Kumamoto Industrial Research Institute

The present study systematically investigates, for the first time, the combined influences of detonator position (top-edge and bottom-edge initiations) and anvil material (steel and sand) on the interfacial microstructure and mechanical performance of explosively welded A1050/AZ31 dissimilar joints. When welding was conducted using a steel anvil with the detonator positioned at the top edge, significant cracking occurred both at the surface and along the weld interface. In contrast, placing the detonator at the bottom edge noticeably reduced these defects. Moreover, the use of a sand anvil nullified these defects by damping the reflecting shockwaves and minimizing vibrations. Hardness measurements revealed substantial increase at the interface under all the conditions, with the highest value observed with the steel anvil. Welds subjected to top-edge detonation showed higher hardness values compared to those of welds subjected to bottom-edge detonation. Overall, the results suggest that sand anvils with bottom-edge detonation provide the optimal weld quality. The rigid steel anvil reflects the shockwave, generating high pressure and velocity at the interface, whereas the sand anvil absorbs a part of the shock energy, suppressing high-magnitude reflections. The position of the detonator influences the propagation dynamics of the detonation wave and the resulting collision velocity, which in turn, affect the interfacial morphology and overall quality of the weld.

ABSTRACTThe endoplasmic reticulum (ER) stress‐response is an adaptive cellular mechanism activated by an accumulation of unfolded proteins within the ER. Although recent evidence shows that the ER stress‐response is activated in aged tissues, and therefore ER stress is considered a candidate driver of aging, the spatiotemporal regulation and roles of the ER stress‐response during aging remain unclear. To address this research gap, we introduced an Ire1‐Xbp1s ER stress‐response pathway‐sensitive reporter into the ultra‐short‐lived vertebrate Nothobranchius furzeri that allows for the analysis of its aging processes within a short period of time. Using this reporter in N. furzeri, we confirmed the previously reported age‐dependent activation of ER stress in various tissues and identified an unexpected role of the Ire1‐Xbp1s ER stress‐response pathway in regulating epidermal tissue homeostasis and aging. The Ire1‐Xbp1s ER stress‐response pathway is active in the young epidermal basal layer but declines with aging. Photo‐isolation chemistry‐based spatial transcriptomics and functional assays revealed that the Ire1‐Xbp1s pathway maintains young epidermal cell proliferation by activating the cell cycle regulator Vcp, whereas the age‐dependent decline in glucose metabolism reduces Ire1‐Xbp1s activity, consequently downregulating cell proliferation. Collectively, our study elucidates a previously unidentified role of the ER stress‐response in skin aging, which can offer insights into therapeutic targets for promoting healthy skin.

Understandingthe polymorphs and amorphous structures of siliconoxide is an essential issue not only for fundamental science but alsofor energy and environmental science. In particular, the amplificationmechanism of chiroptical signals in amorphous silicon oxide has drawnsignificant attention. Here, we explore how the chiroptical signalcan be amplified in amorphous silicon oxide (silica) having nanoscalehelical structures. Our findings reveal that the observed vibrationalcircular dichroism (VCD) signals originate from the formation of symmetry-brokensiloxane ring structures. Furthermore, we demonstrate that the amplificationof siloxane VCD signals is driven by an enthalpy-driven asymmetricring distortion during volumetric shrinkage.

