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A Fe-Co dual-metal co-doped N containing the carbon composite (FeCo-HNC) was prepared by adjusting the ratio of iron to cobalt as well as the pyrolysis temperature with the assistance of functionalized silica template. Fe1Co-HNC, which was formed with 1D carbon nanotubes and 2D carbon nanosheets including a rich mesoporous structure, exhibited outstanding oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities. The ORR half-wave potential is 0.86 V (vs. reversible hydrogen electrode, RHE), and the OER overpotential is 0.76 V at 10 mA cm−2 with the Fe1Co-HNC catalyst. It also displayed superior performance in zinc–air batteries. This method provides a promising strategy for the fabrication of efficient transition metal-based carbon catalysts. [ABSTRACT FROM AUTHOR]

Intelligent membranes with adaptive gating channels play a crucial role in cellular functions and separation processes. This study introduces a novel approach to controlling channel expansion using biomimetic adaptive aggregates, fundamentally overcoming the drawbacks of existing methods relying on intertwined polyelectrolyte chains for channel blockage. Specifically, a pH‐responsive 2D material membrane is constructed through the self‐assembling of protein‐mimetic zwitterionic polydopamine (ZPDA) soft molecular aggregates within graphene oxide (GO) interlayers. Similar to the conformational switch of inserted proteins in cellular membranes, the embedded ZPDA in GO nanofluidic channels undergoes an adaptive conformational transformation in response to pH changes. This dynamic adjustment of ZPDA physicochemical properties allows for reversible regulation of GO nanofluidic channel size and charge by external pH modulation. The resulting GO/ZPDA membrane exhibits programmable separation performance for dye molecules (i.e., water permeance of 18.8–35.4 L m−2 h−1 bar−1 and molecular selectivity of 73.7–32.9) and salt ions (i.e., ionic permeance of 0.69–1.25 mol m−2 h−1 and ionic selectivity of 20.8–21.9). This work sheds new light on the engineering of intelligent stimuli‐responsive 2D nanofluidic channels with adaptive gating properties, holding promise across a wide range of applications including separation, drug delivery, sensing, and catalysis. [ABSTRACT FROM AUTHOR]

The excellent physicochemical properties of two-dimensional transition-metal dichalcogenides (2D TMDCs) such as WS2 and WSe2 provide potential benefits for biomedical applications, such as drug delivery, photothermal therapy, and bioimaging. WS2 and WSe2 have recently been used as chemosensitizers; however, the detailed molecular basis underlying WS2- and WSe2-induced sensitization remains elusive. Our recent findings showed that 2D TMDCs with different thicknesses and different element compositions induced autophagy in normal human bronchial epithelial cells and mouse alveolar macrophages at sublethal concentrations. Here, we explored the mechanism by which WS2 and WSe2 act as sensitizers to increase lung cancer cell susceptibility to chemotherapeutic agents. The results showed that WS2 and WSe2 enhanced autophagy flux in A549 lung cancer cells at sublethal concentrations without causing significant cell death. Through the autophagy-specific RT2 Profiler PCR Array, we identified the genes significantly affected by WS2 and WSe2 treatment. Furthermore, the key genes that play central roles in regulating autophagy were identified by constructing a molecular interaction network. A mechanism investigation uncovered that WS2 and WSe2 activated autophagy-related signaling pathways by interacting with different cell surface proteins or cytoplasmic proteins. By utilizing this mechanism, the efficacy of the chemotherapeutic agent doxorubicin was enhanced by WS2 and WSe2 pre-treatment in A549 lung cancer cells. This study revealed a feature of WS2 and WSe2 in cancer therapy, in which they eliminate the resistance of A549 lung cancer cells against doxorubicin, at least partially, by inducing autophagy. [ABSTRACT FROM AUTHOR]

