It is imperative to derive an appropriate cadmium （Cd） health risk toxicity threshold for paddy soils to ensure the Cd con- centration of rice grains meet the food safety standard. In this study, 20 ...rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 （CK）, 0.3 mg kg-1 （T1） and 0.6 mg kg-1（T2） Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed significant difference （P〈0.05） in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143-0.202, 0.128-0.458 and 0.332-0.806 mg kg-1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain （BCFs） and transfer factors （TFs, root to grain and straw to grain） among the tested cultivars were observed in this study. The bioconcentration factors （BCFgrain） and TFs of the 20 rice cultivars were 0.300-1.112 and 0.342-0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with significant differences among these 20 rice cultivars. The bioconcentration factors （BCFgrain） and TFs among the 20 rice cultivars ranged from 0.300-1.112 and 0.342-0.817, respectively. The species-sensitivity distribu- tion （SSD） of Cd sensitivity of the rice species could be fitted well with Burr-Ill （R2=0.987） based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg-1 in the present study.
Conventional ion batteries utilizing metallic ions as the single charge carriers are limited by the insufficient abundance of metal resources. Although supercapacitors apply both cations and anions ...to store energy through absorption and/or Faradic reactions occurring at the interfaces of the electrode/electrolyte, the inherent low energy density hinders its application. The graphite‐cathode‐based dual‐ion battery possesses a higher energy density due to its high working potential of nearly 5 V. However, such a battery configuration suffers from severe electrolyte decomposition and exfoliation of the graphite cathode, rendering an inferior cycle life. Herein, a new surface‐modification strategy is developed to protect the graphite cathode from the anion salvation effect and the deposition derived from electrolyte decomposition by generating an artificial solid electrolyte interphase (SEI). Such SEI‐modified graphite exhibits superior cycling stability with 96% capacity retention after 500 cycles under 200 mA g−1 at the upper cutoff voltage of 5.0 V, which is much improved compared with the pristine graphite electrode. Through several ex situ studies, it is revealed that the artificial SEI greatly stabilizes the interfaces of the electrode/electrolyte after reconstruction and gradual establishment of the optimal anion‐transport path. The findings shed light on a new avenue toward promoting the performance of the dual‐ion battery (DIB) and hence to make it practical finally.
An artificial layer of a solid electrolyte interphase is fabricated on a graphite cathode for a dual‐ion battery (DIB). Such surface modification can alleviate the electrolyte decomposition at the high working voltage of the anion de‐/intercalation processes and the solvation effect of anions, much improving the cycling stability of the Li//graphite DIB.
This study investigated microstructural changes in alkali-activated slag (AAS) mortars after carbonation using XRD, FTIR, DTG, 1H NMR and SEM examinations. The results showed that decalcification of ...C-S-H was the main reaction in carbonation of AAS. The C-S-H with a low Ca/Si was more vulnerable to decalcification in AAS samples activated by waterglass. Besides, AAS mortars demonstrated a lower CaCO3 formation compared to Portland cement mortars. Calcite and vaterite were the major CaCO3 polymorphs produced by carbonation of AAS precipitated mainly in gel pores and spaces in C-S-H interlayers. Meanwhile, the carbonation also caused a certain volume of contraction in AAS mortars.
•Carbonation affected Portland cement and alkali-activated slag differently.•Carbonation decreased the compressive strength of alkali-activated slag mortar.•C-S-H was the main calcium source during carbonation of alkali-activated slag.•Calcite and vaterite were the major carbonation products of alkali-activated slag.
Hard carbon is regarded as a promising anode material for sodium‐ion batteries (SIBs). However, it usually suffers from the issues of low initial Coulombic efficiency (ICE) and poor rate performance, ...severely hindering its practical application. Herein, a flexible, self‐supporting, and scalable hard carbon paper (HCP) derived from scalable and renewable tissue is rationally designed and prepared as practical additive‐free anode for room/low‐temperature SIBs with high ICE. In ether electrolyte, such HCP achieves an ICE of up to 91.2% with superior high‐rate capability, ultralong cycle life (e.g., 93% capacity retention over 1000 cycles at 200 mA g−1) and outstanding low‐temperature performance. Working mechanism analyses reveal that the plateau region is the rate‐determining step for HCP with a lower electrochemical reaction kinetics, which can be significantly improved in ether electrolyte.
A self‐supporting, flexible, additive‐free and scalable hard carbon paper (HCP) derived from tissue is rationally developed, and it achieves outstanding Na‐storage properties in terms of high initial Coulombic efficiency (91.2%), superior high‐rate capability, ultralong cyclic stability, as well as outstanding low‐T performance in ether electrolyte. More significantly, the Na‐storage and capacity attenuation mechanism of the HCP anode is revealed.
