Local Structures of Ex-Solved Nanoparticles Identified by Machine-Learned Potentials.

In this study, we identify the local structures of ex-solved nanoparticles using machine-learned potentials (MLPs). We develop a method for training machine-learned potentials by sampling local structures of heterointerface configurations as a training set with its efficacy tested on the Ni/MgO system, illustrating that the error in interface energy is only 0.004 eV/Å2. Using the developed scheme, we train an MLP for the Ni/La0.5Ca0.5TiO3 ex-solution system and identify the local structures for both exo- and endo-type particles. The established model aligns well with the experimental observations, accurately predicting a nucleation size of 0.45 nm. Lastly, the density functional theory calculations on the established atomistic model verify that the kinetic barrier for the dry reforming of methane are substantially reduced by 0.49 eV on the ex-solved catalysts compared to that on the impregnated catalysts. Our findings offer insights into the local structures, growth mechanisms, and underlying origin of the catalytic properties of ex-solved nanoparticles.

Conductance stable and mechanically durable bi-layer EGaIn composite-coated stretchable fiber for 1D bioelectronics.

Deformable semi-solid liquid metal particles (LMP) have emerged as a promising substitute for rigid conductive fillers due to their excellent electrical properties and stable conductance under strain. However, achieving a compact and robust coating of LMP on fibers remains a persistent challenge, mainly due to the incompatibility of conventional coating techniques with LMP. Additionally, the limited durability and absence of initial electrical conductivity of LMP restrict their widespread application. In this study, we propose a solution process that robustly and compactly assembles mechanically durable and initially conductive LMP on fibers. Specifically, we present a shearing-based deposition of polymer-attached LMP followed by additional coating with CNT-attached LMP to create bi-layer LMP composite with exceptional durability, electrical conductivity, stretchability, and biocompatibility on various fibers. The versatility and reliability of this manufacturing strategy for 1D electronics are demonstrated through the development of sewn electrical circuits, smart clothes, stretchable biointerfaced fiber, and multifunctional fiber probes.

Ex-Solution Hybrids Functionalized on Oxide Nanofibers for Highly Active and Durable Catalytic Materials.

Ex-solution catalysts containing spontaneously formed metal nanoparticles socketed on the surface of reservoir oxides have recently been employed in various research fields including catalysis and sensing, due to the process efficiency and outstanding chemical/thermal stability. However, since the ex-solution process accompanies harsh reduction heat treatment, during which many oxides undergo phase decomposition, it restricts material selection and further advancement. Herein, we propose an elaborate design principle to uniformly functionalize ex-solution catalysts at porous oxide frameworks via an electrospinning process. As a case study, we selected the ex-solved La0.6Ca0.4Fe0.95Co0.05-xNixO3-δ (x = 0, 0.025 and 0.05) and SnO2 nanofibers as ex-solution hybrids and main frameworks, respectively. We confirmed superior dimethyl sulfide (C2H6S) gas sensing characteristics with excellent long-cycling stability. In particular, the high catalytic activities of ex-solved CoNiFe ternary nanoparticles, strongly socketed on reservoir oxide, accelerate the spillover process of O2 to dramatically enhance the response toward sulfuric analytes with exceptional tolerance. Altogether, our contribution represents an important stepping-stone to a rational design of ex-solved particle-reservoir oxide hybrids functionalized on porous oxide scaffolds for a variety of applications.

Dynamic Surface Evolution of Metal Oxides for Autonomous Adaptation to Catalytic Reaction Environments.

