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Rupture disk corrosion test (RDCT) method has been recently developed for real-time measurement of initiation of stress corrosion cracking (SCC) in a high-temperature water. This work presents a parametric study on the stress distribution of a thin disk specimen of RDCT to consider the fixture shape and friction using finite element analysis (FEA). The FEA results showed a dome-shaped deformation of the specimen. From the stress analysis as a function of friction coefficient, it was suggested that the maximum stress was applied around the dome-edge, which was invariant with change to the friction coefficient. This indicates that friction between the fixture and the specimen has little effect on stress distribution. On the other hand, the stress analysis as a function of a rounded-corner radius (Rc) revealed the location at which the maximum stress was applied shifted from the dome edge to the dome center as Rc increased. From SCC initiation tests using the RDCT apparatus in a primary water environment, it was found that SCC initiates at the dome edge when Rc is 0.5 mm, while SCC initiates near the disk center when Rc is 2.0 mm. This experimental result is in good agreement with the results of FEA.

Despite the extensive global consumption of architectural paint, the toxicological effects of aged exterior paint particles on terrestrial biota remain largely uncharacterized. Herein, we assessed the toxic effect of aged paint particles on soil environments using the nematode Caenorhabditis elegans(C. elegans) as a test organism. Various types of paint particles were generated by fragmentation and sequential sieving (500–1000, 250–500, 100–250, 50–100, 20–50 μm) of paint coatings collected from two old residential areas. The paint particles exerted different levels of toxicity, as indicated by a reduction in the number of C. elegansoffspring, depending on their size, color, and layer structure. These physical characteristics were found to be closely associated with the chemical heterogeneity of additives present in the paint particles. Since the paint particle sizes were larger than what C. eleganstypically consume, we attributed the toxicity to leachable additives present in the paint particles. To assess the toxicity of these leachable additives, we performed sequential washings of the paint particles with distilled water and ethanol. Ethanol washing of the paint particles significantly reduced the soil toxicity of the hydrophobic additives, indicating their potential environmental risk. Liquid chromatography–mass spectrometry analysis of the ethanol leachate revealed the presence of alkyl amines, which exhibited a high correlation with the toxicity of the paint particles. Further toxicity testing using an alkyl amine standard demonstrated that a paint particle concentration of 1.2% in soil could significantly reduce the number of C. elegansoffspring. Our findings provide insights into the potential hazards posed by aged paint particles and their leachable additives in the terrestrial environment.

Fresh ginseng is prone to spoilage due to its high moisture content. For long-term storage, most fresh ginsengs are dried to white ginseng (WG) or steamed for hours at high temperature/pressure and dried to form Korean Red ginseng (KRG). They are further processed for ginseng products when subjected to hot water extraction/concentration under pressure. These WG or KRG preparation processes affect ginsenoside compositions and also other ginseng components, probably during treatments like steaming and drying, to form diverse bioactive phospholipids. It is known that ginseng contains high amounts of gintonin lysophosphatidic acids (LPAs). LPAs are simple lipid-derived growth factors in animals and humans and act as exogenous ligands of six GTP-binding-protein coupled LPA receptor subtypes. LPAs play diverse roles ranging from brain development to hair growth in animals and humans. LPA-mediated signaling pathways involve various GTP-binding proteins to regulate downstream pathways like [Ca2+]itransient induction. Recent studies have shown that gintonin exhibits anti-Alzheimer's disease and anti-arthritis effects in vitroand in vivomediated by gintonin LPAs, the active ingredients of gintonin, a ginseng-derived neurotrophin. However, little is known about how gintonin LPAs are formed in high amounts in ginseng compared to other herbs. This review introduces atypical or non-enzymatic pathways under the conversion of ginseng phospholipids into gintonin LPAs during steaming and extraction/concentration processes, which exert beneficial effects against degenerative diseases, including Alzheimer's disease and arthritis in animals and humans via LPA receptors.