The electric field strength on the plasma membrane of a living cell exposed to a pulsed electric field (PEF) of sub-MV/m is automatically enhanced and exceeds <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$100 \text{MV} / \mathrm{m}$</tex>. While electric fields of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$100 \text{MV} / \mathrm{m}$</tex> are known to permeabilize phospholipid membranes, molecular dynamics (MD) simulations predict that they affect the function and structure of membrane proteins. There is growing interest in the effects of PEF on proteins, not only from a scientific perspective, but also in terms of its application to the physical control of protein function and structure, and the denaturation of proteins that occurs during the field sterilization of food products. However, it is not easy to identify PEF effects on proteins in living cells because other biological events such as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Ca}^{2+}$</tex> ion influx and subsequent biochemical reactions make it difficult to identify PEF effects on proteins. Previously, we experimentally demonstrated that electrical pulses with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \text{MV} / \mathrm{m}$</tex> or more denature urease proteins in aqueous solution. Furthermore, we reported that electrical pulses on the order of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$100 \text{MV} / \mathrm{m}$</tex> disassembled transthyretin aggregates. Based on these studies, we have experimentally investigated the effects of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$100 \text{MV} / \mathrm{m}$</tex> class electric fields on the hierarchical structures of proteins in this study. Two proteins, egg white ovalbumin (OVA) and bovine serum albumin (BSA), with similar molecular weights and different structures, exposed to 10 times of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$130 \text{MV} / \mathrm{m}$</tex>, sub-nanosecond pulses, 1 ns, were analyzed and compared in the respective hierarchical structures. Native-PAGE showed that PEFs with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.5 \text{MV} / \mathrm{m}$</tex> or more altered the tertiary structure of OVA but not of BSE. Native-PAGE showed that PEFs with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$50 \text{MV} / \mathrm{m}$</tex> or more altered the tertiary structure of OVA but not of BSE. Thiol group (TG) quntification indicates that the tertiary structure of OVA was loosen by the cleavage of the sole disulfide bond, whereas no significant change was observed in BSE. Circular dichroism (CD) analysis indicates significant changes in the secondary structure of neither OVA nor BSA. Throughout the experiment, pH and temperature remained unchanged. Hydrogen peroxide concentration was not changed significantly to affect the three-dimensional structure of proteins.

Rh K-edge high-energy-resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) spectroscopy was used to investigate the deactivated structure in an aged Rh/γ-Al2O3 catalyst for automotive gas purification, which has been difficult to identify using conventional XANES spectroscopy. HERFD-XANES spectroscopy uncovered the distinct spectral features of the deactivated structure in the aged Rh/γ-Al2O3 catalyst, which differed from those of supported Rh2O3 and Rh metal species. Spectral simulations of possible deactivated structures revealed the formation of Rh3+ doped in γ-Al2O3 or rhodium aluminate with octahedral coordination (octahedral RhAlOx) as the deactivated structure. The spectrum of octahedral RhAlOx was extracted from the measured spectra of fresh and aged Rh/γ-Al2O3 samples before and after H2 treatment at 600 °C using linear combination fitting analysis, thereby enabling the quantification of the fraction of octahedral RhAlOx present in the aged Rh/γ-Al2O3 catalyst. This study not only demonstrates the identification and quantification of octahedral RhAlOx in aged Rh/Al2O3 using Rh K-edge HERFD-XANES spectroscopy but also highlights the potential of HERFD-XANES spectroscopy to deepen our understanding of catalyst structures and consequently facilitate catalyst development.

The valorization of coffee waste has gained traction due to its potential to generate valuable products, lessen its impact on the environment, and promote sustainability. This review examines the diverse range of coffee waste, including pulp, husk, mucilage, and parchment from the upstream processing of green beans, as well as silverskin (coffee chaff) and spent coffee grounds (SCGs) generated during roasting and brewing. These materials are identified as valuable raw inputs for biorefineries pursuing a bio-circular economy. Recent research has yielded several viable applications for these by-products, categorized into four main areas: (1) agriculture, (2) biofuels and bioenergy, (3) biochemicals and biomaterials, and (4) food ingredients and nutraceuticals. Despite significant advancements in research, the industrial application of coffee waste remains limited. This review summarizes the global commercialization landscape, highlighting that SCGs are particularly advantageous for large-scale upcycling, with applications spanning agriculture, biofuels, and biochemicals. In contrast, coffee husk is primarily utilized in food ingredients and nutraceuticals. The review also addresses the challenges and constraints that must be overcome to facilitate successful commercialization.