Thermal Stability of High-Entropy Alloy Nanoparticles Evaluated by In Situ TEM Observations.

High-entropy alloy (HEA) nanoparticles (NPs) have attracted attention in several fields because of their fascinating properties. The high mechanical strength, good thermal stability, and superior corrosion resistance of HEAs, which are derived from their high configurational entropy, are attractive features. Herein, we investigated the thermal stability of FeCoNiCuPd HEA NPs on reduced graphene oxide via in situ transmission electron microscopy observations at elevated temperatures. The HEA NPs maintained their structure, size, and composition at 700 °C, and their size gradually decreased accompanied by the preferential sublimation of Cu. On the contrary, the deterioration of the monometallic Pd NPs begins at temperatures greater than 700 °C according to Ostwald ripening, which involves the migration of adatoms or mobile molecular species. Theoretical calculations revealed that the detachment of adatoms from clusters (i.e., the first step of Ostwald ripening) was suppressed in the case of HEA NPs because of the high-configuration-entropy effect.

Specific Hydrogen Spillover Pathways Generated on Graphene Oxide Enabling the Formation of Non-Equilibrium Alloy Nanoparticles.

The phenomenon of hydrogen spillover is investigated as a means of realizing a hydrogen-based society for over half a century. Herein, a graphene oxide having a precisely tuned architecture via calcination in air to introduce ether groups onto basal planes along with carbon defects is reported. This material provides specific pathways for the spillover of atomic hydrogen and has practical applications with regard to the synthesis of non-equilibrium solid-solution alloy nanoparticles. A combination of experimental work and simulations confirmed that the presence of ether groups associated with carbon defects facilitated hydrogen spillover within the basal planes of this graphene oxide. This enhanced hydrogen spillover ability, in turn, enables the simultaneous reduction of Ru3+ and Ni2+ ions to form RuNi alloy nanoparticles under hydrogen reduction conditions. Energy dispersive X-ray and X-ray absorption near edge structure simulations establish that this strategy forms unique alloy nanoparticles each comprising a Ru core with a RuNi solid-solution shell having a hexagonal close-packed structure. These non-equilibrium RuNi alloy nanoparticles exhibit greater catalytic activity than monometallic Ru nanoparticles during the hydrolysis of ammonia borane.

Human Induced Pluripotent Stem Cell-Derived Keratinocyte-Like Cells for Research on Protease-Activated Receptor 2 in Nonhistaminergic Cascades of Atopic Dermatitis .

Keratinocytes are the most abundant cells in the epidermis, and as part of the frontline immunologic defense system, keratinocytes function as a barrier to exogenous attacks. Protease-activated receptor 2 (PAR2) is expressed in human keratinocytes and activated in several inflammatory conditions, such as atopic dermatitis (AD). In this study, we demonstrated the differentiation of human induced pluripotent stem cell into keratinocytes by the improved, robust differentiation procedure and confirmed that human induced pluripotent stem cell-derived keratinocyte-like cells (iKera) express PAR2, which is activated by external addition of the ligand peptide and trypsin. The activation of PAR2 led to the release of calcium from intracellular calcium storage, followed by the release of the proinflammatory cytokine tumor necrosis factor α Moreover, PAR2 antagonist I-191 (CAS No. 1690172-25-8) inhibited calcium release in a dose-dependent manner. This is the first study to demonstrate that iKera expresses a functional PAR2 protein. Furthermore, our results indicate crosstalk between the PAR2- and IL-4-mediated inflammatory axes in iKera, suggesting that iKera can be used as a platform for a broad range of mechanism-targeted drug screening in AD. SIGNIFICANCE STATEMENT: This is the first study to provide evidence that human induced pluripotent stem cell-derived keratinocyte-like cells (iKera) express functional protease-activated receptor 2 (PAR2). Furthermore, this study demonstrated in iKera that the IL-4 inflammatory axis can crosstalk with the PAR2-mediated inflammatory axis in keratinocytes. To the best of our knowledge, this is the first report to indicate that iKera can be used for research and as a drug screening platform for atopic dermatitis.