An integrated CO2capture and direct methanation (ICCM) system has recently gained significant attention as a promising process to produce value-added chemicals. Compared to conventional CO2capture and utilization, ICCM is a simplified process that directly converts captured CO2without purification at lower thermal inputs. One of the primary limitations is the deactivation of the sorbent and the embedded catalysts after several thermal cycles. In this study, we formulated thermally stable macroporous structured Ni/CaO dual function materials (DFMs) by incorporating a Zr stabilizer. The textural properties, porosity, CO2capture performance, and catalytic activity of Zr-modified Ni/CaO (Ni/CaZr) were assessed. In situDRIFTS was used to investigate the possible intermediates and reactions during the ICCM. It was found that CH4is produced from the formate and methoxy intermediates route on the CaO surface and the CO intermediate route on the Ni surface. Ni/CaZr had improved thermal stability with the best CO2capture capacity (13–14 mmol of CO2/g), CH4productivity (13–14 mmol of CH4/g), CO2sorption, and desorption kinetics at 500 °C. The benefit of adding Zr for ICCM enhanced the macroporous structures, which enhanced the CO2mass transport and prevented the sintering of Ni and CaO.

A series of 1,4‐bis(N‐alkylpyrrolidinium)butane salts combined with Br−, I−, PF6−, and Tf2N−anions were newly designed and synthesized. In nonpolar CDCl3solution, the axial and equatorial proton peaks of the bis‐pyrrolidinium cation ring are distinguished in 1H NMR. Also, the strengths of ion paring could be estimated from the 1H NMR chemical shift changes of the bridge and pyrrolidinium proton peaks. 1,4‐Bis(N‐hepthylpyrrolidinium)butane I−is an organic ionic plastic crystal showing the lowest fusion entropy value (ΔSf= 3.4 J K·mol−1). Softer crystalline morphologies were found by polarized optical microscope images at plastic crystal phase of each sample and the results were corresponding to differential scanning calorimetry results. 1,4‐Bis(N‐ethylpyrrolidinium)butane Tf2N−showed the softest crystal phase. Ionic conductivity changes and electrochemical stabilities of the bis‐pyrrolidinium PF6−and Tf2N−salts were also measured, and they were stable up to 4.3 V (vs. Li/Li+) and expected to be applied as an electrolyte component. Newly synthesized bis‐pyrrolidinium salts with different Br−, I−, PF6−, and Tf2N−anions are fully characterized for future applications of an electrolyte component of electrochemical devices. These bis‐pyrrolidinium salts have a plastic crystal phase following unique solid–solid phase transitions, morphology changes, and low fusion entropy values. They are electrochemical stable up to 4.3 V.

ABSTRACTThis study provides a new leaching method for selective recovery of manganese from the spent NCM-based cathode active material of lithium-ion secondary batteries (LIBs). The recovery method involves the use of aqueous Mn(II) phase spontaneously generated in sulfate media as a reducing agent, in which Ni(III) and Co(III) are reduced to soluble species while Mn(II) precipitates as Mn(IV) oxides simultaneously. To optimize the process, the effects of time, temperature, and acid concentration on the leaching behavior were investigated. As a result, two-step successive leaching at an optimal condition was proposed, by which the dissolution efficiency of Co and Ni reached up to 99% and ~100%, respectively while Mn leaching was restricted to 15.5%. The leaching residue mainly consisted of manganese oxide (MnO2), containing Mn ~40%. The amount of Mn in the residue increased to ~70% by calcinating at 650 °C, which converted its phase into Mn2O3and Mn3O4. Therefore, our two-step leaching technique will lead to the recovery of nearly all the contents of Li, Co, and Ni in addition to ~70% purity Mn as supplemental benefit from spent LIB materials without using any oxidants or reductants.

ABSTRACTThis study developed a method to assess a building’s risk against disaster, tentatively named the Korean Integrated Disaster Evaluation Simulator (K-IDES). Based on previous studies analyzing FEMA’s risk management series in the US, the FEMA IRVS was selected as a case study for developing a framework for the K-IDES. Through the comparative analysis of domestic building design guides, codes, and special legislation related to disasters, a risk assessment methodology for quantitative results was developed. The assessment method consists of a classification system, a calculation for the quantification of risk, and a simulation in which the developed checklist for the K-IDES is applied to similar types of high-rise buildings to validate its accuracy. The final goal was to systemize an integrated risk management strategy for a building against disasters, checking for vulnerable areas from the conceptual stage of the design, and to utilize the risk management strategy after construction.

