238 research outputs found
Research advances on multifocal electroretinogram in primary open angle glaucoma
Primary open angle glaucoma is a chronic and progressive optic neuropathy. It can lead to serious damage of visual impairment, and it is an important eye disease of blindness. Multifocal electroretinogram is a new way to measure visual electrophysiology. It can measure electroretinogram of the whole visual field of many small parts in a relatively short period of time, and it can reflect the function of regional retina. It has an extremely important value for early diagnosis of primary open angle glaucoma. The research advances on multifocal electroretinogram in diagnosing primary open angle glaucoma were summarized in this paper
Model of a multiverse providing the dark energy of our universe
It is shown that the dark energy presently observed in our universe can be
regarded as the energy of a scalar field driving an inflation-like expansion of
a multiverse with ours being a subuniverse among other parallel universes. A
simple model of this multiverse is elaborated: Assuming closed space geometry,
the origin of the multiverse can be explained by quantum tunneling from
nothing; subuniverses are supposed to emerge from local fluctuations of
separate inflation fields. The standard concept of tunneling from nothing is
extended to the effect that in addition to an inflationary scalar field, matter
is also generated, and that the tunneling leads to an (unstable) equilibrium
state. The cosmological principle is assumed to pertain from the origin of the
multiverse until the first subuniverses emerge. With increasing age of the
multiverse, its spatial curvature decays exponentially so fast that, due to
sharing the same space, the flatness problem of our universe resolves by
itself. The dark energy density imprinted by the multiverse on our universe is
time-dependent, but such that the ratio of its mass
density and pressure (times ) is time-independent and assumes a value
with arbitrary . can be chosen so
small, that the dark energy model of this paper can be fitted to the current
observational data as well as the cosmological constant model.Comment: 32 pages, 4 figure
Electronic Structure, Surface Doping, and Optical Response in Epitaxial WSe2 Thin Films
High quality WSe2 films have been grown on bilayer graphene (BLG) with
layer-by-layer control of thickness using molecular beam epitaxy (MBE). The
combination of angle-resolved photoemission (ARPES), scanning tunneling
microscopy/spectroscopy (STM/STS), and optical absorption measurements reveal
the atomic and electronic structures evolution and optical response of
WSe2/BLG. We observe that a bilayer of WSe2 is a direct bandgap semiconductor,
when integrated in a BLG-based heterostructure, thus shifting the
direct-indirect band gap crossover to trilayer WSe2. In the monolayer limit,
WSe2 shows a spin-splitting of 475 meV in the valence band at the K point, the
largest value observed among all the MX2 (M = Mo, W; X = S, Se) materials. The
exciton binding energy of monolayer-WSe2/BLG is found to be 0.21 eV, a value
that is orders of magnitude larger than that of conventional 3D semiconductors,
yet small as compared to other 2D transition metal dichalcogennides (TMDCs)
semiconductors. Finally, our finding regarding the overall modification of the
electronic structure by an alkali metal surface electron doping opens a route
to further control the electronic properties of TMDCs
Tunable interfacial chemisorption with atomic-level precision in a graphene WSe2 heterostructure
It has long been an ultimate goal to introduce chemical doping at the atomic
level to precisely tune properties of materials. Two-dimensional materials have
natural advantage because of its highly-exposed surface atoms, however, it is
still a grand challenge to achieve this goal experimentally. Here, we
demonstrate the ability to introduce chemical doping in graphene with
atomic-level precision by controlling chemical adsorption of individual Se
atoms, which are extracted from the underneath WSe2, at the interface of
graphene-WSe2 heterostructures. Our scanning tunneling microscopy (STM)
measurements, combined with first-principles calculations, reveal that
individual Se atoms can chemisorbed on three possible positions in graphene,
which generate distinct pseudospin-mediated atomic-scale vortices in graphene.
We demonstrate that the chemisorbed positions of individual Se atoms can be
manipulated by STM tip, which enables us to achieve atomic-scale controlling
quantum interference of the pseudospin-mediated vortices in graphene. This
result offers the promise of controlling properties of materials through
chemical doping with atomic-level precision
Interferon-γ-Directed Inhibition of a Novel High-Pathogenic Phlebovirus and Viral Antagonism of the Antiviral Signaling by Targeting STAT1
Severe fever with thrombocytopenia syndrome (SFTS) is a life-threatening infectious disease caused by a novel phlebovirus, SFTS virus (SFTSV). Currently, there is no vaccine or antiviral available and the viral pathogenesis remains largely unknown. In this study, we demonstrated that SFTSV infection results in substantial production of serum interferon-γ (IFN-γ) in patients and then that IFN-γ in turn exhibits a robust anti-SFTSV activity in cultured cells, indicating the potential role of IFN-γ in anti-SFTSV immune responses. However, the IFN-γ anti-SFTSV efficacy was compromised once viral infection had been established. Consistently, we found that viral nonstructural protein (NSs) expression counteracts IFN-γ signaling. By protein interaction analyses combined with mass spectrometry, we identified the transcription factor of IFN-γ signaling pathway, STAT1, as the cellular target of SFTSV for IFN-γ antagonism. Mechanistically, SFTSV blocks IFN-γ-triggered STAT1 action through (1) NSs-STAT1 interaction-mediated sequestration of STAT1 into viral inclusion bodies and (2) viral infection-induced downregulation of STAT1 protein level. Finally, the efficacy of IFN-γ as an anti-SFTSV drug in vivo was evaluated in a mouse infection model: IFN-γ pretreatment but not posttreatment conferred significant protection to mice against lethal SFTSV infection, confirming IFN-γ's anti-SFTSV effect and viral antagonism against IFN-γ after the infection establishment. These findings present a picture of virus-host arm race and may promote not only the understanding of virus-host interactions and viral pathogenesis but also the development of antiviral therapeutics
Neuroprotective effects of electroacupuncture on hypoxic-ischemic encephalopathy in newborn rats association with increased expression of mTOR
In this study, we observed the therapeutic effects of acupuncture and investigated the underlying molecular mechanisms by constructed a hypoxic-ischemic encephalopathy (HIE) animal model. In the electroacupuncture group, mTOR expression increased since 1d, and continued to rise till the 21st day. All of the differences were significantly (p<0.05 vs the model group). Meanwhile, mTOR expression was analyzed by Western blotting. There was statistical significance between the model group and the electroacupuncture group in the four time periods (p<0.05). The results provide evidence that electroacupuncture treatment protected cortical neurons against HIE-induced neuronal damage and degenerative changes in rats, which is in association with activation of mTOR both at the mRNA level and protein level. Therefore, electroacupuncture may become a potential therapeutic strategy for HIE of newborn.
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