176,102 research outputs found
Background-deflection Brillouin microscopy reveals altered biomechanics of intracellular stress granules by ALS protein FUS
Altered cellular biomechanics have been implicated as key photogenic triggers in age-related diseases. An aberrant liquid-to-solid phase transition, observed in in vitro reconstituted droplets of FUS protein, has been recently proposed as a possible pathogenic mechanism for amyotrophic lateral sclerosis (ALS). Whether such transition occurs in cell environments is currently unknown as a consequence of the limited measuring capability of the existing techniques, which are invasive or lack of subcellular resolution. Here we developed a non-contact and label-free imaging method, named background-deflection Brillouin microscopy, to investigate the three-dimensional intracellular biomechanics at a sub-micron resolution. Our method exploits diffraction to achieve an unprecedented 10,000-fold enhancement in the spectral contrast of single-stage spectrometers, enabling, to the best of our knowledge, the first direct biomechanical analysis on intracellular stress granules containing ALS mutant FUS protein in fixed cells. Our findings provide fundamental insights on the critical aggregation step underlying the neurodegenerative ALS disease
Observing many body effects on lepton pair production from low mass enhancement and flow at RHIC and LHC energies
The spectral function at finite temperature calculated using the
real-time formalism of thermal field theory is used to evaluate the low mass
dilepton spectra. The analytic structure of the propagator is studied
and contributions to the dilepton yield in the region below the bare
peak from the different cuts in the spectral function are discussed. The
space-time integrated yield shows significant enhancement in the region below
the bare peak in the invariant mass spectra. It is argued that the
variation of the inverse slope of the transverse mass () distribution can
be used as an efficient tool to predict the presence of two different phases of
the matter during the evolution of the system. Sensitivity of the effective
temperature obtained from the slopes of the spectra to the medium effects
are studied
High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism
The readout of semiconductor spin qubits based on spin blockade is fast but
suffers from a small charge signal. Previous work suggested large benefits from
additional charge mapping processes, however uncertainties remain about the
underlying mechanisms and achievable fidelity. In this work, we study the
single-shot fidelity and limiting mechanisms for two variations of an enhanced
latching readout. We achieve average single-shot readout fidelities > 99.3% and
> 99.86% for the conventional and enhanced readout respectively, the latter
being the highest to date for spin blockade. The signal amplitude is enhanced
to a full one-electron signal while preserving the readout speed. Furthermore,
layout constraints are relaxed because the charge sensor signal is no longer
dependent on being aligned with the conventional (2, 0) - (1, 1) charge dipole.
Silicon donor-quantum-dot qubits are used for this study, for which the dipole
insensitivity substantially relaxes donor placement requirements. One of the
readout variations also benefits from a parametric lifetime enhancement by
replacing the spin-relaxation process with a charge-metastable one. This
provides opportunities to further increase the fidelity. The relaxation
mechanisms in the different regimes are investigated. This work demonstrates a
readout that is fast, has one-electron signal and results in higher fidelity.
It further predicts that going beyond 99.9% fidelity in a few microseconds of
measurement time is within reach.Comment: Supplementary information is included with the pape
Evolution of Structure and Superconductivity in Ba(NiCo)As
The effects of Co-substitution on Ba(NiCo)As () single crystals grown out of Pb flux are investigated via
transport, magnetic, and thermodynamic measurements. BaNiAs exhibits a
first order tetragonal to triclinic structural phase transition at
upon cooling, and enters a superconducting phase below . The
structural phase transition is sensitive to cobalt content and is suppressed
completely by . The superconducting critical temperature, ,
increases continuously with , reaching a maximum of at the
structural critical point and then decreases monotonically until
superconductivity is no longer observable well into the tetragonal phase. In
contrast to similar BaNiAs substitutional studies, which show an abrupt
change in at the triclinic-tetragonal boundary that extends far into the
tetragonal phase, Ba(NiCo)As exhibits a dome-like phase
diagram centered around the first-order critical point. Together with an
anomalously large heat capacity jump at optimal
doping, the smooth evolution of in the Ba(NiCo)As
system suggests a mechanism for pairing enhancement other than phonon
softening.Comment: 7 pages, 8 figure
Control of Optical Dynamic Memory Capacity of an Atomic Bose-Einstein Condensate
Light storage in an atomic Bose-Einstein condensate is one of the most
practical usage of these coherent atom-optical systems. In order to make them
even more practical, it is necessary to enhance our ability to inject multiple
pulses into the condensate. In this paper, we report that dispersion of pulses
injected into the condensate can be compensated by optical nonlinearity. In
addition, we will present a brief review of our earlier results in which
enhancement of light storage capacity is accomplished by utilizing multi-mode
light propagation or choosing an optimal set of experimental parameters.Comment: 4 figures, 11 page
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