A new relative quantification strategy for glycomics, named deuterium oxide (D2O) labeling for global omics relative quantification (DOLGOReQ), has been developed based on the partial metabolic D2O labeling, which induces a subtle change in the isotopic distribution of glycan ions. The relative abundance of unlabeled to D-labeled glycans was extracted from the overlapped isotopic envelope obtained from a mixture containing equal amounts of unlabeled and D-labeled glycans. The glycan quantification accuracy of DOLGOReQ was examined with mixtures of unlabeled and D-labeled HeLa glycans combined in varying ratios according to the number of cells present in the samples. The relative quantification of the glycans mixed in an equimolar ratio revealed that 92.4 and 97.8% of the DOLGOReQ results were within a 1.5- and 2-fold range of the predicted mixing ratio, respectively. Furthermore, the dynamic quantification range of DOLGOReQ was investigated with unlabeled and D-labeled HeLa glycans mixed in different ratios from 20:1 to 1:20. A good correlation (Pearson’s r> 0.90) between the expected and measured quantification ratios over 2 orders of magnitude was observed for 87% of the quantified glycans. DOLGOReQ was also applied in the measurement of quantitative HeLa cell glycan changes that occur under normoxic and hypoxic conditions. Given that metabolic D2O labeling can incorporate D into all types of glycans, DOLGOReQ has the potential as a universal quantification platform for large-scale comparative glycomic experiments.

In the last decade, several advancements have been made in omics technologies and they have been applied extensively in diverse research areas. Especially in toxicological research, omics technology can efficiently and accurately generate relevant data on the molecular dynamics associated with adverse outcomes. Toxicomics is defined as the combination of toxicology and omics technologies and encompasses toxicogenomics, toxicoproteomics, and toxicometabolomics. This paper reviews the trend of applying omics technologies to evaluate cadmium (Cd) toxicity in zebrafish (D. rerio). Cd is a toxic heavy metal posing several environmental concerns; however, it is being used widely in everyday life. Zebrafish embryos and larvae are employed as standard models for many toxicity tests because they share 71.4% genetic homology with humans. This study summarizes the toxicity of Cd on the nerves, liver, heart, skeleton, etc. of zebrafish and introduces detailed omics techniques to understand the results of the toxicomic studies. Finally, the trend of toxicity evaluation in the zebrafish model of Cd based on omics technology is presented.

Background: Despite improvements in the mechanical properties of alumina ceramics, the outcome of total hip arthroplasty (THA) with contemporary ceramic bearings in young patients remains a matter of concern. We evaluated the results of cementless THA with the use of the delta ceramic bearing, and determined the prevalence of osteolysis, squeaking, and ceramic fracture in patients aged < 30 years at mid-term.Methods: From March 2008 to January 2012, 76 consecutive patients (91 hips), younger than 30 years, underwent cementless THA with Delta ceramic bearings. In each follow-up, the clinical evaluation including noise and radiological evaluations were recorded.Results: Among them, 72 patients (86 THAs) were followed-up for a minimum of 5 years (mean 70.8; 60−95.9 months). There were 44 men (47 hips) and 28 women (39 hips). The mean age at the time of the index arthroplasty was 25.9 (16−30) years and the mean preoperative Harris Hip Score (HHS) was 59.4 (23−79) points. HHS improved to 96.3 (64−100) points at the final follow-up evaluation. 8 hips (9.3%) exhibited grinding or squeaking. No hip had aseptic loosening and no hip was revised. No osteolysis was detected around any acetabular or femoral components.Conclusions: Our results suggest that cementless THA with the use of Delta ceramic bearing provides satisfactory results without osteolysis or ceramic fracture in patients aged <30 years at a mid-term follow-up. Clinical Trials.gov Protocol Registration System (trial no. NCT01838096).

