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Modern neuroimaging techniques enable us to construct human brains as brain networks or connectomes. Capturing brain networks' structural information and hierarchical patterns is essential for understanding brain functions and disease states. Recently, the promising network representation learning capability of graph neural networks (GNNs) has prompted related methods for brain network analysis to be proposed. Specifically, these methods apply feature aggregation and global pooling to convert brain network instances into vector representations encoding brain structure induction for downstream brain network analysis tasks. However, existing GNN-based methods often neglect that brain networks of different subjects may require various aggregation iterations and use GNN with a fixed number of layers to learn all brain networks. Therefore, how to fully release the potential of GNNs to promote brain network analysis is still non-trivial. In our work, a novel brain network representation framework, BN-GNN, is proposed to solve this difficulty, which searches for the optimal GNN architecture for each brain network. Concretely, BN-GNN employs deep reinforcement learning (DRL) to automatically predict the optimal number of feature propagations (reflected in the number of GNN layers) required for a given brain network. Furthermore, BN-GNN improves the upper bound of traditional GNNs' performance in eight brain network disease analysis tasks. [ABSTRACT FROM AUTHOR]

• Simulation of a biomass based integrated gasification combined cycle. • Techno-economic assessment of the system for the feasibility study. • Multi-objective genetic algorithm optimization for better design. • To see the effect of various biomass feedstocks on the system performance. In this research study, a system comprising simultaneous electricity and heat production is selected, simulated, and investigated from the standpoints of energy, exergy, and economics. This integrated energy system is comprised of key components of a gasifier, a gas turbine, a Stirling engine, and a supercritical cycle of S-CO 2 with a water heater. The consequences of cycle coupled with the Stirling engine on system effectiveness and net performance have also been investigated. Various biomass fuels are considered for the comparison. The fundamental and efficient characteristics of the cycle were found by thermodynamic and economic assessment using parametric research, and optimization was then carried out using the target operations of exergy efficiency and expense for wood biomass inside the system. When evaluating both exergy effectiveness and expense, the most acceptable point of system design leads to exergy effectiveness and expense equal to 0.43 percent and 22.79 $/h, respectively. Finally, a multi-objective optimization is carried out to determine the best optimal design parameters. [ABSTRACT FROM AUTHOR]

Relatively low output of alternating current (AC) pulsed electricity generated by impinging a water droplet on a hydrophobic surface is difficult for practical utilization. Though high peak power density has been achieved by using a delicate transistor-like architecture and further been simplified to single electrode, the output is still AC pulsed. Methods have been developed to achieve direct current (DC) output, but either an integrated mechanical switch or an air breakdown electrode is necessary. Furthermore, additional rectification, conversion and storage components are prerequisites for further application. Here we demonstrate a DC droplet-based electricity generator to eliminate the unavoidable energy loss by integrating the rectification, energy conversion and storage components into the same device, through a simple yet delicate structure. We show that the water droplet can not only act as a source of charge generation in the process of contact electrification and electrostatic induction, but also act as a charge shuttle by adjusting its gravity-driven movement to sequentially deliver negative charges to the top charge reservoirs and positive charges to the bottom charge reservoirs, outputting DC electricity. Then the water droplet returns to its initial neutral state. A high output voltage over 1600 V has been achieved without any power management circuit. 400 LEDs can be lightened up by a single droplet with volume of 80 μL, showing a great potential for real-life application on water energy harvesting. [Display omitted] • The DC pulsed output is achieved on the developed DC-DEG without power management. • The open circuit voltage obtained through the charge pumping effect reaches 1600 V. • The functions of rectification and energy storage are integrated in DC-DEG. • Charge conduction process at the water/electrode interface is the dominant process. • The electrode-on-surface design can be applied to any hydrophobic surfaces. [ABSTRACT FROM AUTHOR]

