16,831 research outputs found
Positive exchange bias in ferromagnetic La0.67Sr0.33MnO3 / SrRuO3 bilayers
Epitaxial La0.67Sr0.33MnO3 (LSMO)/ SrRuO3 (SRO) ferromagnetic bilayers have
been grown on (001) SrTiO3 (STO) substrates by pulsed laser deposition with
atomic layer control. We observe a shift in the magnetic hysteresis loop of the
LSMO layer in the same direction as the applied biasing field (positive
exchange bias). The effect is not present above the Curie temperature of the
SRO layer (), and its magnitude increases rapidly as the temperature is lowered
below . The direction of the shift is consistent with an antiferromagnetic
exchange coupling between the ferromagnetic LSMO layer and the ferromagnetic
SRO layer. We propose that atomic layer charge transfer modifies the electronic
state at the interface, resulting in the observed antiferromagnetic interfacial
exchange coupling.Comment: accepted to Applied Physics Letter
Possible and Molecular states in a chiral quark model
We perform a systematic study of the bound state problem of and
systems by using effective interaction in our chiral quark model.
Our results show that both the interactions of and states
are attractive, which consequently result in
and bound states.Comment: arXiv admin note: substantial text overlap with arXiv:1204.395
SUMO Modification Stabilizes Enterovirus 71 Polymerase 3D To Facilitate Viral Replication.
Accumulating evidence suggests that viruses hijack cellular proteins to circumvent the host immune system. Ubiquitination and SUMOylation are extensively studied posttranslational modifications (PTMs) that play critical roles in diverse biological processes. Cross talk between ubiquitination and SUMOylation of both host and viral proteins has been reported to result in distinct functional consequences. Enterovirus 71 (EV71), an RNA virus belonging to the family Picornaviridae, is a common cause of hand, foot, and mouth disease. Little is known concerning how host PTM systems interact with enteroviruses. Here, we demonstrate that the 3D protein, an RNA-dependent RNA polymerase (RdRp) of EV71, is modified by small ubiquitin-like modifier 1 (SUMO-1) both during infection and in vitro Residues K159 and L150/D151/L152 were responsible for 3D SUMOylation as determined by bioinformatics prediction combined with site-directed mutagenesis. Also, primer-dependent polymerase assays indicated that mutation of SUMOylation sites impaired 3D polymerase activity and virus replication. Moreover, 3D is ubiquitinated in a SUMO-dependent manner, and SUMOylation is crucial for 3D stability, which may be due to the interplay between the two PTMs. Importantly, increasing the level of SUMO-1 in EV71-infected cells augmented the SUMOylation and ubiquitination levels of 3D, leading to enhanced replication of EV71. These results together suggested that SUMO and ubiquitin cooperatively regulated EV71 infection, either by SUMO-ubiquitin hybrid chains or by ubiquitin conjugating to the exposed lysine residue through SUMOylation. Our study provides new insight into how a virus utilizes cellular pathways to facilitate its replication. IMPORTANCE: Infection with enterovirus 71 (EV71) often causes neurological diseases in children, and EV71 is responsible for the majority of fatalities. Based on a better understanding of interplay between virus and host cell, antiviral drugs against enteroviruses may be developed. As a dynamic cellular process of posttranslational modification, SUMOylation regulates global cellular protein localization, interaction, stability, and enzymatic activity. However, little is known concerning how SUMOylation directly influences virus replication by targeting viral polymerase. Here, we found that EV71 polymerase 3D was SUMOylated during EV71 infection and in vitro Moreover, the SUMOylation sites were determined, and in vitro polymerase assays indicated that mutations at SUMOylation sites could impair polymerase synthesis. Importantly, 3D is ubiquitinated in a SUMOylation-dependent manner that enhances the stability of the viral polymerase. Our findings indicate that the two modifications likely cooperatively enhance virus replication. Our study may offer a new therapeutic strategy against virus replication
The signal of in nucleon-antinucleon scattering
We study the production of at a nucleon-antinucleon scattering
experiment. Considering the PANDA experiment to be an ideal platform to explore
the production of the charmonium and charmonim-like states, we suggest the
forthcoming PANDA experiment to pay attention to the production of
.Comment: 6 pages, 15 figures. Published version in EPJ
Electric-field-induced phase transition of <001> oriented Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals
oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were poled under
different electric fields, i.e. Epoling=4 kV/cm and Epoling=13 kV/cm. In
addition to the temperature-dependent dielectric constant measurement, X-ray
diffraction was also used to identify the poling-induced phase transitions.
Results showed that the phase transition significantly depends on the poling
intensity. A weaker field (Epoling=4 kV/cm) can overcome the effect of random
internal field to perform the phase transition from rhombohedral ferroelectric
state with short range ordering (microdomain) FESRO to rhombohedral
ferroelectric state with long range ordering (macrodomain) FElRO. But the
rhombohedral ferroelectric to tetragonal ferroelectric phase transition
originating from to polarization rotation can only be induced by a
stronger field (Epoling=13 kV/cm). The sample poled at Epoling=4 kV/cm showed
higher piezoelectric constant, d33>1500 pC/N, than the sample poled at
Epoling=13 kV/cm.Comment: 7 pages, 2 figure
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