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Two-dimensional silicon-carbide (SixCy) materials stand out for their compatibility with current silicon-based technologies, offering unique advantages in nanoelectronics and photocatalysis. In this study, we employ density functional theory and nonequilibrium Green's function methods to investigate the electronic properties, electron transport characteristics, and optoelectronic qualities of experimentally synthesized monolayer Si9C15. Utilizing the modified deformation potential theory formula, we unveil Si9C15's significant directional anisotropy in electron mobility (706.42 cm2 V-1 s-1) compared to holes (432.84 cm2 V-1 s-1) in the a direction. The electrical transport calculations reveal that configurations with a 3 nm channel length demonstrate an ON state when biased, reaching a peak current of 150 nA. Moreover, this maximum current value escalates to 200 nA under tensile strain, marking an increase of approximately 100 times compared to the 5 nm channel, which remains in an OFF state. Si9C15 exhibits high light absorption coefficients (â¼105 cm-1) and suitable band edge positions for water splitting at pH 0-7. Applying 1-5% tensile strain can tune the conduction band minimum and valence band maximum closer to the standard redox potentials, enhancing photocatalytic water splitting efficiency. Remarkably, under illumination at pH 0 and 7, Si9C15 can spontaneously catalyze water splitting, demonstrating its potential as a highly efficient photocatalyst. Our findings emphasize the importance of strain control and device length optimization for performance enhancement in nanoelectronics and renewable energy applications, positioning Si9C15 as a promising material for high-performance field-effect transistors and photocatalytic water splitting.
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OBJECTIVE: To investigate the therapeutic effect and mechanism of sivelestat sodium on acute lung injury (AIL). METHODS: A rat model for ALI/acute respiratory distress syndrome (ALI/ARDS) was established. Pathological examination of lung tissue was conducted to assess lung injury. Blood gas in the arteries was measured using a blood analyzer. Changes in PaO2, PaO2/FiO2, and lung wet/dry (W/D) weight ratio were carefully compared. ELISA assay was conducted to estimate cell adhesion and inflammation response. Finally, real-time reverse transcription polymerase chain reaction and western blotting assay was used to determine the activation of PI3K/AKT/mTOR pathway. RESULTS: ARDS in vivo model was successfully constructed by LPS injection. Compared with the sham group, PaO2 and PaO2/FiO2 were significantly lower in the vehicle group, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8 andTNF-αwere significantly increased. After treatment with different doses of sivelestat sodium, we found PaO2, PaO2/FiO2 were prominently increased, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8, TNF-α levels were decreased in the dose-dependent manner. Meanwhile, compared with the vehicle group, the expression levels of Bax, PI3K, Akt and mTOR were significantly lower, and the expression of Bcl-2 was significantly higher after injection with sivelestat sodium. CONCLUSION: Sivelestat sodium has an interventional effect on ALI in sepsis by inhibiting the PI3K/AKT/mTOR signalling pathway.
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Lesão Pulmonar Aguda , Glicina , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Ratos Sprague-Dawley , Transdução de Sinais , Sulfonamidas , Serina-Treonina Quinases TOR , Animais , Serina-Treonina Quinases TOR/metabolismo , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Transdução de Sinais/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Ratos , Masculino , Glicina/análogos & derivados , Glicina/farmacologia , Glicina/uso terapêutico , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Modelos Animais de DoençasRESUMO
The functional brain connectome is highly dynamic over time. However, how brain connectome dynamics evolves during the third trimester of pregnancy and is associated with later cognitive growth remains unknown. Here, we use resting-state functional Magnetic Resonance Imaging (MRI) data from 39 newborns aged 32 to 42 postmenstrual weeks to investigate the maturation process of connectome dynamics and its role in predicting neurocognitive outcomes at 2 years of age. Neonatal brain dynamics is assessed using a multilayer network model. Network dynamics decreases globally but increases in both modularity and diversity with development. Regionally, module switching decreases with development primarily in the lateral precentral gyrus, medial temporal lobe, and subcortical areas, with a higher growth rate in primary regions than in association regions. Support vector regression reveals that neonatal connectome dynamics is predictive of individual cognitive and language abilities at 2 years of age. Our findings highlight network-level neural substrates underlying early cognitive development.
