The effect of casting processing and natural aging on microstructures and mechanical properties of T5-treated Al–7wt.%Si–0.5 wt.%Mg–0.01 wt.%Sr (ASTM 357) alloys has been investigated. An artificial ...aging gives fine precipitation microstructures, and the thixo-cast processing provides much finer distributions of eutectic Si phases and Al8Si6Mg3Fe phases than the gravity-cast and die-cast processing, leading to higher level of strength-ductility balance in the thixo-cast alloys than that of T6-treated Al–Si based cast alloys. Although the prolonged natural aging significantly changes the subsequent artificial age-hardening behaviors and precipitation microstructures, it is interesting to note that the cast alloys could keep their good strengths even after the T5-treatment including the long-term natural aging. This finding will open up the development of strong and ductile cast Al–7wt.%Si–Mg based alloys which can broaden the application of aluminum alloys in automotive industry.
•Thixo-casting results in uniform dispersion of fine eutectic compounds.•T5-treatment brings about fine distributions of precipitates.•Thixo-casting and subsequent T5-treatment provide good tensile property.•T5-treated alloys could keep good strengths even after prolonged natural aging.
The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial ...points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC s=7 TeV proton–proton collisions with the pseudo-rapidity η ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results, and the DPMJET 3.04 model describes our results well at the lower pseudo-rapidity ranges. However, no model perfectly explains the experimental results over the entire pseudo-rapidity range. The experimental data indicate a more abundant neutron production rate relative to the photon production than any model predictions studied here.
Abstract To develop an effective neuroprotective strategy against ischemic injury, it is important to identify the key molecules involved in the progression of injury. Direct molecular analysis of ...tissue using mass spectrometry (MS) is a subject of much interest in the field of metabolomics. Most notably, imaging mass spectrometry (IMS) allows visualization of molecular distributions on the tissue surface. To understand lipid dynamics during ischemic injury, we performed IMS analysis on rat brain tissue sections with focal cerebral ischemia. Sprague–Dawley rats were sacrificed at 24 h after middle cerebral artery occlusion, and brain sections were prepared. IMS analyses were conducted using matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) in positive ion mode. To determine the molecular structures, the detected ions were subjected to tandem MS. The intensity counts of the ion signals of m/z 798.5 and m/z 760.5 that are revealed to be a phosphatidylcholine, PC (16:0/18:1) are reduced in the area of focal cerebral ischemia as compared to the normal cerebral area. In contrast, the signal of m/z 496.3, identified as a lyso-phosphatidylcholine, LPC (16:0), was clearly increased in the area of focal cerebral ischemia. In IMS analyses, changes of PC (16:0/18:1) and LPC (16:0) are observed beyond the border of the injured area. Together with previous reports—that PCs are hydrolyzed by phospholipase A2 (PLA2 ) and produce LPCs,—our present results suggest that LPC (16:0) is generated during the injury process after cerebral ischemia, presumably via PLA2 activation, and that PC (16:0/18:1) is one of its precursor molecules.
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► Catalytic steam reforming of toluene for hydrogen production over Ni/perovskite. ► Higher activity and lower coke formation on Ni/La0.7Sr0.3AlO3−δ catalyst. ► Transient response ...using H218O revealed lattice oxygen played an important role. ► The rate-determining step of the reaction depended on the activity of lattice oxygen. ► Coke deposited was removed oxidatively by lattice oxygen in/on the perovskite support.
Catalytic steam reforming of aromatic hydrocarbon using toluene as a model compound for hydrogen production over Ni catalyst supported on perovskite oxide was investigated. Ni/La0.7Sr0.3AlO3−δ catalyst showed higher activity and lower coke formation than other Ni-supported catalysts on hydrogen production by toluene steam reforming. Transient response using H218O revealed that the surface lattice oxygen of La0.7Sr0.3AlO3−δ worked as active oxygen by redox mechanism at 873K. Coke deposited on the catalyst surface after the reaction was removed oxidatively by lattice oxygen in/on the perovskite support. The working temperature of the lattice oxygen depended on the catalyst support characteristics. Analyses of the support structure by XRD and XPS revealed that the lattice distortion and the increasing of oxygen vacancies by partial Sr substitution enhanced the redox ability of lattice oxygen. Arrhenius plots showed that the rate-determining step of the reaction changed at a certain temperature at which the lattice oxygen was able to contribute to reaction over Ni/La0.7Sr0.3AlO3−δ and Ni/LaAlO3. The dependence of the reaction rate on the partial pressure of H2O and toluene revealed that the rate-determining step might be the formation of hydroxyl group on the support surface in a lower temperature region and the adsorption of toluene on the Ni surface in a higher temperature region.
•The optimum Cu content is 0.5% in a T5-treated thixo-cast Al–7Si–0.5Mg alloy.•The 0.5%Cu-containing alloy forms a high fraction of plate-like θ’ phases.•The formation of brittle Cu-rich phases is ...suppressed in the 0.5%Cu-containing alloy.•The 0.5%Cu-containing alloy exhibits a good combination of strengths and ductility.