Metal oxides possessing distinctive physical/chemical properties due to different crystal structures and stoichiometries play a pivotal role in numerous current technologies, especially heterogeneous catalysis for production/conversion of high-valued chemicals and energy. To date, many researchers have investigated the effect of the structure and composition of these materials on their reactivity to various chemical and electrochemical reactions. However, metal oxide surfaces evolve from their initial form under dynamic reaction conditions due to the autonomous behaviors of the constituent atoms to adapt to the surrounding environment. Such nanoscale surface phenomena complicate reaction mechanisms and material properties, interrupting the clarification of the origin of functionality variations in reaction environments. In this review, the current findings on the spontaneous surface reorganization of metal oxides during reactions are categorized into three types: 1) the appearance of nano-sized second phase from oxides, 2) the (partial) encapsulation of oxide atoms toward supported metal surfaces, and 3) the oxide surface reconstruction with selective cation leaching in aqueous solution. Then their effects on each reaction are summarized in terms of activity and stability, providing novel insight for those who design metal-oxide-based catalytic materials.

Synthesis of Highly Tunable Alloy Nanocatalyst through Heterogeneous Doping Method.

The combination of supported metal nanoparticles and functional host oxides catalyze many major industrial reactions. However, uniform dispersion and ideal chemical configuration of such nanoparticles, which determines the catalytic activity, are often difficult to achieve. In this study, a unique combination is proposed of heterogeneous doping and ex-solution for the fabrication of Pt-Ni alloy nanoparticles on CeO2 . By manipulating the reducing conditions, both the particle size and composition are precisely controlled, thereby achieving a highly dispersed and stable alloy nanocatalyst. The unique behavior of controlled alloy composition is elucidated through classical diffusion and precipitation kinetics with elemental analysis of the grain boundaries. Finally, Pt-Ni alloy nanocatalysts are successfully tuned showcasing a breakthrough performance compared to single element catalyst in reverse water gas shift reaction with superior stability and reproducibility.

Promoting Ex-Solution from Metal-Organic-Framework-Mediated Oxide Scaffolds for Highly Active and Robust Catalysts.

Ex-solution catalysts, in which a host oxide is decorated with confined metallic nanoparticles, have exhibited breakthrough activity in various catalytic reactions. However, catalysts prepared by conventional ex-solution processes are limited by the low surface area of host oxides, the limited solubility of dopants, and the incomplete conversion of doped cations into metal catalysts. Here, the design of the host oxide structure is reconceptualized using a metal-organic framework (MOF) as an oxide precursor that can absorb a large quantity of ions while also promoting ex-solution at low temperatures (400-500 °C). The MOF-derived metal oxide host can readily incorporate metal cations, from which catalytic nanoparticles can be uniformly ex-solved owing to the short diffusion length in the nano-sized oxides. The distinct ex-solution behaviors of Pt, Pd, and Rh, and their bimetallic combinations are investigated. The MOF-driven mesoporous ZnO particles functionalized with PdPt catalysts ex-solved at 500 °C show benchmark-level of acetone oxidation activity as well as acetone-sensing characteristics by accelerating both oxygen chemisorption and acetone dissociation. Their findings provide a new route for the preparation of highly active catalysts by engineering the architecture and composition of the host oxide to facilitate the ex-solution process rationally.

Extracellular vesicles from dHL-60 cells as delivery vehicles for diverse therapeutics.

Extracellular vesicles (EVs) are membrane-derived heterogeneous vesicles that mediate intercellular communications. They have recently been considered as ideal vehicles for drug-delivery systems, and immune cells are suggested as a potential source for drug-loaded EVs. In this study, we investigated the possibility of neutrophils as a source for drug-loaded EVs. Neutrophil-like differentiated human promyelocytic leukemia cells (dHL-60) produced massive amounts of EVs within 1 h. The dHL-60 cells are also easily loaded with various cargoes such as antibiotics (penicillin), anticancer drug (paclitaxel), chemoattractant (MCP-1), miRNA, and Cas9. The EVs derived from the dHL-60 cells showed efficient incorporation of these cargoes and significant effector functions, such as bactericidal activity, monocyte chemotaxis, and macrophage polarization. Our results suggest that neutrophils or neutrophil-like promyelocytic cells could be an attractive source for drug-delivery EVs.

Neutrophil-derived trail is a proinflammatory subtype of neutrophil-derived extracellular vesicles.

