Critical point theory is used to show the existence of weak solutions to a quasilinear elliptic differential equation under the functional framework of the Musielak–Sobolev spaces in a bounded smooth ...domain with Dirichlet boundary condition.
Reliable joining of Al/steel via friction stir lap welding (FSLW) is strongly dependent on interfacial macro-/micro-structures. However, how the underlying thermo-mechanical process affects them and ...how they can be controlled remain unclear. In this study, a 3D coupled Eulerian–Lagrangian finite element model was integrated with a tracer particle technique to simulate the FSLW of Al alloy 5052 and high-strength DP590 steel, to elucidate the role of tool-induced heat and material flow. The results showed that the material flow recirculated near the shoulder and pin, which mainly originated from the advancing side of the Al and the retreating side of the steel. Increasing the rotational velocity intensified the overall material flow, resulting in increased migration on the steel side. Insufficient steel migration around the pin at lower rotational velocities was mainly responsible for the micro-voids and non-bonding defects at the lap interface. The asynchronous convergence of Al and steel flowing from the advancing and retreating sides, respectively, refilled the instantaneous gap, thereby normally bonding the lapped interface behind the pin. The rotational pin affected the hook structure and steel fragment formation through the shearing and squeezing of the steel migration flow. Material inter-migration produced an intercalated structure at the lapped Al/steel interface. The extremely high temperature, approximately above Al 5052 solidus temperature, under the pin bottom caused the formation of a thicker intermetallic compound (IMC), thereby considerably reducing the interfacial strength. Multi-scale mechanical strength assessments indicated that an intercalated interfacial structure with a thickness of Al-rich IMC layer less than ∼1.0 μm was desirable because it exhibited a higher local interfacial strength than the Al matrix.
Display omitted
•Asynchronous convergence of Al/steel material flow from both sides filled the instantaneous gap and simultaneously bonded the interface behind the pin.•Interface geometric defects formations were closely dependent on the steel migration behaviour in horizontal/vertical direction.•The temperature field and plastic deformation satisfactorily supported the impact of rotation velocities on grain orientation and IMC formation.•Multi-scale mechanical testing was used to evaluate the Al/steel interfacial microstructure-property correlation.•Moderate revolutionary pitch produced a strong Al/steel intercalated structure with local strength higher than Al matrix.
Although it is a key measure to control energy consumption and promote the improvement of industrial structure, energy market allocation reform has rarely been concerned with its impact on ...employment, an important livelihood issue. To fill this gap, this paper takes the Energy-Consumption Rights Trading System (ECRTS) enacted by China in 2016 as a research background and adopts the difference-in-difference approach to explore the effects and mechanisms of the ECRTS on enterprise labor demand. The results show that the ECRTS significantly reduces firms' labor demand, particularly for low-skilled workers, through both production scale effects and technological upgrading effects. Specifically, the ECRTS has led to a decrease in sales revenues and an increase in labor productivity, thereby reducing firms' labor demand. Heterogeneity tests indicate that the ECRTS has a greater impact on employment in firms with lower energy-consumption intensity, domestic capital injections, weaker innovation capacity, and lower market power. The paper also explores the welfare consequences of the policy, finding that while the ECRTS does not improve the environmental performance of firms it does not pass on the compliance costs of regulations to incumbent workers. The overall impact is neutral. This paper extends the study of the economic consequences of the ECRTS and has implications for other developing countries in reconciling energy regulation and employment.
•The ECRTS notably diminished firms' labor demand, particularly affecting low-skilled workers.•The ECRTS decreases enterprise employment via the “production scale effects” and “technological upgrading effects”.•The impact of the ECRTS on labor demand shows obvious heterogeneity across firms.•The ECRTS neither enhances environmental performance nor reduces employee wages.
2D electrode materials with layered structures have shown huge potential in the fields of lithium‐ and sodium‐ion batteries. However, their poor conductivity limits the rate performance and cycle ...stability of batteries. Herein a new colloid chemistry strategy is reported for making 2D ultrathin layered SnSe nanoplates (SnSe NPs) for achieving more efficient alkali‐ion batteries. Due to the effect of weak Van der Waals forces, each semiconductive SnSe nanoplate stacks on top of each other, which can facilitate the ion transfer and accommodate volume expansion during the charge and discharge process. This unique structure as well as the narrow‐bandgap semiconductor property of SnSe simultaneously meets the requirements of achieving fast ionic and electronic conductivities for alkali‐ion batteries. They exhibit high capacity of 463.6 mAh g−1 at 0.05 A g−1 for Na‐ion batteries and 787.9 mAh g−1 at 0.2 A g−1 for Li‐ion batteries over 300 cycles, and also high stability for alkali‐ion batteries.
