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To clarify the effect of constraint conditions on the kink formation, fabrication process of the texture and porosity controlled Ti3SiC2 polycrystals was investigated and microstructural evolution during high temperature deformation was examined in it under high temperature uniaxial compression tests at 1200℃. Dense textured Ti3SiC2 sintered body was fabricated by slip casting in the high magnetic field of 12 T and following pressureless sintering at 1400℃ for 1 h. The porosity of the textured Ti3SiC2 was controlled by dispersing polymethyl methacrylate (PMMA) particles into the textured Ti3SiC2 as a spacer media. The highly textured Ti3SiC2 polycrystals with porosity of 8.4 vol％ and 16.7 vol％, respectively, were successfully fabricated by the slip casting in the high magnetic field. After the high temperature uniaxial compression perpendicular to the c-axis of the textured structure, both the porous and dense Ti3SiC2 showed kink formation, which is a common deformation mode for anisotropic layered materials. However, the average rotation angles of the kink boundaries were higher in the porous specimen than in the dense specimen. Since the crystal rotation is necessary for the kink formation, kink bands would be preferably developed in the porous area due to its weaker constraint than in the dense area. It can be concluded from the microstructural analysis that the constrain factor caused by the neighbor grains affects the crystalline rotation, resulting in the kink boundary formation with different rotation angles.

Abstract The effects of Ti and Si addition on the phase equilibrium and mechanical properties of the equiatomic CoCrFeMnNi high entropy alloy (Cantor alloy) were investigated. The phase equilibrium at 1000 °C was determined from the result of X-ray diffraction and electron probe micro-analysis. Ti addition stabilizes the $$\sigma$$ σ phase, A12 phase and C14-Laves phase, while Si addition stabilizes the A13 phase. The phase relationships were represented by projection onto (Co, Fe, Mn, Ni)–Cr–X(Ti or Si) isothermal ternary cross-section at 1000 °C in Co–Cr–Fe–Mn–Ni–X senary system. Tensile tests were conducted on Cantor-based fcc single solid solution alloys with Ti or Si dissolution at room temperature. The 0.2% yield strength and ultimate tensile strength increased with either element addition. The Ti-added alloy showed higher strength than the Si-added alloy. The difference in ductility in the alloys is related to their strain hardening behavior in the higher strain range. Graphic abstract

The elastic properties of a single-crystalline Ti3SiC2 MAX phase with a nanolayered crystal structure, comprising Ti-Si and two distinct Ti-C bonding layers, that had remained unclear because of the difficulty in growing large single crystals, were studied. Rather than unavailable large single crystals, polycrystalline samples with a crystallographic texture were prepared. By analyzing the polycrystalline elastic constants on the basis of an inverse Voigt–Reuss–Hill approximation, the elastic properties of a single crystal Ti3SiC2 with a hexagonal symmetry were determined. This revealed that the single-crystalline Young's modulus was almost isotropic despite its highly anisotropic layered structure. The shear modulus for (0001) 〈 11 2 ¯ 0 〉 was higher than that for {11 2 ¯ 0}[0001] in contrast to the basal slip-dominated plastic deformation reflecting the layered structure. Furthermore, first-principles calculations revealed that heterogeneous interlayer elastic deformation caused by the stabilization of Ti-Si bonding is the origin of the elastic isotropy in a Ti3SiC2 MAX phase.

Nanoindentation tests were conducted near the grain boundary (GB) of the Al-Mg-Si alloy, and the influence of GB character on the aging precipitation behavior and the mechanical properties was confirmed. After obtaining the GB characters by electron back scattered diffraction (EBSD) analysis and nanoindentation tests were carried out on under aged, peak aged, and over aged samples. And then, the indentation areas were observed by back scattered electrons imaging (BSE) in order to identify indentation positions to the GB. In this study, for the GB character. focusing on the rotation angle, the high-angle GB (HAGB) and the low-angle GB (LAGB) were selected. In addition, coincidence site lattice GBs (CSL) were selected as the special GB. In the 180t under-aged sample, the nano-hardness near GB is higher than that far from GB, while 1801 peak-aged and 250t aged samples, the nano-hardness is tower than that far from GB. Then the amount of change in hardness of HAGB was larger than that of the LAGB. This suggests that the GB character affects the aging precipitation behavior and mechanical properties.

