108,989 research outputs found
Gene expression analysis in microdissected renal tissue - Current challenges and strategies
The architecture and compartmentalization of the kidney has stimulated the development of an array of microtechniques to study the functional differences between the distinct nephron segments. With the vast amounts of genomic sequence data now available, the groundwork has been laid for a comprehensive characterization of the molecular pathways defining the differences in nephron function. With the development of sensitive gene expression techniques the tools for a comprehensive molecular analysis of specific renal microenvironments have been provided: Quantitative RT-PCR technologies now allow the analysis of specific mRNAs from as little as single microdissected renal cells. A more global view of gene expression regulation is a logical development from the application of large scale profiling techniques. In this review, we will discuss the power and pitfalls of these approaches, including their potential for the functional characterization of nephron heterogeneity and diagnostic application in renal disease. Copyright (C) 2002 S. Karger AG, Basel
Entanglement spectroscopy of a driven solid-state qubit and its detector
We study the asymptotic dynamics of a driven quantum two level system coupled
via a quantum detector to the environment. We find multi-photon resonances
which are due to the entanglement of the qubit and the detector. Different
regimes are studied by employing a perturbative Floquet-Born-Markov approach
for the qubit+detector system, as well as non-perturbative real-time path
integral schemes for the driven spin-boson system. We find analytical results
for the resonances, including the red and the blue sidebands. They agree well
with those of exact ab-initio calculations.Comment: 4 pages, 4 figure
Decays in Quantum Hierarchical Models
We study the dynamics of a simple model for quantum decay, where a single
state is coupled to a set of discrete states, the pseudo continuum, each
coupled to a real continuum of states. We find that for constant matrix
elements between the single state and the pseudo continuum the decay occurs via
one state in a certain region of the parameters, involving the Dicke and
quantum Zeno effects. When the matrix elements are random several cases are
identified. For a pseudo continuum with small bandwidth there are weakly damped
oscillations in the probability to be in the initial single state. For
intermediate bandwidth one finds mesoscopic fluctuations in the probability
with amplitude inversely proportional to the square root of the volume of the
pseudo continuum space. They last for a long time compared to the non-random
case
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Block co-polyMOFs: morphology control of polymer-MOF hybrid materials.
The hybridization of block copolymers and metal-organic frameworks (MOFs) to create novel materials (block co-polyMOFs, BCPMOFs) with controlled morphologies is reported. In this study, block copolymers containing poly(1,4-benzenedicarboxylic acid, H2bdc) and morphology directing poly(ethylene glycol) (PEG) or poly(cyclooctadiene) (poly(COD)) blocks were synthesized for the preparation of BCPMOFs. Block copolymer architecture and weight fractions were found to have a significant impact on the resulting morphology, mediated through the assembly of polymer precursors prior to MOF formation, as determined through dynamic light scattering. Simple modification of block copolymer weight fraction allowed for tuning of particle size and morphology with either faceted and spherical features. Modification of polymer block architecture represents a simple and powerful method to direct morphology in highly crystalline polyMOF materials. Furthermore, the BCPMOFs could be prepared from both Zr4+ and Zn2+ MOFs, yielding hybrid materials with appreciable surface areas and tuneable porosities. The resulting Zn2+ BCPMOF yielded materials with very narrow size distributions and uniform cubic morphologies. The use of topology in BCPMOFs to direct morphology in block copolymer assemblies may open new methodologies to access complex materials far from thermodynamic equilibrium
Space Station Human Factors Research Review. Volume 1: EVA Research and Development
An overview is presented of extravehicular activity (EVA) research and development activities at Ames. The majority of the program was devoted to presentations by the three contractors working in parallel on the EVA System Phase A Study, focusing on Implications for Man-Systems Design. Overhead visuals are included for a mission results summary, space station EVA requirements and interface accommodations summary, human productivity study cross-task coordination, and advanced EVAS Phase A study implications for man-systems design. Articles are also included on subsea approach to work systems development and advanced EVA system design requirements
Crustal deformation, the earthquake cycle, and models of viscoelastic flow in the asthenosphere
The crustal deformation patterns associated with the earthquake cycle can depend strongly on the rheological properties of subcrustal material. Substantial deviations from the simple patterns for a uniformly elastic earth are expected when viscoelastic flow of subcrustal material is considered. The detailed description of the deformation pattern and in particular the surface displacements, displacement rates, strains, and strain rates depend on the structure and geometry of the material near the seismogenic zone. The origin of some of these differences are resolved by analyzing several different linear viscoelastic models with a common finite element computational technique. The models involve strike-slip faulting and include a thin channel asthenosphere model, a model with a varying thickness lithosphere, and a model with a viscoelastic inclusion below the brittle slip plane. The calculations reveal that the surface deformation pattern is most sensitive to the rheology of the material that lies below the slip plane in a volume whose extent is a few times the fault depth. If this material is viscoelastic, the surface deformation pattern resembles that of an elastic layer lying over a viscoelastic half-space. When the thickness or breath of the viscoelastic material is less than a few times the fault depth, then the surface deformation pattern is altered and geodetic measurements are potentially useful for studying the details of subsurface geometry and structure. Distinguishing among the various models is best accomplished by making geodetic measurements not only near the fault but out to distances equal to several times the fault depth. This is where the model differences are greatest; these differences will be most readily detected shortly after an earthquake when viscoelastic effects are most pronounced
Equivalence of two mathematical forms for the bound angular momentum of the electromagnetic field
It is shown that the mathematical form, obtained in a recent paper, for the
angular momentum of the electromagnetic field in the vicinity of electric
charge is equivalent to another form obtained previously by Cohen-Tannoudji,
Dupont-Roc and Gilbert. In this version of the paper an improved derivation is
given.Comment: 4 pages pdf, simpler derivatio
On the entanglement of a quantum field with a dispersive medium
In this Letter we study the entanglement of a quantum radiation field
interacting with a dielectric medium. In particular, we describe the quantum
mixed state of a field interacting with a dielectric through plasma and Drude
models and show that these generate very different entanglement behavior, as
manifested in the entanglement entropy of the field. We also present a formula
for a "Casimir" entanglement entropy, i.e., the distance dependence of the
field entropy. Finally, we study a toy model of the interaction between two
plates. In this model, the field entanglement entropy is divergent; however, as
in the Casimir effect, its distance-dependent part is finite, and the field
matter entanglement is reduced when the objects are far.Comment: Final published PRL versio
Standardized Pearson type 3 density function area tables
Tables constituting extension of similar tables published in 1936 are presented in report form. Single and triple parameter gamma functions are discussed. Report tables should interest persons concerned with development and use of numerical analysis and evaluation methods
Civic Engagement and Service Learning Partnerships
Service learning is designed to promote volunteerism and civic awareness. Community engagement in higher education specifically involves university members partnering with local community organizations to address a need. Students engage with community partners through service learning and other activities (Moore & Mendez, 2014). Service learning is a practice that connects new knowledge and social responsibility through active learning (Benson & Younkin, 1996).https://digitalscholarship.unlv.edu/btp_expo/1083/thumbnail.jp
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