7,132 research outputs found
On Nonlinear Bosonic Coherent States
Nonlinear coherent states are an interesting resource for quantum
technologies. Here we investigate some critical features of the single-boson
nonlinear coherent states, which are theoretically constructed as eigenstates
of the annihilation operator and experimentally realized as stationary states
of a trapped laser-driven ion. We show that the coherence and the
minimum-uncertainty properties of such states are broken for values of the
Lamb-Dicke parameter corresponding to the roots of the Laguerre polynomials,
which enter their explicit expression. The case of the multiboson nonlinear
coherent states is also discussed.Comment: published versio
The chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) controls cellular quiescence by hyperpolarizing the cell membrane during diapause in the crustacean Artemia
Cellular quiescence, a reversible state in which growth, proliferation, and other cellular activities are arrested, is important for self-renewal, differentiation, development, regeneration, and stress resistance. However, the physiological mechanisms underlying cellular quiescence remain largely unknown. In the present study, we used embryos of the crustacean Artemia in the diapause stage, in which these embryos remain quiescent for prolonged periods, as a model to explore the relationship between cell-membrane potential (V-mem) and quiescence. We found that V-mem is hyperpolarized and that the intracellular chloride concentration is high in diapause embryos, whereas V-mem is depolarized and intracellular chloride concentration is reduced in postdiapause embryos and during further embryonic development. We identified and characterized the chloride ion channel protein cystic fibrosis transmembrane conductance regulator (CFTR) of Artemia (Ar-CFTR) and found that its expression is silenced in quiescent cells of Artemia diapause embryos but remains constant in all other embryonic stages. Ar-CFTR knockdown and GlyH-101-mediated chemical inhibition of Ar-CFTR produced diapause embryos having a high V-mem and intracellular chloride concentration, whereas control Artemia embryos released free-swimming nauplius larvae. Transcriptome analysis of embryos at different developmental stages revealed that proliferation, differentiation, and metabolism are suppressed in diapause embryos and restored in postdiapause embryos. Combined with RNA sequencing (RNA-Seq) of GlyH-101-treated MCF-7 breast cancer cells, these analyses revealed that CFTR inhibition down-regulates the Wnt and Aurora Kinase A (AURKA) signaling pathways and up-regulates the p53 signaling pathway. Our findings provide insight into CFTR-mediated regulation of cellular quiescence and V-mem in the Artemia model
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Phase Control on Surface for the Stabilization of High Energy Cathode Materials of Lithium Ion Batteries.
The development of high energy electrode materials for lithium ion batteries is challenged by their inherent instabilities, which become more aggravated as the energy densities continue to climb, accordingly causing increasing concerns on battery safety and reliability. Here, taking the high voltage cathode of LiNi0.5Mn1.5O4 as an example, we demonstrate a protocol to stabilize this cathode through a systematic phase modulating on its particle surface. We are able to transfer the spinel surface into a 30 nm shell composed of two functional phases including a rock-salt one and a layered one. The former is electrochemically inert for surface stabilization while the latter is designated to provide necessary electrochemical activity. The precise synthesis control enables us to tune the ratio of these two phases, and achieve an optimized balance between improved stability against structural degradation without sacrificing its capacity. This study highlights the critical importance of well-tailored surface phase property for the cathode stabilization of high energy lithium ion batteries
Blood pressure and renal function responses in workers exposed to lead for up to six years
The Study for Promotion of Health in Recycling Lead (SPHERL) assessed the blood pressure (BP) and renal function (RF) responses for up to 6 years in the workers without previous occupational lead exposure. BP was the average of five consecutive readings and the estimated glomerular filtration rate was derived from serum creatinine (eGFRcrt) and cystatin C (eGFRcys). Blood lead (BL) was measured by inductively coupled plasma mass spectrometry (detection limit 0.5 μg/dL). The statistical methods included multivariable-adjusted mixed models and interval-censored Cox regression analysis. The 234 workers analyzed were on average 28.5 years old and included 91.9% men. The baseline BL concentration was 4.35 μg/dL and increased 3.17-fold over follow-up (median: 2.03 years; range: 0.92–6.45 years). The changes in BP and RF were not significantly correlated with the follow-up-to-baseline BL ratio (p ≥.51 and p ≥.18, respectively). The fully-adjusted changes in systolic/diastolic BP associated with a doubling of BL were −0.25/−0.12 mm Hg (CI: −0.94 to 0.44/−0.66 to 0.42 mm Hg). Accordingly, the incidence of stage-1 or -2 hypertension was not associated with the BL change (p ≥.063). Similarly, the changes in eGFRcrt and eGFRcys associated with a 3-fold BL increment were not significant, amounting to −0.70 mL/min/1.73 m2 (CI: −1.70 to 0.30 mL/min/1.73 m2) and −1.06 mL/min/1.73 m2 (−2.16 to 0.03 mL/min/1.73 m2). In conclusion, the BP and RF responses to an over 3-fold BL increment were small and not significant confirming the safety of modern lead-handing facilities operating under current safety rules.</p
Teleparallel Dark Energy with Purely Non-minimal Coupling to Gravity
We propose the simplest model of teleparallel dark energy with purely a
non-minimal coupling to gravity but no self-potential, a single model
possessing various interesting features: simplicity, self-potential-free, the
guaranteed late-time cosmic acceleration driven by the non-minimal coupling to
gravity, tracker behavior of the dark energy equation of state at earlier
times, a crossing of the phantom divide at a late time, and the existence of a
finite-time future singularity. We find the analytic solutions of the
dark-energy scalar field respectively in the radiation, matter, and dark energy
dominated eras, thereby revealing the above features. We further illustrate
possible cosmic evolution patterns and present the observational constraint of
this model obtained by numerical analysis and data fitting.Comment: 12 pages, 3 figures, Title changed, Revised Version Accepted for
publication in Phys. Lett.