Sap flow is one of the most important physiological water transport processes of trees, and the characteristics of sap flow are greatly affected by the spatial and temporal distribution of water in the SPAC (soil–plant–atmosphere continuum). However, different precipitation characteristics have great influence on the water environment of forest trees, which causes considerable differences in sap flow. Therefore, researching the response of sap flow to precipitation type is the key to accurately determining plant transpiration in semi-arid areas. We used K-means clustering analysis to divide the rainfall during the study period into three rainfall types (the highest rainfall amount and intensity (types I), medium rainfall amount and intensity, with a long duration (types II); and the lowest rainfall amount and intensity (types III)) based on the rainfall amount and intensity in order to compare the differences in the response of sap flow trends and influencing factors of Pinus tabulaeformis and Robinia pseudoacacia under different rainfall types. The results showed that, under the daily scale average sap flow of P. tabulaeformis and R. pseudoacacia, rainfall type II decreased significantly relatively to rainfall types I and III (p < 0.05). In rainfall type II, The sap flow characteristics of R. pseudoacacia were positively correlated with solar radiation (p < 0.05), while those of P. tabulaeformis were positively correlated with temperature, solar radiation, and VPD (p < 0.01). The sap flow of P. tabulaeformis and R. pseudoacacia were significantly positively correlated with temperature, solar radiation, VPD, and soil moisture content (p < 0.01) and negatively correlated with relative humidity (p < 0.05) in rainfall type III. The hourly sap flow of P. tabulaeformis and R. pseudoacacia on rainfall days was higher than before the rainfall. Rainfall type I promoted the daily sap flow of both species, and the proportion of the sap flow in daytime was also higher. On rainy days, the sap flow rates of rainfall type I and III showed a "midday depression". In type I rainfall events, the sap flow "midday depression" after rainfall occurred an hour ahead compared to the sap flow "midday depression" before rainfall. In type II rainfall events, the daytime sap flow rates of P. tabulaeformis and R. pseudoacacia were obviously inhibited, but the nighttime sap flow rate increased. In type III rainfall events, the sap flow before rainfall presented a unimodal curve versus time. The daily average sap flow of R. pseudoacacia was more susceptible to rainfall type II, while P. tabulaeformis was more susceptible to rainfall types I and III. The sap flow rate of R. pseudoacacia decreased on rainy days. The results show that the effects of different rainfall types on the sap flow trends of P. tabulaeformis and R. pseudoacacia were different. They revealed the responses of their sap flow trends to meteorological factors under different rainfall types, which provided basic data and theoretical support for further predicting the sap flow trends on rainy days, clarifying the effects of rainfall amount, rainfall duration, and rainfall intensity on sap flow trends and accurately estimating the transpiration water consumption of typical tree species in the sub-humid climate regions of China. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing is widely recognized as a potential stimulation technology for the development of challenging natural gas hydrate. However, the fracturing behavior of non-diagenetic hydrate reservoirs has peculiar characteristics that are different from those of conventional oil and gas reservoirs. Herein, a fully coupled fluid-mechanical model for simulating hydraulic fracturing in hydrate-bearing sediments (HBS) was established based on the discrete element method, and the influence of hydrate saturation, in situ stress, and injection rate on the meso-fracture evolution was investigated. The results indicate that with the increase in hydrate saturation, the fracture morphology transitions from bi-wing to multi-branch, thereby enhancing fracture complexity. Both tensile and shear failure modes exist, and the tensile failure between the weakly cemented sediment particles is dominant. The tensile strength of HBS is an exponential function of hydrate saturation, with the breakdown pressure being governed by hydrate saturation and in situ stress, with the form being consistent with the classical Kirsch equation. Additionally, lower in situ stress and higher injection rates are conducive to the generation of microcracks, whereas an excessive injection rate reduces the fracture length. These findings contribute to understanding the meso-evolution mechanism of hydraulic fractures and guide the design of on-site hydraulic fracturing plans of natural gas hydrate reservoirs. [ABSTRACT FROM AUTHOR]

This study considers the practical issue of severe noise observed in a multi-stage sleeve control valve within an engineering project. Employing computational fluid dynamics (CFD) methodology, we initially performed numerical simulations to analyze the steady-state flow field within the control valve. Subsequently, we identified the underlying factors contributing to the noise issue within the valve. To assess the aerodynamic noise of the control valve, we applied the FW-H acoustic analogy theory and determined the intensity and distribution characteristics of the aerodynamic noise. Finally, we validated the numerical simulation results of the aerodynamic noise against theoretical calculations. Our findings indicate that the steam medium experiences high-speed flow due to disturbances caused by various components within the valve, resulting in significant turbulence intensity. This intense turbulence leads to pressure fluctuations in the steam, serving as the main catalyst for noise generation. The aerodynamic noise of the control valve exhibits a roughly symmetrical distribution along the pipe–valve system, with noticeable increases in noise levels upstream and downstream of the valve compared to other regions. The distribution cloud map obtained from the numerical simulations serves as a valuable reference for analyzing the locations where aerodynamic noise is generated. Comparing the numerical simulation results with the theoretical calculations at the noise monitoring points, we found that the noise error of the monitoring points was less than 5%, which proves the effectiveness of the numerical simulation method. These results provide essential data support for the acoustic detection of aerodynamic noise in control valves, carrying significant practical implications for engineering applications. [ABSTRACT FROM AUTHOR]