BACKGROUND: Gait analysis, such as portable gait rhythmogram (PGR), provides objective information that helps in the quantitative evaluation of human locomotion. OBJECTIVE: The purpose of this study was to assess the reliability of PGR in post-stroke patients. METHODS: Two raters (A and B) examined 48 post-stroke patients. To assess intra-rater reliability, rater A tested subjects on three separate occasions (Days 1, 2, and 3). To assess inter-rater reliability, raters A and B independently tested participants on the same occasion (Day 3). RESULTS: There was no significant systematic bias between test occasions or raters. Intraclass correlation coefficient values were 0.93–0.97 for intra-rater reliability at both the comfortable speed and maximum speed, and 0.97–0.98 (comfortable speed) and 0.97–0.99 (maximum speed) for inter-rater reliability. The standard error was 1.25–1.49 (comfortable speed) and 1.62–1.77 (maximum speed) for intra-rater investigation, and 1.04–1.32 (comfortable speed) and 0.91–1.26 (maximum speed) for inter-rater investigation. At the 90% confidence level, the minimum detectable change ranged from 2.9–4.1%, and the error of an individual’s score at a given time point ranged from ±2.1–2.9%. CONCLUSIONS: Based on this excellent reliability of the PGR in post-stroke patients, it can be recommended as a simple test of gait analysis in this population.

Background and Aim In recent years, interest in the quality of medical care has rapidly increased worldwide. However, quality indicators that contribute to establishing standard treatment in stroke medicine, especially rehabilitation, are not well-developed in Japan. Japan has established Kaifukuki (convalescent) rehabilitation wards, and the development of quality indicators for stroke rehabilitation in the convalescent phase is an urgent issue. Methods We first reviewed the literature regarding quality indicators for stroke rehabilitation. Next, we extracted candidate indicators from identified reports and guidelines and surveyed educational hospitals certified by the Japanese Association of Rehabilitation Medicine. On the basis of the survey results, we reevaluated the suitability of the proposed indicators in discussions with an expert panel. Results The questionnaire survey highlighted several important items that revealed there is room for improvement in adherence. For stroke rehabilitation in the convalescent phase, we adopted 15 indicators that were feasible as indicators to be used for comparisons between facilities, based on scoring by and opinions of the expert panel. These indicators measured structure (2 indicators), process (5 indicators), and outcome (8 indicators). Conclusion This is the first study to establish quality indicators to standardize stroke rehabilitation in Japan. We developed this set of 15 indicators using an evidence-based approach. However, many tasks remain for continuous quality improvement.

Transdermal administration of drugs improves their bioavailability and is capable of systemic and local treatment. To improve the skin permeability of drugs, nano-sized systems have attracted attention as drug carriers for transdermal drug delivery system. We considered that silk fibroin composed of a crystalline region with many hydrophobic amino acids and an amorphous region with many hydrophilic amino acids was useful as a carrier for transdermal administration of a drug because of the balance between hydrophilicity and hydrophobicity. In this study, silk fibroin nanoparticles with mean volume diameters of 42.3 nm were successfully prepared, and storage stability was confirmed by storing the nanoparticle suspension at 4, 32, and 37 °C for a week. At any storage temperature, the mean volume diameter and standard deviation were stable. The polydispersity indexes were 0.19–0.23, and no specific trends were observed. Then, to investigate the transdermal delivery route of the silk fibroin nanoparticles, skin permeability in vivo was evaluated using mice. Six hours after administration, fluorescent substances were observed in the dermis in addition to the stratum corneum, hair follicles and the epidermis around them. This result indicated that fibroin nanoparticles with the mean volume diameter of 40-nm penetrated the stratum corneum and was delivered deep into the skin. Therefore, it was suggested that small nanoparticles prepared using silk fibroin are useful for drug delivery to the dermis.

