Proton inelastic scattering experiments at energy Ep=200 MeV and a spectrometer scattering angle of 0° were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance ...(IVGDR). Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour may be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA) calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data.
Fatigue life scattering and prediction of Inconel 718 fabricated by selective laser melting were investigated using miniature specimen tests combined with statistical method and machine learning ...algorithms. The relationship between pore features and fatigue life of the selective laser melting-fabricated specimens was analyzed statistically. The results show that the increase in the size and/or the number of the pores in the specimens, and/or the decrease in the distance from a pore center to the specimen surface degraded the fatigue life. The machine learning and statistical analysis results reveal that the fatigue life are most closely related to the location of the pores compared with the size and the number of pores in the specimens. The finding may provide a potential way to get high-throughput statistical data helping in evaluating defect-dominated scattering and prediction of fatigue life of additive manufactured metallic parts using miniature specimen testing assisted by the machine learning approach.
Plastic deformation and fracture behavior of two different types of Cu/X (X
=
Au, Cr) multilayers subjected to tensile stress were investigated via three-point bending experiments. It was found that ...the plastic deformation ability and fracture mode depended on layer thickness and interface/boundary. The Cu/Au multilayer showed significant features of plastic flow before fracture, and such plasticity was gradually suppressed by premature unstable shearing across the layer interface with decreasing layer thickness. In comparison, Cu/Cr multilayers were prone to a quasi-brittle normal fracture with decreasing layer thickness. Both experimental observations and theoretical analyses revealed differences in plasticity and fracture mode between the two types of metallic multilayers and the relevant physical mechanism transition due to length scale constraint and interface/boundary blocking of dislocation motion.
Dynamic impact tests were carried out on red sandstone specimens with single bonded planar joint at various angles based on a split Hopkinson pressure bar (SHPB), to investigate the stress wave ...propagation and fracturing evolution of the specimens comprising two blocks. The results indicate that the bonded joint will reduce the dynamic strength from 3.10% to 32.13% compared with the intact specimen. The larger the joint angle is, the more significant the wave attenuation is. The variation trend of energy absorption rate is similar to the tendency of the dynamic strength, showing a positive correlation between the energy absorption rate and the dynamic strength. Tensile cracks dominate the specimen failure behavior during the dynamic fracturing process by observing the images captured by a high speed camera, leading to the slabbing failure with different degrees of slippage along the joint surface. In addition, it is found that the variation tendency of dynamic strength based on the experimental results is consistent with the theoretical analysis.
The aim of this study is to investigate the influence of extreme temperatures (from 25° to 1000°C) followed by two cooling methods (both rapid and slow) on the mechanical behaviour of clay-rich ...Hawkesbury sandstone under uniaxial conditions. A separate set of samples was tested under continuous heating conditions without cooling to compare the results with those for cooled samples. The stress-strain behaviours were analysed, with simultaneous recording of the acoustic signals and the failure mode. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were also performed to understand the changes observed in the mechanical tests. According to the results, the mechanical, mineralogical and microstructural characteristics of clay-rich sandstones are largely dependent on the thermal field, and, regardless of the cooling method, the compressive strength, Young’s modulus, crack initiation stress and crack damage stress appear to increase when the preheating temperature increase from 25 °C to 600 °C and decrease with increasing preheating temperature for temperatures greater than 600 °C. The SEM results confirmed the transformation of the initial hexagonal kaolinite mineral structure into a fibre-like (needle-type) mineral structure, which is believed to be the reason for the strengthening phenomenon observed at preheated temperatures between 25 °C and 600 °C. Progressive dehydroxylisation of kaolinite in the sandstone cement at temperatures beyond 600 °C was found to be the main reason for the weakening and softening of the sandstone which was observed with increasing preheated temperature beyond 600 °C. Apart from these mineral degradations, induced inter-granular and intra-granular cracks at preheated temperatures beyond 600 °C also play a dominant role in the weakening of clay-rich sandstone.
A comprehensive characterization of pore-fracture alteration of coal after exposure to CO2 is critical to CO2 sequestration in deep coal seams. In order to investigate the effect of supercritical CO2 ...(ScCO2) on pore-fracture structure of coal, three coal samples with different ranks (lignite, bituminous and anthracite) were saturated with ScCO2 for 14 days at 50 ℃ temperature and 10 MPa pressure. Multiscale characterization techniques, i.e. low-temperature N2 adsorption, mercury intrusion porosimetry (MIP) and X-ray CT scanning, were adopted to capture the changes of pore-fracture characteristics from nanometre to millimetre. Results show mesopores and macropores were well-developed in lignite due to its low maturity, whereas fractures were well developed in bituminous and anthracite. Lignite was relatively non-reactive with slight changes in mesopores and macropores as determined by MIP and N2 adsorption. An increase of macropore volume in lignite was observed from CT scanning, which possibly resulted from the shrinkage of coal matrix and collapse of pores caused by the drying effect of ScCO2. However, the induced macroporosity was not well-connected. The mesopores, macropores and fractures increased after ScCO2 treatment in bituminous and anthracite. Swelling-induced cracking, mineral and maceral dissolutions were the main causes for porosity increase in bituminous and anthracite and the induced fracture networks were well-connected. The fractal dimension of pore in three coals reduced after ScCO2 treatment, which indicates the surface of pore surface became smooth and homogeneous. Overall, ScCO2 has great potential of increasing coal porosity and enhancing coal permeability under unconstrained conditions, although the effect is rank dependent, which provides additional pathways for carbon storage and methane recovery.
