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51.
S. Q. Murphy J. L. Hicks W. K. Liu S. J. Chung K. J. Goldammer M. B. Santos 《Physica E: Low-dimensional Systems and Nanostructures》2000,6(1-4)
The temperature dependence of ρxx is studied in the vicinity of the quantum Hall to quantum Hall insulator transition (ν=1→0) in InSb/InAlSb based 2DESs. ρxx displays a symmetric temperature dependence about the transition with
on the QH side and
on the insulating side. A plot of 1/T0 for successive ν displays power-law divergence with 1/T0∝|ν−νc|−γ,2 with γ=2.2±0.3. This critical behavior in addition to the
behavior expected of the quantum transport regime confirms that the QH/QHI transition is indeed a good quantum phase transition. 相似文献
52.
John D. Krutty Andrew D. Dias Junsu Yun William L. Murphy Padma Gopalan 《Macromolecular bioscience》2019,19(2)
Mesenchymal stem cells (MSC), also called marrow stromal cells, are adult cells that have attracted interest for their potential uses in therapeutic applications. There is a pressing need for scalable culture systems due to the large number of cells needed for clinical treatments. Here, a tailorable thin polymer coating—poly(poly(ethylene glycol) methyl ether methacrylate‐ran‐vinyl dimethyl azlactone‐ran‐glycidyl methacrylate) [P(PEGMEMA‐r‐VDM‐r‐GMA); PVG]—to the surface of commercially available polystyrene and glass microcarriers to create chemically defined surfaces for large‐scale cell expansion is applied. These chemically defined microcarriers create a reproducible surface that does not rely on the adsorption of xenogenic serum proteins to mediate cell adhesion. Specifically, this coating method anchors PVG copolymer through ring opening nucleophilic attack by amine residues on poly‐l ‐lysine that is pre‐adsorbed to the surface of microcarriers. Importantly, this anchoring reaction preserves the monomer VDM reactivity for subsequent functionalization with an integrin‐specific Arg‐Gly‐Asp peptide to enable cell adhesion and expansion via a one‐step reaction in aqueous media. MSCs cultured on PVG‐coated microcarriers achieve sixfold expansion—similar to the expansion achieved on PS microcarriers—and retain their ability to differentiate after harvesting. 相似文献
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54.
Sun Su-Rong Wang Hai-Xing Zhu Tao Murphy Anthony B. 《Plasma Chemistry and Plasma Processing》2020,40(1):261-282
Plasma Chemistry and Plasma Processing - The diffuse and constricted arc attachment modes to the anode of an argon wall-stabilized transferred arc are investigated using a 2D chemical... 相似文献
55.
Wendy K. Strangman Allison K. Stewart Megan C. Herring Jeffrey L.C. Wright 《Tetrahedron letters》2018,59(10):934-937
An untargeted metabolomics approach was used to investigate a cultured strain of Microcystis aeruginosa (UTEX LB2386) known to be a prolific producer of a diverse class of cyanopeptides. Identification of a putative new compound with a molecular weight of 996 led to the purification and structure elucidation of this new member of the micropeptin class of cyanopeptides. Micropeptin 996 displayed potent inhibition of the serine protease enzyme chymotrypisin relative to structurally related members of this class. 相似文献
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58.
Gerard J. Murphy 《Integral Equations and Operator Theory》1996,24(3):298-319
The concept of a twisted crossed product associated to a non-classical C*-dynamical system is introduced and studied. The relationship between a covariant projective representation of the system and the corresponding induced representation of the twisted crossed product is investigated, particularly from the point of view of determining when the induced representation is faithful. Conditions are given on the C*-dynamical system that ensure nuclearity, simplicity or primeness of the twisted crossed product. 相似文献
59.
Mast TD Makin IR Faidi W Runk MM Barthe PG Slayton MH 《The Journal of the Acoustical Society of America》2005,118(4):2715-2724
Methods for the bulk ablation of soft tissue using intense ultrasound, with potential applications in the thermal treatment of focal tumors, are presented. An approximate analytic model for bulk ablation predicts the progress of ablation based on tissue properties, spatially averaged ultrasonic heat deposition, and perfusion. The approximate model allows the prediction of threshold acoustic powers required for ablation in vivo as well as the comparison of cases with different starting temperatures and perfusion characteristics, such as typical in vivo and ex vivo experiments. In a full three-dimensional numerical model, heat deposition from array transducers is computed using the Fresnel approximation and heat transfer in tissue is computed by finite differences, accounting for heating changes caused by boiling and thermal dose-dependent absorption. Similar ablation trends due to perfusion effects are predicted by both the simple analytic model and the full numerical model. Comparisons with experimental results show the efficacy of both models in predicting tissue ablation effects. Phenomena illustrated by the simulations and experiments include power thresholds for in vivo ablation, differences between in vivo and ex vivo lesioning for comparable source conditions, the effect of tissue boiling and absorption changes on ablation depth, and the performance of a continuous rotational scanning method suitable for interstitial bulk ablation of soft tissue. 相似文献
60.
Efficient Bayesian Inference for Multivariate Probit Models With Sparse Inverse Correlation Matrices
Aline Talhouk Arnaud Doucet Kevin Murphy 《Journal of computational and graphical statistics》2013,22(3):739-757
We propose a Bayesian approach for inference in the multivariate probit model, taking into account the association structure between binary observations. We model the association through the correlation matrix of the latent Gaussian variables. Conditional independence is imposed by setting some off-diagonal elements of the inverse correlation matrix to zero and this sparsity structure is modeled using a decomposable graphical model. We propose an efficient Markov chain Monte Carlo algorithm relying on a parameter expansion scheme to sample from the resulting posterior distribution. This algorithm updates the correlation matrix within a simple Gibbs sampling framework and allows us to infer the correlation structure from the data, generalizing methods used for inference in decomposable Gaussian graphical models to multivariate binary observations. We demonstrate the performance of this model and of the Markov chain Monte Carlo algorithm on simulated and real datasets. This article has online supplementary materials. 相似文献