A new class of high-temperature materials based on refractory elements was investigated with an aim to improve the energy efficiency of thermal power plants. Alloys based on Nb and Mo composed of BCC solid solution (BCCss) (Nb-Mo) and T2-silicide (Nb,Mo)5(Si,B)3 are promising candidates as high-temperature materials. Further investigation on the alloy phase equilibria of this system is required to improve the mechanical properties and oxidation resistance through optimization of the phase compositions. Cr is one candidate to modify the properties of the alloy because Cr is expected to stabilize the T2 compound phase along with B. Here, the phase equilibria among BCCss and the T2 compound are widely investigated in the Cr-Mo-Nb-Si-B system, and a BCCss-T2 two-phase microstructure is found in Mo-rich alloys. The B/Si ratio in the T2 phase increases with the Cr content, while almost no B solubility was found in BCCss. As the Si content increases in alloys, the A15 silicide phase ((Cr, Mo, Nb)3Si) and/or Laves phase appear. Nanoindentation tests were conducted to investigate the mechanical properties of the BCCss phase of the alloys in the Cr-Mo-Nb-Si-B system. The nanohardness and reduced elastic modulus of these alloys tended to be higher with an increase in Cr.

It is well known that various elements substitute for a certain sub-lattice of intermetallic compounds. There have been various experimental investigations of the effects of substituted elements on mechanical properties, however, there are few reports describing the effects of multi-element substitution. In the present study, L12-type compounds A3B (Ni3Al and Co3(Al,W)) were selected as model compounds because their substitution behavior is well known. It was reported that various elements such as Ni, Co, Cu, Pd and Pt occupy the A-site, whereas Al, Si, Ga, Ge, Ti, V, Nb, Ta, Mo, and W occupy the B-site. These elements are expected to introduce local lattice distortion, which may affect the motion of dislocations over a wide range of temperatures. Several alloys composed of five or more elements including Ni, Co, Al, Mo, and W, were prepared using an Ar-arc melting machine and heat-treated. Several alloys were found to include an (Ni, Co)3(Al, Mo, W, …)-L12 compound as a constituent phase. The nano-hardness of these L12 phases was higher than that of the high-strength Co3(Al,W)-L12 compound, confirming that multi-element substitution is an effective way to improve the mechanical properties of an intermetallic compound without decreasing the phase stability.

Nanoindentation tests were conducted near the grain boundary (GB) of the Al-Mg-Si alloy, and the influence of GB character on the aging precipitation behavior and the mechanical properties was confirmed. After obtaining the GB characters by electron back scattered diffraction (EBSD) analysis, nanoindentation tests were carried out on under-aged, peak-aged, and over-aged samples. And then, the indentation areas were observed by back scattered electrons imaging (BSE) in order to identify indentation positions with respect to the GB. In this study, for the GB character, focusing on the rotation angle, the high-angle GB (HAGB) and the low-angle GB (LAGB) were selected. In addition, coincident site lattice GBs (CSL) were selected as the special GB. In the 180°C under-aged samples, the nano-hardness near GB is higher than that far from GB, while 180°C peak-aged samples, the nano-hardness is lower than that far from GB. Then the range near the GB where the hardness changes was larger at HAGB than at LAGB and CSL3. This suggests that the GB character affects the aging precipitation behavior and mechanical properties.

A novel method (reaction at narrow holes method, RANH method) to fabricate an intermetallic compound fiber / metal matrix composite is proposed. Narrow holes are drilled in the metal matrix A, and then metal fibers B are inserted into these holes. The assembly is heated to elevated temperatures to obtain molten metal B in the holes. Then the reaction between A and B should cause within the narrow holes. During the reaction, intermetallic compound of AmBn replaces the metal B keeping its fiber shape embedded in the metal matrix A. In this study, a Ni-aluminides fiber / Ni composite is fabricated by the novel method. Microstructure and mechanical property of these specimens were investigated. To evaluate the reaction during the RANH method, in-situ observation by laser scanning microscope and differential thermal analysis (DTA) were also carried out. From obtained results, effects of swaging treatment and heating condition on these microstructure and mechanical property were discussed.