Aims: Extracellular vesicles (EVs) are membrane-derived vesicles that mediate intercellular communications. Neutrophils produce different subtypes of EVs during inflammatory responses. Neutrophil-derived trails (NDTRs) are generated by neutrophils migrating toward inflammatory foci, whereas neutrophil-derived microvesicles (NDMVs) are thought to be generated by neutrophils that have arrived at the inflammatory foci. However, the physical and functional characteristics of neutrophil-derived EVs are incompletely understood. In this study, we aimed to investigate the differences between NDTRs and NDMVs. Methods: The generation of neutrophil-derived EVs were visualized by live-cell fluorescence images and the physical characteristics were further analyzed using nanotracking analysis assay, scanning electron microscopic analysis, and marker expressions. Functional characteristics of neutrophil-derived EVs were analyzed using assays for bactericidal activity, monocyte chemotaxis, phenotype polarization of macrophages, and miRNA sequencing. Finally, the effects of neutrophil-derived EVs on the acute and chronic inflammation were examined in vivo. Results: Both EVs share similar characteristics including stimulators, surface marker expression, bactericidal activity, and chemoattractive effect on monocytes via MCP-1. However, the integrin-mediated physical interaction was required for generation of NDTRs whereas NDMV generation was dependent on PI3K pathway. Interestingly, NDTRs contained proinflammatory miRNAs such as miR-1260, miR-1285, miR-4454, and miR-7975, while NDMVs contained anti-inflammatory miRNAs such as miR-126, miR-150, and miR-451a. Although both EVs were easily uptaken by monocytes, NDTRs enhanced proinflammatory macrophage polarization whereas NDMVs induced anti-inflammatory macrophage polarization. Moreover, NDTRs showed protective effects against lethality in a murine sepsis model and pathological changes in a murine chronic colitis model. Conclusion: These results suggest that NDTR is a proinflammatory subtype of neutrophil-derived EVs distinguished from NDMV.

Nanoparticle Ex-solution for Supported Catalysts: Materials Design, Mechanism and Future Perspectives.

Supported metal catalysts represent one of the major milestones in heterogeneous catalysis. Such catalytic systems are feasible for use in a broad range of applications, including renewable energy devices, sensors, automotive emission control systems, and chemical reformers. The lifetimes of these catalytic platforms depend strongly on the stability of the supported nanoparticles. With this regard, nanoparticles synthesized via ex-solution process emphasize exceptional robustness as they are socketed in the host oxide. Ex-solution refers to a phenomenon which yields selective growth of fine and uniformly distributed metal nanocatalysts on oxide supports upon partial reduction. This type of advanced structural engineering is a game-changer in the field of heterogeneous catalysis with numerous studies showing the benefits of ex-solution process. In this review, we highlight the latest research efforts regarding the origin of the ex-solution phenomenon and the mechanism underpinning particle formation. We also propose research directions to expand the utility and functionality of the current ex-solution techniques.

Dopant-Driven Positive Reinforcement in Ex-Solution Process: New Strategy to Develop Highly Capable and Durable Catalytic Materials.

The ex-solution phenomenon, a central platform for growing metal nanoparticles on the surface of host oxides in real time with high durability and a fine distribution, has recently been applied to various scientific and industrial fields, such as catalysis, sensing, and renewable energy. However, the high-temperature processing required for ex-solutions (>700 °C) limits the applicable material compositions and has hindered advances in this technique. Here, an unprecedented approach is reported for low-temperature particle ex-solution on important nanoscale binary oxides. WO3 with a nanosheet structure is selected as the parent oxide, and Ir serves as the active metal species that produces the ex-solved metallic particles. Importantly, Ir doping facilitates a phase transition in the WO3 bulk lattice, which further promotes Ir ex-solution at the oxide surface and eventually enables the formation of Ir particles (<3 nm) at temperatures as low as 300 °C. Low-temperature ex-solution effectively inhibits the agglomeration of WO3 sheets while maintaining well-dispersed ex-solved particles. Furthermore, the Ir-decorated WO3 sheets show excellent durability and H2 S selectivity when used as sensing materials, suggesting that this is a generalizable synthetic strategy for preparing highly robust heterogeneous catalysts for a variety of applications.

