4,652 research outputs found
Quantifying the Influence of Component Failure Probability on Cascading Blackout Risk
The risk of cascading blackouts greatly relies on failure probabilities of
individual components in power grids. To quantify how component failure
probabilities (CFP) influences blackout risk (BR), this paper proposes a
sample-induced semi-analytic approach to characterize the relationship between
CFP and BR. To this end, we first give a generic component failure probability
function (CoFPF) to describe CFP with varying parameters or forms. Then the
exact relationship between BR and CoFPFs is built on the abstract
Markov-sequence model of cascading outages. Leveraging a set of samples
generated by blackout simulations, we further establish a sample-induced
semi-analytic mapping between the unbiased estimation of BR and CoFPFs.
Finally, we derive an efficient algorithm that can directly calculate the
unbiased estimation of BR when the CoFPFs change. Since no additional
simulations are required, the algorithm is computationally scalable and
efficient. Numerical experiments well confirm the theory and the algorithm
Reconstructing Three-decade Global Fine-Grained Nighttime Light Observations by a New Super-Resolution Framework
Satellite-collected nighttime light provides a unique perspective on human
activities, including urbanization, population growth, and epidemics. Yet,
long-term and fine-grained nighttime light observations are lacking, leaving
the analysis and applications of decades of light changes in urban facilities
undeveloped. To fill this gap, we developed an innovative framework and used it
to design a new super-resolution model that reconstructs low-resolution
nighttime light data into high resolution. The validation of one billion data
points shows that the correlation coefficient of our model at the global scale
reaches 0.873, which is significantly higher than that of other existing models
(maximum = 0.713). Our model also outperforms existing models at the national
and urban scales. Furthermore, through an inspection of airports and roads,
only our model's image details can reveal the historical development of these
facilities. We provide the long-term and fine-grained nighttime light
observations to promote research on human activities. The dataset is available
at \url{https://doi.org/10.5281/zenodo.7859205}
DNA repair and synthetic lethality
Tumors often have DNA repair defects, suggesting additional inhibition of other DNA repair pathways in tumors may lead to synthetic lethality. Accumulating data demonstrate that DNA repair-defective tumors, in particular homologous recombination (HR), are highly sensitive to DNA-damaging agents. Thus, HR-defective tumors exhibit potential vulnerability to the synthetic lethality approach, which may lead to new therapeutic strategies. It is well known that poly (adenosine diphosphate (ADP)-ribose) polymerase (PARP) inhibitors show the synthetically lethal effect in tumors defective in BRCA1 or BRCA2 genes encoded proteins that are required for efficient HR. In this review, we summarize the strategies of targeting DNA repair pathways and other DNA metabolic functions to cause synthetic lethality in HR-defective tumor cells
Modulation of the thermodynamic, kinetic and magnetic properties of the hydrogen monomer on graphene by charge doping
The thermodynamic, kinetic and magnetic properties of the hydrogen monomer on
doped graphene layers were studied by ab initio simulations. Electron doping
was found to heighten the diffusion potential barrier, while hole doping lowers
it. However, both kinds of dopings heighten the desorption potential barrier.
The underlying mechanism was revealed by investigating the effect of doping on
the bond strength of graphene and on the electron transfer and the coulomb
interaction between the hydrogen monomer and graphene. The kinetic properties
of H and D monomers on doped graphene layers during both the annealing process
(annealing time 300 s) and the constant-rate heating process (heating
rate 1.0 K/s) were simulated. Both electron and hole dopings were
found to generally increase the desorption temperatures of hydrogen monomers.
Electron doping was found to prevent the diffusion of hydrogen monomers, while
the hole doping enhances their diffusion. Macroscopic diffusion of hydrogen
monomers on graphene can be achieved when the doping-hole density reaches
cm. The magnetic moment and exchange splitting were
found to be reduced by both electron and hole dopings, which was explained by a
simple exchange model. The study in this report can further enhance the
understanding of the interaction between hydrogen and graphene and is expected
to be helpful in the design of hydrogenated-graphene-based devices.Comment: Submitte
Expressions of Neuregulin 1β and ErbB4 in Prefrontal Cortex and Hippocampus of a Rat Schizophrenia Model Induced by Chronic MK-801 Administration
Recent human genetic studies and postmortem brain examinations of schizophrenia patients strongly indicate that dysregulation of NRG1 and ErbB4 may be important pathogenic factors of schizophrenia. However, this hypothesis has not been validated and fully investigated in animal models of schizophrenia. In this study we quantitatively examined NRG1 and ErbB4 protein expressions by immunohistochemistry and Western blot in the brain of a rat schizophrenia model induced by chronic administration of MK-801 (a noncompetitive NMDA receptor antagonist). Our data showed that NRG1β and ErbB4 expressions were significantly increased in the rat prefrontal cortex and hippocampus but in different subregions. These findings suggest that altered expressions of NRG1 and ErbB4 might be attributed to the schizophrenia. Further study in the role and mechanism of NRG1 and ErbB4 may lead to better understanding of the pathophysiology for this disorder
catena-Poly[di-μ1,1-azido-(1,10-phenanthroline)cadmium(II)]
The asymmetric unit of the title CdII compound, [Cd(N3)2(C12H8N2)]n, contains a CdII atom, located on a twofold axis passing through the middle of the phenanthroline molecule, one azide ion and half of a 1,10-phenanthroline molecule. The CdII atom exhibits a distorted octahedral coordination including one chelating 1,10-phenanthroline ligand and four azide ligands. The crystal structure features chains along the c direction in which azide groups doubly bridge two adjacent CdII atoms in an end-on (EO) mode. Interchain π–π stacking interactions, with centroid–centroid separations of 3.408 (2) Å between the central aromatic rings of 1,10-phenanthroline molecules, lead to a supramolecular sheet parallel to the bc plane
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