Ultrathin two-dimensional (2D) semiconducting layered materials offer great potential for extending Moore's law of the number of transistors in an integrated circuit
. One key challenge with 2D ...semiconductors is to avoid the formation of charge scattering and trap sites from adjacent dielectrics. An insulating van der Waals layer of hexagonal boron nitride (hBN) provides an excellent interface dielectric, efficiently reducing charge scattering
. Recent studies have shown the growth of single-crystal hBN films on molten gold surfaces
or bulk copper foils
. However, the use of molten gold is not favoured by industry, owing to its high cost, cross-contamination and potential issues of process control and scalability. Copper foils might be suitable for roll-to-roll processes, but are unlikely to be compatible with advanced microelectronic fabrication on wafers. Thus, a reliable way of growing single-crystal hBN films directly on wafers would contribute to the broad adoption of 2D layered materials in industry. Previous attempts to grow hBN monolayers on Cu (111) metals have failed to achieve mono-orientation, resulting in unwanted grain boundaries when the layers merge into films
. Growing single-crystal hBN on such high-symmetry surface planes as Cu (111)
is widely believed to be impossible, even in theory. Nonetheless, here we report the successful epitaxial growth of single-crystal hBN monolayers on a Cu (111) thin film across a two-inch c-plane sapphire wafer. This surprising result is corroborated by our first-principles calculations, suggesting that the epitaxial growth is enhanced by lateral docking of hBN to Cu (111) steps, ensuring the mono-orientation of hBN monolayers. The obtained single-crystal hBN, incorporated as an interface layer between molybdenum disulfide and hafnium dioxide in a bottom-gate configuration, enhanced the electrical performance of transistors. This reliable approach to producing wafer-scale single-crystal hBN paves the way to future 2D electronics.
The remote hydrogen plasma is able to create abundant S‐vacancies on amorphous molybdenum sulfide (a‐MoSx) as active sites for hydrogen evolution. The results demonstrate that the plasma‐treated ...a‐MoSx exhibits superior performance and higher stability than Pt in a proton exchange membrane based electrolyzers measurement as a proof‐of‐concept of industrial application.
2D transition metal dichalcogenide (TMD) layered materials are promising for future electronic and optoelectronic applications. The realization of large‐area electronics and circuits strongly relies ...on wafer‐scale, selective growth of quality 2D TMDs. Here, a scalable method, namely, metal‐guided selective growth (MGSG), is reported. The success of control over the transition‐metal‐precursor vapor pressure, the first concurrent growth of two dissimilar monolayer TMDs, is demonstrated in conjunction with lateral or vertical TMD heterojunctions at precisely desired locations over the entire wafer in a single chemical vapor deposition (VCD) process. Owing to the location selectivity, MGSG allows the growth of p‐ and n‐type TMDs with spatial homogeneity and uniform electrical performance for circuit applications. As a demonstration, the first bottom‐up complementary metal‐oxide‐semiconductor inverter based on p‐type WSe2 and n‐type MoSe2 is achieved, which exhibits a high and reproducible voltage gain of 23 with little dependence on position.
Dissimilar transition metal dichalcogenides (TMDs) are grown concurrently and location‐selectively by a new method. Precise control over the transition‐metal‐precursor vapor pressure allows successful lateral and vertical heterojunction growth, as well as growth of p‐ and n‐type TMDs at desired locations. A new synthetic strategy for future (opto)electronic applications is thus provided.
Research on electronic channel materials has traditionally focused on bulk and nanocrystals, nanowires, and nanotubes. However, the recent surge of interest in two-dimensional (2D) transition-metal ...dichalcogenides (TMDs) has emerged as a game-changer in this field. The atomically thin structure of 2D TMDs offers unique electronic and optical properties, which have been shown to have significant potential in various applications, such as optoelectronics, energy harvesting, and spintronics. Epitaxy growth of single-crystal 2D TMDs on oxide or metallic substrates has opened up new opportunities for direct integration into existing manufacturing pathways. In this article, we discuss recent advances in achieving continuous single-crystallinity of 2D TMDs on oxide and metallic substrates by controlling the nucleation and growth rate of crystalline domains. We also review strategies for the controlled introduction of defects through postgrowth processing and substrate engineering. Finally, we highlight emerging strategies, new opportunities, and remaining challenges for bridging the gap between lab innovations and commercialization. The ability to grow high-quality 2D TMDs on scalable and industry-compatible substrates represents a significant breakthrough in the field of electronic materials and has the potential to revolutionize the semiconductor industry. Despite the remaining challenges, the future of 2D TMDs looks promising. Their integration into existing manufacturing pathways could open up new avenues for advanced electronic devices with improved performance and reduced power consumption.