Exceptional Tunability over Size and Density of Spontaneously Formed Nanoparticles via Nucleation Dynamics.

The ex-solution process, in which metal nanoparticles are grown on a host oxide, can be used to synthesize nanocatalysts with excellent thermal and chemical durability via spontaneous heterogeneous nucleation. However, this technique lacks a means to control the particle size and density because the amounts of ex-solved metal elements vary with the reduction conditions. Here, we devise a strategy to achieve small particle sizes and high particle densities concurrently by controlling the temperature (T), oxygen partial pressure (pO2) and ramping rate of the temperature. Quantitative analyses of Co particles ex-solved on Sr0.98Ti0.95Co0.05O3-δ thin films using ex situ SEM and in situ TEM reveal that the increasing T and decreasing the pO2 lead to smaller particle sizes with higher density levels and vice versa, contrary to common ex-solution examples. We find that nucleation thermodynamics dictates such counterintuitive behaviors of particle characteristics, which are attributed to our specific ex-solution conditions in which particle interactions are minimized and all the Co atoms are ex-solved under highly reducible conditions. We also demonstrated the feasibility of our strategy via CO oxidation with typical powder-based catalysts, suggesting that this method can be extended to various chemical/electrochemical applications.

Growth Kinetics of Individual Co Particles Ex-solved on SrTi0.75Co0.25O3-δ Polycrystalline Perovskite Thin Films.

A precise control of the size, density, and distribution of metal nanoparticles dispersed on functional oxide supports is critical for promoting catalytic activity and stability in renewable energy and catalysis devices. Here, we measure the growth kinetics of individual Co particles ex-solved on SrTi0.75Co0.25O3-δ polycrystalline thin films under a high vacuum, and at various temperatures and grain sizes using in situ transmission electron microscopy. The ex-solution preferentially occurs at grain boundaries and corners which appear essential for controlling particle density and distribution, and enabling low temperature ex-solution. The particle reaches a saturated size after a few minutes, and the size depends on temperature. Quantitative measurements with a kinetic model determine the rate limiting step, vacancy formation enthalpy, ex-solution enthalpy, and activation energy for particle growth. The ex-solved particles are tightly socketed, preventing interactions among them over 800 °C. Furthermore, we obtain the first direct clarification of the active reaction site for CO oxidation-the Co-oxide interface, agreeing well with density functional theory calculations.

In situ synthesis of supported metal nanocatalysts through heterogeneous doping.

Supported metal nanoparticles hold great promise for many fields, including catalysis and renewable energy. Here we report a novel methodology for the in situ growth of architecturally tailored, regenerative metal nanocatalysts that is applicable to a wide range of materials. The main idea underlying this strategy is to selectively diffuse catalytically active metals along the grain boundaries of host oxides and then to reduce the diffused metallic species to form nanoclusters. As a case study, we choose ceria and zirconia, the most recognized oxide supports, and spontaneously form various metal particles on their surface with controlled size and distribution. Metal atoms move back and forth between the interior (as cations) and the exterior (as clusters) of the host oxide lattice as the reductive and oxidative atmospheres repeat, even at temperatures below 700 °C. Furthermore, they exhibit excellent sintering/coking resistance and reactivity toward chemical/electrochemical reactions, demonstrating potential to be used in various applications.

Dataset on the changes of neutrophils treated with retinoic acid.

The data presented in this article are related to the research article entitled "Retinoic acid induces hypersegmentation and enhances cytotoxicity of neutrophils against cancer cells" (S. Shrestha, S.Y. Kim, Y.J. Young, J.K. Kim, J.M. Lee, M. Shin, D.K. Song, C.W. Hong, 2017) [1]. This article complements the potential of retinoic acid to induce changes in effector function of human neutrophils. Here the datasets describe the rate of apoptosis, changes in numbers of nuclear lobes, and the expressions of surface markers in human neutrophils in presence or absence of retinoic acid. The tumor growth in recipient mice with adoptive transfer of retinoic acid-treated neutrophils was evaluated. The included data is made publicly available to criticism and extended analysis.