Taurine Stimulates AMP-Activated Protein Kinase and Modulates the Skeletal Muscle Functions in Rats via the Induction of Intracellular Calcium Influx.

Taurine (2-aminoethanesulfonic acid) is a free amino acid abundantly found in mammalian tissues. Taurine plays a role in the maintenance of skeletal muscle functions and is associated with exercise capacity. However, the mechanism underlying taurine function in skeletal muscles has not yet been elucidated. In this study, to investigate the mechanism of taurine function in the skeletal muscles, the effects of short-term administration of a relatively low dose of taurine on the skeletal muscles of Sprague-Dawley rats and the underlying mechanism of taurine function in cultured L6 myotubes were investigated. The results obtained in this study in rats and L6 cells indicate that taurine modulates the skeletal muscle function by stimulating the expression of genes and proteins associated with mitochondrial and respiratory metabolism through the activation of AMP-activated protein kinase via the calcium signaling pathway.

Overcoming Acidic H2O2/Fe(II/III) Redox-Induced Low H2O2 Utilization Efficiency by Carbon Quantum Dots Fenton-like Catalysis.

Fenton reaction has important implications in biology- and environment-related remediation. Hydroxyl radicals (•OH) and hydroxide (OH-) were formed by a reaction between Fe(II) and hydrogen peroxide (H2O2). The acidic H2O2/Fe(II/III) redox-induced low H2O2 utilization efficiency is the bottleneck of Fenton reaction. Electron paramagnetic resonance, surface-enhanced Raman scattering, and density functional theory calculation indicate that the unpaired electrons in the defects of carbon quantum dots (CQDs) and the carboxylic groups at the edge have a synergistic effect on CQDs Fenton-like catalysis. This leads to a 33-fold higher H2O2 utilization efficiency in comparison with Fe(II)/H2O2 Fenton reaction, and the pseudo-first-order reaction rate constant (kobs) increases 38-fold that of Fe(III)/H2O2 under equivalent conditions. The replacement of acidic H2O2/Fe(II/III) redox with CQD-mediated Fe(II/III) redox improves the sluggish Fe(II) generation. Highly effective production of •OH in CQDs-Fe(III)/H2O2 dramatically decreases the selectivity of toxic intermediate benzoquinone. The inorganic ions and dissolved organic matter (DOM) in real groundwater show negligible effects on the CQDs Fenton-like catalysis process. This work presents a process with a higher efficiency of utilization of H2O2in situ chemical oxidation (ISCO) to remove persistent organic pollutants.

Effect of Long-Term Supplementation with Acetic Acid on the Skeletal Muscle of Aging Sprague Dawley Rats.

Mitochondrial function in skeletal muscle, which plays an essential role in oxidative capacity and physical activity, declines with aging. Acetic acid activates AMP-activated protein kinase (AMPK), which plays a key role in the regulation of whole-body energy by phosphorylating key metabolic enzymes in both biosynthetic and oxidative pathways and stimulates gene expression associated with slow-twitch fibers and mitochondria in skeletal muscle cells. In this study, we investigate whether long-term supplementation with acetic acid improves age-related changes in the skeletal muscle of aging rats in association with the activation of AMPK. Male Sprague Dawley (SD) rats were administered acetic acid orally from 37 to 56 weeks of age. Long-term supplementation with acetic acid decreased the expression of atrophy-related genes, such as atrogin-1, muscle RING-finger protein-1 (MuRF1), and transforming growth factor beta (TGF-ß), activated AMPK, and affected the proliferation of mitochondria and type I fiber-related molecules in muscles. The findings suggest that acetic acid exhibits an anti-aging function in the skeletal muscles of aging rats.

Dual Active Centers Bridged by Oxygen Vacancies of Ruthenium Single-Atom Hybrids Supported on Molybdenum Oxide for Photocatalytic Ammonia Synthesis.