ObjectiveThe mechanisms underlying type 2 diabetes resolution after Roux-en-Y gastric bypass (RYGB) are unclear. We suspected that glucose excretion may occur in the small bowel based on observations in humans. The aim of this study was to evaluate the mechanisms underlying serum glucose excretion in the small intestine and its contribution to glucose homeostasis after bariatric surgery.Design2-Deoxy-2-[18F]-fluoro-D-glucose (FDG) was measured in RYGB-operated or sham-operated obese diabetic rats. Altered glucose metabolism was targeted and RNA sequencing was performed in areas of high or low FDG uptake in the ileum or common limb. Intestinal glucose metabolism and excretion were confirmed using 14C-glucose and FDG. Increased glucose metabolism was evaluated in IEC-18 cells and mouse intestinal organoids. Obese or ob/obmice were treated with amphiregulin (AREG) to correlate intestinal glycolysis changes with changes in serum glucose homeostasis.ResultsThe AREG/EGFR/mTOR/AKT/GLUT1 signal transduction pathway was activated in areas of increased glycolysis and intestinal glucose excretion in RYGB-operated rats. Intraluminal GLUT1 inhibitor administration offset improved glucose homeostasis in RYGB-operated rats. AREG-induced signal transduction pathway was confirmed using IEC-18 cells and mouse organoids, resulting in a greater capacity for glucose uptake via GLUT1 overexpression and sequestration in apical and basolateral membranes. Systemic and local AREG administration increased GLUT1 expression and small intestinal membrane translocation and prevented hyperglycaemic exacerbation.ConclusionBariatric surgery or AREG administration induces apical and basolateral membrane GLUT1 expression in the small intestinal enterocytes, resulting in increased serum glucose excretion in the gut lumen. Our findings suggest a novel, potentially targetable glucose homeostatic mechanism in the small intestine.

With increasing interest in the effects of microplastics on the soil environment, there is a need to thoroughly evaluate the potential adverse effects of these particles as a function of their characteristics (size, shape, and composition). In addition, extractable chemical additives from microplastics have been identified as an important toxicity pathway in the aquatic environment. However, currently, little is known about the effects of such additives on the soil environment. In this study on nematodes (Caenorhabditis elegans), we adopted an ecotoxicological approach to assess the potential effects of 13 different microplastics (0.001–1% of soil dry weight) with different characteristics and extractable additives. We found that poly(ethylene terephthalate) (PET) fragments and polyacrylicnitrile (PAN) fibers show the highest toxicity, while high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS) fragments induced relatively less adverse effects on nematodes. In addition, low-density polyethylene (LDPE) induced no toxicity within our test concentration range for the acute period. Acute toxicity was mainly attributed to the extractable additives: when the additives were extracted, the toxic effects of each microplastic disappeared in the acute soil toxicity test. The harmful effects of the LDPE films and PAN fibers increased when the microplastics were maintained in the soil for a long-term period with frequent wet–dry cycles. We here provide clear evidence that microplastic toxicity in the soil is highly related to extractable additives. Our results suggest that future experiments consider extractable additives as key explanatory variables.

ABSTRACTA Western diet comprising high fat, high carbohydrate, and low fiber content has been suggested to contribute to an increased prevalence of colitis. To clarify the effect of dietary cellulose (an insoluble fiber) on gut homeostasis, for 3 months mice were fed a high-cellulose diet (HCD) or a low-cellulose diet (LCD) based on the AIN-93G formulation. Histologic evaluation showed crypt atrophy and goblet cell depletion in the colons of LCD-fed mice. RNA-sequencing analysis showed a higher expression of genes associated with immune system processes, especially those of chemokines and their receptors, in the colon tissues of LCD-fed mice than in those of HCD-fed mice. The HCD was protective against dextran sodium sulfate-induced colitis in mice, while LCD exacerbated gut inflammation; however, the depletion of gut microbiota by antibiotic treatment diminished both beneficial and non-beneficial effects of the HCD and LCD on colitis, respectively. A comparative analysis of the cecal contents of mice fed the HCD or the LCD showed that the LCD did not influence the diversity of gut microbiota, but it resulted in a higher and lower abundance of Oscillibacterand Akkermansiaorganisms, respectively. Additionally, linoleic acid, nicotinate, and nicotinamide pathways were most affected by cellulose intake, while the levels of short-chain fatty acids were comparable in HCD- and LCD-fed mice. Finally, oral administration of Akkermansia muciniphilato LCD-fed mice elevated crypt length, increased goblet cells, and ameliorated colitis. These results suggest that dietary cellulose plays a beneficial role in maintaining gut homeostasis through the alteration of gut microbiota and metabolites.

