6,408 research outputs found
Visualizing mitochondrial FoF1-ATP synthase as the target of the immunomodulatory drug Bz-423
Targeting the mitochondrial enzyme FoF1-ATP synthase and modulating its
catalytic activities with small molecules is a promising new approach for
treatment of autoimmune diseases. The immuno-modulatory compound Bz-423 is such
a drug that binds to subunit OSCP of the mitochondrial FoF1-ATP synthase and
induces apoptosis via increased reactive oxygen production in coupled, actively
respiring mitochondria. Here we review the experimental progress to reveal the
binding of Bz-423 to the mitochondrial target and discuss how subunit rotation
of FoF1-ATP synthase is affected by Bz-423. Briefly, we report how F\"orster
resonance energy transfer (FRET) can be employed to colocalize the enzyme and
the fluorescently tagged Bz-423 within the mitochondria of living cells with
nanometer resolution.Comment: 10 pages, 2 figure
Entangled Dynamics in Macroscopic Quantum Tunneling of Bose-Einstein Condensates
Tunneling of a quasibound state is a non-smooth process in the entangled
many-body case. Using time-evolving block decimation, we show that repulsive
(attractive) interactions speed up (slow down) tunneling, which occurs in
bursts. While the escape time scales exponentially with small interactions, the
maximization time of the von Neumann entanglement entropy between the remaining
quasibound and escaped atoms scales quadratically. Stronger interactions
require higher order corrections. Entanglement entropy is maximized when about
half the atoms have escaped.Comment: 5 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1105.516
36 degree step size of proton-driven c-ring rotation in FoF1-ATP synthase
Synthesis of the biological "energy currency molecule" adenosine triphosphate
ATP is accomplished by FoF1-ATP synthase. In the plasma membrane of Escherichia
coli, proton-driven rotation of a ring of 10 c subunits in the Fo motor powers
catalysis in the F1 motor. While F1 uses 120 degree stepping, Fo models predict
a step-by-step rotation of c subunits 36 degree at a time, which is here
demonstrated by single-molecule fluorescence resonance energy transfer.Comment: 8 pages, 1 figur
Creep in Photovoltaic Modules: Examining the Stability of Polymeric Materials and Components
Interest in renewable energy has motivated the implementation of new polymeric materials in photovoltaic modules. Some of these are non-cross-linked thermoplastics, in which there is a potential for new behaviors to occur, including phase transformation and visco-elastic flow. Differential scanning calorimetry and rheometry data were obtained and then combined with existing site-specific time-temperature information in a theoretical analysis to estimate the displacement expected to occur during module service life. The analysis identified that, depending on the installation location, module configuration and/or mounting configuration, some of the thermoplastics are expected to undergo unacceptable physical displacement. While the examples here focus on encapsulation materials, the concerns apply equally to the frame, junction-box, and mounting-adhesive technologies
Many-body Anderson localization in one dimensional systems
We show, using quasi-exact numerical simulations, that Anderson localization
of one-dimensional particles in a disordered potential survives in the presence
of attractive interaction between particles. The localization length of the
composite particle can be computed analytically for weak disorder and is in
good agreement with the quasi-exact numerical observations using Time Evolving
Block Decimation. Our approach allows for simulation of the entire experiment
including the final measurement of all atom positions.Comment: 12pp, 5 fig, version accepted in NJ
Top Management Team Diversity: A systematic Review
Empirical research investigating the impact of top management team (TMT)
diversity on executives’ decision making has produced inconclusive results.
To synthesize and aggregate the results on the diversity-performance
link, a meta-regression analysis (MRA) is conducted. It integrates more
than 200 estimates from 53 empirical studies investigating TMT diversity
and its impact on the quality of executives’ decision making as reflected
in corporate performance. The analysis contributes to the literature by
theoretically discussing and empirically examining the effects of TMT diversity
on corporate performance. Our results do not show a link between TMT
diversity and performance but provide evidence for publication bias. Thus,
the findings raise doubts on the impact of TMT diversity on performance
The on-top pair-correlation density in the homogeneous electron liquid
The ladder theory, in which the Bethe-Goldstone equation for the effective
potential between two scattering particles plays a central role, is well known
for its satisfactory description of the short-range correlations in the
homogeneous electron liquid. By solving exactly the Bethe-Goldstone equation in
the limit of large transfer momentum between two scattering particles, we
obtain accurate results for the on-top pair-correlation density , in both
three dimensions and two dimensions. Furthermore, we prove, in general, the
ladder theory satisfies the cusp condition for the pair-correlation density
at zero distance .Comment: 8 pages, 4 figure
Current-density functional theory of time-dependent linear response in quantal fluids: recent progress
Vignale and Kohn have recently formulated a local density approximation to
the time-dependent linear response of an inhomogeneous electron system in terms
of a vector potential for exchange and correlation. The vector potential
depends on the induced current density through spectral kernels to be evaluated
on the homogeneous electron-gas. After a brief review of their theory, the case
of inhomogeneous Bose superfluids is considered, with main focus on dynamic
Kohn-Sham equations for the condensate in the linear response regime and on
quantal generalized hydrodynamic equations in the weak inhomogeneity limit. We
also present the results of calculations of the exchange-correlation spectra in
both electron and superfluid boson systems.Comment: 12 pages, 2 figures, Postscript fil
Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics
The evaluation of produced items at the time of delivery is, in practice,
usually amended by at least one inspection at later time points. We extend the
methodology of acceptance sampling for variables for arbitrary unknown
distributions when additional sampling infor- mation is available to such
settings. Based on appropriate approximations of the operating characteristic,
we derive new acceptance sampling plans that control the overall operating
characteristic. The results cover the case of independent sampling as well as
the case of dependent sampling. In particular, we study a modified panel
sampling design and the case of spatial batch sampling. The latter is advisable
in photovoltaic field monitoring studies, since it allows to detect and analyze
local clusters of degraded or damaged modules. Some finite sample properties
are examined by a simulation study, focusing on the accuracy of estimation
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