Photocatalytic synthesis of ammonia (NH3 ) holds significant potential compared with the Haber-Bosch process. However, the reported photocatalysts suffer from low efficiency owing to localized electron deficiency. Herein, Ru-SA (single atoms)/Hx MoO3-y hybrids with abundant of Mon+ (4

Electrochemical Reactors for Continuous Decentralized H2 O2 Production.

The global utilization of H2 O2 is currently around 4 million tons per year and is expected to continue to increase in the future. H2 O2 is mainly produced by the anthraquinone process, which involves multiple steps in terms of alkylanthraquinone hydrogenation/oxidation in organic solvents and liquid-liquid extraction of H2 O2 . The energy-intensive and environmentally unfriendly anthraquinone process does not meet the requirements of sustainable and low-carbon development. The electrocatalytic two-electron (2 e- ) oxygen reduction reaction (ORR) driven by renewable energy (e.g. solar and wind power) offers a more economical, low-carbon, and greener route to produce H2 O2 . However, continuous and decentralized H2 O2 electrosynthesis still poses many challenges. This Minireview first summarizes the development of devices for H2 O2 electrosynthesis, and then introduces each component, the assembly process, and some optimization strategies.

Photocatalytic Dissolution of Precious Metals by TiO2 through Photogenerated Free Radicals.

Exploring the pathways for photocatalytic dissolution of precious metals (PMs) is crucial for optimizing recovery. In this work, we systematically investigated the selectivity and solvation effects observed for dissolution by focusing on photocatalysis, precious metals and solvents. By combining transient characterization, reaction kinetics, and density functional theory, we determined that the radicals generated in photocatalysis were the key active species in the entire reaction. The cyano functional group in the solvent was the driving factor for dissolution of gold, and the importance of chlorine radicals for dissolution of platinum group precious metals was further confirmed. In addition, the catalytic properties of different precious metals can promote different transformations of functional groups, leading to selective dissolution. The structures of photocatalytic precious metal leaches also precisely explains the special coordination forms of precious metals and functional group ligands.

Effects of long-term taurine supplementation on age-related changes in skeletal muscle function of Sprague-Dawley rats.

Taurine (2-aminoethanesulfonic acid) is a free amino acid found abundantly in mammalian tissues. Increasing evidence suggests that taurine plays a role in the maintenance of skeletal muscle function and increase of exercise capacity. Most energy drinks contain this amino acid; however, there is insufficient research on the effects of long-term, low-dose supplementation of taurine. In this study, we investigated the effects of long-term administration of taurine at low doses on aging in rodents. In Experiment 1, we examined age-related changes in aging Sprague-Dawley (SD) rats (32-92 weeks old) that O2 consumption and spontaneous activity decreased significantly with aging. In Experiment 2, we examined the effects of long-term (21-week) administration of taurine on healthy aging SD rats. SD rats were stabilized for 32-34 weeks and divided into three groups, administrated water (control), 0.5% taurine (25 mg/kg  body weight (BW)/day), or 1% taurine (50 mg/kg  BW/day) from age 34 to 56 weeks (5 days/week, 5 mL/kg BW). Our findings suggest that long-term administration of taurine at relatively low dose could attenuate the age-related decline in O2 consumption and spontaneous locomotor activity. Upon intestinal absorption, taurine might modulate age-related changes in respiratory metabolism and skeletal muscle function via peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), succinate dehydrogenase (SDH), cytochrome c (Cycs), myocyte enhancer factor 2A (MEF2A), glucose transporter 4 (GLUT4), and myoglobin, which are regulated by the activation of AMP-activated protein kinase (AMPK). This article examines the mechanism underlying the effects of taurine on age-related changes, which may have potential clinical implications.

How the Morphology of NiOx-Decorated CeO2 Nanostructures Affects Catalytic Properties in CO2 Methanation.

