conducting polymer sensors, as stand-alone chemiresistive sensors and as absorbent coatings on quartz crystal microbalances. The plasma polymers were derived from combinations of pyrrole and three silicon containing monomers. In the chemiresistive sensors, conductivity was induced in the polymer matrix by doping with iodine. The paper describes the experimental polymerization conditions, the physical characteristics of the polymers, and the application of the different polymers to sensing common volatile analytes. 相似文献
86.
Transport cross sections and collision integrals are tabulated for a wide range of energies and temperatures for the interactions
B–B and Al–Al. For aluminum, a semiclassical approximation was used to determine the scattering phase shifts from which the
transport cross sections were calculated. For boron, the smaller reduced mass and the deep potential wells required the phase
shifts at lower energies to be determined from a numerical solution of the time-independent Schroedinger equation; the semiclassical
approximation was used at higher energies where the two methods agree. The variations of the collision integrals for viscosity
and diffusion are presented graphically as a function of temperature. The results are applied to estimate the transport properties
of gallium.
Received: 9 July 1999 / Accepted: 18 August 1999 / Published online: 2 November 1999 相似文献
87.
Fenske Emilie K. Roach Benjamin D. Hexel Cole R. Glasgow David C. Stewart Ian R. Partridge John D. Giaquinto Joseph M. 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(2):759-771
Journal of Radioanalytical and Nuclear Chemistry - Analysis of irradiated material shortly after irradiation can be non-trivial due to highly radioactive activation and fission isotopes increasing... 相似文献
88.
Dr. Suzanne J. Partridge Dr. David M. Withall Dr. John C. Caulfield Prof. John A. Pickett Prof. Robert A. Stockman Prof. Neil J. Oldham Dr. Michael A. Birkett 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(25):7231-7234
Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol ( 1 ) and (4aS,7S,7aR)-nepetalactone ( 2 ) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8-oxogeranial into the reactive enol of (S)-8-oxocitronellal, and cyclization of this enol intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically-labelled monoterpenoids as molecular probes. Topical application of deuterium-labelled probes synthesized from geraniol and nerol resulted in production of 2H4−lactol 1 and 2H4−lactone 2 . However, deuterium incorporation was not evident using labelled probes synthesized from (S)-citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants. 相似文献
89.
90.
Earles JC Gordon KC Stephenson AW Partridge AC Officer DL 《Physical chemistry chemical physics : PCCP》2011,13(4):1597-1605
A series of tetraphenylporphyrins appended at the β-pyrrolic position with an ethynylphenylene- or ethynylpyridine-substituent have been subjected to spectroscopic and density functional theory (DFT) analyses. The mean absolute deviation between corresponding experimental and DFT-derived vibrational spectra is up to 10.2 cm(-1), suggesting that the DFT B3LYP/6-31G(d) method provides an accurate model of the β-substituted porphyrin systems. The configuration interactions that give rise to prominent electronic absorptions have been calculated using time-dependant DFT (TD-DFT) and have been rationalized with reference to the energy and topology of DFT calculated molecular orbitals. As the electron withdrawing capacity of the β-substituent increases the LUMO orbital gains appreciable amplitude over the substituent moiety and is stabilised. This represents a departure from the assumptions underpinning the Gouterman four-orbital model, resulting in atypical electronic absorption spectra. This phenomenon is also manifested in the enhancement patterns of the resonance Raman spectra insofar as B-band excitation engenders an enhancement of substituent based modes. These observations demonstrate that the β-substituent exerts an appreciable electronic influence on the porphyrin π-electron system and provides a means of introducing charge-transfer character to prominent electronic transitions. 相似文献