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An optimal power allocation (OPA) policy for orthogonal frequency division multiplexing (OFDM)-based cognitive radio networks (CRNs) using underlay spectrum access model is presented under multiple secondary users (SUs) with energy harvesting (EH). The proposed algorithm can allocate transmission power to each SU on each subcarrier with the objective of maximizing the average throughput of secondary network over a finite time interval. We consider both the interference power constraint limited by primary user (PU) and the minimum throughput constraint of each SU to improve the throughput of SUs while guaranteeing the communication quality of PU. To balance current throughput and expected future throughput, a dynamic programming (DP) problem is defined and solved by the backward induction method. Moreover, for each time slot, a convex immediate optimization is presented to obtain an optimal solution, which can be solved by the Lagrange dual method. Simulation results show that our policy can achieve better performance than some traditional policies and ensure good quality of service (QoS) of PU when SUs access the spectrum. [ABSTRACT FROM AUTHOR]

Four polydimethylsiloxane (PDMS) coatings with different surface free energies have been prepared and applied to smooth and roughened aluminum plates to form hydrophobic and superhydrophobic surfaces. Their surface wettability in terms of water contact angle (CA), sliding angle (SA) and water droplet impact dynamics was studied under an ambient (50% relative humidity, RH at 25 °C) and three different condensing environments (low, highly and extremely condensing, i.e. 30%, 60% and 90% RH at −10 °C). In addition, the surface ice adhesion was investigated under the extremely condensing condition. Different PDMS coatings on either smooth or roughened surfaces displayed a very similar impact to static and dynamic wettability under the ambient environment. However, the water impact behavior and ice adhesion under the extremely condensing condition between the hydrophobic and superhydrophobic surfaces are significantly different. One of the superhydrophobic surfaces (R2180) demonstrated an excellent water repelling capability to retard ice accumulation, and reduced ice adhesion strength even under the extremely condensing condition, and thus will be a good candidate for ice-phobic applications. This excellent ice-phobic property is attributed to the low surface free energy of the coating, which effectively prevents the water condensation inside the cavities of the hierarchical superhydrophobic structures and thus maintains “air cushion” on the solid/water interface, indicated by a very low solid-liquid contact area increase after surface is exposed to this condensing weather condition. This result demonstrates that the “air cushion” in a superhydrophobic surface could be maintained even under an extremely condensing condition by carefully selection of coating composition with a very low surface free energy. [ABSTRACT FROM AUTHOR]

• T-phage-inspired multilegged design for microrobot. • A rotationally asymmetric structure. • Multiple working modes: forward motion, backward motion, steering, climbing, and swimming. • The maximum velocity of 120 mm/s under a driving voltage of 50 V p-p and the maximum carrying weight of 10.6 gs, 6 times more than the weight of the microrobot. • Miniaturization capability and ability to work in various environments, i.e., a narrow tube and water. T-phages use contractile tails to recognize host bacterial and move on the surface of bacterial. This virus demonstrates remarkable locomotive capabilities in recognition and infection progress. The field of microrobotics focuses on achieving these functions in mobile robotic systems of centimeter size. However, owing to the structure size and weight, it has been a challenge to satisfy high robustness, fast motion, adequate carrying capacity, low driving voltage, and versatile environmental adaptability in one robot. In addition, functional microrobots require multimodal locomotive strategies that reconcile the constraints imposed by different applications. Inspired by the unique structure of T-phage in the micro-world, we develop a T-phage Mimic MicroRobot (TMMR), which is composed of a triangular prism core with piezoelectric elements and legs attached on bases, mimicking the core and the tail fibers of the T-phage, respectively. The triangular prism structure avoids rollover while moving, indicating the robustness of the design. TMMR of 2.5 × 2.5 × 2.6 mm3 weighs 1.74 gs and can be easily further miniaturized. It is capable of moving forward, backward, and steering at a low voltage of 25 V. Working mechanisms for each type of motion are analyzed using the finite element method. Results show that TMMR reaches 120 mm/s, 4.8 body lengths per second (BL/s), and carry an object weighing 10.6 gs, 6 times more than its weight. By sealing the body and adding passive flaps, TMMR achieves a "swimming" motion with a velocity of 16 mm/s. TMMR shows potential for versatile applications in a narrow and constrained environment. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: In this work, we have fabricated superhydrophobic aluminum surfaces by a facile chemical etching method. Surface morphology and composition were studied by using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). To comparatively investigate the effect of environmental factors on superhydrophobic behaviors of surfaces with different low-surface-energy coatings under controllable condensation conditions, contact and sliding angles were measured from −10°C to 30°C under relative humidity (RH) of 30, 60 and 90%, respectively. The calculation of the solid–liquid contact area fraction quantitatively explained the increased wettability characterized by descending contact angle and ascending sliding angle under low temperature and high humidity, and indicated a transition of the equilibrium state from Cassie–Baxter to Wenzel on rough surfaces. The wettability restoration test showed that the loss of superhydrophobicity during condensation could be recovered completely after a drying process at room temperature. [Copyright &y& Elsevier]

