139 research outputs found
Recommended from our members
Disruption of Persistent Nociceptive Behavior in Rats with Learning Impairment
Despite the subjective nature of pain experience with cognitive and affective dimensions, preclinical pain research has largely focused on its sensory dimension. Here, we examined the relationship between learning/memory and nociceptive behavior in rats with combined learning impairment and persistent nociception. Learning impairment was induced by bilateral hippocampal injection of a mixed Aβ solution, whereas persistent nociception produced in these rats by complete Freund’s adjuvant-induced ankle inflammation. Those rats with learning impairment showed a diminished development of thermal hyperalgesia and mechanical allodynia and a shorter time course of nociceptive behavior without alteration of their baseline nociceptive threshold. In rats with pre-established hyperalgesia and allodynia due to ankle inflammation, bilateral intra-hippocampal injection of cycloheximide (a protein synthesis inhibitor) promoted the earlier recovery of nociceptive behavior. Moreover, expression of Aβ, NR1 subunit of the N-methyl-D-aspartate receptor, and protein kinase Cγ was upregulated, whereas the choline acetyl transferase expression was downregulated, in the hippocampus, thalamus, amygdala, and/or spinal cord of rats with combined learning impairment and persistent nociception. The data indicate that learning impairment could disrupt the response to a state of persistent nociception, suggesting an important role for cognitive maladaptation in the mechanisms of chronic pain. These results also suggest that a preclinical model of combined learning impairment and persistent nociception may be useful to explore the brain mechanisms underlying the transition from acute to chronic pain
Magnetic Borophenes from an Evolutionary Search
A computational methodology based on ab initio evolutionary algorithms and spin-polarized density functional theory was developed to predict two-dimensional magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A metastable borophene with nonzero thickness is an antiferromagnetic semiconductor from first-principles calculations, and can be further tuned into a half-metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for magnetism, but also result in an out-of-plane negative Poisson\u27s ratio under uniaxial tension, making it the first elemental material possessing auxetic and magnetic properties simultaneously
Analysis of corrections to the eikonal approximation
Various corrections to the eikonal approximations are studied for two- and
three-body nuclear collisions with the goal to extend the range of validity of
this approximation to beam energies of 10 MeV/nucleon. Wallace's correction
does not improve much the elastic-scattering cross sections obtained at the
usual eikonal approximation. On the contrary, a semiclassical approximation
that substitutes the impact parameter by a complex distance of closest approach
computed with the projectile-target optical potential efficiently corrects the
eikonal approximation. This opens the possibility to analyze data measured down
to 10 MeV/nucleon within eikonal-like reaction models.Comment: 10 pages, 8 figure
Metabolomics and transcriptomics analyses provide new insights into the nutritional quality during the endosperm development of different ploidy rice
Autotetraploid rice is developed from diploid rice by doubling the chromosomes, leading to higher nutritional quality. Nevertheless, there is little information about the abundances of different metabolites and their changes during endosperm development in autotetraploid rice. In this research, two different kinds of rice, autotetraploid rice (AJNT-4x) and diploid rice (AJNT-2x), were subjected to experiments at various time points during endosperm development. A total of 422 differential metabolites, were identified by applying a widely used metabolomics technique based on LC-MS/MS. KEGG classification and enrichment analysis showed the differences in metabolites were primarily related to biosynthesis of secondary metabolites, microbial metabolism in diverse environments, biosynthesis of cofactors, and so on. Twenty common differential metabolites were found at three developmental stages of 10, 15 and 20 DAFs, which were considered the key metabolites. To identify the regulatory genes of metabolites, the experimental material was subjected to transcriptome sequencing. The DEGs were mainly enriched in starch and sucrose metabolism at 10 DAF, and in ribosome and biosynthesis of amino acids at 15 DAF, and in biosynthesis of secondary metabolites at 20 DAF. The numbers of enriched pathways and the DEGs gradually increased with endosperm development of rice. The related metabolic pathways of rice nutritional quality are cysteine and methionine metabolism, tryptophan metabolism, lysine biosynthesis and histidine metabolism, and so on. The expression level of the genes regulating lysine content was higher in AJNT-4x than in AJNT-2x. By applying CRISPR/Cas9 gene-editing technology, we identified two novel genes, OsLC4 and OsLC3, negatively regulated lysine content. These findings offer novel insight into dynamic metabolites and genes expression variations during endosperm development of different ploidy rice, which will aid in the creation of rice varieties with better grain nutritional quality
Prediction of high-Tc superconductivity in ternary lanthanum borohydrides
The study of superconductivity in compressed hydrides is of great interest
due to measurements of high critical temperatures (Tc) in the vicinity of room
temperature, beginning with the observations of LaH10 at 170-190 GPa. However,
the pressures required for synthesis of these high Tc superconducting hydrides
currently remain extremely high. Here we show the investigation of crystal
structures and superconductivity in the La-B-H system under pressure with
particle-swarm intelligence structure searches methods in combination with
first-principles calculations. Structures with six stoichiometries, LaBH,
LaBH3, LaBH4, LaBH6, LaBH7 and LaBH8, were predicted to become stable under
pressure. Remarkably, the hydrogen atoms in LaBH8 were found to bond with B
atoms in a manner that is similar to that in H3S. Lattice dynamics calculations
indicate that LaBH7 and LaBH8 become dynamically stable at pressures as low as
109.2 and 48.3 GPa, respectively. Moreover, the two phases were predicted to be
superconducting with a critical temperature (Tc) of 93 K and 156 K at 110 GPa
and 55 GPa, respectively. Our results provide guidance for future experiments
targeting new hydride superconductors with both low synthesis pressures and
high Tc.Comment: 16 pages, 5 figures
Theory and Experiments of Pressure-Tunable Broadband Light Emission from Self-Trapped Excitons in Metal Halide Crystals
Hydrostatic pressure has been commonly applied to tune broadband light
emissions from self-trapped excitons (STE) in perovskites for producing white
light and study of basic electron-phonon interactions. However, a general
theory is still lacking to understand pressure-driven evolution of STE
emissions. In this work we first identify a theoretical model that predicts the
effect of hydrostatic pressure on STE emission spectrum, we then report the
observation of extremely broadband photoluminescence emission and its wide
pressure spectral tuning in 2D indirect bandgap CsPb2Br5 crystals. An excellent
agreement is found between the theory and experiment on the peculiar
experimental observation of STE emission with a nearly constant spectral
bandwidth but linearly increasing energy with pressure below 2 GPa. Further
analysis by the theory and experiment under higher pressure reveals that two
types of STE are involved and respond differently to external pressure. We
subsequently survey published STE emissions and discovered that most of them
show a spectral blue-shift under pressure, as predicted by the theory. The
identification of an appropriate theoretical model and its application to STE
emission through the coordinate configuration diagram paves the way for
engineering the STE emission and basic understanding of electron-phonon
interaction
- …