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Encéfalo , Cognição , Conectoma , Imageamento por Ressonância Magnética , Humanos , Conectoma/métodos , Feminino , Masculino , Imageamento por Ressonância Magnética/métodos , Cognição/fisiologia , Recém-Nascido , Encéfalo/crescimento & desenvolvimento , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Pré-Escolar , Desenvolvimento da Linguagem , Desenvolvimento Infantil/fisiologiaRESUMO
The first 1,000 days of human life lay the foundation for brain development and later cognitive growth. However, the developmental rules of the functional connectome during this critical period remain unclear. Using high-resolution, longitudinal, task-free functional magnetic resonance imaging data from 930 scans of 665 infants aged 28 postmenstrual weeks to 3 years, we report the early maturational process of connectome segregation and integration. We show the dominant development of local connections alongside a few global connections, the shift of brain hubs from primary regions to high-order association cortices, the developmental divergence of network segregation and integration along the anterior-posterior axis, the prediction of neurocognitive outcomes, and their associations with gene expression signatures of microstructural development and neuronal metabolic pathways. These findings advance our understanding of the principles of connectome remodeling during early life and its neurobiological underpinnings and have implications for studying typical and atypical development.
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Encéfalo , Conectoma , Imageamento por Ressonância Magnética , Humanos , Lactente , Masculino , Feminino , Encéfalo/metabolismo , Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Pré-Escolar , Rede Nervosa/fisiologia , Recém-NascidoRESUMO
We present a theoretical design of a class of 2D semiconducting materials, namely, group III (In/Ga)-V (P/As)-VI (S/Se) monolayers, whose global-minimum structures are predicted based on the particle swarm optimization method. Electronic structure calculations suggest that all group III-V-VI monolayers exhibit quasi-direct semiconducting characteristics with desirable band gaps ranging from 1.76 to 2.86 eV (HSE06 functional). Moreover, most group III-V-VI monolayers possess highly anisotropic carrier mobilities with large anisotropic ratios (3.4-6 for electrons, 2.2-25 for holes). G0W0+BSE calculations suggest that these monolayers show high optical anisotropy and relatively large exciton binding energies (0.33-0.75 eV), comparable to that (0.5 eV) of MoS2 monolayer. In particular, the GaPS monolayer manifests strikingly anisotropic I-V curves with a large ON/OFF ratio of â¼105 (106 for the GaPS bilayer) and anisotropic lattice thermal conductivity. Furthermore, the GaPS monolayer is predicted to exhibit both in-plane and out-of-plane negative Poisson ratios (NPRs) and prominent anisotropic Young moduli.
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Functional connectome gradients represent fundamental organizing principles of the brain. Here, we report the development of the connectome gradients in preterm and term babies aged 31-42 postmenstrual weeks using task-free functional MRI and its association with postnatal cognitive growth. We show that the principal sensorimotor-to-visual gradient is present during the late preterm period and continuously evolves toward a term-like pattern. The global measurements of this gradient, characterized by explanation ratio, gradient range, and gradient variation, increased with age (p < 0.05, corrected). Focal gradient development mainly occurs in the sensorimotor, lateral, and medial parietal regions, and visual regions (p < 0.05, corrected). The connectome gradient at birth predicts cognitive and language outcomes at 2-year follow-up (p < 0.005). These results are replicated using an independent dataset from the Developing Human Connectome Project. Our findings highlight early emergent rules of the brain connectome gradient and their implications for later cognitive growth.