• Strigolactone improves the antioxidative system and maintains strawberries quality. • Strigolactone enhances endogenous hydrogen sulfide synthesis of strawberries. • Strigolactone enhances the phenylpropane metabolism of strawberries. • Strigolactone regulates the synthesis of NO mainly through the NOS-like pathway. Strawberries (Fragaria × ananassa Duch. cv. Akihime) were treated with different concentrations of exogenous strigolactone (SL) (0, 0.5, 1, 2, and 4 μmol L−1). Changes in the antioxidant system, nitric oxide (NO) synthesis, hydrogen sulfide (H 2 S) synthesis, and phenylpropanoid metabolism of postharvest strawberries were studied. Among the treatments, 1 μmol L−1 SL significantly inhibited peroxidase and polyphenol oxidase activities, and enhanced the ability to scavenge ·DPPH, ·OH, and ·O 2 ·-. Treatment with 1 μmol L−1 SL effectively reduced weightlessness rate and respiratory intensity, maintained the water content, inhibited the increase in POD activity and the decrease in the activities of CAT and SOD, maintained the reduced ascorbic acid, and reduced glutathione contents. Exogenous SL effectively increased the activities of 4-coumaric acid coenzyme A ligase and phenylalanine ammonia-lyase, thus promoting the accumulation of flavonoids, lignin, and total phenols. These findings suggested that SL alleviated the oxidative damage of strawberries by improving the defense capability of the antioxidant system. SL improved nitric oxide synthase (NOS)-like activity and the contents of l -arginine and endogenous NO, but had no significant effects on nitrate reductase activity and nitrite content, suggesting that SL regulates the synthesis of NO mainly through the NOS-like pathway. Exogenous SL promoted the cleavage of l -cysteine by activating l -cysteine desulfhydrase, d -cysteine desulfhydrase, O -acetylserine thiolyase, and serine acetyltransferase, thus increasing endogenous H 2 S content in strawberries. SL maintained fruit quality by improving the antioxidative system and the metabolism of phenylpropanoid, NO, and H 2 S in strawberries during storage. [ABSTRACT FROM AUTHOR]