Durable papers should exhibit high mechanical strength and good soiling resistance. In this study, cellulose nanofibrils (CNF) was investigated as an additive to the polyvinyl alcohol (PVA) impregnation solution to improve the durability of paper. The impregnation suspensions were prepared by adding CNF to PVA solution in various ratios, and were used to impregnate a base paper. The PVA-CNF suspensions exhibited good dispersion stability; however, the low shear viscosity increased as its CNF content increased. The pickup weights of the papers impregnated with the PVA-CNF suspensions were found to be lower than those of the control sample, which were impregnated with the pure PVA solution only. Although the strength of the paper was not significantly improved by the addition of CNF, when the paper was impregnated with a PVA-CNF suspension containing 5 % CNF content, the product exhibited similar strength to the papers impregnated with only a 3 % PVA solution despite its lower pickup weight. The mechanical strength of the impregnated paper was affected by the pickup weight and penetration of the impregnating agent. The addition of a wet strengthening agent to the mixed suspensions was seen to enhance the wet soiling resistance of the papers.

A novel quantitative mass spectrometric method based on partial metabolic deuterium oxide (D2O) labeling, named “Deuterium Oxide Labeling for Global Omics Relative Quantification (DOLGOReQ)”, was developed for relative quantification of lipids on a global scale. To assess the precision and robustness of DOLGOReQ, labeled and unlabeled lipids from HeLa cells were mixed in various ratios based on their cell numbers. Using in-house software developed for automated high-throughput data analysis of DOLGOReQ, the number of detectable mass isotopomers and the degree of deuterium labeling were exploited to filter out low quality quantification results. Quantification of an equimolar mixture of HeLa cell lipids exhibited high reproducibility and accuracy across multiple biological and technical replicates. Two orders of magnitude of effective dynamic range for reasonable relative quantification could be established with HeLa cells mixed from 10:1 to 1:10 ratios between labeled and unlabeled samples. The quantification precision of DOLGOReQ was also illustrated with lipids commonly detected in both positive and negative ion modes. Finally, quantification performance of DOLGOReQ was demonstrated in a biological sample by measuring the relative change in the lipidome of HeLa cells under normal and hypoxia conditions.

Certified reference materials (CRMs), KRISS CRM 111‐01‐010 and 111‐01‐011, were first developed in Korea to provide SI‐traceability in the measurement of triglycerides (TGs) in human frozen serum. For absolute TG quantification in KRISS CRMs, isotope dilution‐liquid chromatography–tandem mass spectrometry (ID‐LC–MS/MS) was used. Both certification and short‐term stability assessment of TG in KRISS CRMs were performed for each of 10 and eight selected units. The TG certified values and expanded uncertainties in KRISS CRMs were as follows: 0.608 ± 0.025 mmol/kg for CRM 111‐01‐010 and 1.825 ± 0.072 mmol/kg for CRM 111‐01‐011. The short‐term TG stability results were not significantly changed relative to the certified values, and therefore both KRISS CRMs were stable during the monitoring period at each temperature. Based on our experiments, the developed KRISS CRMs can provide accurate, precise, and reproducible TG measurements in human frozen serum for clinical laboratories with SI‐traceability.

Most wound generation tools have a limitation of generating circular wounds on live cells cultured in a Petri dish, since those wounds have been mostly formed by placing a circle-shaped sticker on the target area before cell culture. It does not mean an actual circular wound with cell debris, but a cell empty space from the initial stage of cell culture. Here, we report a new method of generating microscale circular wounds in a controlled manner at the benchtop affordable level. We also analyzed how those wounds were radially closed according to two stress components, such as ‘stretched’ and ‘compressed’ sides. To demonstrate our proof-of-concept validation, we designed and fabricated a hybrid poly(dimethylsiloxane) (PDMS)-dish device with a connected array of circular microstructures. We performed pressure analysis by using two different types of cells, such as the HeLa cell line and primary total finger cartilage (TFC) chondrocytes, as models. We measured and analyzed the wound closure status, such as the cell recovery direction and time, at the cellular level by differential interference contrast (DIC) and fluorescence microscopy. The results showed that TFC cells required larger mechanical pressure than HeLa cells for wound generation. This may imply that the shape and size of the wounds would depend on the amount of the extracellular matrix and the presence or absence of the cell adhesion protein. It was confirmed that the direction of cell migration was changed depending on the degree of confluence and the starting point of cells on the rim of the circular wounds. This approach can be useful as a new assay for studying fundamentals of radial cell migration dynamics for circular wound closure of different types of cells.