Autophagy Primes Neutrophils for Neutrophil Extracellular Trap Formation during Sepsis.

RATIONALE: Neutrophils are key effectors in the host's immune response to sepsis. Excessive stimulation or dysregulated neutrophil functions are believed to be responsible for sepsis pathogenesis. However, the mechanisms regulating functional plasticity of neutrophils during sepsis have not been fully determined. OBJECTIVES: We investigated the role of autophagy in neutrophil functions during sepsis in patients with community-acquired pneumonia. METHODS: Neutrophils were isolated from patients with sepsis and stimulated with phorbol 12-myristate 13-acetate (PMA). The levels of reactive oxygen species generation, neutrophil extracellular trap (NET) formation, and granule release, and the autophagic status were evaluated. The effect of neutrophil autophagy augmentation was further evaluated in a mouse model of sepsis. MEASUREMENTS AND MAIN RESULTS: Neutrophils isolated from patients who survived sepsis showed an increase in autophagy induction, and were primed for NET formation in response to subsequent PMA stimulation. In contrast, neutrophils isolated from patients who did not survive sepsis showed dysregulated autophagy and a decreased response to PMA stimulation. The induction of autophagy primed healthy neutrophils for NET formation and vice versa. In a mouse model of sepsis, the augmentation of autophagy improved survival via a NET-dependent mechanism. CONCLUSIONS: These results indicate that neutrophil autophagy primes neutrophils for increased NET formation, which is important for proper neutrophil effector functions during sepsis. Our study provides important insights into the role of autophagy in neutrophils during sepsis.

Retinoic acid induces hypersegmentation and enhances cytotoxicity of neutrophils against cancer cells.

Hypersegmentation of nuclei is considered a distinct characteristic of the antitumoral phenotype of neutrophils. Retinoic acid, a metabolite of retinol, reorganizes and induces segmentation of the nucleus during the differentiation of neutrophils. However, the role of retinoic acid in the phenotype polarization of neutrophils has not been fully established. Here, we investigated the effect of retinoic acid on phenotype polarization of neutrophils. Retinoic acid-induced the hypersegmentation of human neutrophils via retinoic acid receptors and mTOR pathways. Retinoic acid-induced hypersegmented neutrophils enhanced neutrophil extracellular traps (NETs) formation in response to phorbol-12-myristate 13-acetate (PMA) and fMLP (N-Formylmethionine-leucyl-phenylalanine) stimulation, and increased cytotoxicity against various tumor cells. Moreover, retinoic acid treatment attenuated tumor growth in a murine model of tumor. Taken together, these results suggests that retinoic acid induces the phenotype polarization of neutrophils to exert antitumor effects.

Effects of korean red ginseng on hearing and blood glucose levels in steroid therapy for sudden sensorineural hearing loss.

OBJECTIVES: Korean red ginseng (KRG) has hypoglycemic, antioxidant, antithrombotic, and other beneficial effects in human. The present study evaluate the therapeutic effects of KRG on hearing recovery and glucocorticoid-induced hyperglycemia in patients with idiopathic sudden sensorineural hearing loss (SSNHL) undergoing systemic steroid therapy. METHODS: The patients were divided into 2 groups: the steroid, and the combination of steroid and red ginseng. Pure tone averages (PTA) were assessed at the first visit and 2-month follow-up. All patients underwent fasting blood glucose analyses just before and on the fifth day of treatment. Both groups were treated with a 10-day course of oral methylprednisolone at tapering doses starting from a daily dose of 48 mg. To the combination group, KRG extract was administered by mouth at a daily dose of 3 g for 20 days in addition to methylprednisolone. Hearing gain was calculated comparing the initial PTA and PTA at 2 months' follow-up. Treatment responses were classified according to Siegel's criteria. RESULTS: Pretreatment conditions were similar between the steroid (n=37) and combination groups (n=36). At 2 months after the treatment, PTA improved significantly in both groups, but there was no significant difference in the mean hearing gain & recovery rate. The non-diabetic subjects in the steroid group (n=27) exhibited a 24% increase in the mean blood glucose level during the systemic steroid therapy, while those in the combination group (n=34) showed no changes. CONCLUSION: Although the KRG did not provide greater therapeutic effects on hearing recovery, we suggest that red ginseng can be a useful adjuvant to the current steroid therapy to normalize glucocorticoid-induced hyperglycemia in non-diabetic patients during the treatment of SSNHL.