Effects of morphology and exposed crystal planes of NiOx-decorated CeO2 (NiCeO2) nanostructured catalysts on activity during CO2 methanation were examined, using nanorod (NR), nanocube (NC), and nanooctahedron (NO) structures. The NiCeO2 nanorods (NiCeO2-NR) showed superior activity to NiCeO2-NC and NiCeO2-NO along with excellent selectivity for CH4. This material also demonstrated exceptional durability, with no significant loss of catalytic activity or structural change after use. Comprehensive physicochemical characterization as well as density functional theory calculations determined that the high performance of the NiCeO2-NR was closely related to the large quantity of surface oxygen vacancies and the high degree of reversibility associated with the Ce4+ ↔ Ce3+ redox cycle of the support. These effects originate from the enhanced reactivity of oxygen atoms on the (110) surfaces of the oxide compared with the (100) and (111) surfaces. This information is expected to assist in the rational design of practical catalysts for the activation of CO2 molecules and other important transformations.

Characteristic evaluation of a simple hand-made semiconductor dosimeter for mammography.

Daily quality control of mammography equipment is important for providing optimal images and determining appropriate doses. To popularise dosimeters, the Measurement Division, the Japanese Society of Radiological Technology hold a seminar on making simple dosimeters. At this seminar, a hand-made dosimeter for mammography (HD-M) can be made at low cost. However, HD-Ms employ semiconductors, and their energy responses are subject to significant variations. This investigation involved the determination of precautions when using HD-Ms, examining their energy response characteristics and measurable energy ranges. HD-M has four types of selectors for response correction. When the selector and the tube voltage were equal, the HD-M readings matched that of the ionisation chamber within 5%. However, in case of target filter combinations and measuring tube voltages that the selector does not support, the HD-M readings differed by up to 53% from the ionisation chamber values. HD-M may use different measurement circuits and semiconductor elements depending on the time of the seminar. In this study, it was clarified that the correction factork, which is the average value of the ratio of the measured value of the ionisation chamber dosimeter to the measured value of HD-M, changes from 0.62 to 1.53 depending on irradiation conditions such as the combination of target filters and the tube voltage. It was demonstrated that HD-M functions sufficiently as a dosimeter for daily management by determining the correction factor using the method proposed in this study.

Construction of Hybrid MoS2 Phase Coupled with SiC Heterojunctions with Promoted Photocatalytic Activity for 4-Nitrophenol Degradation.

Phase engineering has been recognized as a promising method for boosting the catalytic activity of molybdenum sulfide (MoS2) in the field of electrocatalysts and photocatalysts. The metallic 1T-MoS2 exhibits much higher catalytic activity than natural semiconducting 2H-MoS2 but suffers from harsh synthetic conditions and metastable physical/chemical properties. The hybrid 1T/2H phase MoS2 shows higher catalytic activity than the 2H-MoS2 and exhibits better stability than the 1T-MoS2, which is more favorable than the 2H-MoS2 in the photocatalytic reactions. In this study, we report a hydrothermal synthesis of the hybrid 1T/2H-MoS2 phase coupled with SiC as a heterojunction photocatalyst for 4-nitrophenol (4-NP) degradation. SiC acts as a counterpart of the heterojunction structure and a morphology modifier, which dramatically promotes the reaction rate and visible light responsibility, providing new candidates and strategies in photocatalysis.

Design of Advanced Functional Materials Using Nanoporous Single-Site Photocatalysts.

Nanoporous silica solids can offer opportunities for hosting photocatalytic components such as various tetra-coordinated transition metal ions to form systems referred to as "single-site photocatalysts". Under UV/visible-light irradiation, they form charge transfer excited states, which exhibit a localized charge separation and thus behave differently from those of bulk semiconductor photocatalysts exemplified by TiO2 . This account presents an overview of the design of advanced functional materials based on the unique photo-excited mechanisms of single-site photocatalysts. Firstly, the incorporation of single-site photocatalysts within transparent porous silica films will be introduced, which exhibit not only unique photocatalytic properties, but also high surface hydrophilicity with self-cleaning and antifogging applications. Secondary, photo-assisted deposition (PAD) of metal precursors on single-site photocatalysts opens up a new route to prepare nanoparticles. Thirdly, visible light sensitive photocatalysts with single and/or binary oxides moieties can be prepared so as to use solar light, the ideal energy source.

