1,827 research outputs found
A “Double-Multi” Model for Electromigration of Lithiums and Chlorides in ASR Affected Concrete
Existing reinforced concrete structures experience severe durability degradation when subjected to alkali– silica reaction (ASR) and chloride attack. A special electrochemical rehabilitation treatment, containing lithium compound anolyte, has been developed to drive lithium ions into concrete as well as remove chlorides simultaneously, for mitigating both the ASR-induced cracks and the chloride-induced corrosion. Good performance of introduced lithiums in controlling ASR-induced expansion has already been proved. Unfortunately, the migration mechanism of lithium in concrete under an external electric field is seldom investigated in existing literature. In this study, with help of the “double-multi” model, the efficiency of impregnation of lithium ions and simultaneously the removal of chloride ions through a specific electrochemical treatment are numerically evaluated, which results into the distribution profiles of all typical ionic species. The heterogeneous concrete model examines the aggregate effect, especially on the interaction with lithiums which are supposed to mitigate ASR. The ionic interaction between different species and the electrochemical reaction at electrodes are also considered. Through a relative thorough modelling of multi-phase and multi-species, a systemic parametric analysis based on a series of significant factors during electrochemical treatment (e.g., current density, treatment time, temperature, cathode position and concentration of lithium solution) reveals some important tendencies of ionic electromigration in concrete, which are supposed to guide the field application
Probing Thermal Electrons in GRB Afterglows
Particle-in-cell simulations have unveiled that shock-accelerated electrons
do not follow a pure power-law distribution, but have an additional low-energy
"thermal" part, which owns a considerable portion of the total energy of
electrons. Investigating the effects of these thermal electrons on gamma-ray
burst (GRB) afterglows may provide valuable insights into the particle
acceleration mechanisms. We solve the continuity equation of electrons in the
energy space, from which multi-wavelength afterglows are derived by
incorporating processes including synchrotron radiation, synchrotron
self-absorption, synchrotron self-Compton scattering, and gamma-gamma
annihilation. First, there is an underlying positive correlation between
temporal and spectral indices due to the cooling of electrons. Moreover,
thermal electrons would result in the simultaneous non-monotonic variation in
both spectral and temporal indices at multi-wavelength, which could be
individually recorded by the 2.5-meter Wide Field Survey Telescope and Vera
Rubin Observatory Legacy Survey of Space and Time (LSST). The thermal electrons
could also be diagnosed from afterglow spectra by synergy observation in the
optical (with LSST) and X-ray bands (with the Microchannel X-ray Telescope on
board the Space Variable Objects Monitor). Finally, we use Monte Carlo
simulations to obtain the distribution of peak flux ratio () between
soft and hard X-rays, and of the time delay () between peak times of
soft X-ray and optical light curves. The thermal electrons significantly raise
the upper limits of both and . Thus the distribution of
GRB afterglows with thermal electrons is more dispersive in the plane.Comment: 17 pages, 15 figure
2-Amino-5-methylpyridinium 3-aminobenzoate
In the title compound, C6H9N2
+·C7H6NO2
−, the H atom of the N—H group and an H atom of the 2-amino group from the cation are involved in intermolecular N—H⋯O hydrogen bonds with the O atoms of the carboxylate group of the anion, forming an R
2
2(8) ring motif. These ring motifs are, in turn, connected by further N—H⋯O hydrogen bonds, forming a two-dimensional network. The crystal structure is further stabilized by π⋯π stacking interactions involving the benzene and pyridinium rings with a centroid–centroid distance of 3.7594 (8) Å
Core Collapse Supernova Explosions in Active Galactic Nucleus Accretion Disks
Astrophysical events that occur in active galactic nucleus (AGN) disks are
believed to differ significantly from the ordinary in the interstellar medium.
We show that stars located in the outer region of the AGN disk would explode
near the original migration starting points instead of being accreted by the
central supermassive black hole due to the effect of viscosity. AGN disks
provide a dense environment for supernova (SN) explosions, which inevitably
involve ejecta-disk interactions. In this paper, we investigate the light
curves (LCs) of core-collapse SN exploded in AGN disks. In addition to the
fundamental energy source of ---- decay reaction powering the SN LCs, the forward-reverse shock
produced during interactions may contribute significantly to the observed flux.
