Irradiation Resistance of Multicomponent Alloys Egami, T.; Guo, W.; Rack, P. D. ...
Metallurgical and materials transactions. A, Physical metallurgy and materials science,
01/2014, Letnik:
45, Številka:
1
Journal Article
Recenzirano
High-entropy alloys (HEAs) are characterized not only by high values of entropy but also by high atomic-level stresses originating from mixing of elements with different atomic sizes. Particle ...irradiation on solids produces atomic displacements and thermal spikes. The high atomic-level stresses in HEAs facilitate amorphization upon particle irradiation, followed by local melting and re-crystallization due to thermal spikes. We speculate that this process will leave much less defects in HEAs than in conventional alloys. For this reason, they may be excellent candidates as new nuclear materials. We discuss initial results of computer simulation on model binary alloys and an electron microscopy study on Zr-Hf-Nb alloys, which demonstrate extremely high irradiation resistance of these alloys against electron damage to support this speculation.
Summary
Immunoglobulin (Ig)A is the most abundant immunoglobulin in humans, and in the airway mucosa secretory IgA (sIgA) plays a pivotal role in first‐line defense against invading pathogens and ...antigens. IgA has been reported to also have pathogenic effects, including possible worsening of the prognosis of idiopathic pulmonary fibrosis (IPF). However, the precise effects of IgA on lung fibroblasts remain unclear, and we aimed to elucidate how IgA activates human lung fibroblasts. We found that sIgA, but not monomeric IgA (mIgA), induced interleukin (IL)‐6, IL‐8, monocyte chemoattractant protein (MCP)‐1 and granulocyte–macrophage colony‐stimulating factor (GM‐CSF) production by normal human lung fibroblasts (NHLFs) at both the protein and mRNA levels. sIgA also promoted proliferation of NHLFs and collagen gel contraction comparable to with transforming growth factor (TGF)‐β, which is involved in fibrogenesis in IPF. Also, Western blot analysis and real‐time quantitative polymerase chain reaction (PCR) revealed that sIgA enhanced production of α‐smooth muscle actin (α‐SMA) and collagen type I (Col I) by NHLFs. Flow cytometry showed that NHLFs bound sIgA, and among the known IgA receptors, NHLFs significantly expressed CD71 (transferrin receptor). Transfection of siRNA targeting CD71 partially but significantly suppressed cytokine production by NHLFs co‐cultured with sIgA. Our findings suggest that sIgA may promote human lung inflammation and fibrosis by enhancing production of inflammatory or fibrogenic cytokines as well as extracellular matrix, inducing fibroblast differentiation into myofibroblasts and promoting human lung fibroblast proliferation. sIgA’s enhancement of cytokine production may be due partially to its binding to CD71 or the secretory component.
Secretory IgA in airway mucosa plays a pivotal role in first‐line defense against invading pathogens and antigens, but IgA has been reported to also have pathogenic effects. Here we show that sIgA, but not monomeric IgA, induced normal human lung fibroblasts to produce inflammatory cytokines and undergo activation by enhancing proliferation and differentiation into myofibroblasts. Secretory IgA’s enhancement of cytokine production may be partially due to its binding to CD71 or the secretory component.
The analysis of functional connectivity at rest (rFC) enables us to know how brain regions within and between networks interact. In this study, we used resting-state functional magnetic resonance ...imaging and a creativity test of divergent thinking (DT) to investigate the relationship between creativity measured by DT and rFC. We took the medial prefrontal cortex (mPFC) to be the seed region and investigated correlations across subjects between the score of the DT test and the strength of rFC between the mPFC and other brain regions. Our results showed that the strength of rFC with the mPFC significantly and positively correlated with creativity as measured by the DT test in the posterior cingulate cortex (PCC). These results showed that higher creativity measured by DT is associated with rFC between the mPFC and the PCC, the key nodes of the default mode network (DMN). Increased rFC between these regions is completely opposite from that is generally expected from the association between higher creativity and reduced deactivation in DMN during an externally directed attention-demanding task shown in our previous study but is similar to the pattern seen in relatives of schizophrenia. These findings are comparable to the previously reported psychological associations between schizotypy and creativity.