Metal-organic framework-based nanomaterials for photocatalytic hydrogen peroxide production.

As an environmentally friendly and renewable energy source, hydrogen peroxide (H2O2) could be produced photocatalytically through selective two-electron reduction of O2 using effective photocatalysts. Metal organic frameworks (MOFs), as hybrid porous materials consisting of organic linkers and metal oxide clusters, have aroused great interest in the design of effective catalysts for photocatalysis under visible light irradiation due to their unique properties, such as large surface area, good chemical stability, and diverse and tunable chemical components. In this perspective, we highlight our recent progress in the application of various MOF-based nanomaterials for photocatalytic H2O2 production from the selective two-electron reduction of O2 in a single-phase system (acetonitrile) and two-phase system (water/benzyl alcohol). Photocatalytic H2O2 production in the single-phase system achieved a higher activity using NiO as a cocatalyst of the MOF rather than Pt. Photocatalytic H2O2 production in the two-phase system using various hydrophobic MOFs showed further improved activity compared to the single-phase system. It has been possible to design a hydrophobic MOF-based photocatalyst with high activity and stability under recycling conditions. These studies gathered in this perspective revealed the novel application of MOFs in the field of energy production.

DNA methylation accumulation in gastric mucosa adjacent to cancer after Helicobacter pylori eradication.

Molecular irreversibleness with Helicobacter pylori (H. pylori) infection might have a role in gastric tumorigenesis after H. pylori eradication. We performed comprehensive DNA methylation profiling of gastric mucosa after H. pylori eradication with or without gastric cancer. Using four different groups of biopsies obtained from gastric body without history of H. pylori infection (Hp-), gastric body without cancer after H. pylori eradication (cancer-free body), gastric body with early gastric cancer diagnosed after H. pylori eradication (EGC body) and their paired samples from adjacent mucosa of cancer (EGC ADJ), methylation status of five candidate genes (MYOD1, SLC16A12, IGF2, RORA and PRDM5) was examined by the bisulfite pyrosequencing. An Infinium Methylation EPIC BeadChip array was also used to characterize the methylation status of greater than 850,000 CpG sites. The EGC ADJ group showed highest methylation levels of five candidate genes among the four groups of biopsies. In the gastric body (cancer-free body + EGC body), methylation levels were significantly decreased in patients with longer period after eradication, while such association was not observed in EGC ADJ group. Hyper methylated samples were associated with shorter telomere, an indicator for rapid cell turnover, and higher DNMT1 protein expression, an enzyme related to methyl transfer reaction. The genome-wide methylation analysis demonstrated strikingly higher methylation levels especially at CpG islands in the EGC ADJ group. Exclusively hypermethylated promoter CpG islands in the same group frequently coded zinc finger proteins. Our data show that DNA methylation accumulation is associated with molecular irreversibleness and gastric carcinogenesis after H. pylori eradication.

Induced miR-31 by 5-fluorouracil exposure contributes to the resistance in colorectal tumors.

Drug resistance makes treatment difficult in cancers. The present study identifies and analyzes drug resistance-related miRNA in colorectal cancer. We established 4 types of 5-fluorouracil (5-FU)-resistant colon cancer cell lines in vitro and in vivo. We then analyzed the miRNA expression profile by miRNA array in these 4 cell lines, and identified the drug resistance-related miRNAs. We examined the expression levels of the identified miRNA in 112 colorectal tumor samples from the patients. We identified 12 possible miRNAs involved in 5-FU resistance by miRNA arrays. We then examined the relationship between miR-31, which was the most promising among them, and drug resistance. The ectopic expression of mimic miR-31 showed significant 5-FU resistance in the parental DLD-1 cells, while anti-miR-31 caused significant growth inhibition in DLD/F cells; that is, 5-FU-resistant colon cancer cell line DLD-1 under exposure to 5-FU. When we exposed high doses of 5-FU to parent or 5-FU-resistant cells, the expression levels of miR-31 were raised higher than those of controls. Notably, the expression levels of miR-31 were positively correlated with the grade of clinical stages of colorectal tumors. The protein expression levels of factors inhibiting hypoxia-inducible factor 1 were downregulated by transfection of mimic miR-31 into DLD-1 cells. This study provides evidence supporting the association of miR-31 with 5-FU drug resistance and clinical stages of colorectal tumors.