Hexagonal boron nitride (h-BN) and graphene have emerged as promising materials for proton exchange membranes because of their high proton conductivity and chemical stability. However, the defects and grain boundaries generated during the growth and transfer of two-dimensional materials limit their practical applicability. Here, we report the fabrication of membrane electrode assemblies using large-area single-oriented AA′-stacked trilayer h-BN (3L-BN), which exhibits very few defects during the growth and transfer, as a proton exchange membrane for use in fuel cell systems. The fuel cell based on AA′-stacked 3L-BN showed a H2permeation current density as low as 2.69 mA cm–2and an open circuit voltage (OCV) as high as 0.958 V; this performance is much superior to those for cells based on Nafion (3.7 mA cm–2and 0.942 V, respectively) and single-layer h-BN (10.08 mA cm–2and 0.894 V, respectively). Furthermore, the fuel cell with the AA′-stacked 3L-BN membrane almost maintained its original performance (OCV, maximum power density, and H2permeation current density) even after 100 h of an accelerated stress test at 30% RH and 90 °C, while the fuel cells with the Nafion and single-layer BN membranes exhibited severely deteriorated performances. The stability of the cell based on the AA′-stacked 3L-BN membrane was better because the membrane prevented gas crossover and suppressed the generation of reactive radicals during cell operation.

Graphical abstract The optical characteristics of PCDA-mBzA upon thermal stimulus can be simply modulated between irreversibility and reversibility by repetitive adsorption and desorption of cadmium ion at terminal functional group. Abstract Although the reversibility of 10, 12-pentacosadiynoic amino meta-acid (PCDA-mBzA) against temperature and pH was reported, the modulation of reversibility by ion adsorption at terminal functional group has not been investigated. In this work, we developed a simple method for modulating the reversibility of PCDA-mBzA films upon a thermal stimulus by cadmium ion adsorption inducing the breakage of the outer hydrogen bonding of two hydrogen bonds, which are responsible for the reversible properties of PCDA-mBzA. External reflection-Fourier transform infrared (ER-FTIR) analyses revealed that the hydrogen bonding between the carboxylic acid groups was broken through ion adsorption and only a single hydrogen bond between the amide groups remained in the PCDA-mBzA polymer. In addition, PCDA-mBzA films could recover their original property through cadmium ion desorption. These results present that the transition between reversibility and irreversibility can be modulated artificially simply through the adsorption and desorption of metal ions. [ABSTRACT FROM AUTHOR]

Iron- and nitrogen-codoped carbon (Fe–N/C) catalysts have emerged as promising alternatives to Pt-based catalysts for the oxygen reduction reaction (ORR) owing to their prominent ORR activity among nonprecious metal catalysts (NPMCs). This high ORR activity originates from atomically dispersed Fe coordinated with nitrogen atoms (Fe–Nxsite). However, the rational design of Fe–N/C catalysts with abundant Fe–Nxactive sites remains a challenge. In this work, we demonstrate that a silica-coating-mediated synthetic strategy enables the preparation of Fe–N/C catalysts enriched with active Fe–Nxsites while mitigating the formation of less active Fe and Fe3C species. The silica-coating-mediated strategy was generally applicable to various types of Fe and N precursors, including iron porphyrin, iron acetate/1,10-phenanthroline, and iron chloride/polyaniline. This strategy was also effective in the preparation of Fe–N/C catalysts with various carbon supports and a wide range of Fe contents and pyrolysis temperatures. The strategy could be further extended to S- or P-doped Fe–N/C catalysts, in which the formation of inactive FeS and Fe2P species was suppressed. As a result, Fe–N/C catalysts prepared with the silica coating exhibited improved ORR activity up to a factor of 11 compared to silica-uncoated counterparts. Significantly, the S-doped Fe–N/C catalyst exhibited very high ORR activity with half-wave potential at 0.91 V (vs RHE) in alkaline media. In anion-exchange membrane fuel cell (AEMFC) tests, the S-doped Fe–N/C-based cathode showed a current density of 977 mA cm–2at 0.6 V, which is the highest performance among reported AMEFCs with NPMC-based cathodes. The S-doped Fe–N/C-based cathode also demonstrated promising volumetric current density in an acidic proton exchange membrane fuel cell. Thus, the silica-coating-mediated strategy is generally effective in preparing atomically dispersed catalytic entities and may be applicable to other catalytic reactions whereby monatomic catalysts exhibit high catalytic activities.

