Transition‐metal oxides as electrocatalysts for the oxygen evolution reaction (OER) provide a promising route to face the energy and environmental crisis issues. Although palmeirite oxide A2Mo3O8 as ...OER catalyst has been explored, the correlation between its active sites (tetrahedral or octahedral) and OER performance has been elusive. Now, magnetic Co2Mo3O8@NC‐800 composed of highly crystallized Co2Mo3O8 nanosheets and ultrathin N‐rich carbon layer is shown to be an efficient OER catalyst. The catalyst exhibits favorable performance with an overpotential of 331 mV@10 mA cm−2 and 422 mV@40 mA cm−2, and a full water‐splitting electrolyzer with it as anode catalyst shows a cell voltage of 1.67 V@10 mA cm−2 in alkaline. Combined HAADFSTEM, magnetic, and computational results show that factors influencing the OER performance can be attributed to the tetrahedral Co sites (high spin, t23e4), which improve the OER kinetics of rate‐determining step to form *OOH.
Magnetic Co2Mo3O8@NC‐800 composed of single‐crystal Co2Mo3O8 and ultrathin nitrogen‐rich carbon was synthesized to uncover its OER active sites (Td Co2+ or Oh Co2+). Electrochemical data, magnetism data, and computations suggest that the Td Co2+ atoms (high spin, t23e4) in Co2Mo3O8 act as active sites facilitating the rate‐determining step, forming *OOH to promote the reaction kinetics for OER.
Carbon nanodots (C-dots) possessing photoluminescence (PL) properties have become interesting materials for sensing and imaging, with the advantages of water-dispersibility, biocompatibility, ...chemical and photo stability. They can be prepared from organic matter such as tea, grass, coffee, and small organic molecules like glycine and glucose through hydrothermal routes. In this review, we focus on the recent advances in the synthesis and characterization of C-dots along with their optical (absorption, PL, upconverted PL) properties and analytical applications. Having bright PL, biocompatibility, chemical and photo stability, as well as low toxicity, C-dots have been used for the detection of metal ions and for cell imaging. C-dots prepared from organic matter such as used tea and ginger possess a great inhibitory effect on the growth of cancer cells, showing their excellent potential as new drugs.
This study uses scenario analysis to assess the socioeconomic impacts of achieving zero-carbon energy by 2030. Three scenarios are developed: 1) business as usual; 2) accelerated deployment of ...renewable energy and electric vehicles; and 3) scenario 2 plus comprehensive energy efficiency improvements. Quantitative models are used to evaluate the impacts on employment, productivity, consumer costs, inequality and energy security under each scenario. The results show that scenario 3, with the most ambitious decarbonization and efficiency measures, can generate the most jobs (2.1 million more than business as usual) and the lowest consumer costs (12% reduction). However, it may also lead to a small productivity loss (1.2% lower than business as usual) due to higher costs of new technologies. Income and health inequality are projected to decrease across all scenarios due to improved energy access and reduced fuel poverty. Energy security is expected to improve significantly in scenarios 2 and 3 due to reduced oil dependence. This study provides an analytical framework to assess the integrated socioeconomic impacts of zero-carbon transitions under uncertainty. The scenarios and findings can inform policymaking by highlighting the opportunities and challenges around the low-carbon transition, enabling decision makers to maximize benefits and minimize negative consequences.
Obesity has become epidemic worldwide, which triggers several obesity-associated complications. Obesity is characterized by excess fat storage mainly in the visceral white adipose tissue (vWAT), ...subcutaneous WAT (sWAT), and other tissues. Myriad studies have demonstrated the crucial role of canonical Wnt/β-catenin cascade in the development of organs and physiological homeostasis, whereas recent studies show that genetic variations/mutations in the Wnt/β-catenin pathway are associated with human metabolic diseases. In this review, we highlight the regulation of updated Wnt/β-catenin signaling in obesity, especially the distinctly depot-specific roles between subcutaneous and visceral adipose tissue under high-fed diet stimulation and WAT browning process.
Scalability and flexibility are widely considered as two major design goals for 5G networks. Aiming at these goals, this article first identifies a promising architecture based on the heterogeneous ...cloud radio access network (H-CRAN), reviews the challenges in MIMO precoding for H-CRAN, and then proposes a scalable and flexible massive MIMO precoding scheme by exploiting the null-space of user signals. Specifically, the system can accomplish effective radio resource management and flexible spatial coordination by distinguishing the intended and victim users' CSI, and avoid the interference by precoding within the null-space for the CSI of victim users. Simulation results indicate that the proposed scheme is capable to effectively alleviate the interference to victim users and support high QoS as well as spectral efficiency.
This paper presents a new method for extracting blocks and calculating block size automatically from rock surface 3D point clouds. Block size is an important rock mass characteristic and forms the ...basis for several rock mass classification schemes. The proposed method consists of four steps: 1) the automatic extraction of discontinuities using an improved Ransac Shape Detection method, 2) the calculation of discontinuity intersections based on plane geometry, 3) the extraction of block candidates based on three discontinuities intersecting one another to form corners, and 4) the identification of “true” blocks using an improved Floodfill algorithm. The calculated block sizes were compared with manual measurements in two case studies, one with fabricated cardboard blocks and the other from an actual rock mass outcrop. The results demonstrate that the proposed method is accurate and overcomes the inaccuracies, safety hazards, and biases of traditional techniques.
•A new method is developed to automatically extract blocks from rock outcrops.•The extraction of block information is based on raw point clouds.•An improved Ransac algorithm was used to extract the discontinuity information.•A “Plane number algorithm” was developed to identify block candidates.•The “Floodfill algorithm” was used to distinguish true from “molds” of blocks.