Abstract: The effect of Ag particle size on oxygen reduction reaction (ORR) at the cathode was investigated in anion exchange membrane direct glycerol fuel cells (AEM-DGFC) with oxygen as an oxidant. At the anode, high purity glycerol (99.8 wt%) or crude glycerol (88 wt%, from soybean biodiesel) was used as fuel, and commercial Pt/C served as the anode catalyst. A solution phase-based nanocapsule synthesis method was successfully developed to prepare the non-precious Ag/C cathode catalyst, with LiBEt3H as a reducing agent. XRD and TEM characterizations show that as-synthesized Ag nanoparticles (NP) with a size of 2–9 nm are well dispersed on the Vulcan XC-72 carbon black support. Commercial Ag nanoparticles with a size of 20–40 nm were also supported on carbon black as a control sample. The results show that higher peak power density was obtained in AEM-DGFC employing an Ag-NP catalyst with smaller particle size: nanocapsule made Ag-NP > commercial Ag-NP (Alfa Aesar, 99.9%). With the nanocapsule Ag-NP cathode catalyst, the peak power density and open circuit voltage (OCV) of AEM-DGFC with high-purity glycerol at 80 °C are 86 mW cm−2 and 0.73 V, respectively. These are much higher than 45 mW cm−2 and 0.68 V for the AEM-DGFC with the commercial Ag/C cathode catalyst, which can be attributed to the enhanced kinetics and reduced internal resistance. Directly fed with crude glycerol, the AEM-DGFC with the nanocapsule Ag-NP cathode catalyst shows an encouraging peak power density of 66 mW cm−2, which shows great potential of direct use of biodiesel waste fuel for electricity generation. [Copyright &y& Elsevier]

• Hydroxychloroquine delays jujube fruit senescence. • Hydroxychloroquine enhances antioxidant nutrients in jujube fruit. • Hydroxychloroquine-delayed senescence can be reversed using 2,6-dinitrophenol. • Jujube fruit senescence may be regulated by autophagy and the antioxidant capacity. Autophagy, a mechanism of recycling intracellular constituents, favors plant growth, especially under nutrient starvation. However, autophagy's role in regulating postharvest fruit senescence is unclear. Here, effects of the autophagy inhibitor hydroxychloroquine (HCQ) and activator LiCl on postharvest jujube fruit senescence were investigated. HCQ significantly reduced weight loss and decay incidence, and enhanced firmness compared with those of the control. LiCl had the opposite effects. Protein oxidation and H 2 O 2 increased significantly in LiCl-treated compared with HCQ-treated fruit. The contents of vitamin C, total thiol, and phenolics, and total antioxidant capacity and DPPH-radical scavenging capacity, followed the order: HCQ > control > LiCl. The HCQ-mediated reduction in fruit respiration was significantly enhanced by ATP and partly reversed by 2,4-dinitrophenol, a mitochondrial uncoupler. Thus, jujube fruit senescence may be regulated by autophagy and the antioxidant capacity. A mechanism of autophagy-mediated postharvest fruit senescence involving mitochondrial biogenesis and respiration was proposed. [ABSTRACT FROM AUTHOR]

Coal and gas outburst disasters affect safe production from coal mines. There has been limited progress in understanding and predicting these outbursts in the past years. Therefore, a novel large scale three-dimensional simulation experimental apparatus to study mechanisms of coal and gas outburst was developed. The experimental apparatus has dimensions of 1.5 m × 0.8 m × 0.8 m and can achieve a gas seal of 6 MPa. Its hydraulic sub-system can perform axial (3000 t) and horizontal symmetric (2000 t) loading. The outburst port can be initiated actively and instantaneously, similar to the sudden excitation of an outburst. The apparatus realizes the roadway network simulation of various fluid migration routes, resistance characteristics, and ventilation facilities. Simultaneously, 90 test channels and a sampling frequency of up to 4 Ms/s can be used to monitor the time–space distribution law of multiple parameters in the apparatus and realize the real-time observation of the experimental phenomena. The experimental apparatus can be used to simulate the entire process of the coal and gas outburst, including accumulation, motivation, development, and termination stages as well as systematically study the features and mechanisms of the outburst. A complete simulation experiment of an outburst under a high geo-stress was performed. The distribution and variation of the gas pressure and geo-stress before, during, and after the outburst were analyzed. The distribution of the outburst-pulverized coal and gas concentration rule was obtained, which shows the characteristics of the extrusion type. This experiment validates the capability and reliability of the newly developed coal and gas outburst simulation apparatus. [ABSTRACT FROM AUTHOR]