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In this study, we have investigated the electron mobility of monolayered (ML) tetrahex-GeC2 by solving the linearized Boltzmann transport equation (BTE) with the normalized full-band relaxation time approximation (RTA) using density functional theory (DFT). Contrary to what the deformation potential theory (DPT) suggested, the ZA acoustic mode was determined to be the most restrictive for electron mobility, not the LA mode. The electron mobility at 300 K is 803 cm2 (V s)-1, exceeding the 400 cm2 (V s)-1 of MoS2 which was calculated using the same method and measured experimentally. The ab initio quantum transport simulations were performed to assess the performance limits of sub-10 nm DG ML tetrahex-GeC2 n-type MOSFETs, including gate lengths (Lg) of 3 nm, 5 nm, 7 nm, and 9 nm, with the underlap (UL) effect considered for the first two. For both high-performance (HP) and low-power (LP) applications, their on-state currents (Ion) can meet the requirements of similar nodes in the ITRS 2013. In particular, the Ion is more remarkable for HP applications than that of the extensively studied MoS2. For LP applications, the Ion values at Lg of 7 and 9 nm surpass those of arsenene, known for having the largest Ion among 2D semiconductors. Subthreshold swings (SSs) as low as 69/53 mV dec-1 at an Lg of 9 nm were observed for HP/LP applications, and 73 mV dec-1 at an Lg of 5 nm for LP applications, indicating the excellent gate control capability. Moreover, the delay time τ and power dissipation (PDP) at Lg values of 3 nm, 5 nm, 7 nm, and 9 nm are all below the upper limits of the ITRS 2013 HP/LP proximity nodes and are comparable to or lower than those of typical 2D semiconductors. The sub-10 nm DG ML tetrahex-GeC2 n-type MOSFETs can be down-scaled to 9 nm and 5 nm for HP and LP applications, respectively, displaying desirable Ion, delay time τ, and PDP in the ballistic limit, making them a potential choice for sub-10 nm transistors.
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Flavonoids, such as anthocyanins and proanthocyanidins (PAs), play essential roles in plant growth, development, and stress response. Red-fleshed apples represent a valuable germplasm resource with high flavonoid content. Understanding and enriching the regulatory network controlling flavonoid synthesis in red-fleshed apples holds significant importance for cultivating high-quality fruits. In this study, we successfully isolated an NAC transcription factor, MdNAC14-Like, which exhibited a significant negative correlation with the content of anthocyanin. Transient injection of apple fruit and stable expression of callus confirmed that MdNAC14-Like acts as an inhibitor of anthocyanin synthesis. Through yeast monohybrid, electrophoretic mobility shift, and luciferase reporter assays, we demonstrated the ability of MdNAC14-Like to bind to the promoters of MdMYB9, MdMYB10, and MdUFGT, thus inhibiting their transcriptional activity and subsequently suppressing anthocyanin synthesis. Furthermore, our investigation revealed that MdNAC14-Like interacts with MdMYB12, enhancing the transcriptional activation of MdMYB12 on the downstream structural gene MdLAR, thereby promoting PA synthesis. This comprehensive functional characterization of MdNAC14-Like provides valuable insights into the intricate regulatory network governing anthocyanin and PA synthesis in apple.
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Malus , Proantocianidinas , Malus/genética , Malus/metabolismo , Antocianinas/metabolismo , Proantocianidinas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Flavonoides/metabolismoRESUMO
Utilizing two-dimensional (2D) heterostructures in photocatalysis can enhance optical ab-sorption and charge separation, thereby increasing solar energy conversion efficiency and tackling environmental issues. Density functional theory (DFT) was employed in this study to investigate the structural and optoelectronic properties of the AgBr/SiH van der Waals (vdW) heterostructures. All three configurations (A1, A2, and A3) were stable, with direct bandgaps of 1.83 eV, 0.99 eV, and 1.36 eV, respectively. The type-II band alignment in these structures enables electrons to be transferred from the SiH layer to the AgBr layer, and holes to move in the opposite direction. In the ultraviolet region, the optical absorption coefficients of the A1, A2, and A3 configurations are approximately 4.0 × 105 cm-1, significantly higher than that of an isolated AgBr monolayer (2.4 × 104 cm-1). In the visible light region, the A1 configuration has an absorption coefficient of 4 × 104 cm-1, higher than that of an isolated AgBr (2.2 × 104 cm-1). The band edges of the A1 configuration satisfy the redox potential for photocatalytic water splitting at pH 0-7. When the biaxial tensile strain is 5% for the A2 configuration and 2% for the A3 configuration, it can allow photocatalytic water splitting from half-reactions without strain to photocatalytic overall water splitting at pH 0-7. With a 5% biaxial tensile strain in the visible light region, the A1 and A3 configurations experience a rise in the maximum absorption coefficient of 5.7 × 104 cm-1 and 4.6 × 104 cm-1, respectively. The findings indicate that the AgBr/SiH vdW heterostructure configurations could be utilized in photocatalytic water-splitting processes with great potential.
