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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.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.compind.2005.12.003 Byline: Tae-Young Kim (a), Sunjae Lee (a), Kwangsoo Kim (a), Cheol-Han Kim (b) Keywords: Virtual enterprise; Modeling framework; Enterprise engineering; Enterprise architecture; Meta-modeling Abstract: The virtual enterprise (VE), in general collaborations among business partners in value chains, has become a prime candidate model for competitiveness under the increasingly turbulent business environment. In order to quickly respond to the rapidly changing business environment, agility and interoperability are the main requirements for the VEs. This paper suggests a framework for designing the agile and interoperable VEs. Existing approaches, such as enterprise architecture, model driven architecture, domain specific methodology, meta-modeling, framework-based development, etc., are reviewed, revealing that none offers a complete solution that supports all the aspects of the VE modeling in an elegant manner. Thus, this paper develops a systematic modeling framework by harmonizing these approaches and combining the individual advantages of each approach to produce integrated synergy effects. This modeling framework can be used for business managers or business domain experts to build an agile and interoperable VE quickly and systematically with insights. It also supports a coherent enterprise modeling in which various stakeholders having their own aspects and methodology, such as an IT manager and a business manager, can communicate effectively. Author Affiliation: (a) Department of Industrial and Management Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, Republic of Korea (b) Division of Information Communications and Internet Engineering, Daejeon University, 96-3 Yongun-dong, Dong-gu, Daejoen 300-716, Republic of Korea Article History: Accepted 15 December 2005

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.

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.

We report the electrical properties of synthesized large-area monolayer molybdenum disulfide (MoS2) field-effect transistors (FETs) with low-cost inkjet-printed Ag electrodes. The monolayer MoS2film was grown by a chemical vapor deposition (CVD) method, and the top-contact Ag source/drain electrodes (S/D) were deposited onto the films using a low-cost drop-on-demand inkjet-printing process without any masks and surface treatments. The electrical characteristics of FETs were comparable to those fabricated by conventional deposition methods such as photo- or electron beam lithography. The contact properties between the S/D and the semiconductor layer were also evaluated using the Y-function method and an analysis of the output characteristic at the low drain voltage regimes. Furthermore, the electrical instability under positive gate-bias stress was studied to investigate the charge-trapping mechanism of the FETs. CVD-grown large-area monolayer MoS2FETs with inkjet-printed contacts may represent an attractive approach for realizing large-area and low-cost thin-film electronics.

A stable electrolyte is required for use in the open-packing environment of a Li-O2battery system. Herein, a gelled quasi-solid-state electrolyte containing SiO2nanoparticles was designed, in order to obtain a solidified electrolyte with a high discharge capacity and long cyclability. We successfully fabricated an organic–inorganic hybrid matrix with a gelled structure, which exhibited high ionic conductivity, thereby enhancing the discharge capacity of the Li-O2battery. In particular, the improved electrochemical stability of the gelled cathode led to long-term cyclability. The organic–inorganic hybrid matrix with the gelled structure played a beneficial role in improving the ionic conductivity and long-term cyclability and diminished electrolyte evaporation. The experimental and theoretical findings both suggest that the preferential binding between amorphous SiO2and polyethylene glycol dimethyl ether (PEGDME) solvent led to the formation of the solidified gelled electrolyte and improved electrochemical stability during cycling, while enhancing the stability of the quasi-solid state Li-O2battery.

We investigated the physical properties of molybdenum disulfide (MoS2) atomic crystals with a sulfur vacancy passivation after treatment with alkanethiol molecules including their electrical, Raman, and photoluminescence (PL) characteristics. MoS2, one of the transition metal dichalcogenide materials, is a promising two-dimensional semiconductor material with good physical properties. It is known that sulfur vacancies exist in MoS2, resulting in the n-type behavior of MoS2. The sulfur vacancies on the MoS2surface tend to form covalent bonds with sulfur-containing groups. In this study, we deposited alkanethiol molecules on MoS2field effect transistors (FETs) and then characterized the electrical properties of the devices before and after the alkanethiol treatment. We observed that the electrical characteristics of MoS2FETs dramatically changed after the alkanethiol treatment. We also observed that the Raman and PL spectra of MoS2films changed after the alkanethiol treatment. These effects are attributed to the thiol (−SH) end groups in alkanethiols bonding at sulfur vacancy sites, thus altering the physical properties of the MoS2. This study will help us better understand the electrical and optical properties of MoS2and suggest a way of tailoring the properties of MoS2by passivating a sulfur vacancy with thiol molecules.

