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Photoelectrochemical water splitting is the most efficient green engineering approach to convert the sun light into hydrogen energy. The formation of high surface area core-shell ...heterojunction with enhanced light-harvesting efficiency, elevated charge separation, and transport are key parameters in achieving the ideal water splitting performance of the photoanode. Herein, we demonstrate a first green engineering interfacial growth of the BiVO4 nanoparticles onto self-assembled WO3 nanoplates forming WO3/BiVO4 core-shell heterojunction for efficient PEC water splitting performance. The three different WO3 nanostructures (nanoplates, nanobricks, and stacked nanosheets) were self-assembled on fluorine doped tin oxide glass substrates via hydrothermal route at various pH (0.8–1.2) of the solutions. In comparison to nanobricks and stacked nanosheets, WO3 nanoplates displayed considerably elevated photocurrent density. Moreover, a simple and low cost green approach of modified chemical bath deposition technique was established for the optimal decoration of a BiVO4 nanoparticles on vertically aligned WO3 nanoplates. The boosted photoelectrochemical current density of 1.7 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination was achieved for the WO3/BiVO4 heterojunction which can be attributed to a suitable band alignment for the efficient charge transfer from BiVO4 to WO3, increased light harvesting capability of outer BiVO4 layer, and high charge transfer efficiency of WO3 nanoplates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Concepts of non-volatile memory to replace conventional flash memory have suffered from low material reliability and high off-state current, and the use of a thick, rigid blocking oxide layer in ...flash memory further restricts vertical scale-up. Here, we report a two-terminal floating gate memory, tunnelling random access memory fabricated by a monolayer MoS2/h-BN/monolayer graphene vertical stack. Our device uses a two-terminal electrode for current flow in the MoS2 channel and simultaneously for charging and discharging the graphene floating gate through the h-BN tunnelling barrier. By effective charge tunnelling through crystalline h-BN layer and storing charges in graphene layer, our memory device demonstrates an ultimately low off-state current of 10(-14) A, leading to ultrahigh on/off ratio over 10(9), about ∼10(3) times higher than other two-terminal memories. Furthermore, the absence of thick, rigid blocking oxides enables high stretchability (>19%) which is useful for soft electronics.
Recent studies have demonstrated that mobile sampling can improve the spatial granularity of land use regression (LUR) models. Mobile sampling campaigns deploying low-cost (<$300) air quality sensors ...could potentially offer an inexpensive and practical approach to measure and model air pollution concentration levels. In this study, we developed LUR models for street-level fine particulate matter (PM2.5) concentration levels in Seoul, South Korea. 169 h of data were collected from an approximately three week long campaign across five routes by ten volunteers sharing seven AirBeams, a low-cost ($250 per unit), smartphone-based particle counter, while geospatial data were extracted from OpenStreetMap, an open-source and crowd-generated geographical dataset. We applied and compared three statistical approaches in constructing the LUR models – linear regression (LR), random forest (RF), and stacked ensemble (SE) combining multiple machine learning algorithms – which resulted in cross-validation R2 values of 0.63, 0.73, and 0.80, respectively, and identification of several pollution ‘hotspots.’ The high R2 values suggest that study designs employing mobile sampling in conjunction with multiple low-cost air quality monitors could be applied to characterize urban street-level air quality with high spatial resolution, and that machine learning models could further improve model performance. Given this study design's cost-effectiveness and ease of implementation, similar approaches may be especially suitable for citizen science and community-based endeavors, or in regions bereft of air quality data and preexisting air monitoring networks, such as developing countries.
•Mobile sampling with low-cost air quality sensors could offer a cost-effective approach to characterize urban air quality.•A sampling campaign deploying multiple AirBeams across five routes was conducted during a three week period in Seoul.•Land use regression (LUR) models were constructed using the collected data and the OpenStreetMap (OSM) geospatial data.•Three approaches – linear regression, random forest, and stacked ensemble – were employed to construct the LUR models.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Diabetes mellitus is a worldwide health concern due to its high prevalence; almost 8.3% of the global population suffers from diabetes. It is a group of metabolic diseases classified by hyperglycemia ...resulting from defects in insulin secretion, insulin action, or both. Owing to the lack of simple diagnosis and treatment strategies, diabetes is a major cause of death worldwide, and more than 50% of cases remain undiagnosed. In addition, without timely diagnosis, diabetes-related complications and morbidity increase exponentially. Therefore, early diagnosis of diabetes is essential to prevent devastating complications. The current method of investigation requires a painful needle-prick to take blood, which could discourage individuals from seeking diagnosis. Recently, researchers have attempted to use patient saliva as a non-invasive method for identifying cases of diabetes. In this feature article, we discuss recent trends in the development of diagnostic tools for diabetes mellitus using patient saliva.