• More than 700 metabolites are identified for the first time in jujube leaves. • Antioxidant components and taste components are the main differential metabolites between leaf buds and mature leaves. • Cyanidin O -syringic acid and apigeninidin chloride play important roles in leaf bud coloration. • Differentially expressed genes in flavonoid biosynthesis are identified. Jujube leaf is well known for its high nutritional value and medicinal benefits. However, a thorough and dynamic assessment of the metabolites present in jujube leaves is lacking. Here, the primary and secondary metabolites from purple leaf buds and green mature leaves were investigated using ultra-high-performance liquid chromatography/tandem mass spectrometry. A total of 778 metabolites were characterized and more than 700 compounds were reported for the first time. Analysis of differentially accumulated metabolites showed that the flavonoids were the major differential metabolites and determined the leaf coloration. The transcriptome data indicated that 20 flavonoid structural genes and three main types of flavonoid regulatory genes were significantly differentially expressed. Moreover, light had a significant influence on flavonoid accumulation. These results improve our understanding of metabolite accumulation and the molecular mechanisms of flavonoid biosynthesis in jujube leaf. [ABSTRACT FROM AUTHOR]

• Multi-index synthetical evaluation of bond behavior of steel fiber. • Features of complete load-slip curve of hooked-end steel fiber embedded in mortars. • Quantitative characterization of bond performance of hooked-end steel fiber. • Effects of mortar strength, sand and embedded length. Focusing on the fundamental issue of the bond performance of steel fiber in cementitious matrix of concrete, a multi-index synthetical evaluation was carried out to link the bond mechanisms to the features of complete load-slip curve of hooked-end steel fiber under a pull-out test. The features of curve at ascending portion, peak and descending portion of hooked-end steel fiber embedded in mortar were quantitatively characterized by the indexes of strength and energy dissipation capacity. Eight groups of specimens were experimentally investigated with the factors including the mortar strength ranged from 25 MPa to 90 MPa, the river sand and manufactured sand, and the embedded length of fiber varied from 6 mm to 14 mm. Except the bond strength used conventionally, the debonding strength and the residual bond strength are extracted to represent the strengthening effect, while the pull-out work and the debonding energy ratio, slipping energy ratio and pull-out energy ratio are extracted to represent the toughening effect of steel fiber on matrix of concrete. Meanwhile, the strength use efficiency of steel fiber is introduced to estimate if the fracture of steel fiber happens and to determine a rational tensile strength of steel fiber matched with concrete. Results indicated that the higher mortar strength and manufactured sand benefit to the bond performance of hooked-end steel fiber, and the hooked-end steel fiber used in this test with tensile strength of 1150 MPa matches better with mortars of 65 ~ 90 MPa compressive strength. The hooked-end plays a controlling role providing reliable bond performance of steel fiber, the rational length of hooked-end steel fiber can be optimized in view of the bond requirement. This gives a useful method to quantitatively evaluate the validity and adaptability of steel fiber used for concrete. [ABSTRACT FROM AUTHOR]

• Essential elements availability: a new method was established. • Soaking promotes the accumulation of essential elements in germinating seed. • Essential element soaking simultaneously improves antioxidant capacity. Fertilizer application is typically used to increase the availability of essential elements. In this study, an improved method for essential element supplementation based on seed germination was established. Solutions of essential elements (Fe2+, Zn2+, Cu2+, Mn2+, SeO 3 2+, or I− or their combination) were applied to germinating soybean seeds, and the contents of the essential elements in the soybean sprouts were analyzed by atomic absorption spectroscopy. Compared with the control (seeds treated with water), the contents of iron, zinc, copper, manganese, selenium, and iodine in soybean sprouts produced by germinating seeds treated with solutions containing 10 mM essential elements were approximately 10–2000 times higher. Moreover, treatment with essential element solution increased the total antioxidant capacity and content of total thiols in the soybean sprouts. This rapid and simple technique can be used to improve nutrition for humans and livestock in regions deficient in essential elements. [ABSTRACT FROM AUTHOR]