• SE-tattoo is conformable, sweat permeable, and imperceptible on hairy skin. • Design a biocompatible water-based conductive ink for spray fabrication method. • SE-tattoo shows high adhesiveness, high conductivity, and fast curing ability (<20 s) • Reliable and versatile solution for bidirectional human–machine interaction. Biopotential signals recorded by skin surface electrodes reflect the state of the body and corresponding organ functions. These signals are commonly utilized in clinical diagnosis, health monitoring, sports training, and human–computer interaction. However, the utilization of conventional electrodes on hairy skin causes a number of issues, including suboptimal skin compliance, obstructed sweat secretion and impaired tactile perception, making it difficult to obtain long-term and high-fidelity biopotential recordings. Here, we propose an imperceptible spray-on electrode tattoo (SE-tattoo) with sweat-permeability, high adhesiveness, high conductivity, and fast curing ability (<20 s). The water-based conductive ink is sprayed directly on the hairy skin to form a conformable conductive tattoo that neither affects nor is affected by the skin hair. We demonstrate it for heart health monitoring, sports training, electro-tactile display and close-loop teleoperation control. The SE-tattoo offers a reliable and versatile solution to biopotential recordings and serves as a promising platform for bidirectional human–machine interaction. One-Sentence Summary: Imperceptible sweat-permeable SE-tattoo enables high-fidelity biopotential recordings for bidirectional human–machine interaction. [ABSTRACT FROM AUTHOR]

• The hydration and microstructure of ternary LHPC blends incorporated a large amount of FA and PS were revealed. • The synergistic impacts between FA and PS in LHPC ternary blends decreased the drying shrinkage, cumulative heat, and refined pore structure. • The single addition of PS had the lowest strength-normalized cost. • LHPC-FA-PS ternary blends pronounced advantages in the strength-normalized energy consumption and the carbon footprint. This paper presents the benefits of utilizing phosphorus slag (PS) to replace fly ash (FA) in low-heat Portland cement (LHPC) blends. After the first three days, PS exhibits worse mechanical properties and lower hydration heat compared to FA, presumably owing to its retarding effect. Meanwhile, the mechanical properties of PS are approached that of FA at 180 days. Based on the Krstulovic-Dabic (K-D) model, the Q max values of LHPC, L75F25 (where the letters stand for the material and the numerals indicate the composition percentage), L65F35, L75P25, L65P35, and L50F25P25 are: 370.4 J/g, 312.5 J/g, 323.6 J/g, 333.3 J/g, 322.6 J/g, and 238.1 J/g, respectively. The effects of pozzolanic reaction and pore structure refinement of PS are more pronounced than that of FA, resulting in the Q max of PS being relatively higher compared to FA. The number of gel capillaries (d < 10 nm) in L75P25 is 12% higher compared to L75F25 at 90 days. The pozzolanic reaction in FA is mainly occurred within 3 days to 28 days. However, in PS the corresponding period is from 28 days to 90 days. Furthermore, the synergistic impact between FA and PS in LHPC ternary blends is further decreased the drying shrinkage and cumulative heat, increases the H/LHPC content, and refines the pore structure. L75P25 has the lowest strength-normalized cost, which is 0.069 $/t/MPa ∼ 0.100 $/t/MPa less compared to L75F25. LHPC-FA-PS ternary blends has pronounced advantages on the strength-normalized energy consumption and carbon footprint. The strength-normalized carbon footprint and energy consumption of L50F25P25 are 1.89 kg/t/MPa and 5.57 MJ/t/MPa lower compared to L75F25, respectively. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in rivers and lakes arising due to rapid economic development has been extensively studied by various countries due to its direct impact on ecological health and human well-being. However, there is a lack of comprehensive and systematic reviews addressing the current research status of this subject. In this study, we conducted a visual metrological analysis of the literature from 2001 to 2021 using the Web of Science (WoS) and China National Knowledge Infrastructure (CNKI) citation databases. The results show that studies conducted in other countries initially outnumbered those in China; after 2010, China emerged as the foremost contributor. Furthermore, both the WoS and CNKI databases indicate active engagement of Chinese researchers through a significant proportion of published papers on metal research, with prominent contributions coming from institutions such as the Chinese Academy of Sciences (CAS) and University CAS. Nevertheless, Chinese research institutions still have relatively low total paper citation numbers and have yet to establish themselves as key players in international scientific research efforts. Additionally, core authors from different countries share substantial similarities in their research directions and focuses. Consistent research hotspots regarding heavy metals in rivers and lakes were identified across both databases, including heavy metal pollution, adsorption, human activities, water quality, and sediment. [ABSTRACT FROM AUTHOR]