•Diagnostic tools for diabetes mellitus using patient saliva.•Physiological considerations in the use of saliva as a diagnostic tool.•Correlation of salivary composition with blood components.•Recent developments in the diagnosis of diabetes mellitus using patient saliva.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Nanoporous materials: High‐aspect‐ratio, ordered porous Co3O4 layers were formed by self‐organizing anodization of a cobalt substrate and subsequent annealing. The key for successful formation of ...such layers is to sufficiently suppress competing oxygen evolution during anodization. The aligned Co3O4 channel layers behave as a highly efficient water oxidation catalyst (see picture).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Acute exacerbations of idiopathic pulmonary fibrosis are associated with high mortality and are of unknown cause. The effect of air pollution on exacerbations of interstitial lung disease is unknown. ...This study aims to define the association of air pollution exposure with acute exacerbation of idiopathic pulmonary fibrosis. Patients with idiopathic pulmonary fibrosis and corresponding air pollution data were identified from a longitudinal cohort. Air pollution exposures were assigned to each patient for ozone, nitrogen dioxide, particulate matter, sulfur dioxide and carbon monoxide based on geo-coded residential addresses. Cox proportional hazards models were used to estimate the association of air pollution exposures and acute exacerbations. Acute exacerbation was significantly associated with antecedent 6-week increases in mean level, maximum level and number of exceedances above accepted standards of ozone (hazard ratio (HR) 1.57, 95% CI 1.09-2.24; HR 1.42, 95% CI 1.11-1.82; and HR 1.51, 95% CI 1.17-1.94, respectively) and nitrogen dioxide (HR 1.41, 95% CI 1.04-1.91; HR 1.27, 95% CI 1.01-1.59; and HR 1.20, 95% CI 1.10-1.31, respectively). Increased ozone and nitrogen dioxide exposure over the preceding 6 weeks was associated with an increased risk of acute exacerbation of idiopathic pulmonary fibrosis, suggesting that air pollution may contribute to the development of this clinically meaningful event.
Primary cilia are evolutionarily conserved cellular organelles that organize diverse signalling pathways. Defects in the formation or function of primary cilia are associated with a spectrum of human ...diseases and developmental abnormalities. Genetic screens in model organisms have discovered core machineries of cilium assembly and maintenance. However, regulatory molecules that coordinate the biogenesis of primary cilia with other cellular processes, including cytoskeletal organization, vesicle trafficking and cell-cell adhesion, remain to be identified. Here we report the results of a functional genomic screen using RNA interference (RNAi) to identify human genes involved in ciliogenesis control. The screen identified 36 positive and 13 negative ciliogenesis modulators, which include molecules involved in actin dynamics and vesicle trafficking. Further investigation demonstrated that blocking actin assembly facilitates ciliogenesis by stabilizing the pericentrosomal preciliary compartment (PPC), a previously uncharacterized compact vesiculotubular structure storing transmembrane proteins destined for cilia during the early phase of ciliogenesis. The PPC was labelled by recycling endosome markers. Moreover, knockdown of modulators that are involved in the endocytic recycling pathway affected the formation of the PPC as well as ciliogenesis. Our results uncover a critical regulatory step that couples actin dynamics and endocytic recycling with ciliogenesis, and also provides potential target molecules for future study.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Vertical integration of 2D layered materials to form van der Waals heterostructures (vdWHs) offers new functional electronic and optoelectronic devices. However, the mobility in vertical carrier ...transport in vdWHs of vertical field‐effect transistor (VFET) is not yet investigated in spite of the importance of mobility for the successful application of VFETs in integrated circuits. Here, the mobility in VFET of vdWHs under different drain biases, gate biases, and metal work functions is first investigated and engineered. The traps in WSe2 are the main source of scattering, which influences the vertical mobility and three distinct transport mechanisms: Ohmic transport, trap‐limited transport, and space‐charge‐limited transport. The vertical mobility in VFET can be improved by suppressing the trap states by raising the Fermi level of WSe2. This is achieved by increasing the injected carrier density by applying a high drain voltage, or decreasing the Schottky barrier at the graphene/WSe2 and metal/WSe2 junctions by applying a gate bias and reducing the metal work function, respectively. Consequently, the mobility in Mn vdWH at +50 V gate voltage is about 76 times higher than the initial mobility of Au vdWH. This work enables further improvements in the VFET for successful application in integrated circuits.