We studied noise characteristics of a nanocomposite of polyimide (PI) and phenyl-C61-butyric acid methyl ester (PCBM) (denoted as PI:PCBM), a composite for the organic nonvolatile resistive memory material. The current fluctuations were investigated over a bias range that covers various intermediate resistive states and negative differential resistance (NDR) in organic nanocomposite unipolar resistive memory devices. From the analysis of the 1/fγtype noises, scaling behavior between the relative noise power spectral density S̃and resistance Rwas observed, indicating a percolating behavior. Considering a linear rate equation of the charge trapping–detrapping at traps, the percolation behavior and NDR could be understood by the modulation of the conductive phase fraction φ with an external bias. This study can enhance the understanding of the NDR phenomena in organic nanocomposite unipolar resistive memory devices in terms of the current path formation and the memory switching.

Rare-earth (RE)-doped BiFeO3(BFO) thin films were grown on LaAlO3(LAO) substrates by using pulsed laser deposition technique. All of the BFO films doped with 10% of RE exhibit a rhombohedral single phase. As for the Pr and Nd doping cases, the ferromagnetic phase is less favored because the Fe2+amount is not dominant. When dopant concentration was increased to 20%, the RE-doped BFO films go through a structural transition from rhombohedral to pure orthorhombic phase (for Ho, Sm), a mixed phase of orthorhombic and tetragonal (for Pr, Nd), or pure tetragonal (for Eu). As an important consequence, magnetic properties of RE-doped BFO films have drastically changed. Our results give a guide for how to tailor the ferromagnetism of BFO films by appropriate controlling the type of RE dopant as well as dopant concentration. The experimental findings are completed by performing density functional theory calculations to explore the effect of RE doping in BFO for the considered three phases.

An image-space telecentric lens for an intra-oral 3D scanner was designed and fabricated for dental application. Since a telecentric function can provide the same results regardless of image plane position, it helps to realize a more accurate image for an intra-oral scanner. The performance of the designed lens meets the required properties for HD resolution. In particular, lateral color is corrected within 1 pixel. This system achieves depth of focus of more than 3 mm. For user convenience, the developed system consists of a prism part and an imaging part. Both parts are optimized to reduce the front size and weight of the system. In order to make the parallax sights, parallax angle was determined to be 8 degrees between two optical systems.

In South Korea, Damunwhastudents (students from multicultural family backgrounds) have difficulties at school because of others' derogatory perception of them and the different linguistic and cultural settings. In light of this issue, this paper addresses the Damunwhastudents' identities and participation within the language communities from a community of practice perspective and a critical pedagogy perspective. Four students (two from international marriage families and two from immigrant workers' families), their teachers, and their supervisors participated in the study from March to April 2013. The findings suggest that Damunwhastudents' participation in Korean society depends on their resources, others' perception of the participants' identities, and cultural capital. The findings show that students are losing their connection with their first language communities and that their linguistic resources and cultural diversity are undervalued. The study implies that cultural sensitivity should be promoted and that explicit support for Damunwhastudents is needed.