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Despite the advantages of quaternary two-dimensional (2D) materials, fewer studies have been done on them than binary 2D materials. Calculations of quaternary 2D monolayer Cu2Cl2Se2Hg2based on density functional theory and Green's function surface analysis provide insights into its structural, dynamic, and thermal stability. This material has a direct band gap of 0.91/2.0 eV (Perdew-Burke-Ernzerhof/Heyd-Scuseria-Ernzerhof) and demonstrates anisotropic carrier mobility. The electron mobility in theadirection is 1.2 × 103cm2V-1s-1, which is significantly higher than the hole mobility of 0.48 × 103cm2V-1s-1. In thebdirection, the electron mobility is 1.01 × 103cm2V-1s-1and is 8.9 times larger than the hole mobility of 0.11 × 103cm2V-1s-1. The light absorption coefficients of Cu2Cl2Se2Hg2are 1.0 × 105cm-1and 2.5 × 105cm-1in the visible and ultraviolet ranges, respectively. Uniaxial strain leads to an anisotropic alteration in the band gap and band edge position. By manipulating the strain direction and level in Cu2Cl2Se2Hg2, it is possible to increase the current ON/OFF ratio for field-effect transistors (FETs) and to facilitate photocatalytic water splitting through a redox reaction. The research reveals that Cu2Cl2Se2Hg2, a 2D monolayer in the quaternary form, has promising capabilities as an alternative for creating crystal-oriented FETs and photocatalytic water splitting systems.
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Two-dimensional (2D) semiconducting materials with distinct anisotropic physical properties have attracted intense interests. Herein, we show theoretical predictions that MgXN2 (X = Hf/Zr) monolayers are auxetic semiconductors with highly anisotropic electronic, optical, and mechanical properties. The density functional theory calculations coupled with a PSO algorithm (global-minimum search) suggest that both MgHfN2 (MgZrN2) monolayers exhibit orthorhombic symmetry (Pmma) and are direct-gap (indirect-gap) semiconductors with a bandgap of 2.43 eV (2.13 eV). Specifically, the MgHfN2 monolayer exhibits highly anisotropic hole mobility as well as very high electron mobility (â¼104 cm2 V-1 s-1). G0W0+BSE calculations indicate that both monolayers bear notable optical anisotropy and relatively large exitonic binding energy (â¼0.6 eV). In addition, both monolayers acquire remarkable mechanical anisotropy with a negative in-plane Poisson's ratio (â¼-0.2) and high Young's modulus (â¼260 N/m). The combination of highly anisotropic electronic, optical, and mechanical properties endows MgXN2 monolayers as potentially useful parts in multifunctional nanoelectronic devices.