Microplastics are plastic fragments widely distributed in the environment and accumulate in the organisms. However, the research on microplastics effects in mammals is limited. Polyethylene is the ...main kind of microplastics in the environment. We hypothesized that polyethylene exposure disrupts host intestine metabolism by modifying intestine microflora composition and then lipopolysaccharide (LPS) pathway. Female mice were orally exposed to 0, 0.002 and 0.2 μg/g/d polyethylene microplastics (PE MPs) for 30 days. Colon mucin density was quantized after AB-PAS staining. Mucin 2 (MUC2), inflammatory factors (IL-1β, IL-6, IL-8 and IL-10), short-chain fatty acid receptors (GPR41 and GPR43), LPS receptors (TLR4 and MyD88) and LPS pathway downstream genes (ERK1 and NF-κB) mRNA levels in colon were measured. Feces were collected on the 15th day of exposure for gut microflora analysis. Blood biochemical analysis was performed. Results showed that 0.2 μg/g/d PE MPs exposure significantly decreased colon mucin expression (p < 0.05), decreased IL-1β (p < 0.05) and increased IL-8 and IL-10 levels (p < 0.01 and p < 0.001 respectively). Microflora data showed that in 0.2 μg/g/d PE MPs group the number of Firmicutes decreased and the number of Bacteroides increased (both p < 0.01). Predicted KEGG metabolic pathways by piecrust method indicated that PE MPs enhanced amino acids metabolism in microflora. ERK1 and NF-κB mRNA were significantly lower in 0.2 μg/g/d PE MPs group (both p < 0.001). Blood total protein, albumin and globulin levels significantly increased after 0.2 μg/g/d PE MPs exposure (p < 0.01, p < 0.01 and p < 0.05 respectively). These results indicate that PE MPs exposure induced decreased mucin production, a slight immune response and increased the microflora amino acid metabolism in the mice colon by modifying colon microflora composition.
Polyethylene microplastics exposure decreased colon mucin release and increased amino acid metabolism by modifying colon microflora composition.
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•PE MPs exposure caused a decrease of colon mucin secretion in mice colon.•PE MPs exposure induced a mild inflammatory response in the colonic epithelium.•PE MPs exposure decreased the Firmicutes and increased the Bacteroides in gut microflora.•Alternation of microflora composition induced by PE MPs increased amino acid metabolism.•Both blood albumin and globulin levels increased after PE MPs exposure.
In this study, shear tests on artificial rock joints with different roughness were conducted under five normal stress levels. Test results showed that the shear strength of rock joints had a positive ...correlation with roughness and the applied normal stress. Observation of joint specimens after shear tests indicated that asperity damage was mainly located in the steep areas facing the shear direction. The damaged joint surfaces tend to be rough, which implies that tensile failure plays an important role in shear behavior. As a result of the anisotropic characteristic of joint roughness, two quantitative 2D roughness parameters, i.e., the revised root-mean-square of asperity angle tan
−1
(
Z
2r
) and the maximum contact coefficient
C
m
, were proposed considering the shear direction. The proposed roughness parameters can capture the difference of roughness in forward and reverse directions along a single joint profile. The normalized tensile strength and the proposed roughness parameters were used to perform a rational derivation of peak dilatancy angle. A negative exponential-type function was found to be appropriate to model the peak dilatancy angle. Using the new model of peak dilatancy angle, we obtained a new criterion for peak shear strength of rock joints. The good agreement between test results and predicted results by the new criterion indicated that the proposed criterion is capable of estimating the peak shear strength of rock joints. Comparisons between the new criterion and published models from available literature revealed that the proposed criterion has a good accuracy for predicting the peak shear strength of joints investigated in this study.
Widely used disposable plastic tableware is usually buried or directly discharged into the natural environment after using, which poses potential threats to the natural environment and human health. ...To solve this problem, nondegradable plastic tableware needs to be replaced by tableware composed of biodegradable structural materials with both food safety and the excellent mechanical and thermal properties. Here, a food‐safe sargassum cellulose nanofiber (SCNF) is extracted from common seaweed in an efficient and low energy consuming way under mild reaction conditions. Then, by assembling the SCNF into a dense bulk material, a strong sargassum cellulose nanofiber structural material (SCNSM) with high strength (283 MPa) and high thermal stability (>160 °C) can be prepared. The SCNSM also possesses good machinability, which can be processed into tableware with different shapes, e.g., knives and forks. The overall performance of the SCNSM‐based tableware is better than commercial plastic, wood‐based, and poly(lactic acid) tableware, which shows great application potential in the tableware field.
A food‐safe sargassum cellulose nanofiber (SCNF) is extracted through an efficient and low energy consuming way. Then, by assembling the SCNF into a dense bulk material, a strong structural material can be prepared. It possesses good machinability, which can be processed into tableware with better overall performance than that of commercial tableware, showing great application potential in the tableware field.
There is a resurgence of interests in organic electrochemistry, which is generally accepted as a green synthetic tool. In this context, many electrochemical methods have been developed in the past ...decade to access various nitrogen-centered radicals (NCRs) from readily available precursors in a controlled fashion, enabling the rapid development of many NCR-mediated new reactions for the construction of nitrogen-containing organic compounds. In this review, recent advances in the chemistry of electrochemically generated NCRs are critically highlighted, based on the electrochemical strategies for their formation and the types of NCRs. Focus is put on the mechanism for the electrochemical generation of different NCRs and their synthetic applications.
Recent advances in the chemistry of electrochemically generated NCRs are critically highlighted with focus on the mechanism for the electrochemical generation of different NCRs and their synthetic applications. Display omitted
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