Adsorption behavior and mechanisms for 4-methyl imidazole (4MI) from aqueous solutions onto MFI-type zeolite (ZSM5) samples was investigated. The amount of 4MI-reduction in a solution at pH 3 was ...almost consistent with the amount of exchangeable sodium in Na-ZSM5 and was not affected by the equilibrium concentration (Ce). Therefore, it was suggested that the adsorption of 4MI in the imidazolium form depended on the cation-exchange reaction. The adsorption isotherm of the neutral 4MI molecule could be fitted using the Langmuir model and the adsorption capacity was lower at Ce < 150 mg/L than the cation exchange capacity of the zeolite adsorbent. When Ce > 880 mg/L, the adsorption capacity of 4MI in the neutral form steeply increased because of self-condensation, as suggested by XPS and NMR analyses. Moreover, TG-DTA curves of 4MI-adsorbed zeolite revealed that 4MI adsorbed at pH 3 was more stable for heating up to 370 °C in comparison with 4MI adsorbed at a high pH condition started to desorb at approximately 260 °C. The above results suggested the advantage of using a zeolite adsorbent in selective removal of 4MI at low pH against the molecules of similar size and weaker basic properties, especially from solutions of low concentrations.
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•4MI adsorption to MFI-zeolite from aqueous solution was investigated at different pH.•4MI uptake at low pH depended on the cation-exchange reaction.•The adsorption isotherm of neutral 4MI could be fitted by the Langmuir model.•Adsorption of 4MI in the imidazolium form was higher than neutral 4MI at low Ce.•The advantage of zeolite for selective removal of 4MI was revealed.
The organizing of magnetic skyrmions shows several forms similar to atomic arrays of solid states. Using Lorentz transmission electron microscopy, we report the first direct observation of a stable ...liquid-crystalline structure of skyrmions in chiral magnet Co8.5Zn7.5Mn4(110) thin film, caused by magnetic anisotropy and chiral surface twist. Elongated skyrmions are oriented and periodically arranged only in the ⟨110⟩ directions, whereas they exhibit short-range order along the ⟨001⟩ directions, indicating a smectic skyrmion state. In addition, skyrmions possess anisotropic interaction with an opposite sign depending on the crystal orientation, in contrast to existing isotropic interaction.
House dust mites (HDMs) are a common source of allergens that trigger both allergen‐specific and innate immune responses in humans. Here, we examined the effect of allergen concentration and the ...involvement of Toll‐like receptor 4 (TLR4) in the process of sensitization to house dust mite allergens in an HDM extract‐induced asthma mouse model. Intranasal administration of HDM extract induced an immunoglobulin E response and eosinophilic inflammation in a dose‐dependent manner from 2.5 to 30 μg/dose. In TLR4‐knockout mice, the infiltration of eosinophils and neutrophils into the lung was decreased compared with that in wild‐type mice in the early phase of inflammation (total of three doses). However, in the late phase of inflammation (total of seven doses), eosinophil infiltration was significantly greater in TLR4‐knockout mice than in wild‐type mice. This suggests that the roles of TLR4 signaling are different between the early phase and the later phase of HDM allergen‐induced inflammation. Thus, innate immune response through TLR4 regulated the response to HDM allergens, and the regulation was altered during the phase of inflammation.
Perpendicular L1 0 -FePt/MgO/Fe/L1 0 -FePt magnetic tunnel junction (MTJ) films with the (001) texture were successfully developed to obtain a large tunnel magnetoresistance (TMR) above 100 % at room ...temperature. The TMR ratio in the L1 0 -FePt/MgO/Fe/L1 0 -FePt MTJ was strongly dependent on the Fe interfacial layer thickness. The lattice mismatch between the MgO(001) barrier layer and the L1 0 -FePt(001) layer is too large for the MgO barrier layer to grow epitaxially on the L1 0 -FePt(001) layer. The insertion of the Fe interfacial layer improves the quality of the MgO(001) barrier layer and achieves an epitaxy in the L1 0 -FePt/MgO/Fe/L1 0 -FePt stack. As a result, the optimization of the Fe interfacial layer thickness is a key to obtain the large TMR ratio in the MgO-based MTJ with the L1 0 -FePt electrodes.
▶ High flux CHA-type zeolite membrane. ▶ Dehydration of methanol, ethanol, 2-propanol by pervaporation. ▶ Optimizing the crystal growth conditions.
CHA-type zeolite membranes have excellent ...dehydration performance and acid stability. However, the permeation flux of the membrane is still lower than that of commercially available NaA-type zeolite membranes. In this paper, the influences of the crystal growth conditions and the support properties on the dehydration performance were determined in order to prepare high flux CHA-type zeolite membranes. As a result, the permeation flux increased to 14.0
kg
m
−2
h
−1 for a 90
wt% ethanol solution at 348
K (separation factor
>
10,000). The membrane was also used to dehydrate methanol and 2-propanol. The results suggest that the CHA-type zeolite membranes are effective for the separation of water from organic solvents.
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