Background Repetitive transcranial magnetic stimulation (rTMS) and Repetitive facilitative exercise (RFE) improves motor impairment after stroke. Objective To investigate whether neuromuscular electrical stimulation (NMES) can facilitate the effects of rTMS and RFE on the function of the hemiparetic hand in stroke patients. Methods This randomized double-blinded crossover study divided 20 patients with hemiparesis into two groups and provided treatment for 4 weeks at 5 days/week. NMES-before-sham group and NMES-following-sham group performed NMES sessions and sham NMES sessions for each 2 weeks. Patients received NMES or sham NMES for the affected extensor muscle concurrently with 1 Hz rTMS for the unaffected motor cortex for 10 min and performed RFE for 60 min. The Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT), Box and Block Test (BBT) and Modified Ashworth Scale (MAS) were used for evaluation. Results FMA and ARAT improved significantly during both sessions. The gains in the BBT during an NMES session were significantly greater than those during a sham NMES session. MAS for the wrist and finger significantly decreased only during an NMES session. Conclusions NMES combined with rTMS might facilitate, at least in part, the beneficial effects of RFE on motor function and spasticity of the affected upper limb.

A new control scheme for eliminating garbage collection during high-speed analysis of big-graph data stored in NAND flash memory is proposed and evaluated. During big-graph analysis, intermediate results of the analysis are stored in NAND flash memory and updated repeatedly. Under a conventional control scheme, excessive data copying, called “garbage collection,” occurs because overwriting data to NAND flash memory is prohibited. Such excessive data copying degrades performance of big-graph analysis. In contrast, under the proposed control scheme, the controller of NAND flash memory writes the intermediate results, which are updated at the same time, to the same block of NAND flash memory, and the excessive data copying is eliminated completely because all the data in the block can be erased at the same time before the intermediate results are updated. As a result, the proposed scheme shortens analysis time by 88 percent and increases analysis speed for big graphs 8.7 times. The proposed scheme can be applied to three-dimensional NAND flash memory and increases analysis speed 9.5 times. Also, the proposed scheme can be applied to an emerging high-density memory such as three-dimensional vertical chain-cell phase-change memory. These results show that the proposed control scheme enables high-speed analysis of big graphs.

The effect of crystal orientation on incipient plasticity during nanoindentation was investigated by experiments and molecular statics simulation. Pop-in behavior is a result of dislocation activity, and is therefore influenced by crystal orientation. Experimental results using single crystals indicated that indentations on the basal plane had higher pop-in loads and larger pop-in displacements than those on the prismatic plane, an effect also captured by molecular statics simulation. The difference can be traced to the types of activated dislocations, with not only basal but also pyramidal dislocations active for indentations on the basal plane, but only basal dislocations triggered at the first pop-in on the prismatic plane.

Background: Risk factors for atrial fibrillation (AF) recurrence in patients who have undergone AF catheter ablation have not been fully clarified. The objective of this study was to assess whether the left atrium (LA) and LA appendage (LAA) volumes, and cardio-metabolic markers such as polyunsaturated fatty acids (PUFAs) levels were associated with AF recurrence. Methods: Seventy-seven consecutive patients with AF (mean age, 59 ± 8 years; male, 81%; paroxysmal AF, 64%) undergoing catheter ablation were enrolled. Using contrast-enhanced cardiac multi-detector computed tomography (MDCT) scan, the LA and LAA volume and orifice area were assessed. Radiofrequency ablation was performed by an irrigation catheter, initially targeting the pulmonary veins with a wide area circumferential ablation. Results: Patients with AF recurrence (36%) exhibited both larger LAA volumes and an LAA orifice area than those without AF recurrence, whereas the LA diameter and LA volumes were not significantly different. Notably, AF recurrence occurred in all patients with a large LAA (≥ 25 mL), and the LAA volume was significantly and negatively associated with docosahexaenoic acid (DHA) levels (β = -0.33, P = 0.003). A multiple regression analysis revealed that the log N-terminal proB-type natriuretic peptide and plasma DHA levels were independent factors for the LAA volume when adjusted for age, AF detected age, left ventricular (LV) ejection fraction, end-systolic LV diameter. Conclusions: These results suggest that the association between LAA volume and low plasma DHA levels may be an important factor for post-ablation AF recurrence. Cardiol Res. 2017;8(3):96-104 doi: https://doi.org/10.14740/cr542w

