120 research outputs found
Fabrication of Nonporous Layer on Surface of ALPORAS by Friction Stir Incremental Forming
Porous metals having nonporous (skin) layer at the surface have a potential to improve the mechanical properties of the porous metals. To fabricate nonporous layer on surface of porous metals, friction stir incremental forming process is applied to form surface of a commercial closed-cell type aluminum foam (ALPORAS) in this study. In the process, the cell walls near the surface of the aluminum foam are plastically deformed by a rotating tool with a high rotation rate, fabricated the nonporous layer at the surface. The nonporous layer with thinner than 0.4 mm is fabricated at the surface without internal fracture of the aluminum foam under forming conditions of a tool rotation rate of 8000 rpm, a tool feed rate of 60 mm/min, and total forming depth of 7.0 mm.8th International Conference on Porous Metals and Metallic Foams, Metfoam 201
Detection of the reaction intermediates catalyzed by a copper amine oxidase
Consecutive temporal analyses of enzyme structure have been performed during reactions in order to clarify the structure-based reaction mechanism. Four intermediate structures have been determined
Effect of the sample work function on alkali metal dosing induced electronic structure change
Alkali metal dosing (AMD) has been widely used as a way to control doping
without chemical substitution. This technique, in combination with angle
resolved photoemission spectroscopy (ARPES), often provides an opportunity to
observe unexpected phenomena. However, the amount of transferred charge and the
corresponding change in the electronic structure vary significantly depending
on the material. Here, we report study on the correlation between the sample
work function and alkali metal induced electronic structure change for three
iron-based superconductors: FeSe, Ba(FeCo)As and
NaFeAs which share a similar Fermi surface topology. Electronic structure
change upon monolayer of alkali metal dosing and the sample work function were
measured by ARPES. Our results show that the degree of electronic structure
change is proportional to the difference between the work function of the
sample and Mulliken's absolute electronegativity of the dosed alkali metal.
This finding provides a possible way to estimate the AMD induced electronic
structure change.Comment: 4 page
Experimental evidence of strain relaxed domain structure in (100)/(001)-oriented epitaxial lead titanate thick films grown by metal organic chemical vapor deposition
Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238U Beam at 345 MeV/nucleon
A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238U
beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center.
Fission fragments were analyzed and identified by using the superconducting
in-flight separator BigRIPS. We observed 45 new neutron-rich isotopes: 71Mn,
73,74Fe, 76Co, 79Ni, 81,82Cu, 84,85Zn, 87Ga, 90Ge, 95Se, 98Br, 101Kr, 103Rb,
106,107Sr, 108,109Y, 111,112Zr, 114,115Nb, 115,116,117Mo, 119,120Tc,
121,122,123,124Ru, 123,124,125,126Rh, 127,128Pd, 133Cd, 138Sn, 140Sb, 143Te,
145I, 148Xe, and 152Ba
Robust and highly efficient hiPSC generation from patient non-mobilized peripheral blood-derived CD34+ cells using the auto-erasable Sendai virus vector
Background: Disease modeling with patient-derived induced pluripotent stem cells (iPSCs) is a powerful tool forelucidating the mechanisms underlying disease pathogenesis and developing safe and effective treatments. Patientperipheral blood (PB) cells are used for iPSC generation in many cases since they can be collected with minimuminvasiveness. To derive iPSCs that lack immunoreceptor gene rearrangements, hematopoietic stem and progenitorcells (HSPCs) are often targeted as the reprogramming source. However, the current protocols generally requireHSPC mobilization and/or ex vivo expansion owing to their sparsity at the steady state and low reprogrammingefficiencies, making the overall procedure costly, laborious, and time-consuming.Methods: We have established a highly efficient method for generating iPSCs from non-mobilized PB-derivedCD34+ HSPCs. The source PB mononuclear cells were obtained from 1 healthy donor and 15 patients and werekept frozen until the scheduled iPSC generation. CD34+ HSPC enrichment was done using immunomagnetic beads,with no ex vivo expansion culture. To reprogram the CD34+-rich cells to pluripotency, the Sendai virus vectorSeVdp-302L was used to transfer four transcription factors: KLF4, OCT4, SOX2, and c-MYC. In this iPSC generationseries, the reprogramming efficiencies, success rates of iPSC line establishment, and progression time wererecorded. After generating the iPSC frozen stocks, the cell recovery and their residual transgenes, karyotypes, T cellreceptor gene rearrangement, pluripotency markers, and differentiation capability were examined.Results:We succeeded in establishing 223 iPSC lines with high reprogramming efficiencies from 15 patients with 8 different disease types. Our method allowed the rapid appearance of primary colonies (~ 8 days), all of which were expandable under feeder-free conditions, enabling robust establishment steps with less workload. After thawing, the established iPSC lines were verified to be pluripotency marker-positive and of non-T cell origin. A majority of the iPSC lines were confirmed to be transgene-free, with normal karyotypes. Their trilineage differentiation capability was also verified in a defined in vitro assay.Conclusion:This robust and highly efficient method enables the rapid and cost-effective establishment of transgene-free iPSC lines from a small volume of PB, thus facilitating the biobanking of patient-derived iPSCs and their use for the modeling of various diseases
Transient activation of c-MYC expression is critical for efficient platelet generation from human induced pluripotent stem cells
A specific kinetic pattern of c-MYC expression is essential for optimal generation of functional platelets from human induced pluripotent stem cells
Isotope production in proton-, deuteron-, and carbon-induced reactions on Nb 93 at 113 MeV/nucleon
Isotope-production cross sections for p-, d-, and C-induced spallation reactions on Nb93 at 113 MeV/nucleon were measured using the inverse-kinematics method employing secondary targets of CH2, CD2, and C. The measured cross sections for Mo90, Nb90, Y86,88 produced by p-induced reactions were found to be consistent with those measured by the conventional activation method. We performed benchmark tests of the reaction models INCL-4.6, JQMD, and JQMD-2.0 implemented in the Particle and Heavy Ion Transport code System (PHITS) and of the nuclear data libraries JENDL-4.0/HE, TENDL-2017, and ENDF/B-VIII.0. The model calculations also showed generally good agreement with the measured isotope-production cross sections for p-, d-, and C-induced reactions. It also turns out that, among the three nuclear data libraries, JENDL-4.0/HE provides the best agreement with the measured data for the p-induced reactions. We compared the present Nb93 data with the Zr93 data, that were measured previously by the same inverse kinematics method (Kawase et al., Prog. Theor. Exp. Phys. 2017, 093D03 (2017)2050-391110.1093/ptep/ptx110), with particular attention to the effect of neutron-shell closure on isotope production in p- and d-induced spallation reactions. The isotopic distributions of the measured production cross sections in the Zr93 data showed noticeable jumps at neutron number N=50 in the isotopic chains of ΔZ=0 and -1, whereas no such jump appeared in isotopic chain of ΔZ=0 in the Nb93 data. From INCL-4.6 + GEM calculations, we found that the jump formed in the evaporation process is smeared out by the intranuclear cascade component in Nb91 produced by the Nb93(p,p2n) and (d,d2n) reactions on Nb93. Moreover, for Nb93, the distribution of the element-production cross sections as a function of the change in proton number ΔZ is shifted to smaller ΔZ than for Zr93, because the excited Nb prefragments generated by the cascade process are more likely to emit protons than the excited Zr prefragments, due to the smaller proton-separation energies of the Nb isotopes
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