On the Two-Stage Aging of Al-Mg-Si Alloys

The two-stage aging effect in three Al-Mg-Si alloys containing 0.5, 1.0 and 1.5% Mg₂Si respectively is investigated by electrical resistivity measurements, tensile tests and electron microscopy. The critical temperature for homogeneous nucleation of precipitates exists between 160 and 200°C for an 1.0% Mg₂Si alloy, and for an 1.5% Mg₂Si alloy between 200 and 260°C. The Temperatures are also correspoding to the highest temperatures for the resistivity increase respectively. The slight decrease in resistivity perhaps due to redissolution of clusters is observed for 0.5% Mg₂Si alloy in the initial stage of isothermal aging at a low temperature. The activation energy Eₛ for migration of solute atoms in the fast reaction is estimated as 0.77 eV for all three alloys in good agreement with the values reported for a 1.4% Mg2Si alloy. The deleterious effect of two-stage aging is observed in only limited cases, though it appearts unfortunately often in practice. The whole effect of two-stage aging appears to be explained only by the stability of clusters or zones formed during preaging. The conservation in zone number is not observed. The nucleation or stabilization of clusters which takes place during heating to aging temperature must be considered not only for quenching effect but also for two-stage aging effect

Photo-Induced Cell Damage Analysis for Single- and Multifocus Coherent Anti-Stokes Raman Scattering Microscopy

In this study, we investigated photo-induced damage to living cells during single- and multifocus excitations for coherent anti-Stokes Raman scattering (CARS) imaging. A near-infrared pulsed laser (709 nm) was used to induce cell damage. We compared the photo-induced cell damage in the single- and the multifocus excitation schemes with the condition to obtain the same CARS signal in the same frame rate. For the evaluation of cell viability, we employed 4',6-diamidino-2-phenylindole (DAPI) fluorophores that predominantly stained the damaged cells. One- and two-photon fluorescence of DAPI fluorophores were, respectively, excited by an ultraviolet light source and the same near-infrared light source and were monitored to evaluate the cell viability during near-infrared pulsed laser irradiation. We found lower uptake of DAPI fluorophores into HeLa cells during the multifocus excitation compared with the single-focus excitation scheme in both the one- and the two-photon fluorescence examinations. This indicates a reduction of photo-induced cell damage in the multifocus excitation. Our findings suggested that the multifocus excitation scheme is expected to be suitable for CARS microscopy in terms of minimal invasiveness

Photo-Induced Cell Damage Analysis for Single- and Multifocus Coherent Anti-Stokes Raman Scattering Microscopy

In this study, we investigated photo-induced damage to living cells during single-and multifocus excitations for coherent anti-Stokes Raman scattering (CARS) imaging. A near-infrared pulsed laser (709 nm) was used to induce cell damage. We compared the photo-induced cell damage in the single- and the multifocus excitation schemes with the condition to obtain the same CARS signal in the same frame rate. For the evaluation of cell viability, we employed 4', 6-diamidino-2-phenylindole (DAPI) fluorophores that predominantly stained the damaged cells. One-and two-photon fluorescence of DAPI fluorophores were, respectively, excited by an ultraviolet light source and the same near-infrared light source and were monitored to evaluate the cell viability during near-infrared pulsed laser irradiation. We found lower uptake of DAPI fluorophores into HeLa cells during the multifocus excitation compared with the single- focus excitation scheme in both the one- and the two-photon fluorescence examinations. This indicates a reduction of photo-induced cell damage in the multifocus excitation. Our findings suggested that the multifocus excitation scheme is expected to be suitable for CARS microscopy in terms of minimal invasiveness

Spatial Domain Resource Sharing for Overlapping Cells in Indoor Environment

As microcell wireless systems become more widespread, intercell interference among the access points will increase due to the limited frequency resource. In the overlapping cell scenario, radio resources should be shared by multiple cells. Although time and frequency resource sharing has been described in many papers, there is no detailed report on dynamic spatial resource sharing among multiple cells for microcell wireless systems. Thus, we present the effectiveness of spatial resource sharing among two access points. We introduce two scenarios based on the zero forcing method; one is the primary-secondary AP scenario and the other is the cooperative AP scenario. To evaluate the transmission performance of spatial resource sharing, channel matrices are measured in an indoor environment. The simulation results using the measured channel matrices show the potential of spatial resource sharing