Background: Schwann cells (SCs) respond to nerve injury by transforming into the repair-related cell phenotype, which can provide the essential signals and spatial cues to promote axonal regeneration and induce target reinnervation. Endothelial cells (ECs) contribute to intraneural angiogenesis contributing to creating a permissive microenvironment. The coordination between ECs and SCs within injury sites is crucial in the regeneration process, however, it still unclear. As the intercellular vital information mediators in the nervous system, exosomes have been proposed to take a significant role in regulating regeneration. Thus, the main purpose of this study is to determine the facilitative effect of ECs-derived exosomes on SCs and to seek the underlying mechanism. Results: In the present study, we collected exosomes from media of ECs. We demonstrated that exosomes derived from ECs possessed the favorable neuronal affinity both in vitro and in vivo. Further research indicated that EC-exosomes (EC-EXO) could boost and maintain repair-related phenotypes of SCs, thereby enhancing axonal regeneration, myelination of regenerated axons and neurologically functional recovery of the injured nerve. MiRNA sequencing in EXO-treated SCs and control SCs indicated that EC-EXO significantly up-regulated expression of miR199-5p. Furthermore, this study demonstrated that EC-EXO drove the conversion of SC phenotypes in a PI3K/AKT/PTEN-dependent manner. Conclusion: In conclusion, our research indicates that the internalization of EC-EXO in SCs can promote nerve regeneration by boosting and maintaining the repair-related phenotypes of SCs. And the mechanism may be relevant to the up-regulated expression of miR199-5p and activation of PI3K/AKT/PTEN signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Schwann cells (SCs) respond to nerve injury by transforming into the repair-related cell phenotype, which can provide the essential signals and spatial cues to promote axonal regeneration and induce target reinnervation. Endothelial cells (ECs) contribute to intraneural angiogenesis contributing to creating a permissive microenvironment. The coordination between ECs and SCs within injury sites is crucial in the regeneration process, however, it still unclear. As the intercellular vital information mediators in the nervous system, exosomes have been proposed to take a significant role in regulating regeneration. Thus, the main purpose of this study is to determine the facilitative effect of ECs-derived exosomes on SCs and to seek the underlying mechanism. Results: In the present study, we collected exosomes from media of ECs. We demonstrated that exosomes derived from ECs possessed the favorable neuronal affinity both in vitro and in vivo. Further research indicated that EC-exosomes (EC-EXO) could boost and maintain repair-related phenotypes of SCs, thereby enhancing axonal regeneration, myelination of regenerated axons and neurologically functional recovery of the injured nerve. MiRNA sequencing in EXO-treated SCs and control SCs indicated that EC-EXO significantly up-regulated expression of miR199-5p. Furthermore, this study demonstrated that EC-EXO drove the conversion of SC phenotypes in a PI3K/AKT/PTEN-dependent manner. Conclusion: In conclusion, our research indicates that the internalization of EC-EXO in SCs can promote nerve regeneration by boosting and maintaining the repair-related phenotypes of SCs. And the mechanism may be relevant to the up-regulated expression of miR199-5p and activation of PI3K/AKT/PTEN signaling pathway. [ABSTRACT FROM AUTHOR]