Efficacy of intratympanic steroid therapy for idiopathic sudden sensorineural hearing loss: comparison with systemic steroid therapy and combined therapy.

CONCLUSION: Intratympanic steroid therapy (IT-S) was as effective as systemic steroid therapy (SST) or combined therapy (CT) and could be considered a first-line therapeutic modality for idiopathic sudden sensorineural hearing loss (SSNHL). Due to its known safety and efficacy, IT-S will be particularly suitable for patients with SSNHL who have chronic diseases such as diabetes mellitus, hypertension, or chronic renal failure. OBJECTIVES: Systemic high dose steroid therapy is the main therapeutic modality for SSNHL. Comparable therapeutic efficacies for IT-S and CT with SST and IT-S for SSNHL have been reported recently. We compared the efficacy of IT-S, SST, and CT for treating SSNHL. METHODS: A retrospective, multicenter study investigating the therapeutic efficacy of SST, IT-S, and CT for SSNHL was designed and involved 735 patients with idiopathic SSNHL who were diagnosed and treated at seven tertiary referral medical centers of the Catholic University of Korea between 2007 and 2011. Patients were divided into three groups according to the treatment methods they received: IT-S group, SST group, and CT group (SS plus IT-S). Hearing was evaluated by pure tone audiogram performed before initial treatment and at 4 weeks following the final treatment. More than a 10 dB HL decrease in average air conduction threshold of hearing at 500, 1000, 2000, and 3000 Hz was defined as improved hearing. RESULTS: Among 735 patients with SSNHL, 94 were included in the IT-S group, 444 in the SST, and 197 in the CT group. Age, gender, interval from disease onset to start of treatment, and initial hearing level were not different among the three groups. Patients who had concomitant medical disorders such as diabetes mellitus, hypertension, or chronic renal failure were more frequently treated with IT-S. No difference in the level of hearing gain or ratio of hearing improvement was observed among the three groups (p = 0.147 and p = 0.067, respectively).

Vasoconstriction potency induced by aminoamide local anesthetics correlates with lipid solubility.

Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency) of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine) were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED(50)) of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED(50)) of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED(50) in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (r(2) = 0.9563; P < 0.001). The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa.

Anatomic limitations of posterior tympanotomy: what is the major radiologic determinant for the view field through posterior tympanotomy?

To radiologically evaluate the anatomic factors that may determine the view field or the accessibility of the posterior tympanotomy into the posterior mesotympanum, a cohort of 30 patients with pneumatic mastoids and 30 patients with unilateral sclerotic mastoids were included. Anatomic relationships were evaluated according to 5 parameters. The reference parameter of the view field through posterior tympanotomy was the maximum view to the stapes area through posterior tympanotomy. Direct distance between the chorda tympani nerve and the facial nerve (FN) and angle between the cortex of the external auditory canal and the FN showed significant positive correlations in pneumatic and sclerotic mastoids. However, the location of the FN was negatively correlated with the maximum view to the stapes area through posterior tympanotomy only in pneumatic mastoids. In particular, the angle between the cortex of the external auditory canal and the FN showed the best correlation with the maximum view to the stapes area through posterior tympanotomy. The angle between the cortex of the external auditory canal and the FN was the most important anatomic determinant for visibility through posterior tympanotomy. This study suggests that pneumatic mastoids, but not sclerotic mastoids, may have a more complex relationship including more factors than those considered in this study. Although this study was performed radiologically, this study can present the insight to surgeons or radiologists.