Enhanced luminescence efficiency in Eu-doped GaN superlattice structures revealed by terahertz emission spectroscopy

Eu-doped Gallium nitride (GaN) is a promising candidate for GaN-based red light-emitting diodes, which are needed for future micro-display technologies. Introducing a superlattice structure comprised of alternating undoped and Eu-doped GaN layers has been observed to lead to an order-of-magnitude increase in output power; however, the underlying mechanism remains unknown. Here, we explore the optical and electrical properties of these superlattice structures utilizing terahertz emission spectroscopy. We find that ~0.1% Eu doping reduces the bandgap of GaN by ~40 meV and increases the index of refraction by ~20%, which would result in potential barriers and carrier confinement within a superlattice structure. To confirm the presence of these potential barriers, we explored the temperature dependence of the terahertz emission, which was used to estimate the barrier potentials. The result revealed that even a dilutely doped superlattice structure induces significant confinement for carriers, enhancing carrier recombination within the Eu-doped regions. Such an enhancement would improve the external quantum efficiency in the Eu-doped devices. We argue that the benefits of the superlattice structure are not limited to Eu-doped GaN, which provides a roadmap for enhanced optoelectronic functionalities in all rare-earth-doped semiconductor systems.Murakami F., Takeo A., Mitchell B., et al. Enhanced luminescence efficiency in Eu-doped GaN superlattice structures revealed by terahertz emission spectroscopy. Communications Materials 4, 100 (2023); https://doi.org/10.1038/s43246-023-00428-6

Microstructure of Oxide Insulator Coating before and after Thermal Cycling Test

Erbium oxide (Er2O3) was shown to be a high potential candidate for tritium permeation barrier and electrical insulator coating for advanced breeding blanket systems such as liquid Li, Li-Pb or molten-salt blankets. Recently, we succeeded to form Er2O3 coating layer on large interior surface area of metal pipe using Metal Organic Chemical Vapor Deposition (MOCVD) process. In this paper, we investigated the microstructure of Er2O3 coating layer on stainless steel 316 (SUS 316) plate before and after heat treatments with hydrogen or argon gases. From the results of TEM observations, we confirmed that Er2O3 coating layer with 700 nm thickness was formed on the SUS 316 plate and this layer was identified to poly-crystal phase because the diffraction fleck which was arranged like a ring was observed in the selected electron diffraction pattern. No macroscopic defects such as crack and peeling in Er2O3 coating layer were observed before and after thermal cycling test. The change of microstructure of the Er2O3 coating layer on before and after heat cycling test was reported

Effects of mild calorie restriction and high-intensity interval walking in middle-aged and older overweight Japanese

We investigated whether a combination of mild calorie restriction (MCR) and high-intensity interval walking (HIW) improved physical fitness more than HIW alone in middle-aged and older overweight Japanese (40-69 years old, BMI >= 23.6 kg/m(2)). Forty-seven women and 16 men were divided into MCR + HIW and HIW groups. All subjects performed HIW: >= 5 sets of 3-min low-intensity walking (40% peak aerobic capacity for walking, VO2peak) and 3-min high-intensity walking (>= 70% VO2peak) per day, >= 4 days per week, for 16 weeks while energy expenditure was monitored with a tri-axial accelerometer. The MCR + HIW group consumed meal replacement formula (240 kcal): a mixture of low-carbohydrates and -fat and high-protein, for either lunch or dinner everyday and therefore, had similar to 87% of the energy intake of the HIW group during the intervention period. Although the HIW group showed improvements in BMI, blood pressure, and several blood chemicals, the MCR + HIW group had greater improvement. Moreover, the medical expenditure for the 6 months including the intervention period was 59% lower in the MCR + HIW group than in the HIW group. Our strategy of a short-term combination of MCR and HIW may thus prevent lifestyle-associated diseases and improve health in middle-aged and older overweight Japanese.ArticleEXPERIMENTAL GERONTOLOGY. 44(10):666-675 (2009)journal articl

White Paper from Workshop on Large-scale Parallel Numerical Computing Technology (LSPANC 2020): HPC and Computer Arithmetic toward Minimal-Precision Computing