The structural and functional features of lymphatic vessels in the peripheral nervous system (pLVs) is still unclear. Here, we clarify the existence of pLVs in rats, PROX1-EGFP transgenic mice and human, and exhibit a clear three-dimensional structure for helping understand its structural features. Moreover, two specific phenotypes of lymphatics endothelial cells (Rnd1Hi LECs and Ccl21Hi LECs) in peripheral nerves are well characterized by single-cell sequencing. Subsequently, the ability of trans-lymphatic delivery to peripheral nerves via pLVs has been dynamically demonstrated. After peripheral nerve injury (PNI), extensive lymphangiogenesis occurs in the lesion area and further enhances the efficiency of retrograde lymphatic-nerve transport. In PNI animal models, subcutaneously footpad-injected exosomes are efficiently delivered to sciatic nerve via pLVs which can promote nerve regeneration. The trans-lymphatic delivery to peripheral nerves via pLVs can subtly bypass BNB which provides an easy and alternative delivery route for PNI treatment. First, we confirmed the existence of lymphatic vessels in the epineurium and perineurium of peripheral nerves (named pLVs) in rats, PROX1-EGFP transgenic mice and human. In addition, we characterized the specialized three-dimensional (3D) morphologic features of pLVs by using light-sheet fluorescent microscope (LSFM). Furthermore, the ability of trans-lymphatic delivery to peripheral nerves via pLVs was dynamically demonstrated by using second-window near-infrared (NIR-II) in vivo imaging system and subcutaneously footpad injected exosomes could promote nerve regeneration via this novel delivery route. The trans-lymphatic delivery to peripheral nerves via pLVs can subtly bypass BNB which provides an easy and alternative delivery route for PNI treatment, and thus deserves further clinical explorations. [Display omitted] • pLVs exist in the epineurium and perineurium of peripheral nerves. • The trans-lymphatic delivery to peripheral nerves via pLVs provides a simple delivery route for PNI treatment. • Lymphangiogenesis enhances the efficiency of retrograde lymphatic-nerve transport after PNI. • Subcutaneously footpad-injected exosomes can be efficiently delivered to sciatic nerve via pLVs for promoting regeneration. [ABSTRACT FROM AUTHOR]

In this work, Q&P1180 steels were butt welded by friction stir welded (FSW) and rapid cooling FSW (RCFSW), aiming to investigate the influence of rapid cooling on the microstructure and deformation behavior of joints. The results showed that for FSW and RCFSW joints, stir zone (SZ) composed of martensite phase, and inter-critical heat affected zone (ICHAZ) composed of ferrite/martensite dual-phase microstructure, and subcritical heat affected zone (SCHAZ) consisted of ferrite, martensite, carbide and residual austenite phases. Compared with FSW joint, the grain of HAZ was refined, the contents of residual austenite and ferrite increased, while the content of cementite decreased in RCFSW joint. The tensile strength and elongation of FSW joint were 1292 MPa and 7.5 %, respectively. Compared to FSW joint, the tensile strength of RCFSW joint slightly decreased (1237 MPa), while the elongation greatly increased to 13.5 %. During tensile deformation, the strain was mainly concentrated in HAZ of FSW joint, while the strain transferred from HAZ to basal material (BM) of RCFSW joints, and finally fractured in BM. • The tensile strengths of Q&P1180 steel FSW and RCFSW joints were higher than that of BM. • The elongation of RCFSW joint was 80 % higher than that of FSW joint. • The enhanced stability of residual austenite contributes to the sustained deformation and increase of plasticity. [ABSTRACT FROM AUTHOR]

Empathy mechanism in communication is the cornerstone for effective and meaningful interaction. Establishing an empathy mechanism in conversation agent (CA) requires accurate recognition of users' emotions to facilitate generates appropriate empathetic responses. Therefore, we proposed a Multimodal Emotion Recognition Model (MERM) to recognizes a user's emotional state from multimodal data (audio, facial expressions, and conversation text) during conversation, and an Interactive Empathetic Conversation Model (IECM) to generate empathetic responses based on the MERM. Comparative and ablation study results indicated that the proposed models outperform existing methods in recognizing the user's emotions and generating appropriate empathetic responses. We also conducted an experiment study, the results indicated that the CA significantly enhances the user's emotional experience. [ABSTRACT FROM AUTHOR]