The purpose of this study was to investigate the factors influencing functional outcomes in elderly patients with united intertrochanteric fractures treated with hip nails and to ascertain whether decreased femoral offset due to lag screw sliding has a negative effect on functional outcomes in these patients. This retrospective study included 65 patients older than 65 years with united intertrochanteric fractures treated with hip nails. Functional outcomes were assessed using the Short Form-36 (SF-36) and a visual analog scale (VAS) 6 months postoperatively. Mean patient age was 77.8 years (range, 65–90 years); mean follow-up was 20.7 months (range, 12–38 months). More lag screw sliding occurred as bone mineral density (BMD) decreased. It was also greater in unstable fractures and acceptable reduction status. Less accurate reduction and greater lag screw sliding showed significant negative effects on most subscales of the SF-36, especially Physical Functioning and Role Physical. A significant positive correlation was observed between the extent of lag screw sliding and VAS. Lag screw sliding affected by fracture type, reduction quality, and BMD has a negative effect on functional outcomes in elderly patients with united intertrochanteric fractures. Therefore, the preservation of anatomical femoral offset as much as possible is needed to obtain better functional outcome through the minimization of lag screw sliding by more accurate reduction, which is a controllable factor, especially in osteoporotic unstable intertrochanteric fractures. [The purpose of this study was to investigate the factors influencing functional outcomes in elderly patients with united intertrochanteric fractures treated with hip nails and to ascertain whether decreased femoral offset due to lag screw sliding has a negative effect on functional outcomes in these patients. This retrospective study included 65 patients older than 65 years with united intertrochanteric fractures treated with hip nails. Functional outcomes were assessed using the Short Form-36 (SF-36) and a visual analog scale (VAS) 6 months postoperatively. Mean patient age was 77.8 years (range, 65–90 years); mean follow-up was 20.7 months (range, 12–38 months). More lag screw sliding occurred as bone mineral density (BMD) decreased. It was also greater in unstable fractures and acceptable reduction status. Less accurate reduction and greater lag screw sliding showed significant negative effects on most subscales of the SF-36, especially Physical Functioning and Role Physical. A significant positive correlation was observed between the extent of lag screw sliding and VAS. Lag screw sliding affected by fracture type, reduction quality, and BMD has a negative effect on functional outcomes in elderly patients with united intertrochanteric fractures. Therefore, the preservation of anatomical femoral offset as much as possible is needed to obtain better functional outcome through the minimization of lag screw sliding by more accurate reduction, which is a controllable factor, especially in osteoporotic unstable intertrochanteric fractures. [Orthopedics.2014; 37(12):e1101–e1107.]

This mixed-methods study investigates the differences in demotivation between Chinese and Korean English teachers. A questionnaire on demotivation was conducted on 58 Chinese and 94 Korean in-service teachers to find out the dominant factors in teacher demotivation. Follow-up interviews with teachers were conducted to explore the reasons as to why teachers found the salient factors to be demotivating. The results indicated that the number of students per English classroom was the detrimental factor for both Chinese and Korean teachers. Moreover, the only factor that Chinese teachers perceived to be more demotivating than Korean teachers was the excessive interference or expectations of school parents. For Korean teachers, large amounts of administrative tasks and students’ lack of interest in English were found to be the most detrimental factors. From the findings of this study, practical implications as well as research suggestions are provided.

Molybdenum disulfide (MoS2) films, which are only a single atomic layer thick, have been synthesized by chemical vapor deposition (CVD) and have gained significant attention due to their band-gap semiconducting properties. However, in order for them to be useful for the fabrication of practical devices, patterning processes that can be used to form specific MoS2structures must be integrated with the existing synthetic approaches. Here, we report a method for the synthesis of centimeter-scale, high-quality single-layer MoS2that can be directly patterned during CVD, so that postpatterning processes can be avoided and device fabrication can be streamlined. Utilizing X-ray photoelectron spectroscopic imaging, we characterize the chemical states of these CVD-synthesized single-layer MoS2films and demonstrate that the triangular-shaped MoS2are single-crystalline single-domain monolayers. We also demonstrate the use of these high-quality and directly patterned MoS2films in electronic device applications by fabricating and characterizing field effect transistors.