This paper discusses the visibility issue of the moiré pattern, which may appear on display screens as a result of the interference between screen pixel array and other periodical structures having size of pitch close to that of the pixel array. One such example of a periodic structure is a touch screen electrode panel (TSP) mesh. An analytical method for visibility simulation using the human eye’s contrast sensitivity function is developed. This method is based on the representation of the periodical structures as a 2D Fourier series and visibility criterion as a root mean square value of the moiré pattern. The resulting visibility dependence on TSP mesh parameters is described in the form of an F/θ plot. The newly proposed design method, by optimizing the geometrical structure of the TSP electrode, realized the lowest visibility on the metal mesh for a transparent touch screen.

As two-dimensional (2D) transition metal dichalcogenides electronic devices are scaled down to the sub-micrometer regime, the active layers of these materials are exposed to high lateral electric fields, resulting in electrical breakdown. In this regard, understanding the intrinsic nature in layer-stacked 2D semiconducting materials under high lateral electric fields is necessary for the reliable applications of their field-effect transistors. Here, we explore the electrical breakdown phenomena originating from avalanche multiplication in MoS2field-effect transistors with different layer thicknesses and channel lengths. Modulating the band structure and bandgap energy in MoS2allows the avalanche multiplication to be controlled by adjusting the number of stacking layers. This phenomenon could be observed in transition metal dichalcogenide semiconducting systems due to its quantum confinement effect on the band structure. The relationship between the critical electric field for avalanche breakdown and bandgap energy is well fitted to a power law curve in both monolayer and multilayer MoS2.

Environment-friendly and cost-effective carbons were prepared for application in high-performance supercapacitors using bean dregs via carbonization and activation. The prepared samples were characterized using scanning electron microscopy and Brunauer–Emmett–Teller analysis. Furthermore, the electrochemical properties and capacitive behavior of the electrodes were systematically studied using cyclic voltammetry and AC impedance analysis. The porous carbon activated at 900 °C for 60 min had the largest specific surface area (3700 m2g−1) and the highest capacitance (260 F g−1) at a scan rate of 1 mV s−1.

We investigated the effects of the structural defects intentionally created by electron-beam irradiation with an energy of 30 keV on the electrical properties of monolayer MoS2field effect transistors (FETs). We observed that the created defects by electron beam irradiation on the MoS2surface working as trap sites deteriorated the carrier mobility and carrier concentration with increasing the subthreshold swing value and shifting the threshold voltage in MoS2FETs. The electrical properties of electron-beam irradiated MoS2FETs were slightly improved by treating the devices with thiol-terminated molecules which presumably passivated the structural defects of MoS2. The results of this study may enhance the understanding of the electrical properties of MoS2FETs in terms of creating and passivating defect sites.

We report an in-depth analysis of the design and fabrication of multilayer dielectric (MLD) diffraction gratings for spectral beam combining at a wavelength of 1055 nm. The design involves a near-Littrow grating and a modal analysis for high diffraction efficiency. A range of wavelengths, grating periods, and angles of incidence were examined for the near-Littrow grating, for the 0^th and –1^st diffraction orders only. A modal method was then used to investigate the effect of the duty cycle on the effective indices of the grating modes, and the depth of the grating was determined for only the –1^st-order diffraction. The design parameters of the grating and the matching layer thickness between grating and MLD reflector were refined for high diffraction efficiency, using the finite-difference time-domain (FDTD) method. A high reflector was deposited by electron-beam evaporation, and a grating structure was fabricated by photolithography and reactive-ion etching. The diffraction efficiency and laser-induced damage threshold of the fabricated MLD diffraction gratings were measured, and the diffraction efficiency was compared with the design’s value.

This paper presents the components influencing English as a Foreign Language (EFL) learning demotivation and resilience. Semi-structured interview data from 23 EFL students and nine teachers were thematically analyzed guided by the Grounded Theory approach after systematic reiterative comparative reviewing. The major demotivators were teachers’ lack of clear delivery for elementary school students, excessive afterschool learning programs at private institutes for junior high school students, and impractical EFL lessons focusing on grammar rather than spoken English for high school students. In order to curb these demotivators and maintain high EFL learning motivation levels, four distinctive components influencing their resilience were identified: social support, emotional regulation, a clear learning goal, and tenacity in EFL learning. This study illustrates that emotional regulation, not negative emotions such as anxiety, is crucial, and students’ clearly stated short-term learning goal is a crucial component in maintaining high academic resilience. Participants cultivated specific components influencing resilience as they advanced academically. Additionally, high-proficiency EFL students exhibited greater tenacity and utilized various coping strategies. We argue for the necessity to refine the sub-constructs of EFL learning demotivation and resilience and recommend the need for a follow-up confirmatory study to prove the conceptual validity of these constructs.