If the stellar winds manage to create a cavity surrounded by a shell near the
star before the SN explosion, the ejecta-winds-disk configurations are
expected. We present various SN LCs from different types of progenitors and
find that the SN LCs are dominated by the radiation of ejecta-disk
interaction-induced shocks. The resulting SNe in the AGN disk is a promising
transient source for UV and optical band detection by the Neil Gehrels Swift
Observatory (Swift), the Ultraviolet Explorer (UVEX) and wide field survey
telescopes such as Ultraviolet Transient Astronomy Satellite (ULTRASAT), Wide
Field Survey Telescope (WFST) and Legacy Survey of Space and Time (LSST) at the
Vera C. Rubin Observatory. These detections could aid in the investigation of
AGN discs and the associated high-energy transient occurrences.Comment: 16 pages, 6 figures, 2 tables, matches the published version in Ap
Cell nucleus elastography with the adjoint-based inverse solver
Background and Objectives: The mechanics of the nucleus depends on cellular
structures and architecture, and impact a number of diseases. Nuclear mechanics
is yet rather complex due to heterogeneous distribution of dense
heterochromatin and loose euchromatin domains, giving rise to spatially
variable stiffness properties. Methods: In this study, we propose to use the
adjoint-based inverse solver to identify for the first time the nonhomogeneous
elastic property distribution of the nucleus. Inputs of the inverse solver are
deformation fields measured with microscopic imaging in contracting
cardiomyocytes. Results: The feasibility of the proposed method is first
demonstrated using simulated data. Results indicate accurate identification of
the assumed heterochromatin region, with a maximum relative error of less than
5%. We also investigate the influence of unknown Poisson's ratio on the
reconstruction and find that variations of the Poisson's ratio in the range
[0.3-0.5] result in uncertainties of less than 15% in the identified stiffness.
Finally, we apply the inverse solver on actual deformation fields acquired
within the nuclei of two cardiomyocytes. The obtained results are in good
agreement with the density maps obtained from microscopy images. Conclusions:
Overall, the proposed approach shows great potential for nuclear elastography,
with promising value for emerging fields of mechanobiology and mechanogenetics
Improved colonic inflammation by nervonic acid via inhibition of NF-κB signaling pathway of DSS-induced colitis mice
Background: Nervonic acid (C24:1Δ15, 24:1 ω-9, cis-tetracos-15-enoic acid; NA), a long-chain monounsaturated fatty
acid, plays an essential role in prevention of metabolic diseases, and immune regulation, and has anti-inflammatory
properties. As a chronic, immune-mediated inflammatory disease, ulcerative colitis (UC) can affect the large intestine.
The influences of NA on UC are largely unknown.
Purpose: The present study aimed to decipher the anti-UC effect of NA in the mouse colitis model. Specifically, we
wanted to explore whether NA can regulate the levels of inflammatory factors in RAW264.7 cells and mouse
colitis model.
Methods: To address the above issues, the RAW264.7 cell inflammation model was established by lipopolysaccharide
(LPS), then the inflammatory factors tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β
(IL-1β), and Interleukin-10 (IL-10) were detected by Enzyme-linked immunosorbent assay (ELISA). The therapeutic
effects of NA for UC were evaluated using C57BL/6 mice gavaged dextran sodium sulfate (DSS). Hematoxylin and
eosin (H&E) staining, Myeloperoxidase (MPO) kit assay, ELISA, immunofluorescence assay, and LC-MS/MS were
used to assess histological changes, MPO levels, inflammatory factors release, expression and distribution of intestinal
tight junction (TJ) protein ZO-1, and metabolic pathways, respectively. The levels of proteins involved in
the nuclear factor kappa-B (NF-κB) pathway in the UC were investigated by western blotting and RT-qPCR.
Results: In vitro experiments verified that NA could reduce inflammatory response and inhibit the activation of
key signal pathways associated with inflammation in LPS-induced RAW264.7 cells. Further, results from the
mouse colitis model suggested that NA could restore intestinal barrier function and suppress NF-κB signal
pathways to ameliorate DSS-induced colitis. In addition, untargeted metabolomics analysis of NA protection
against UC found that NA protected mice from colitis by regulating citrate cycle, amino acid metabolism, pyrimidine
and purine metabolism.
Conclusion: These results suggested that NA could ameliorate the secretion of inflammatory factors, suppress the
NF-κB signaling pathway, and protect the integrity of colon tissue, thereby having a novel role in prevention or
treatment therapy for UC. This work for the first time indicated that NA might be a potential functional food
ingredient for preventing and treating inflammatory bowel disease (IBD).National Key Research and Development, China | Ref. 2021YFE0109200Universidade de Vigo/CISUGThe Provincial Major Scientific and Technological Innovation Project of Shandong | Ref. 2022TZXD0029The Provincial Major Scientific and Technological Innovation Project of Shandong | Ref. 2022TZXD0032The Provincial Major Scientific and Technological Innovation Project of Shandong | Ref. 2021SFGC0904The Provincial Major Scientific and Technological Innovation Project of Shandong | Ref. 2021TZX D004The Natural Science Foundation of Shandong | Ref. ZR2020MH401The Natural Science Foundation of Shandong | Ref. ZR2021QH351National Wheat Industry Technology System of China | Ref. CARS-03–2
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