We investigated the effect of irradiation on molybdenum disulfide (MoS2) field effect transistors with 10 MeV high-energy proton beams. The electrical characteristics of the devices were measured before and after proton irradiation with fluence conditions of 1012, 1013, and 1014cm–2. For a low proton beam fluence condition of 1012cm–2, the electrical properties of the devices were nearly unchanged in response to proton irradiation. In contrast, for proton beam fluence conditions of 1013or 1014cm–2, the current level and conductance of the devices significantly decreased following proton irradiation. The electrical changes originated from proton-irradiation-induced traps, including positive oxide-charge traps in the SiO2layer and trap states at the interface between the MoS2channel and the SiO2layer. Our study will enhance the understanding of the influence of high-energy particles on MoS2-based nanoelectronic devices.

This paper analyzes two recent Korean immigrants’ ESL learning motivation using Dörnyei’s (2009, The L2 motivational self-system. In Z. Dörnyei & E. Ushioda (Eds.), Motivation, language identity and the L2 self, pp. 9–42) Second Language (L2) Motivational Self-System, which is synthesized with Engeström’s (1999, Activity theory and individual and social transformation. In Y. Engeström, R. Miettinen, & R. Punamáki (Eds.), Perspectives on activity theory, pp. 19–38) Activity Theory (AT) framework. Over a 10-month period, the author conducted semi-structured monthly interviews and stimulated recall tasks. The findings of this case study suggest the following: (1) when sociocultural factors are mediated by L2 learners’ beliefs, these factors may directly influence learners’ ideal L2 self and ought-to L2 self; (2) learners’ sensitivity with inclusive attitudes can transform the L2 learning environment into meaningful affordances; and (3) if there is no tension among elements in individual’s AT system, the individual’s ideal L2 self can be maintained. From the Vygotskian AT perspective, this paper implies that affordances may positively affect maintenance of the ideal L2 self and the ought-to L2 self and that AT can function as a coherent framework for these two L2 selves.

We investigated the gate bias stress effects of multilayered MoS2field effect transistors (FETs) with a back-gated configuration. The electrical stability of the MoS2FETs can be significantly influenced by the electrical stress type, relative sweep rate, and stress time in an ambient environment. Specifically, when a positive gate bias stress was applied to the MoS2FET, the current of the device decreased and its threshold shifted in the positive gate bias direction. In contrast, with a negative gate bias stress, the current of the device increased and the threshold shifted in the negative gate bias direction. The gate bias stress effects were enhanced when a gate bias was applied for a longer time or when a slower sweep rate was used. These phenomena can be explained by the charge trapping due to the adsorption or desorption of oxygen and/or water on the MoS2surface with a positive or negative gate bias, respectively, under an ambient environment. This study will be helpful in understanding the electrical-stress-induced instability of the MoS2-based electronic devices and will also give insight into the design of desirable devices for electronics applications.

All-in-one treatments represent a paradigm shift in future medicine. For example, inflammatory bowel disease (IBD) is mainly diagnosed by endoscopy, which could be applied for not only on-site monitoring but also the intestinal lesion-targeted spray of injectable hydrogels. Furthermore, molecular conjugation to the hydrogels would program both lesion-specific adhesion and drug-free therapy. This study validated this concept of all-in-one treatment by first utilizing a well-known injectable hydrogel that underwent efficient solution-to-gel transition and nanomicelle formation as a translatable component. These properties enabled spraying of the hydrogel onto the intestinal walls during endoscopy. Next, peptide conjugation to the hydrogel guided endoscopic monitoring of IBD progress upon adhesive gelation with subsequent moisturization of inflammatory lesions, specifically by nanomicelles. The peptide was designed to mimic the major component that mediates intestinal interaction with Bacillus subtilisflagellin during IBD initiation. Hence, the peptide-guided efficient adhesion of the hydrogel nanomicelles onto Toll-like receptor 5 (TLR5) as the main target of flagellin binding and Notch-1. The peptide binding potently suppressed inflammatory signaling without drug loading, where TLR5 and Notch-1 operated collaboratively through downstream actions of tumor necrosis factor-alpha. The results were produced using a human colorectal cell line, clinical IBD patient cells, gut-on-a-chip, a mouse IBD model, and pig experiments to validate the translational utility.