Intermetallic compounds (IMCs) play an important role in the welding quality of steel and aluminum (Al) alloys by friction stir welding (FSW). However, the evolution mechanism of IMCs and their effects on the mechanical properties of FSW joints are still unclear and need to be further elucidated. In this work, QP980 steel and 6061 Al alloy are successfully welded by FSW. The microstructure and mechanical properties of joints are characterized. The results show that an IMC layer composed of Al 3 Fe, Al 5 Fe 2 , Al 2 Fe, and Al 6 Mn phases is generated at the weld interface. The joint efficiency is about 70.1%. The formation sequence of IMCs in the same binary system is affected by the effective enthalpy of formation, while it is related to the element concentration in different binary systems. Furthermore, the formation sequence is Al 3 Fe, Al 5 Fe 2 , Al 2 Fe, and Al 6 Mn phases. The interfacial bonding strength is enhanced by the low lattice mismatch between IMCs and matrix. The interfacial bonding strength of IMCs with Fe and Al matrices in the joint is in ascending order: Al 2 Fe and Fe, Al 2 Fe and Al, Al 5 Fe 2 and Fe, Al 5 Fe 2 and Al, Al 6 Mn and Fe, Al 3 Fe and Fe, Al 6 Mn and Al, as well as Al 3 Fe and Al. It is noted that the bonding strength between the Al 2 Fe and Fe is lowest, indicating that Al 2 Fe phase is responsible for the joint fracture during tensile test. • Besides Al-Fe phases, Al-Mn IMCs were also found in the dissimilar FSW joint of QP980 steel and 6061 Al alloy. • The formation sequence of IMCs in the FSW joint was Al 3 Fe, Al 2 Fe, Al 5 Fe and Al 6 Mn. • The bonding strength between the Al 2 Fe and Fe was the lowest, indicating that the Al 2 Fe phase was responsible for the joint fracture during tensile test. [ABSTRACT FROM AUTHOR]

The present study aimed to identify novel intervertebral disc degeneration (IDD)‑associated long noncoding (lnc)RNAs and genes. The lncRNA and mRNA microarray dataset GSE56081 was downloaded from the Gene Expression Omnibus database and included 5 samples from patients with degenerative lumbar nucleus pulposus and 5 normal controls. Differentially expressed lncRNAs or differentially expressed genes (DEGs) were identified and co‑expression network analysis was performed followed by functional analysis for genes in the network. Additionally, a microRNA (miRNA)‑lncRNA‑mRNA competing endogenous RNA (ceRNA) regulatory network was constructed based on DEGs and lncRNAs in the co‑expression network. Furthermore, a literature search was performed to identify specific miRNAs that had been previously associated with IDD and a specific miRNA‑associated ceRNA network was extracted from the co‑expression network. A total of 967 genes and 137 lncRNAs were differentially expressed between IDD samples and controls. A co‑expression network was constructed and contained 39 differentially expressed lncRNAs and 209 DEGs, which were primarily involved in ʻskeletal system developmentʼ, ʻresponse to mechanical stimulusʼ and ʻbone developmentʼ. Furthermore, a ceRNA network was established, including 79 miRNAs, 9 downregulated lncRNAs and 148 DEGs. The identified miRNAs included a previously reported disease‑associated miRNA, hsa‑miR‑140. The present study demonstrated that hsa‑miR‑140 was regulated by three lncRNAs in the hsa‑miR‑140‑associated ceRNA network, including KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1), OIP5 antisense RNA 1 (OIP5‑AS1) and UGDH antisense RNA 1 (UGDH‑AS1). KCNQ1OT1 was co‑expressed with neurochondrin (NCDN) and lon peptidase 2, peroxisomal. In addition, the lncRNAs OIP5‑AS1 and UGDH‑AS1 targeted several overlapping co‑expressed genes, including forkhead box F1 (FOXF1) and polycystin 1, transient receptor potential channel interacting (PKD1). Therefore, KCNQ1OT1 may regulate the expression of NCDN, and OIP5‑AS1 and UGDH‑AS1 may affect the expression of FOXF1 and PKD1 in IDD. Further experiments are required to validate the results of the present study, which may provide valuable insights into the identification of novel biomarkers associated with IDD. [ABSTRACT FROM AUTHOR]