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OBJECTIVE: To investigate the overall incidence and associated factors of epileptiform discharges in children during sevoflurane anesthesia. METHODS: Our group systematically searched the PubMed, Cochrane library (Central) and EMBASE for the relevant trials from their inception until September 2020. The primary endpoint was the incidence of epileptiform discharges during sevoflurane induction. The secondary endpoints were the incidence of different types of epileptiform discharges, factors associated with these epileptiform events, and other adverse events such as seizure-like movements. RESULTS: After screening of 713 records, eleven studies involving 448 participants were included into the final analysis. Meta-analysis indicated that the overall incidence of Epileptiform EEG discharges was 38.1% (95%confidence interval [CI], 19.1%-59.2%) during sevoflurane anesthesia in children. Subgroup analysis showed that the incidence of these EEG patters was lower when participants were inducted by using the low initial concentration of sevoflurane, compared with the high initial concentration sevoflurane (1.7%, 95%CI, 0.0% to 8.4% versus 47.7%, 95%CI, 25.5% to 70.3%, P < 0.05). The longer exposure (>3 min) of high concentration sevoflurane during induction showed higher rate of epileptiform discharges than a shorter exposure (≤3 min) (48.4%, 95%CI, 20.1% to 77.3% versus 5.7%, 95%CI, 0.00% to 23.5%; P < 0.05). No significant difference for the incidence of epileptiform discharges was observed in subgroup analysis of addition of nitrous oxide (69.2%, 95%CI, 34.0% to 95.7% versus 41.3%, 95%CI, 15.6% to 69.7%, Pï¹¥0.05) and type of EEG monitoring (26.9%, 95%CI, 3.8% to 60.7% versus 53.1%, 95%CI, 25.4% to 79.8%, Pï¹¥0.05). CONCLUSIONS: The incidence of epileptiform EEG events in children during sevoflurane anesthesia varied from 19.1%-59.2%. The low initial concentration technique and shorter exposure time of high concentration sevoflurane may be associated with a decreased incidence of these epileptiform discharges in EEG. SIGNIFICANCE: Epileptiform EEG discharges during sevoflurane anesthesia in children should arouse clinicians' attention. The use of low initial concentration technique and shorter exposure time of high concentration sevoflurane may be associated with a lower occurrence of these paradoxical events.
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Anestesia , Anestésicos Inalatórios , Éteres Metílicos , Anestesia/métodos , Anestésicos Inalatórios/efeitos adversos , Criança , Eletroencefalografia/métodos , Humanos , Éteres Metílicos/efeitos adversos , Óxido Nitroso , Sevoflurano/efeitos adversosRESUMO
The development of efficient heterojunctions through a simple and facile method is an effective way to enhance the photocatalytic performance of bismuth-based oxide semiconductors for industrial applications. Here, the novel ï¬ower-like type II SnS2/Bi2WO6 heterostructure consisting of bismuth tungstate (Bi2WO6) nanosheets and tin bisulfide (SnS2) nanoplates was successfully designed and synthesized. The crystal structure, composition, morphology, and photoelectric properties of the heterostructure were systematically characterized. In addition, the photocatalytic activity of SnS2/Bi2WO6 was analyzed and compared with Bi2WO6 or SnS2 alone or physical mixture of SnS2 and Bi2WO6. 2%SnS2/Bi2WO6 presents a 3.1 times greater degradation rate constant (0.0065 min-1) than that of Bi2WO6 (0.0021 min-1) under low visible light irradiation (5.3 mW·cm-2, a 44 W LED), while SnS2 alone exhibits no photocatalytic effect toward glyphosate. Furthermore, 2%SnS2/Bi2WO6 maintains 93% of its original photocatalytic activity even after four cycles. The possible photocatalytic degradation pathway of glyphosate and photocatalytic mechanism are also proposed. The excellent photocatalytic performance of SnS2/Bi2WO6 is attributed to the decoration of SnS2 nanoplates on the surface of Bi2WO6, appropriate (113)/(020) ratio, increased visible-light absorption, and effective separation of photoinduced carriers. This paper reports a new methodology that can act as a reference basis to design and develop visible-light responsive photocatalysts with outstanding photocatalytic performance for carbon dioxide reduction, water splitting, and pollutant degradation.