Al3Nb is known as a high oxidation resistant material, while it is quite brittle. As the fracture toughness of Al3Nb single crystal and its dependence on the composition are not obtained, the micro-sized fracture testing proposed by Suzuki et al. was performed. Al3Nb single crystal micron-order size cantilevers with a chevron-notch were fabricated in a grain of two-phase polycrystalline alloys by using FIB (Focused Ion Beam). From the load-displacement curves during the bending by a nanoindenter, the average value of fracture toughness of Nb-rich Al3Nb is evaluated to be 2.90 MPam1/2, while the fracture toughness of Al-rich Al3Nb is also evaluated to be 2.82 MPam1/2. From this result, the fracture toughness of Al3Nb is less dependent on its Al/Nb ratio. Furthermore the fracture toughness of Al3 (Nb, V) was evaluated to be 2.82 MPam1/2.The fracture toughness of Al3Nb is seemingly insensitive to V addition.

For the improvement of oxidation resistance of Nb-based alloys, PdAl-B2 is expected as Al reservoir for Al2O3 surface layer because it is in equilibrium with Nbss (bcc) phase. However, PdAl forms cracks during casting caused by B2 -> β’ transformation. To suppress B2 -> β’ transformation, Rh, Ru and Ir were chosen as additive elements. It is found that bcc / B2 two-phase field in Nb-Pd-Ir-Al system is limited to be small fraction of Ir, while (Pd,Rh)Al-B2 is in equilibrium with bcc solid solution in a wide composition range and addition of Rh prevents occurrence of B2 -> β’ transformation. Composition range of (Pd,Ru)Al-B2 in equilibrium with bcc phase is wider than (Pd,Ir)Al-B2 but narrower than (Pd,Rh)Al-B2. Rh and Ru addition are also beneficial for improving eutectic temperature of Nb-bcc / B2 aluminide two-phase alloys.

[Purpose] Gait analysis, such as portable gait rhythmogram (PGR) provides objective information that helps in the quantitative evaluation of human locomotion. The purpose of this study was to assess the reliability of PGR in post-stroke patients. [Subjects and Methods] Two raters (A and B) examined 44 post-stroke patients. To assess intra-rater reliability, rater A tested subjects on three separate occasions (Days 1, 2, and 3). To assess inter-rater reliability, raters A and B independently tested participants on the same occasion (Day 3). [Results] There was no significant systematic bias between test occasions or raters. Intraclass correlation coefficient values were 0.93-0.97 for intra-rater reliability at both the comfortable speed and maximum speed, and 0.97-0.98 (comfortable speed) and 0.87-0.99 (maximum speed) for inter-rater reliability. The standard error was 1.25-1.49 (comfortable speed) and 1.62-1.77 (maximum speed) for intra-rater investigation, and 1.04-1.32 (comfortable speed) and 0.91-1.26 (maximum speed) for inter-rater investigation. At the 90% confidence level, the minimum detectable change ranged from 2.9-4.1%, and the error of an individual's score at a given time point ranged from ±2.1-2.9%. [Conclusion] Based on this excellent reliability of the PGR in post-stroke patients, it can be recommended as a simple test of gait analysis in this population.