Graphical abstract
Therapeutic drug monitoring (TDM) is recommended during valproic acid (VPA) use, and total serum concentration has been widely adopted. However, the free form of VPA is responsible for its ...pharmacologic and toxic effects, and the total and free concentrations are highly discordant because of VPA's highly protein bound and saturable binding characteristics. Therefore, free VPA monitoring is increasingly advocated. Nevertheless, the correlation between free VPA concentration and associated adverse effects remains unknown. To determine the optimal safety range of free VPA concentration in adult patients. This prospective cohort study enrolled adult patients undergoing VPA therapy with TDM. Patient characteristics, VPA use, and adverse effects (thrombocytopenia, hyperammonemia, and hepatotoxicity) were recorded. A multivariate logistic regression model was applied to identify the predictors of adverse effects, and the receiver operating characteristic curve was applied to locate the cutoff point of free VPA concentration. A total of 98 free serum concentrations from 51 patients were included for final analysis. In total, 31 (31.6%), 27 (27.6%), and 4 (4.1%) episodes of hyperammonemia, thrombocytopenia, and hepatotoxicity were observed, respectively. Free VPA concentration was a predicting factor for thrombocytopenia but not for hyperammonemia. A free VPA concentration of >14.67 mcg/mL had the greatest discriminating power (area under the curve = 0.77) for the occurrence of thrombocytopenia. A free VPA serum concentration of 14.67 mcg/mL had the optimal discriminating power for the occurrence of thrombocytopenia. Ammonemia should be monitored even if free VPA concentration is within the safety range.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Matagenome analysis of PCE/TCE-contaminated groundwater.•Bacterial community of PCE/TCE-contaminated site using RDP and LCA methods was assessed.•SPRS caused the variation of bacterial ...community.•The detection of some genes related to TCE degradation pathway using KEGG analysis.
The compositions of bacterial community in one site contaminated with PCE/TCE after the slow polycolloid-releasing substrate (SPRS) (contained vegetable oil, cane molasses, and surfactants) addition were analyzed. Results show that SPRS caused a rapid enhancement of reductive dechlorination of TCE. The transformation of PCE/TCE into ethene was observed after 20 days of operation. To compare the change of bacterial communities before and after SPRS addition, 16S rRNA amplicon sequencing using the metagenome analysis was performed. Results demonstrated the detection of the increased amounts of Dehalogenimonas by 2.2-fold, Pseudomonas by 3.4-fold and Sulfuricurvum by 4-fold with the analysis of the ribosomal database project (RDP). Metagenomic DNA was extracted from PCE/TCE-contaminated groundwater after SPRS addition, and subjected to sequencing. Results obtained from metagenomic sequencing indicate that genes from Dehalococcoides mccartyi was ranked as the second abundant bacteria among all of the detected bacteria via the analysis of the lowest common ancestor (LCA). Abundance of these bacterial groups, as shown above suggests their role in TCE biodegradation. Functional analysis of the metagenome, with the specific reference to chloroalkane and chloroalkene degradation, revealed the presence of some genes responsible for TCE biodegradation. Overall, results of this study provided new insights for a better understanding of the potential of biostimulation on TCE-contaminated sites.
A well-dispersed PtCu alloy nanoparticles (NPs) on three-dimensional nitrogen-doped graphene (PtCu/3D N-G) electrocatalyst has been successfully synthesized by a conventional hydrothermal method ...combined with a high-efficiency microwave-assisted polyol process. The morphology, composition, and structures are well-characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. Cyclic voltammograms illustrate that the as-prepared PtCu/3D N-G electrocatalyst possesses the larger electrochemical active surface area, lower onset potential, higher current density, and better tolerance to CO poisoning than PtCu NPs on reduced graphene oxide and XC-72 carbon black in acid solution. In addition, long-time chronoamperometry reveals that the PtCu/3D N-G catalyst exhibits excellent stability even longer than 60 min toward acid methanol electrooxidation. The remarkably enhanced performance is related to the combined effects of uniformly interconnected three-dimensional porous graphene networks, nitrogen doping, modified Pt alloy NPs, and strong binding force between Pt alloy NPs and 3D N-G structures.
This study aimed to report the long-term survival of fixed-bearing medial unicompartmental knee arthroplasty (UKA) with a mean of 14-year follow-up, and to determine possible risk factors of failure.
...We retrospectively evaluated 337 fixed-bearing medial UKAs implanted between 2003 and 2014. Demographic and radiographic parameters were measured, including pre-operative and post-operative anatomical femorotibial angle (aFTA), posterior tibial slope (PTS), and anatomical medial proximal tibial angle (aMPTA). Multivariate logistic regression analysis was applied to figure out risk factors.
The mean follow-up time was 14.0 years. There were 32 failures categorized into implant loosening (n = 11), osteoarthritis progression (n = 7), insert wear (n = 7), infection (n = 4), and periprosthetic fracture (n = 3). Cumulative survival was 91.6% at 10 years and 90.0% at 15 years. No statistically significant parameters were found between the overall survival and failure groups. Age and hypertension were significant factors of implant loosening with odds ratio (OR) 0.909 (p = 0.02) and 0.179 (p = 0.04) respectively. In the insert wear group, post-operative aFTA and correction of PTS showed significance with OR 0.363 (p = 0.02) and 0.415 (p = 0.03) respectively. Post-operative aMPTA was a significant factor of periprosthetic fracture with OR 0.680 (p < 0.05).
The fixed-bearing medial UKA provides successful long-term survivorship. Tibial component loosening is the major cause of failure. Older age and hypertension were factors with decreased risk of implant loosening.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level ...to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m−2 h−1 bar−1, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation.Carbon nanomaterials such as graphene show intriguing molecular transport properties, but to achieve regular channels over a large area requires perfect sheet alignment. Here, a large-area two-dimensional conjugated-polymer-framework is grown with regular pore distribution, enabling 99.5% salt rejection by forward osmosis.
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