Abstract
Atmospheric NO
2
is of great concern due to its adverse effects on human health and the environment, motivating research on NO
2
detection and remediation. Existing low-cost room-temperature ...NO
2
sensors often suffer from low sensitivity at the ppb level or long recovery times, reflecting the trade-off between sensor response and recovery time. Here, we report an atomically dispersed metal ion strategy to address it. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO
2
sensor as characterized by a combination of ultra–low limit of detection, high sensitivity and stability, fast response and recovery. With the help of theoretical calculations, we reveal the high performance of the PbCdSe QD gel arises from the unique tuning effects of Pb ionic sites on NO
2
binding at their neighboring Cd sites.
The recent extraction of hybrid features improves point cloud registration performance by emphasizing more integrated information. However, hybrid features ignore the large dimensional differences, ...big semantic gaps, and mutual interference between the shape features and spatial coordinates. This paper proposes a novel Multi-Features Guidance Network (MFGNet) for partial-to-partial point cloud registration to overcome the intrinsic flaws of hybrid features, which leverages the shape features and the spatial coordinates to account for correspondences searching independently. The proposed network mainly includes four parts: keypoints’ feature extraction, correspondences search, correspondences credibility computation, and singular value decomposition (SVD), among which correspondences search and correspondences credibility computation are the cores of the network. Specifically, the correspondences search module utilizes the shape features and the spatial coordinates to guide correspondences matching independently and fusing the matching results to obtain the final matching matrix. Moreover, based on the conflicted relationship between the two matching matrices, the correspondences credibility computation module scores each correspondence pair’s reliability, which can reduce the impact of mismatched or non-matched points significantly. Empirical experiments on the ModelNet40 dataset validate the effectiveness of the proposed MFGNet, which achieves 0.19
∘
, 0.24
∘
and 1.3
∘
mean absolute errors for rotation matrix and 0.0010, 0.0011, and 0.0068 mean absolute errors for translation vectors, respectively, under the settings of unseen point clouds, unseen categories, and Gaussian noise.
In this paper, over 150 journal papers were reviewed with respect to AC impedance modeling and validation in solid oxide fuel cell (SOFC) diagnosis. Different models based on experimental AC ...impedance data and their advantages and disadvantages in data interpretation were discussed. The challenges currently faced by AC impedance modeling and validation were identified and possible directions and approaches in addressing these challenges were suggested.
Comparable to San Andreas fault in western United States, the Tanlu fault zone (TLFZ) is a large-scale continental tectonic belt in eastern China and has played an important role controlling the ...regional tectonics and earthquake activity in eastern China. It is known there exists an earthquake gap in the southern segment around Suqian, Jiangsu province, where no earthquakes greater than M5.5 occurred. Fine fault zone structure could help to understand the fault activity and the potential earthquake hazards. However, only regional scale velocity model is available in this region, making it difficult to characterize detailed fault structures. In this study, we obtained local Vs model in the upper crust in this region by ambient noise tomography with a dense seismic array. For the Suqian segment, Cretaceous brittle normal faulting controlled the development of the eastern and western graben as well as the central horst between them. The graben-boundary faults are known simply as F1-F4 from east to west, and the NNE-striking fault F5 is between F1 and F2. The eastern boundary fault F1 and western boundary fault F4 separated by about 30 km are associated with intermittent high velocity anomalies in the shallow crust and are inactive. In comparison, faults F2, F5 and F3 are mainly associated with low velocity anomalies and are relatively active. These high velocity anomalies are very likely caused by the upwelling magma migrated along faults F1 and F4 in the crust, which on freezing could weld the fault zone and make it less active. Because faults F1 and F4 are hindered to move, the deformation could be transferred to nearby faults F2, F3 and F5. Our study sheds light on what controls fault activities along the TLFZ by obtaining local velocity structure in the Suqian segment.
•Fine crustal Vs model is determined by ambient noise tomography with a dense array for the Suqian segment of Tanlu fault zone•Intermittent high velocity anomalies are imaged around faults F1 and F4 that are inactive and have very few earthquakes•High velocity anomalies in the crust are caused by upwelling hot mantle materials that likely welded the fault zone.