Although previous research has highlighted the disproportional contributions of star employees to their teams, an emerging line of research has begun to examine the potentially negative consequences ...of team stars. Drawing on a social model of team creativity, we develop a dualistic model of the influences of team creative stars on team creativity. Specifically, we explore the roles of two types of team members-star and nonstar employees-in driving team creativity. Across two multiwave and multisource field samples, we find that a creative star who occupies a central position in the team workflow network has both a positive direct effect on team creativity and a negative indirect effect on team creativity via reducing nonstars' learning (i.e., exploratory and exploitative activities). Our study also reveals that team coordination can mitigate the detrimental effect of a star's centrality on nonstars' learning behavior, and subsequently buffer the indirect effect on team creativity.
Diabetic Retinopathy (DR) grading is challenging due to the presence of intra-class variations, small lesions and imbalanced data distributions. The key for solving fine-grained DR grading is to find ...more discriminative features corresponding to subtle visual differences, such as microaneurysms, hemorrhages and soft exudates. However, small lesions are quite difficult to identify using traditional convolutional neural networks (CNNs), and an imbalanced DR data distribution will cause the model to pay too much attention to DR grades with more samples, greatly affecting the final grading performance. In this article, we focus on developing an attention module to address these issues. Specifically, for imbalanced DR data distributions, we propose a novel Category Attention Block (CAB), which explores more discriminative region-wise features for each DR grade and treats each category equally. In order to capture more detailed small lesion information, we also propose the Global Attention Block (GAB), which can exploit detailed and class-agnostic global attention feature maps for fundus images. By aggregating the attention blocks with a backbone network, the CABNet is constructed for DR grading. The attention blocks can be applied to a wide range of backbone networks and trained efficiently in an end-to-end manner. Comprehensive experiments are conducted on three publicly available datasets, showing that CABNet produces significant performance improvements for existing state-of-the-art deep architectures with few additional parameters and achieves the state-of-the-art results for DR grading. Code and models will be available at https://github.com/he2016012996/CABnet .
The rapid growth in automobile production in China during the past few decades has caused numerous tires to be scrapped, and their disposal has become a significant challenge. This study proposes a ...Triple Exponential Smoothing prediction model to predict the supply of waste tires in 2019–2023, and the demand for these tires in three road construction scenarios. In addition, performance analysis is conducted to evaluate the carbon emissions produced in the production process of crumb rubber, modified asphalt, and styrene–butadiene–styrene modified asphalt. The reduction potential of carbon emissions when using crumb rubber for road construction is measured to contribute to the sustainable management of waste tires. The results demonstrate that the prediction model employed for prediction of waste tire production is robust, and the prediction results can be used to evaluate waste tire recycling. In addition, crumb rubber can be used as an efficient and environmentally friendly method for recycling end-of-life tires. Expanding the proportion of rubber powder asphalt application is an effective method for balancing the supply and demand contradiction of crumb rubber. Moreover, the potential for energy savings and emissions reduction, in addition to the economic benefits of using crumb rubber modified asphalt, are significantly higher than those employing styrene–butadiene–styrene modified asphalt. These results indicate the possibility of a circular economy and decreased dependence on non-renewable asphalt resources.
•A forecast model was established to reveal the recycling pressure of waste tires.•This study analyzes the supply and demand of WRP and its potential application.•There is a huge demand for WRP modified asphalt in road construction.•The energy conservation of WRP modified asphalt is compared with SBS’s.•The WRP modified asphalt is one of the best ways to recycle waste tires.
The graphite material from exhausted Li-ion batteries (LIBs) is reused as a favorable anode for Na-ion batteries (NIBs) and K-ion batteries (KIBs) through a recycling treatment. The optimized ...electrode delivers improved electrochemical performance, such as 162 mA h g −1 in NIBs at 0.2 A g −1 and 320 mA h g −1 in KIBs at 0.05 A g −1 . In addition, the insights into Na/K-ion de-/intercalation model evolution and corresponding electrochemical analysis are conducted through in operando X-ray diffraction and a series of other characterization methods, discovering a visible transitional stage for NIBs and an irreversible initial cycle phase transformation for KIBs. In a word, we not only provide a new recycling concept for waste graphite anodes but also carry out a series of significant intercalation mechanism studies, which contribute to anode recycling and shed light on the development of graphite material for promising alternative ion batteries.
Prion diseases are caused by the misfolding of prion protein (PrP). Misfolded PrP forms protease-resistant aggregates in vivo (PrP
) that are able to template the conversion of the native form of the ...protein (PrP
), a property shared by in vitro-produced PrP fibrils. Here we produced amyloid fibrils in vitro from recombinant, full-length human PrP
(residues 23-231) and determined their structure using cryo-EM, building a model for the fibril core comprising residues 170-229. The PrP fibril consists of two protofibrils intertwined in a left-handed helix. Lys194 and Glu196 from opposing subunits form salt bridges, creating a hydrophilic cavity at the interface of the two protofibrils. By comparison with the structure of PrP
, we propose that two α-helices in the C-terminal domain of PrP
are converted into β-strands stabilized by a disulfide bond in the PrP fibril. Our data suggest that different PrP mutations may play distinct roles in modulating the conformational conversion.
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