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Functional hubs with disproportionately extensive connectivities play a crucial role in global information integration in human brain networks. However, most resting-state functional magnetic resonance imaging (R-fMRI) studies have identified functional hubs by examining spontaneous fluctuations of the blood oxygen level-dependent signal within a typical low-frequency band (e.g., 0.01-0.08 Hz or 0.01-0.1 Hz). Little is known about how the spatial distributions of functional hubs depend on frequency bands of interest. Here, we used repeatedly measured R-fMRI data from 53 healthy young adults and a degree centrality analysis to identify voxelwise frequency-resolved functional hubs and further examined their test-retest reliability across two sessions. We showed that a wide-range frequency band (0.01-0.24 Hz) accessible with a typical sampling rate (fsample = 0.5 Hz) could be classified into three frequency bands with distinct patterns, namely, low-frequency (LF, 0.01-0.06 Hz), middle-frequency (MF, 0.06-0.16 Hz), and high-frequency (HF, 0.16-0.24 Hz) bands. The functional hubs were mainly located in the medial and lateral frontal and parietal cortices in the LF band, and in the medial prefrontal cortex, superior temporal gyrus, parahippocampal gyrus, amygdala, and several cerebellar regions in the MF and HF bands. These hub regions exhibited fair to good test-retest reliability, regardless of the frequency band. The presence of the three frequency bands was well replicated using an independent R-fMRI dataset from 45 healthy young adults. Our findings demonstrate reliable frequency-resolved functional connectivity hubs in three categories, thus providing insights into the frequency-specific connectome organization in healthy and disordered brains.
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Conectoma , Encéfalo/diagnóstico por imagem , Conectoma/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Reprodutibilidade dos Testes , Descanso , Adulto JovemRESUMO
Recently, the crystal structure of violet phosphorus and its monolayer violet phosphorene (VP) have been reconfirmed experimentally, and they were verified to be more thermally stable than their allotrope, black phosphorus. Here, we calculated the carrier mobility of monolayer VP using density functional theory. It is found that the carrier mobility is highly anisotropic and the hole mobility reaches 9.86 × 103 cm2 V-1 s-1 in the a-direction, endowing the potential application of VP in p-type semiconductor channel materials. Moreover, the Schottky barrier of the graphene/VP heterojunction turns into an ohmic contact when the electric field strength is >2 V nm-1. Therefore, VP and graphene/VP heterojunctions have potential prospects in electronic devices.
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Functional brain networks require dynamic reconfiguration to support flexible cognitive function. However, the developmental principles shaping brain network dynamics remain poorly understood. Here, we report the longitudinal development of large-scale brain network dynamics during childhood and adolescence, and its connection with gene expression profiles. Using a multilayer network model, we show the temporally varying modular architecture of child brain networks, with higher network switching primarily in the association cortex and lower switching in the primary regions. This topographical profile exhibits progressive maturation, which manifests as reduced modular dynamics, particularly in the transmodal (e.g., default-mode and frontoparietal) and sensorimotor regions. These developmental refinements mediate age-related enhancements of global network segregation and are linked with the expression profiles of genes associated with the enrichment of ion transport and nucleobase-containing compound transport. These results highlight a progressive stabilization of brain dynamics, which expand our understanding of the neural mechanisms that underlie cognitive development.
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Encéfalo , Imageamento por Ressonância Magnética , Adolescente , Mapeamento Encefálico , Córtex Cerebral , Criança , Cognição , Humanos , Imageamento por Ressonância Magnética/métodos , Vias NeuraisRESUMO
While past studies have enriched our understanding of the impact of returnee executives on firm market strategy and outcomes, we know relatively little about the relationship between returnee executives and firm nonmarket strategies. Grounded in upper echelons theory, this study explores the relationship between returnee executives and corporate philanthropy, the latter of which is an important nonmarket strategy in emerging economies such as China. Using data on publicly listed Chinese companies from 2010 to 2017, we find that the proportion of returnee executives is negative related to corporate philanthropy. We also find that this negative relationship is strengthened by executive ownership, but weakened by corporate prominence and political connections. Our study makes important theoretical contributions to strategic leadership research, upper echelons theory, and the literature of corporate philanthropy. The managerial implications are also discussed.