Abstract: Subchronic exposure to arsenic induces apoptosis in the hippocampus of the mouse brains through the Bcl-2/Bax pathway: Yachen WANG, et al. Department of Occupational and Environmental ...Health, Dalian Medical University, P.R. China - Objectives: The aim of this study was to identify whether arsenic (As) exposure could induce hippocampal neural apoptosis in vivo. Methods: Sixty-four mice were randomly divided into 4 groups of 16 each. Group 1 orally received drinking water alone as a control. Groups 2-4 were given arsenic trioxide (As2O3) orally at the doses of 1 ppm, 2 ppm and 4 ppm, respectively. All the treatments continued for 60 days. Morphological changes in the hippocampus were observed by HE staining. Apoptosis in the hippocampus was examined by TUNEL assay and transmission electron microscopy. The expression levels of Bcl-2 and Bax genes and their proteins in the hippocampus were determined by real-time PCR and Western blotting. The activity of caspase-3 was determined by spectrophotometry. Results: Abnormal histopathological changes and apoptosis were found in the hippocampus of As-exposed mice. The expressions of the Bcl-2 gene and its protein in the hippocampus of As-exposed mice were significantly lower than those in the control group (p<0.05). However, the expressions of the Bax gene and its protein, and the expression ratio of Bax/Bcl-2 in the hippocampus were significantly higher in the groups exposed to As than in the control group (p<0.05). Moreover, the activity of caspase-3 in the hippocampus of mice exposed to As was higher than that in the control (p<0.05). Conclusions: These results indicate that subchronic exposure to As induces apoptosis in the hippocampus of mice by disturbing normal Bax/Bcl-2 regulatory pathways. Meanwhile, it is suggested that the induced apoptosis in the hippocampus may be at least partly responsible for As-induced neurotoxicity.
In this brief, a sparse-Bayesian-learning algorithm is applied to estimate the coefficients of the power amplifier (PA) behavioral models and inverse models from the view of probability. With this ...sparse learning method, the needed number of samplings can be reduced significantly. In addition, it also provides researchers with ideas that obtain the needed subspace of the preselected model. The performance of the algorithm is validated experimentally on a gallium nitride (GaN) PA, and the signal used to test the proposed approach is an Long Term Evolution (LTE) signal. A comparison with the state-of-the-art estimation algorithm in an open-loop digital-predistortion system is also presented, and the vast majority of tests show that the number of model coefficients is reduced by at least 50%.
Tailings from gold mines gradually approach ultra-fine, making mine backfill costs higher and strength lower, which poses a serious threat to the safety of underground personnel and equipment. It is ...well known that suitable chemical admixtures can enhance the working properties of mortar materials. Therefore, in order to achieve the purpose of reducing the cost of ultra-fine tailings backfill and improving the working performance of ultra-fine tailings filling slurry, this paper provides a study on the effect of sodium silicate and calcium chloride on the properties of ultra-fine tailings cemented backfill materials. The results of experimental studies through rheology, strength, and microstructural tests, etc., showed that the optimal proportioning parameters of cementitious materials are 76.92% blast furnace slag, 19.24% carbide slag, and admixtures of 2.88% sodium silicate and 0.96% calcium chloride. The 3, 7, and 28-day uniaxial compressive strength of the ultra-fine tailings cemented paste backfill with the newly formulated blast furnace slag-based cementitious material increased by 124%, 142%, and 14%, respectively, compared to that of the ultra-fine tailings cemented paste backfill with the P. O42.5 cement. The setting time for ultra-fine tailings cemented backfill slurry is shortened by the addition of admixtures, and the shear stress of the slurry is correlated with the amount of hydration product generation and its formation of flocculating structure. Moreover, the cost of the newly prepared cementitious material is much lower than that of traditional cement, which lays a good foundation for the cemented filling of ultra-fine tailings.