The mobility in vertical carrier transport of vertical field‐effect transistors (VFETs) composed of 2D layered materials has not previously been investigated in spite of the importance of the mobility for the successful application of VFETs in integrated circuits. The mobility in VFETs of van der Waals heterostructures under different drain biases, gate biases, and metal work functions is investigated and engineerd.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Modulation of the structure, composition, and morphology through a simple refinement of the synthetic parameters is central to obtaining signature catalytic properties, enabling an understanding of ...the underlying growth and reaction mechanisms. In this study, a bismuth vanadate (BiVO4) model photocatalyst with several nanostructures (including pillar-like, dendrites, and microgranules) was fabricated by simple hydrothermal, solvothermal, and solid-state reaction (SSR) methods. As the solvothermal reaction temperature was increased, the tetragonal phase transformed into a monoclinic phase, and the inorganic nuclei interacted, self-assembled, and grew continuously to yield a well-defined architecture indicating the critical role of temperature in stabilizing the crystal structure and surface atomic features principally in an ethanol/water mixture. In contrast, conventional hydrothermal synthesis (only water as a solvent) resulted in single-phase BiVO4 pillars enriched with rough surfaces, sharp edges, and porous structures. The growth mechanism of the BiVO4 dendrites was investigated by the morphological evolutions from different reaction products obtained under different reaction conditions. BiVO4 has a bandgap energy in the visible spectral range (2.50–2.27 eV). Hence, BiVO4 architectures with exclusively controlled surfaces and crystal structures can be used as efficient photocatalysts to remove organic pollutants (methylene blue dye) in water. The solvothermally prepared BVO-SLR’24 with a mixed-phase (monoclinic and tetragonal zircon) structure exhibited superior photocatalytic activities for the decomposition of organic contaminants, which may be due to the unique connectivity between crystals, accelerated electron transfer, and heterojunction formation, compared to BiVO4 prepared with pure phase pillars and microgranules. This work highlights the significance of synthesis methodology and microstructural modification with the photophysical properties to reinvigorate the conventional design of visible-light-driven (VLD) photocatalysts.
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•2,4,6-TNT is reduced on anodic TiO2 nanotubes.•Diffusion dominates electrochemical reduction of 2,4,6-TNT.•2,4,6-TNT was selectively detected by TiO2 nanotubes in a mixture of ...explosive compounds.
The feasibility of electrochemical detection of 2,4,6-trinitrotoluene (2,4,6-TNT) using TiO2 nanotubes synthesized through electrochemical anodization of Ti was explored. TiO2 nanotube arrays with distinctly different surface features, including an initiation layer and tube wall structures, were prepared, and the efficacy for the electrochemical reduction of 2,4,6-TNT was comparatively evaluated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrochemical sensing properties of the anodic TiO2 nanotubes were not affected by the surface morphology based on the different anodization conditions. The mechanism governing the mass transfer of 2,4,6-TNT during electrochemical reduction was dominated by diffusion, as determined based on LSV analyses at various scan rates. Importantly, the TiO2 nanotube arrays can distinguish 2,4,6-TNT and cyclotrimethylenetrinitramine (RDX) in mixture solutions of 2,4,6-TNT, RDX, and pentaerythritol tetranitrate (PETN), with four distinct reduction peaks in the voltammogram. Further studies are needed to enhance the efficacy of the TiO2 nanotube arrays for the electrochemical reduction of explosive compounds, where introducing metal dopants, quantum dots, or vacancy engineering are prospectively effective strategies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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