Blood pressure and hypertension in relation to lead exposure updated according to present-day blood lead levels
Lead is an environmental hazard that should be addressed worldwide. Over time, human lead exposure in the western world has fallen drastically to levels comparable to those in humans living in the pre-industrial era, who were mainly exposed to natural sources of lead. To re-evaluate the health risks possibly associated with present-day lead exposure, a three‑pronged approach was applied. First, we critically assessed the recently published population metrics describing the adverse health effects associated with lead exposure at the population level. Next, we summarized the key results of the Study for Promotion of Health in Recycling Lead (SPHERL; NCT02243904) and put these results in perspective with those of the published population metrics. Last but not least, we performed a brief literature review on the present-day lead exposure level in Poland. To our best knowledge, SPHERL is the first prospective study that accounted for interindividual variability between people in their vulnerability to the toxic effects of lead exposure by assessing the participants’ health status before and after occupational lead exposure, with blood pressure and hypertension as one of the primary outcomes. The overall conclusion of this comprehensive review on blood pressure and hypertension is that mainstream ideas about the public and occupational health risks related to lead exposure urgently need to be updated, because a large part of the available literature became obsolete given present-day exposure levels, which sharply declined over the past 40 years
Experimental Demonstration of Five-photon Entanglement and Open-destination Teleportation
Universal quantum error-correction requires the ability of manipulating
entanglement of five or more particles. Although entanglement of three or four
particles has been experimentally demonstrated and used to obtain the extreme
contradiction between quantum mechanics and local realism, the realization of
five-particle entanglement remains an experimental challenge. Meanwhile, a
crucial experimental challenge in multi-party quantum communication and
computation is the so-called open-destination teleportation. During
open-destination teleportation, an unknown quantum state of a single particle
is first teleported onto a N-particle coherent superposition to perform
distributed quantum information processing. At a later stage this teleported
state can be readout at any of the N particles for further applications by
performing a projection measurement on the remaining N-1 particles. Here, we
report a proof-of-principle demonstration of five-photon entanglement and
open-destination teleportation. In the experiment, we use two entangled photon
pairs to generate a four-photon entangled state, which is then combined with a
single photon state to achieve the experimental goals. The methods developed in
our experiment would have various applications e.g. in quantum secret sharing
and measurement-based quantum computation.Comment: 19 pages, 4 figures, submitted for publication on 15 October, 200
Automatic Determination of Stellar Atmospheric Parameters and Construction of Stellar Spectral Templates of the Guoshoujing Telescope (LAMOST)
A number of spectroscopic surveys have been carried out or are planned to
study the origin of the Milky Way. Their exploitation requires reliable
automated methods and softwares to measure the fundamental parameters of the
stars. Adopting the ULySS package, we have tested the effect of different
resolutions and signal-to-noise ratios (SNR) on the measurement of the stellar
atmospheric parameters (effective temperature Teff, surface gravity log g, and
metallicity [Fe/H]). We show that ULySS is reliable to determine these
parameters with medium-resolution spectra (R~2000). Then, we applied the method
to measure the parameters of 771 stars selected in the commissioning database
of the Guoshoujing Telescope (GSJT). The results were compared with the
SDSS/SEGUE Stellar Parameter Pipeline (SSPP), and we derived precisions of 167
K, 0.34 dex, and 0.16 dex for Teff, log g and [Fe/H] respectively. Furthermore,
120 of these stars are selected to construct the primary stellar spectra
template library (Version 1.0) of GSJT, and will be deployed as basic
ingredients for the GSJT automated parametrization pipeline.Comment: 23 pages, 15 figures, accepted by RA
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