Cadmium (Cd) and selenium (Se) could jointly affect plant growth. To investigate the affect of Se on the Cd accumulation in Juglans regia and the physiological mechanism by which Se regulates ...Cd-induced oxidative stress, in this study, the effects of different foliar application doses of Se (0 (Se0), 20 (Se20), and 200 (Se200) μM) on J. regia (variety Xinfeng) seedlings under Cd stress (5 mM) were determined. The results show that exogenous application of Se (Se20 and Se200) increased walnut biomass compared with Se0 under Cd stress. Under Cd stress, exogenous application of 20 μM Se increased the catalase (CAT), peroxidase (POD), and ascorbate oxidase (AAO) activities in walnut roots and the CAT and AAO activities in walnut leaves, and exogenous application of 200 μM Se increased the CAT, POD, and AAO activities in walnut roots. Furthermore, under Cd stress, exogenous application of 20 and 200 μM Se both decreased the contents of superoxide (O2•−), hydrogen peroxide (H2O2), and malondialdehyde (MDA) in walnut roots and the content of MDA in walnut leaves. Moreover, application of 20 and 200 μM Se both reduced the accumulation of Cd in the root, wood, bark, and leaves of walnuts, and application of 200 μM Se enhanced Se concentration in the root, wood, bark, and leaves. Overall, exogenous application of Se, especially 200 μM Se, could reduce Cd accumulation and enhance CAT, POD, and AAO activities in Cd-stressed walnut roots, thus alleviating Cd stress. This study provides technical guidance for reducing the effects of Cd stress on walnut growth.
There is a complex cadmium (Cd) and iron (Fe) interaction in soil. To explore the influences of Fe application on the growth, Cd accumulation, and antioxidant capacity of poplar under Cd exposure, ...Populus tremula × P. alba ‘717’ was treated with different concentrations of Cd (0 and 100 μM) and Fe (50 and 150 μM). In addition, the root architecture, leaf chlorophyll content, Cd accumulation, and antioxidant enzyme activity were analyzed. The results showed that the high-dose Fe (150 μM) did not change poplar biomass in zero-Cd treatment but increased the chlorophyll content, total root surface area, net photosynthetic rate, and biomass accumulation of Cd-stressed poplar. In addition, under Cd stress, high-dose Fe increased the translocation factor (TF) of Cd, decreased root and leaf malondialdehyde (MDA) content, and enhanced root and leaf SOD activity. That is, high-dose Fe could alleviate the suppression of Cd on the growth of poplar and enhance the transport of Cd to aboveground tissues and the SOD activity in roots and leaves, thus alleviating the Cd-induced oxidative stress. This study will provide reference for the remediation of Cd-contaminated soils using poplar.
Ultrafine tailings (UFT) characterized by the average particle size <19 μm are increasingly discharged from mining process. Due to the large specific surface area and high content of clay components ...for UFT, cemented ultrafine tailings backfill (CUFTB) usually exhibits the poor flowability and strength, which poses an obstacle to the practical application in mine filling. Therefore, this study aims to explore the feasibility of modifying CUFTB through incorporating cold-bonded tailings lightweight aggregates (CBTLWAs). A series of mini slump cone, unconfined compressive strength (UCS), digital image correlation (DIC), microanalysis tests were conducted to investigate the effects of CBTLWAs with uniform particle sizes (d=2, 4, 6, 8 mm) and full particle gradations (Talbot coefficients n=0.2, 0.4, 0.6, 0.8) on slump flow (SF), UCS, microstructure, and deformation behaviour of CUFTB. Results indicate that adding CBTLWAs as a partial substitute for UFT effectively improves the flowability and strength of CUFTB. With CBTLWAs dosage increases from 15 to 40 wt%, the SF values increase steadily, and the highest values are observed when d=2 mm and n=0.6. After curing of 3–180 days, the UCS values exceed 1.0 MPa, and the highest values are found in CUFTB when d=8 mm and n=0.4 or 0.6. There is an optimal dosage (20–30 wt%) for CBTLWAs depending on the particle sizes and gradations. Hydration reactions of IWRs-based binder generated C-S-H, calcite, and ettringite. CBTLWAs bonded with CUFTB matrix to form a skeleton structure, hindering the propagation of cracks and enhancing the ductility. CUFTB incorporating CBTLWAs exhibits a hybrid mode of shear and tensile failure. The utilization of CBTLWAs shows a promising solution to address the challenges associated with performance modification for CUFTB. This provides a more environmentally responsible approach to solid wastes management and contributes to the sustainability of mining industry.
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•Lightweight aggregates are used to modify flowability and strength of CUFTB.•Effect of uniform size and particle size gradation of CBTLWA are investigated.•There are optimal particle size, gradation, and dosage for performance improvement.•CUFTB containing CBTLWA show the hybrid mode of shear and tensile failure.
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