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The rational design and construction of cost-effective nickel-based phosphide or sulfide (photo)electrocatalysts for hydrogen production from water splitting has sparked a huge investigation surge in recent years. Whereas, nickel phosphides (Nix Py ) possess more than ten stoichiometric compositions with different crystalline. Constructing Nix Py with well crystalline and revealing their intrinsic catalytic mechanism at atomic/molecular levels remains a great challenge. Herein, an easy-to-follow phase-controllable phosphating strategy is first proposed to prepare well crystalline Nix Py (Ni3 P and Ni12 P5 ) modified CdS@Ni3 S2 heterojunction electrocatalysts. It is found that Ni3 P modified CdS@Ni3 S2 (CdS@Ni3 S2 /Ni3 P) exhibits remarkable stability and bifunctional electrocatalytic activities in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory results suggest that P-Ni sites and P sites in CdS@Ni3 S2 /Ni3 P, respectively, serve as OER and HER active sites during electrocatalytic water splitting processes. Moreover, benefiting from the advantageous photocatalyst@electrocatalyst core@shell structure, CdS@Ni3 S2 /Ni3 P delivers an advantaged photoassisted electrocatalytic water splitting property. The champion electrical to hydrogen and solar to hydrogen energy conversion efficiencies of CdS@Ni3 S2 /Ni3 P, respectively, reach 93.35% and 4.65%. This work will provide a general guidance for synergistically using solar energy and electric energy for large-scale H2 production from water splitting.
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Mussel foot proteins (Mfps) show strong adhesion to underwater substrates, making mussels tightly cling to reefs to withstand the sea current. Therefore, Mfps-inspired tissue adhesives have aroused much research interest, but tough underwater biological tissue adhesion is still a great challenge. Herein, we report a tough and reversible wet tissue-selective adhesive hydrogel made of poly(acrylic acid-co-catechol) and chitosan (CS). It provides negatively charged -COO-, positively charged -NH3+, catechol group and hydrophobic alkyl chain, resemble amino acids, catechol and hydrophobic units in Mfps. Due to the covalent/electrostatic attraction/π-π/cationic-π/hydrogen bonding, in addition to the hydrophobic interaction from the long hydrophobic alkyl chain of the catechol derivative, the hydrogel has a high cohesion strength and toughness, i.e., tensile stress, fracture strain and fracture toughness of â¼0.57 MPa, 2510% and 6620 J m-2, respectively. As a tissue adhesive, its adhesion bonding to the porcine skin surface is so strong that its adhesion strength is almost equal to the tearing strength of the hydrogel. The 180-degree peeling adhesion energy of the hydrogel to blood-wetted porcine skin is notably â¼1010 J m-2. It can tightly and seamlessly adhere to the porcine small intestine, and has a bursting pressure of up to 520 mmHg. The hydrogel can be handily debonded from the porcine skin surface in the presence of aqueous solution at pH 8.0, and its adhesiveness is reversible for at least 20 cycles. It is supposed that the synergistic interactions of the adhesive catechol group, displacement of water on the wet skin surface by the positively charged -NH3+ groups of CS and the water-repelling potential of the hydrophobic unit of the catechol derivative, the protection of the catechol group from oxidation into a less adhesive quinone group, and the energy dissipation capacity of the mechanically tough hydrogel contribute to the strong and repeatable wet tissue adhesion.
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Bivalves , Adesivos Teciduais , Adesividade , Adesivos , Animais , Hidrogéis , SuínosRESUMO
In this study, we present that 2D tetrahex-GeC2 materials possess novel electronic and carrier transport properties based on density functional theory computations combined with the nonequilibrium Green's function method. We show that under the 4% (-4%) in-plane expansion (compression) along the a-direction (b-direction) of the tetrahex-GeC2 monolayer, the bandgap can be enlarged to a desirable 1.26 eV (1.32 eV), close to that of silicon. The carrier transport properties of both the sub-10 nm tetrahex-GeC2 monolayer and the bilayer show strong anisotropy within the bias from -1 to 1 V. The current ON (a-direction)/OFF (b-direction) ratio amounts to 105 for the tetrahex-GeC2 monolayer. A striking negative differential conductance arises with the maximum Ipeak/Ivalley on the order of 104 under the 4% uniaxial expansion along the b-direction of the tetrahex-GeC2 monolayer. Overall, the 2D tetrahex-GeC2 monolayer and bilayer possess highly tunable electronic and carrier transport properties under uniaxial strain, which can be exploited for potential applications in nanoelectronics.