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19,049
result(s) for
"Xu, Ye"
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Measurement of Milli-Charged particles with a moderately large cross section from the Earth’s core at IceCube
A
bstract
It is assumed that heavy dark matter
ϕ
with O(TeV) mass captured by the Earth may decay to relativistic light milli-charged particles (MCPs). These MCPs could be measured by the IceCube neutrino telescope. The massless hidden photon model was taken for MCPs to interact with nuclei, so that the numbers and fluxes of expected MCPs may be evaluated at IceCube. Meanwhile, the numbers of expected neutrino background events were also evaluated at IceCube. Based on the assumption that no events are observed at IceCube in 10 years, the corresponding upper limits on MCP fluxes were calculated at 90% C. L. These results indicated that the MCPs from the Earth’s core could be directly detected at O(1TeV) energies at IceCube when 2
×
10
−
5
≲
ϵ
2
≲ 4
.
5
×
10
−
3
. And a new region of 4 GeV <
m
MCP
< 10 GeV and 4
.
47
×
10
−
3
≲
ϵ
≲ 9
.
41
×
10
−
2
is ruled out in the
m
MCP
-
ϵ
plane with 10 years of IceCube data.
Journal Article
Measurement of high energy dark matter from the Sun at IceCube
A
bstract
It is assumed that heavy dark matter particles (HDMs) with a mass of O(TeV) are captured by the Sun. HDMs can decay to relativistic light dark matter particles (LDMs), which could be measured by km
3
neutrino telescopes (like the IceCube detector). The numbers and fluxes of expected LDMs and neutrinos were evaluated at IceCube with the
Z′
portal dark matter model. Based on the assumption that no events are observed at IceCube in 6 years, the corresponding upper limits on LDM fluxes were calculated at 90% C. L.. These results indicated that LDMs could be directly detected in the O(1TeV)-O(10TeV) energy range at IceCube with 100 GeV ≲
m
Z′
≲ 350 GeV and
τ
ϕ
≲ 5 × 10
22
ṡ.
Journal Article
وجوه لا تلتقيها مرتين : حكايات غير عادية عن أبطال عاديين
\"وجوه لا تلتقيها مرتين\" يروي حكايات غير عادية عن أبطال عاديين، ربما تجدهم في مجتمعك بغض النظر عن طبيعة تكوين هذا المجتمع أو نطاقه الجغرافي أو خلفياته الثقافية والاقتصادية، وهو كتاب واقعي غير مثالي، تعرض فيه الصحفية الشهيرة لي يوان تشنغ الأحداث الخفية والتفاصيل المبهمة التي أفرزت التنمية الصينية الهائلة، والنقلة الاجتماعية كتجربة غير مسبوقة، ولكن من منظور إنساني، فهو لا يتطرق إلى استراتيجيات ولا سياسات ولا خطط خمسية، بل يركز على الفرد، كونه إنسانا فحسب.
Book
Search for Milli-Charged particles from the Sun at IceCube
A
bstract
It is assumed that heavy dark matter particles
ϕ
with O(TeV) mass captured by the Sun may decay to relativistic light milli-charged particles (MCPs). These MCPs could be measured by the IceCube detector. The massless hidden photon model was taken for MCPs to interact with nuclei, so that the numbers and fluxes of expected MCPs and neutrinos may be evaluated at IceCube. Based on the assumption that no events are observed at IceCube in 6 years, the corresponding upper limits on MCP fluxes were calculated at 90% C. L. These results indicated that MCPs could be directly detected in the secondaries’ energy range O(100GeV)-O(10TeV) at IceCube, when
ϵ
2
≳ 10
−
10
. And a new region of 0.6 MeV <
m
MCP
< 10 MeV and 6
×
10
−
6
<
ϵ
≲ 10
−
4
is ruled out in the
m
MCP
-
ϵ
plane with 6 years of IceCube data.