Excessive fat accretion is a crucial problem during broiler production. Abdominal fat weight (AbFW) and abdominal fat percentage (AbFP) are major phenotypic indices of fat traits. The present study ...used F2 females derived from a cross between Beijing-You and Cobb-Vantress chickens. Cohorts with extreme AbFP and AbFW phenotypes were chosen to construct high- and low-abdominal fat libraries (HAbF and LAbF, respectively) to investigate the expression profiles by RNA-sequencing and microRNA (miRNA)-sequencing. Compared with the LAbF library, 62 differentially expressed miRNAs (DEMs) and 303 differentially expressed genes (DEGs) were identified in the HAbF birds. Integrated analysis of DEMs and DEGs showed that a total of 106 DEGs were identified as target genes for the 62 DEMs. These genes were designated as intersection genes, and 11 of these genes are involved in lipid metabolism pathways. The miRNA gga-miR-19b-3p accelerated the proliferation of preadipocytes, as well as adipocyte differentiation, by down- regulating ACSL1. These findings suggest that some strong candidate miRNAs and genes, important in relation to abdominal adipose deposition, were identified by the integrated analysis of DEMs and DEGs. These findings add to our current understanding of the molecular genetic controls underlying abdominal adipose accumulation in chickens.
Although the serological antibody responses induced by SARS-CoV-2 vaccines are well characterized, little is known about their ability to elicit mucosal immunity.
This study aims to examine and ...compare the mucosal and systemic responses of recipients of two different vaccination platforms: mRNA (Comirnaty) and inactivated virus (CoronaVac).
Serial blood and nasal epithelial lining fluid (NELF) samples were collected from the recipients of either Comirnaty or CoronaVac. The plasma and NELF immunoglobulins A and G (IgA and IgG) specific to SARS-CoV-2 S1 protein (S1) and their neutralization effects were quantified.
Comirnaty induced nasal S1-specific immunoglobulin responses, which were evident as early as 14 ± 2 days after the first dose. In 64% of the subjects, the neutralizing effects of NELF persisted for at least 50 days. Moreover, 85% of Comirnaty recipients exhibited S1-specific IgA and IgG responses in plasma by 14 ± 2 days after the first dose. By 7 ± 2 days after the booster, all plasma samples possessed S1-specific IgA and IgG responses and were neutralizing. The induction of S1-specific plasma antibodies by CoronaVac was IgG dominant, and 83% of the subjects possessed S1-specific IgG by 7 ± 2 days after the booster, with neutralizing effects.
Comirnaty induces S1-specific IgA and IgG responses with neutralizing activity in the nasal mucosa; a similar response is not seen with CoronaVac.
The presence of a nasal response with mRNA vaccine may provide additional protection compared with inactivated virus vaccine. However, whether such widespread immunological response may produce inadvertent adverse effects in other tissues warrants further investigation.
Cathelicidins are a major group of natural antimicrobial peptides which play essential roles in regulating host defense and immunity. In addition to the antimicrobial and immunomodulatory activities, ...recent studies have reported the involvement of cathelicidins in cardiovascular diseases by regulating inflammatory response and microvascular dysfunction. However, the role of cathelicidins in myocardial apoptosis upon cardiac ischemia/reperfusion (I/R) injury remains largely unknown.
CRAMP (cathelicidin-related antimicrobial peptide) levels were measured in the heart and serum from I/R mice and in neonatal mouse cardiomyocytes treated with oxygen glucose deprivation/reperfusion (OGDR). Human serum cathelicidin antimicrobial peptide (LL-37) levels were measured in myocardial infarction (MI) patients. The role of CRAMP in myocardial apoptosis upon I/R injury was investigated in mice injected with the CRAMP peptide and in CRAMP knockout (KO) mice, as well as in OGDR-treated cardiomyocytes.
We observed reduced CRAMP level in both heart and serum samples from I/R mice and in OGDR-treated cardiomyocytes, as well as reduced LL-37 level in MI patients. Knockdown of CRAMP enhanced cardiomyocyte apoptosis, and CRAMP KO mice displayed increased infarct size and myocardial apoptosis. In contrast, the CRAMP peptide reduced cardiomyocyte apoptosis and I/R injury. The CRAMP peptide inhibited cardiomyocyte apoptosis by activation of Akt and ERK1/2 and phosphorylation and nuclear export of FoxO3a. c-Jun was identified as a negative regulator of the CRAMP gene. Moreover, lower level of serum LL-37/neutrophil ratio was associated with readmission and/or death in MI patients during 1-year follow-up.
CRAMP protects against cardiomyocyte apoptosis and cardiac I/R injury via activation of Akt and ERK and phosphorylation and nuclear export of FoxO3a. Increasing LL-37 might be a novel therapy for cardiac ischemic injury.
Thermal management has become a critical issue for high heat flux electronics and energy systems. Integrated two-phase microchannel liquid-cooling technology has been envisioned as a promising ...solution, but with great challenges in flow instability. In this work, silicon nanowires were synthesized in situ in parallel silicon microchannel arrays for the first time to suppress the flow instability and to augment flow boiling heat transfer. Significant enhancement in flow boiling heat transfer performance was demonstrated for the nanowire-coated microchannel heat sink, such as an early onset of nucleate boiling, a delayed onset of flow oscillation, suppressed oscillating amplitudes of temperature and pressure drop, and an increased heat transfer coefficient.
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