Ultrathin layered SnSe nanoplates that stack on top of each other and are held together by partial weak Van der Waals' forces are synthesized by a facial colloid chemistry method for alkali–ion batteries. They have narrow‐bandgap semiconductor properties and large surface area, resulting in high‐performance alkali–ion batteries with low voltage, high rate ability, and long cyclic life.
For organic solar cells to be competitive, the light-absorbing molecules should simultaneously satisfy multiple key requirements, including weak-absorption charge transfer state, high dielectric ...constant, suitable surface energy, proper crystallinity, etc. However, the systematic design rule in molecules to achieve the abovementioned goals is rarely studied. In this work, guided by theoretical calculation, we present a rational design of non-fullerene acceptor o-BTP-eC9, with distinct photoelectric properties compared to benchmark BTP-eC9. o-BTP-eC9 based device has uplifted charge transfer state, therefore significantly reducing the energy loss by 41 meV and showing excellent power conversion efficiency of 18.7%. Moreover, the new guest acceptor o-BTP-eC9 has excellent miscibility, crystallinity, and energy level compatibility with BTP-eC9, which enables an efficiency of 19.9% (19.5% certified) in PM6:BTP-C9:o-BTP-eC9 based ternary system with enhanced operational stability.
Video Anomaly detection, aiming to detect the abnormal behaviors in surveillance videos, is a challenging task since the anomalous events are diversified and complicated in different situations. And ...this makes it difficult to use one single static network architecture to extract useful information from diverse abnormal patterns. Therefore, in this article, we propose a novel Dynamic Self-Supervised Network (DSS-Net) to explore both spatial and temporal anomalous information. In our DSS-Net, we design a dynamic network to adaptively select suitable network architecture to extract latent features from different anomalous patterns and normal patterns. Specifically, we generate spatial and temporal pseudo-abnormal data as the input of the dynamic network to conduct self-supervised learning. And we have a specific design on Hybrid Anomaly Dynamic Convolution (HAD-Conv) to extract features for diversified anomalous events adaptively. We utilize both normal and pseudo-abnormal data to encourage the dynamic network to mine the discriminative information. Furthermore, we design a feature separation loss to maximize the difference between the anomalous and normal videos. We evaluate our proposed method on four public anomaly detection datasets and achieve competitive results compared with the state-of-the-art approaches.
MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in tumor metastasis. In this study, we describe the down-regulation and function of miR-139 in colorectal ...cancer (CRC) metastasis. MiR-139 was found underexpressed in 34 CRC tissues compared to their corresponding nontumor tissues. Decreased miR-139 in CRC tissue was associated with disease progression and metastasis. Re-expression of miR-139 did not inhibit CRC cell growth but suppresses CRC cell metastasis and invasion in vitro and in vivo. MiR-139 might suppress CRC cells invasion and metastasis by targeting type I insulin-like growth factor receptor (IGF-IR). We also found miR-139 directed migration inactivation of human CRC cells involves down-regulation of matrix metalloproteinase 2 (MMP-2). The IGF-IR/MEK/ERK signaling was inhibited by miR-139 overexpression and then resulted in MMP-2 promoter suppression. Taken together, our results provide evidence that miR-139 might function as a metastasis suppressor in CRC. Targeting miR-139 may provide a strategy for blocking CRC metastasis.
Abstract
High environmental noise, narrow bandwidth, low carrier frequency, large transmission delay and other factors restrict the data transmission rate in underwater acoustic communication. To ...this end, improving communication quality and efficiency through adaptive adjustment is necessary for underwater acoustic communication system because of the restrict factor. The proposed method uses Deep Reinforcement Learning (DRL) to select the optimal transportation parameters and maximize the transmission efficiency with. The adaptive communication parameter setting is mapped into a Markov decision process with an unknown state transition probability. The system returns channel information including Channel State Information (CSI) and Signal Noise Ratio (SNR). We validate our estimation and adaptation techniques using the well-known simulator SWellEx_96 in varying underwater environments. Our results show that, for many practical cases, a dynamic adjustment of the prefix length, number of sub-carriers, filter length, and over-sampling factor may enable the utilization of OFDM modulations in underwater communications.
