5,608 research outputs found
Ground-state properties via machine learning quantum constraints
Ground-state properties are central to our understanding of quantum many-body
systems. At first glance, it seems natural and essential to obtain the ground
state before analyzing its properties; however, its exponentially large Hilbert
space has made such studies costly, if not prohibitive, on sufficiently large
system sizes. Here, we propose an alternative strategy based upon the
expectation values of an ensemble of operators and the elusive yet vital
quantum constraints between them, where the search for ground-state properties
simply equates to simple, classical constrained minimization. These quantum
constraints are generally obtainable via machine learning on a large number of
sample quantum many-body states systematically consistent with physical
presumptions. We showcase our perspective on 1D fermion chains and spin chains
for applicability, effectiveness, and several unique advantages, especially for
strongly correlated systems, thermodynamic-limit systems, property designs,
etc.Comment: 6 pages, 4 figure
The Hop-Like Stress-Induced Protein 1 Cochaperone is a Novel Cell-Intrinsic Restriction Factor for Mitochondrial Tombusvirus Replication
Recent genome-wide screens reveal that the host cells express an arsenal of proteins that inhibit replication of plus-stranded RNA viruses by functioning as cell-intrinsic restriction factors of viral infections. One group of cell-intrinsic restriction factors against tombusviruses contains tetratricopeptide repeat (TPR) domains that directly interact with the viral replication proteins. In this paper, we find that the TPR domain-containing Hop-like stress-inducible protein 1 (Sti1p) cochaperone selectively inhibits the mitochondrial membrane-based replication of Carnation Italian ringspot tombusvirus (CIRV). In contrast, Sti1/Hop does not inhibit the peroxisome membrane-based replication of the closely related Tomato bushy stunt virus (TBSV) or Cucumber necrosis virus (CNV) in a yeast model or in plants. Deletion of STI1 in yeast leads to up to a 4-fold increase in CIRV replication, and knockdown of the orthologous Hop cochaperone in plants results in a 3-fold increase in CIRV accumulation. Overexpression of Sti1p derivatives in yeast reveals that the inhibitory function depends on the TPR1 domain known to interact with heat shock protein 70 (Hsp70), but not on the TPR2 domain interacting with Hsp90. In vitro CIRV replication studies based on isolated mitochondrial preparations and purified recombinant proteins has confirmed that Sti1p, similar to the TPR-containing Cyp40-like Cpr7p cyclophilin and the Ttc4 oncogene-like Cns1 cochaperone, is a strong inhibitor of CIRV replication. Sti1p interacts and colocalizes with the CIRV replication proteins in yeast. Our findings indicate that the TPR-containing Hop/Sti1 cochaperone could act as a cell-intrinsic virus restriction factor of the mitochondrial CIRV, but not against the peroxisomal tombusviruses in yeast and plants.
IMPORTANCE: The host cells express various cell-intrinsic restriction factors that inhibit the replication of plus-stranded RNA viruses. In this paper, the authors find that the Hop-like stress-inducible protein 1 (Sti1p) cochaperone selectively inhibits the mitochondrial membrane-based replication of Carnation Italian ringspot tombusvirus (CIRV) in yeast. Deletion of STI1 in yeast or knockdown of the orthologous Hop cochaperone in plants leads to increased CIRV replication. In addition, overexpression of Sti1p derivatives in yeast reveals that the inhibitory function depends on the TPR1 domain known to interact with heat shock protein 70 (Hsp70), but not on the TPR2 domain interacting with Hsp90. In vitro CIRV replication studies based on isolated mitochondrial preparations and purified recombinant proteins have confirmed that Sti1p is a strong inhibitor of CIRV replication. The authors\u27 findings reveal that the Hop/Sti1 cochaperone could act as a cell-intrinsic restriction factor against the mitochondrial CIRV, but not against the related peroxisomal tombusviruses
A tunable plasmonic refractive index sensor with nanoring-strip graphene arrays
In this paper, a tunable plasmonic refractive index sensor with
nanoring-strip graphene arrays is numerically investigated by the finite
difference time domain (FDTD) method. The simulation results exhibit that by
changing the sensing medium refractive index nmed of the structure, the sensing
range of the system is large. By changing the doping level ng, we noticed that
the transmission characteristics can be adjusted flexibly. The resonance
wavelength remains entirely the same and the transmission dip enhancement over
a big range of incidence angles [0,45] for both TM and TE polarizations, which
indicates that the resonance of the graphene nanoring-strip arrays is
insensitive to angle polarization. The above results are undoubtedly a new way
to realize various tunable plasmon devices, and may have a great application
prospect in biosensing, detection and imaging
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