Identification of potential markers of fatal hypothermia by a body temperature-dependent gene expression assay.

Diagnosis of fatal hypothermia is considered to be difficult in forensic practice and even if findings due to cold exposure are evident, cold exposure is not necessarily a direct cause of death. Identification of useful molecular markers for the diagnosis of fatal hypothermia has not been successful. In this study, to identify novel molecular markers that inform the diagnosis of fatal hypothermia, we focused on skeletal muscle, which plays a role in cold-induced thermogenesis in mammals. We made rat models of mild, moderate, and severe hypothermia and performed body temperature-dependent gene expression analysis in the iliopsoas muscle using next-generation sequencing (NGS). NGS showed that after severe hypothermia, the expression levels of 91 mRNAs were more than double those in mild and moderate hypothermia and control animals. Gene ontology (GO) analysis indicated that these mRNAs are involved in a number of biological processes, including response to stress and lipids, and cellular response to hypoxia. The expression of four genes [connective tissue growth factor (Ctgf), JunB proto-oncogene, AP-1 transcription factor subunit (Junb), nuclear receptor subfamily 4, group A, member 1 (Nr4a1), and Syndecan 4 (Sdc4)] and the level of one protein (CTGF) were induced only by severe hypothermia. These genes and protein are involved in muscle regeneration, tissue repair, and lipid metabolism. These results indicate that heat production to maintain body temperature in a process leading to fatal hypothermia might be performed by the iliopsoas muscle, and that Ctgf, Junb, Nr4a1, and Sdc4 genes are potential diagnostic markers for fatal hypothermia.

Single-site and nano-confined photocatalysts designed in porous materials for environmental uses and solar fuels.

Silica-based micro-, meso-, macro-porous materials offer attractive routes for designing single-site photocatalysts, supporting semiconducting nanoparticles, anchoring light-responsive metal complexes, and encapsulating metal nanoparticles to drive photochemical reactions by taking advantage of their large surface area, controllable pore channels, remarkable transparency to UV/vis and tailorable physicochemical surface characteristics. This review mainly focuses on the fascinating photocatalytic properties of silica-supported Ti catalysts from single-site catalysts to nanoparticles, their surface-chemistry engineering, such as the hydrophobic modification and synthesis of thin films, and the fabrication of nanocatalysts including morphology controlled plasmonic nanostructures with localized surface plasmon resonance. The hybridization of visible-light responsive metal complexes with porous materials for the construction of functional inorganic-organic supramolecular photocatalysts is also included. In addition, the latest progress in the application of MOFs as excellent hosts for designing photocatalytic systems is described.

Two-Phase System Utilizing Hydrophobic Metal-Organic Frameworks (MOFs) for Photocatalytic Synthesis of Hydrogen Peroxide.

Much effort has been devoted to photocatalytic production of hydrogen peroxide (H2 O2 ) as an alternative to fossil fuels. From an economic point of view, reductive synthesis of H2 O2 from O2 coupled with the oxidative synthesis of value-added products is particularly interesting. We herein report application of MIL-125-NH2 , a photoactive metal-organic framework (MOF), to a benzylalcohol/water two-phase system that realized photocatalytic production and spontaneous separation of H2 O2 and benzaldehyde. Hydrophobization of the MOF enabled its separation from the aqueous phase. This resulted in enhanced photocatalytic efficiency and enabled application of various aqueous solutions including extremely low pH solution which is favorable for H2 O2 production but fatal to MOF structure. In addition, a highly concentrated H2 O2 solution was obtained by simply reducing the volume of the aqueous phase.