Journal Article
DJ-1 upregulates the Nrf2/GPX4 signal pathway to inhibit trophoblast ferroptosis in the pathogenesis of preeclampsia
Ferroptosis is a newly discovered mode of cell death that involves disorders in iron metabolism and the accumulation of reactive oxygen species (ROS) in the plasma membrane. Preeclampsia (PE) is a gestational idiopathic disease that is characterized by hypertension and albuminuria, begins after 20 weeks of pregnancy. DJ-1 is a prerequisite for activating and stabilizing Nrf2 to allow translocation to the nucleus to carry out further functions. Detecting the expression levels of DJ-1, the Nrf2/GPX4 signaling pathway and ferroptosis markers in placental tissues of pregnant women with and without PE. Analyzing the effects of the ferroptosis inducer (RSL3) and the inhibitor (Fer-1) on the mortality rate of BeWo cells and DJ-1+/+, DJ-1−/− BeWo cells. Ferroptosis markers (MDA concentration and morphology of trophoblast cells) and DJ-1 and its downstream the Nrf2/GPX4 signaling pathway increased significantly in PE pathological state. The expression levels of DJ-1 protein in the control group and the PE group were positively correlated with the expression levels of Nrf2/GPX4 signaling pathway protein, and negatively correlated with the MDA concentration. BeWo cells were sensitive to the ferroptosis inducer (RSL3) and the inhibitor (Fer-1). The high expression levels of DJ-1 in BeWo cells can resist ferroptosis by regulating the Nrf2/GPX4 signaling pathway. Ferroptosis is involved in the pathogenesis of PE. DJ-1 can mediate the trophoblast cells ferroptosis and play a protective role in the pathogenesis of preeclampsia by regulating the Nrf2/GPX4 signaling pathway.
Journal Article
Anti-SARS-CoV-2 activities in vitro of Shuanghuanglian preparations and bioactive ingredients
Human infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and there is no cure currently. The 3CL protease (3CLpro) is a highly conserved protease which is indispensable for CoVs replication, and is a promising target for development of broad-spectrum antiviral drugs. In this study we investigated the anti-SARS-CoV-2 potential of Shuanghuanglian preparation, a Chinese traditional patent medicine with a long history for treating respiratory tract infection in China. We showed that either the oral liquid of Shuanghuanglian, the lyophilized powder of Shuanghuanglian for injection or their bioactive components dose-dependently inhibited SARS-CoV-2 3CLpro as well as the replication of SARS-CoV-2 in Vero E6 cells. Baicalin and baicalein, two ingredients of Shuanghuanglian, were characterized as the first noncovalent, nonpeptidomimetic inhibitors of SARS-CoV-2 3CLpro and exhibited potent antiviral activities in a cell-based system. Remarkably, the binding mode of baicalein with SARS-CoV-2 3CLpro determined by X-ray protein crystallography was distinctly different from those of known 3CLpro inhibitors. Baicalein was productively ensconced in the core of the substrate-binding pocket by interacting with two catalytic residues, the crucial S1/S2 subsites and the oxyanion loop, acting as a “shield” in front of the catalytic dyad to effectively prevent substrate access to the catalytic dyad within the active site. Overall, this study provides an example for exploring the in vitro potency of Chinese traditional patent medicines and effectively identifying bioactive ingredients toward a specific target, and gains evidence supporting the in vivo studies of Shuanghuanglian oral liquid as well as two natural products for COVID-19 treatment.
Journal Article
Lasing and anti-lasing in a single cavity
Lasing, light amplification by stimulated emission of radiation, is a key attribute for many important applications in optical communications, medicine and defence. Conversely, anti-lasing represents the time-reversed counterpart of laser emission, where incoming radiation is coherently absorbed. Here, we experimentally realize lasing and anti-lasing at the same frequency in a single cavity using parity–time symmetry. Because of the time-reversal property, the demonstrated lasing and anti-lasing resonances share common resonant features such as identical frequency dependence, coherent in-phase response and fine spectral resolution. Lasing and anti-lasing in a single device offers a new route for light modulation with high contrast approaching the ultimate limit.
A cavity that can switch between lasing and anti-lasing could inspire a new design of optical modulator.
Journal Article