Cu content has been successfully optimized in a thixo-cast and directly aged (T5-treatment) Al–7Si–0.5Mg (wt.%) alloy. Even after the 0.5% Cu addition, plate-like Al2Cu (θ’) phases, which contribute to high strengths and large plasticity, are precipitated. The formation of a large fraction of Cu-containing brittle phases could be suppressed as well. Then, the Al–7Si–0.5Mg–0.5Cu alloy exhibits high ultimate tensile strength, 0.2% proof stress, and elongation to failure of 296 MPa, 209 MPa, and 8.8%, respectively. This results in a high quality index similar to that of solution-treated and subsequently aged (T6-treated) Al–7Si–Mg alloys. A Cu addition over 1.0% further improves the strengths; however, this leads to poor ductility because of the high fraction of Cu-containing brittle phases.
Summary
Background Atopic dermatitis (AD)‐specific genes have not yet been clarified.
Objectives To identify gene expression specific to active atopic skin lesions.
Methods We analysed 23 000 ...genes in skin biopsy samples from 17 patients with AD and four normal controls using Affymetrix oligonucleotide arrays.
Results Four of the 10 genes with the greatest differences in expression between patients and controls, S100A8 and S100A7 (upregulated), and loricrin and filaggrin (downregulated), were epidermal differentiation genes located on 1q21, a locus previously reported to have a genetic linkage with AD.
Conclusions Our results, showing downregulation of the cornified envelope genes and upregulation of the alternative keratinization pathway, are the first to suggest abnormal epidermal differentiation and defective defences as key abnormalities in AD.
Iron (Fe) based alloys are widely used in the nuclear industry because the activation of Fe is low and the irradiation data for Fe alloys is abundant. The interaction between helium (He) atoms and ...defects in Fe alloys is an important issue in fusion reactors, since the rate of He generation is high. In the present study, well-annealed Fe specimens were cold-rolled until the original thickness was reduced by 10% or 40%, and then annealed at 673 or 723K for 1h, respectively, to annihilate the vacancy clusters formed during cold rolling. He atoms were implanted at 100eV without causing displacement damage in the annealed cold-rolled samples, which contained only dislocations. Upon He implantation, the yield stress (lower yield stress) and tensile strength decreased, and the total elongation increased. The former effect became stronger with increasing deformation (elongation induced by cold rolling from 10% to 40%), whereas the latter became weaker.
Since its discovery in 2008, the Andromeda galaxy nova M31N 2008-12a has been observed in eruption every single year. This unprecedented frequency indicates an extreme object, with a massive white ...dwarf and a high accretion rate, which is the most promising candidate for the single-degenerate progenitor of a Type Ia supernova known to date. The previous three eruptions of M31N 2008-12a have displayed remarkably homogeneous multiwavelength properties: (i) from a faint peak, the optical light curve declined rapidly by two magnitudes in less than two days, (ii) early spectra showed initial high velocities that slowed down significantly within days and displayed clear He/N lines throughout, and (iii) the supersoft X-ray source (SSS) phase of the nova began extremely early, six days after eruption, and only lasted for about two weeks. In contrast, the peculiar 2016 eruption was clearly different. Here we report (i) the considerable delay in the 2016 eruption date, (ii) the significantly shorter SSS phase, and (iii) the brighter optical peak magnitude (with a hitherto unobserved cusp shape). Early theoretical models suggest that these three different effects can be consistently understood as caused by a lower quiescence mass accretion rate. The corresponding higher ignition mass caused a brighter peak in the free-free emission model. The less massive accretion disk experienced greater disruption, consequently delaying the re-establishment of effective accretion. Without the early refueling, the SSS phase was shortened. Observing the next few eruptions will determine whether the properties of the 2016 outburst make it a genuine outlier in the evolution of M31N 2008-12a.
The purpose of this study was to evaluate surgical outcomes in elderly patients who had undergone free fibula flap transfer for malignant head and neck tumours. A retrospective chart review was ...performed to identify patients who had undergone free fibula flap transfer for mandibular reconstruction after malignant tumour resection at Jichi Medical University Hospital between May 2009 and April 2015. Enrolled patients were divided into an elderly group (≥80years old) and a younger group (<80years old). Seventeen patients met the inclusion criteria and were included in the elderly group. Age at surgery ranged from 80 to 92years. Thirteen patients (76.5%) experienced postoperative complications. Surgical site complications occurred in seven patients. The success rate of free fibula flap transfer was 100%. Systemic complications occurred in nine patients, most commonly delirium (n=6). No perioperative mortality was encountered. The overall 1-year survival rate was 94.1% (16/17). No patient reported gait disturbance as a donor site complication or any other major complication. The incidence of postoperative complications did not differ significantly between the elderly and younger groups. Almost no difference in postoperative course was seen between the groups. Elderly patients appear to tolerate free fibula flap reconstruction just as well as younger patients.
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