Deoxynivalenol (DON) is one of the most common feed contaminants, and it poses a serious threat to the health of dairy cows. The existing studies of biological toxicity of DON mainly focus on the ...proliferation, oxidative stress, and inflammation in bovine mammary epithelial cells, while its toxicity on the biosynthesis of milk components has not been well documented. Hence, we investigated the toxic effects and the underlying mechanism of DON on the bovine mammary alveolar cells (MAC-T). Our results showed that exposure to various concentrations of DON significantly inhibited cell proliferation, induced apoptosis, and altered the cell morphology which was manifested by cell distortion and shrinkage. Moreover, the transepithelial electrical resistance (TEER) values of MAC-T cells exposed to DON were gradually decreased in a time- and concentration- dependent manner, but lactate dehydrogenase (LDH) leakage was significantly increased with the maximum increase of 2.4-fold, indicating the cell membrane and tight junctions were damaged by DON. Importantly, DON significantly reduced the synthesis of β-casein and lipid droplets, along with the significantly decreases of phospho-mTOR, phospho-4EBP1, phospho-JAK2, and phospho-STAT5. Gene expression profiles showed that the expressions of several genes related to lipid synthesis and metabolism were changed, including acyl-CoA synthetase short-chain family member 2 (ACSS2), fatty acid binding protein 3 (FABP3), 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1), and insulin-induced gene 1 (INSIG1). GO and KEGG enrichment analyses revealed that the differentially expressed genes (DEGs) were significantly enriched in ribosome, glutathione metabolism, and lipid biosynthetic process, which play important roles in the toxicological process induced by DON. Taken together, DON affects the proliferation and functional differentiation of MAC-T cells, which might be related to the cell junction disruption and morphological alteration. Our data provide new insights into functional differentiation and transcriptomic alterations of MAC-T cells after DON exposure, which contributes to a comprehensive understanding of DON-induced toxicity mechanism.
•DON exposure inhibited cell proliferation and induced apoptosis.•DON exposure altered cell morphology and destroyed tight junctions.•DON exposure decreased the synthesis of β-casein and lipid droplets.•DON exposure changed the expression of 3744 genes in MAC-T cells.•DEGs were enriched in glutathione metabolism and lipid biosynthetic process.
Protein disulfide isomerase family A member 3 (PDIA3) is a multifunctional protein, and it plays a vital role in modulating various cell biological functions under physiological and pathological ...conditions. Our previous study on Mediterranean buffalo demonstrated that PDIA3 is a potential candidate gene associated with milk yield based on genome-wide association study analysis. However, the genetic effects of the PDIA3 gene on milk performance in dairy cattle and the corresponding mechanism have not been documented. This study aims to explore the genetic effects of PDIA3 polymorphisms on milk production traits in 362 Chinese Holstein cattle. The results showed that 4 SNPs were identified from the 5′ untranslated region of the PDIA3 gene in the studied population, of which 2 SNPs (g.-1713 C>T and g.-934 G>A) were confirmed to be significantly associated with milk protein percentage, whereas g.-434 C>T was significantly associated with milk fat percentage. Notably, linkage disequilibrium analysis indicated that 3 SNPs (g.-1713 C>T, g.-934 G>A, and g.-695 A>C) formed one haplotype block, which was found to be significantly associated with milk protein percentage. The luciferase assay demonstrated that allele C of g.-434 C>T exhibited a higher promotor activity compared with allele T, suggesting that g.-434 C>T might be a potential functional mutation affecting PDIA3 expression. Furthermore, overexpression of the PDIA3 gene was found to induce higher levels of triglyceride and BODIPY fluorescence intensity. In addition, PDIA3 overexpression was also found to positively regulate the synthesis and secretion of α-casein, β-casein, and κ-casein, whereas knockdown of this gene showed the opposite effects. In summary, our findings revealed significant genetic effects of PDIA3 on milk composition traits, and the identified SNP and the haplotype block might be used as genetic markers for dairy cow selected breeding.
