101 research outputs found
Control of laser-plasma instabilities by non-collinear polychromatic light
Normal broadband lasers with collinear polychromatic components have immense
potential for mitigating laser plasma instabilities (LPIs). However, the
projection complexity of collinear polychromatic light (CPL) is a significant
challenge owing to the demand for a large bandwidth and beamlet number. Here,
we propose a theoretical LPI model and optical design for non-collinear
polychromatic light (NCPL), which has a small angle and large
frequency difference 1\% between the double-color beamlets. LPI models of
the NCPL demonstrate a decoupling threshold for the shared daughter waves under
a multibeam configuration. Compared with the CPL, the wavevector couplings are
further reduced by the introduced angle. Therefore, both the growth rate and
saturation level of LPIs are greatly reduced by using the NCPL. The two- and
three-dimensional simulation results indicate that the NCPL reduces the
absolute and convective decoupling thresholds of the CPL and is sufficient to
effectively mitigate the reflectivity, hot-electron generation, and intensity
of cross-beam energy transfer. An optical design for the efficient generation
of ultraviolet NCPL has been presented based on the unsaturated optical
parametric amplification and non-collinear sum-frequency generation
Polychromatic drivers for inertial fusion energy
Although tremendous achievements have been made toward inertial confinement
fusion, laser plasma instabilities (LPIs) remain to be an inevitable problem
for current drive schemes. To mitigate these instabilities, significant efforts
have been paid to produce high-power broadband ultraviolet lasers. However, no
practical scheme has been demonstrated up to now for efficient triple-frequency
conversion of broadband laser. Here we propose the design of polychromatic
drivers for the generation of multicolor beams mainly based upon the optical
parametric amplification, which can significantly enhance the third-harmonic
conversion efficiency. Each polychromatic light has four colors of
monochromatic beamlets with a full spectrum width of 3\%, and the beamlet
colors of any two adjacent flanges are different. The suppression effects of
such polychromatic lights have been investigated via large scale
particle-in-cell simulations, which indicate that more than 35\% of the
incident energy can be saved from the LPIs compared with monochromatic lasers
for the direct-drive scheme, or high-density filled target for the
indirect-drive scheme. The proposed polychromatic drivers are based on the
matured technologies, and thus may pave the way towards realization of robust
and high-efficiency fusion ignition
Na/K-ATPase Y260 Phosphorylation-Mediated Src Regulation in Control of Aerobic Glycolysis and Tumor Growth
We report here the identification of α1 Na/K-ATPase as a major regulator of the proto-oncogene Src kinase and the role of this regulation in control of Warburg effect and tumor growth. Specifically, we discovered Y260 in α1 Na/K-ATPase as a Src-specific phosphorylation and binding site and that Y260 phosphorylation is required for Src-mediated signal transduction in response to a number of stimuli including EGF. As such, it enables a dynamic control of aerobic glycolysis. However, such regulation appears to be lost or attenuated in human cancers as the expression of Na/K-ATPase α1 was significantly decreased in prostate, breast and kidney cancers, and further reduced in corresponding metastatic lesions in patient samples. Consistently, knockdown of α1 Na/K-ATPase led to a further increase in lactate production and the growth of tumor xenograft. These findings suggest that α1 Na/K-ATPase works as a tumor suppressor and that a loss of Na/K-ATPase-mediated Src regulation may lead to Warburg phenotype in cancer
Na/K-ATPase mimetic pNaKtide Peptide inhibits the growth of human cancer cells
Cells contain a large pool of non-pumping Na/K-ATPase that participates in signal transduction. Here, we show that the expression of α1 Na/K-ATPase is significantly reduced in human prostate carcinoma as well as in several human cancer cell lines. This down-regulation impairs the ability of Na/K-ATPase to regulate Src-related signaling processes. Supplement of pNaKtide, a peptide derived from α1 Na/K-ATPase, reduces activities of Src and Src effectors. Consequently, these treatments stimulate apoptosis and inhibit growth in cultures of human cancer cells. Moreover, administration of pNaKtide inhibits angiogenesis and growth of tumor xenograft. Thus, the new findings demonstrate the in vivo effectiveness of pNaKtide, and suggest that the defect in Na/K-ATPase-mediated signal transduction may be targeted for developing new anti-cancer therapeutics
An emerging recombinant human enterovirus 71 responsible for the 2008 outbreak of Hand Foot and Mouth Disease in Fuyang city of China
Hand, foot and mouth disease (HFMD), a common contagious disease that usually affects children, is normally mild but can have life-threatening manifestations. It can be caused by enteroviruses, particularly Coxsackieviruses and human enterovirus 71 (HEV71) with highly variable clinical manifestations. In the spring of 2008, a large, unprecedented HFMD outbreak in Fuyang city of Anhui province in the central part of southeastern China resulted in a high aggregation of fatal cases. In this study, epidemiologic and clinical investigations, laboratory testing, and genetic analyses were performed to identify the causal pathogen of the outbreak. Of the 6,049 cases reported between 1 March and 9 May of 2008, 3023 (50%) were hospitalized, 353 (5.8%) were severe and 22 (0.36%) were fatal. HEV71 was confirmed as the etiological pathogen of the outbreak. Phylogenetic analyses of entire VP1 capsid protein sequence of 45 Fuyang HEV71 isolates showed that they belong to C4a cluster of the C4 subgenotype. In addition, genetic recombinations were found in the 3D region (RNA-dependent RNA polymerase, a major component of the viral replication complex of the genome) between the Fuyang HEV71 strain and Coxsackievirus A16 (CV-A16), resulting in a recombination virus. In conclusion, an emerging recombinant HEV71 was responsible for the HFMD outbreak in Fuyang City of China, 2008
Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst
The recently discovered neutron star transient Swift J0243.6+6124 has been
monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT).
Based on the obtained data, we investigate the broadband spectrum of the source
throughout the outburst. We estimate the broadband flux of the source and
search for possible cyclotron line in the broadband spectrum. No evidence of
line-like features is, however, found up to . In the absence of
any cyclotron line in its energy spectrum, we estimate the magnetic field of
the source based on the observed spin evolution of the neutron star by applying
two accretion torque models. In both cases, we get consistent results with
, and peak luminosity of which makes the source the first Galactic ultraluminous
X-ray source hosting a neutron star.Comment: publishe
Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
As China's first X-ray astronomical satellite, the Hard X-ray Modulation
Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15,
2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy
satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was
designed to perform pointing, scanning and gamma-ray burst (GRB) observations
and, based on the Direct Demodulation Method (DDM), the image of the scanned
sky region can be reconstructed. Here we give an overview of the mission and
its progresses, including payload, core sciences, ground calibration/facility,
ground segment, data archive, software, in-orbit performance, calibration,
background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech.
Astron. arXiv admin note: text overlap with arXiv:1910.0443
The Mode-2 Internal Solitary Wave Mooring Observations in Andaman Sea
Observation Data of the Second Mode Internal Solitary Waves in Central Andaman Sea (10.17°N, 95.47°E)
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