In numerical computations, precision of floating-point computations is a key factor to determine the performance (speed and energy-efficiency) as well as the reliability (accuracy and reproducibility). However, precision generally plays a contrary role for both. Therefore, the ultimate concept for maximizing both at the same time is the minimal-precision computing through precision-tuning, which adjusts the optimal precision for each operation and data. Several studies have been already conducted for it so far (e.g. Precimoniuos and Verrou), but the scope of those studies is limited to the precision-tuning alone. Hence, we aim to propose a broader concept of the minimal-precision computing system with precision-tuning, involving both hardware and software stack. In 2019, we have started the Minimal-Precision Computing project to propose a more broad concept of the minimal-precision computing system with precision-tuning, involving both hardware and software stack. Specifically, our system combines (1) a precision-tuning method based on Discrete Stochastic Arithmetic (DSA), (2) arbitrary-precision arithmetic libraries, (3) fast and accurate numerical libraries, and (4) Field-Programmable Gate Array (FPGA) with High-Level Synthesis (HLS). In this white paper, we aim to provide an overview of various technologies related to minimal- and mixed-precision, to outline the future direction of the project, as well as to discuss current challenges together with our project members and guest speakers at the LSPANC 2020 workshop; https://www.r-ccs.riken.jp/labs/lpnctrt/lspanc2020jan/

Impact of administering umbilical cord-derived mesenchymal stem cells to cynomolgus monkeys with endometriosis

Purpose: This study aimed to explore whether umbilical cord-derived mesenchymal stem cells (UC-MSCs) could be used as a therapeutic resource for endometriosis. Methods: Of seven cynomolgus monkeys with endometriosis, five were administered UC-MSCs (intervention group) and two were administered saline (control group). First, intravenous US-MSC treatment was administered for three months. Second, weekly intravenous US-MSC administration combined with monthly intraperitoneal US-MSC administration was conducted for 3 months. Finally, weekly intraperitoneal US-MSC administration was conducted for 3 months. The dose of UC-MSCs was set to 2 × 106 cells/kg for all administration routes. Laparoscopic findings and serum cancer antigen 125 (CA125) levels were also evaluated. The Revised American Society for Reproductive Medicine classification was used for laparoscopic evaluation. Results: Laparoscopic findings showed exacerbation of endometriosis after intraperitoneal UC-MSC administration, although no changes were observed in the control group. Intravenous UC-MSC administration decreased the level of CA125 in all monkeys; however, the difference was not significant. Intraperitoneal UC-MSC administration significantly exacerbated endometriosis compared with intravenous administration (p = 0.02). Conclusions: This study revealed that intraperitoneal UC-MSC administration exacerbates endometriosis in a nonhuman primate model of the disease.journal articl

Aggravated brain injury after neonatal hypoxic ischemia in microglia-depleted mice.

BACKGROUND:Neuroinflammation plays an important role in neonatal hypoxic-ischemic encephalopathy (HIE). Although microglia are largely responsible for injury-induced inflammatory response, they play beneficial roles in both normal and disease states. However, the effects of microglial depletion on neonatal HIE remain unclear.METHODS:Tamoxifen was administered to Cx3cr1CreER/+Rosa26DTA/+ (microglia-depleted model) and Cx3cr1CreER/+Rosa26DTA/- (control) mice at P8 and P9 to assess the effect of microglial depletion. The density of microglia was quantified using Iba-1 staining. Moreover, the proportion of resident microglia after the HI insult was analyzed using flow cytometric analysis. At P10, the HI insult was conducted using the Rice-Vannucci procedure at P10. The infarct size and apoptotic cells were analyzed at P13. Cytokine analyses were performed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) at P13.RESULTS:At P10, tamoxifen administration induced > 99% microglial depletion in DTA+ mice. Following HI insult, there was persisted microglial depletion over 97% at P13. Compared to male DTA- mice, male DTA+ mice exhibited significantly larger infarct volumes; however, there were no significant differences among females. Moreover, compared to male DTA- mice, male DTA+ mice had a significantly higher density of TUNEL+ cells in the caudoputamen, cerebral cortex, and thalamus. Moreover, compared to female DTA- mice, female DTA+ mice showed a significantly greater number of TUNEL+ cells in the hippocampus and thalamus. Compared to DTA- mice, ELISA revealed significantly lower IL-10 and TGF-β levels in both male and female DTA+ mice under both normal conditions and after HI (more pronounced).CONCLUSION:We established a microglial depletion model that aggravated neuronal damage and apoptosis after the HI insult, which was predominantly observed in males