Long-term fear memory formation in the hippocampus and neocortex depends upon brain-derived neurotrophic factor (BDNF) signaling after acquisition. Incremental, appetitive odor discrimination learning is thought to depend substantially on the differentiation of adult-born neurons within the olfactory bulb (OB)—a process that is closely associated with BDNF signaling. We sought to elucidate the role of neurotrophin signaling within the OB on odor memory consolidation. Male mice were trained on odor–reward associative discriminations after bilateral infusion of the kinase inhibitor K252a, or vehicle control, into the OB. K252a is a partially selective inhibitor of tyrosine kinase (Trk) receptors, including the TrkB receptor for BDNF, though it also inhibits other plasticity-related kinases such as PKC and CaMKII/IV. K252a infusion into the OB did not impair odor acquisition or short-term (2 h) memory for the learned discriminations, but significantly impaired long-term (48 h) odor memory (LTM). This LTM deficit also was associated with reduced selectivity for the conditioned odorant in a reward-seeking digging task. Infusions of K252a immediately prior to testing did not impair LTM recall. These results indicate that kinase activation in the OB is required for the consolidation of odor memory of incrementally acquired information.

The purpose of the study is to explore the structural relationships among second language (L2) proficiency and the constructs of L2 learners’ resilience, motivation, and demotivation. A total of 869 undergraduate students in South Korea participated in the study. The data were analyzed by means of factor analysis, correlations, and structural equation modeling (SEM). The factor analysis identified seven resilience factors (life satisfaction, sociability, communicative efficacy, self-composure, strategic competence, metacognitive adaptation, and realistic optimism), six motivation factors (ought-to L2 self, ideal L2 self, instrumental motivation, parental support, academic motivation, awareness of importance), and six demotivation factors (negative perception of English-speaking countries, compulsory EFL learning, perceived inappropriateness of textbooks or tasks, low self-esteem, unsupportive learning environment, unsupportive teachers). The SEM corroborated that resilience, L2 learning motivation, and L2 learning demotivation contribute to L2 proficiency. L2 learning demotivation had more explanatory power for L2 proficiency than did L2 learning motivation. Resilience had both a direct and an indirect effect on L2 proficiency via L2 learning demotivation. The findings suggest that teachers should equip learners with strategies to manage adversity in L2 learning.

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have gained considerable attention as an emerging semiconductor due to their promising atomically thin film characteristics with good field-effect mobility and a tunable band gap energy. However, their electronic applications have been generally realized with conventional inorganic electrodes and dielectrics implemented using conventional photolithography or transferring processes that are not compatible with large-area and flexible device applications. To facilitate the advantages of 2D TMDCs in practical applications, strategies for realizing flexible and transparent 2D electronics using low-temperature, large-area, and low-cost processes should be developed. Motivated by this challenge, we report fully printed transparent chemical vapor deposition (CVD)-synthesized monolayer molybdenum disulfide (MoS2) phototransistor arrays on flexible polymer substrates. All the electronic components, including dielectric and electrodes, were directly deposited with mechanically tolerable organic materials by inkjet-printing technology onto transferred monolayer MoS2, and their annealing temperature of <180 °C allows the direct fabrication on commercial flexible substrates without additional assisted-structures. By integrating the soft organic components with ultrathin MoS2, the fully printed MoS2phototransistors exhibit excellent transparency and mechanically stable operation.

AbstractThis exploratory study focused on the factors that constitute second language (L2) learners’ resilience, and how these factors are related to L2 learning by investigating what relation resilience may have to motivated behaviour and proficiency in English learning. A total of 1620 secondary school learners of English participated in a questionnaire survey. By analysing the quantitative data, five resilience factors were extracted: perceived happiness, empathy, sociability, persistence, and self-regulation. Confirmative factor analysis using AMOS proved that these five factors are distinctive constructs. Among the factors, persistence was identified to play the most influential role in L2 learning. Persistence showed the highest correlations with, and the strongest explanatory power for, motivated behaviour and English proficiency. It is suggested that resilience can be further explored as an individual differences factor in L2 learning, which is involved in L2 learning process and outcomes.