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Porous intermetallics show potential in the field of filtration and separation as well as in the field of catalysis. Herein, porous TiFe2 intermetallics were fabricated by the reactive synthesis of elemental powders. The phase transformation and pore formation of porous TiFe2 intermetallics were investigated, and its corrosion behavior and hydrogen evolution reaction (HER) performance in alkali solution were studied. Porous TiFe2 intermetallics with porosity in the range of 34.4%–56.4% were synthesized by the diffusion reaction of Ti and Fe elements, and the pore formation of porous TiFe2 intermetallic compound is the result of a combination of the bridging effect and the Kirkendall effect. The porous TiFe2 samples exhibit better corrosion resistance compared with porous 316L stainless steel, which is related to the formation of uniform nanosheets on the surface that hinder further corrosion, and porous TiFe2 electrode shows the overpotential of 220.6 and 295.6 mV at 10 and 100 mA·cm−2, suggesting a good catalytic performance. The synthesized porous Fe-based intermetallic has a controllable pore structure as well as excellent corrosion resistance, showing its potential in the field of filtration and separation. [ABSTRACT FROM AUTHOR]

Huanglongbing (HLB) is a highly destructive, fast-spreading disease of citrus, causing substantial economic losses to the citrus industry worldwide. Nutrient levels and their cellular distribution patterns in stems and leaves of grapefruit were analysed after graft-inoculation with lemon scions containing 'Candidatus Liberibacter asiaticus' (Las), the heat-tolerant Asian type of the HLB bacterium. After 12 months, affected plants showed typical HLB symptoms and significantly reduced Zn concentrations in leaves. Micro-XRF imaging of Zn and other nutrients showed that preferential localization of Zn to phloem tissues was observed in the stems and leaves collected from healthy grapefruit plants, but was absent from HLB-affected samples. Quantitative analysis by using standard references revealed that Zn concentration in the phloem of veins in healthy leaves was more than 10 times higher than that in HLB-affected leaves. No significant variation was observed in the distribution patterns of other elements such as Ca in stems and leaves of grapefruit plants with or without graft-inoculation of infected lemon scions. These results suggest that reduced phloem transport of Zn is an important factor contributing to HLB-induced Zn deficiency in grapefruit. Our report provides the first in situ, cellular level visualization of elemental variations within the tissues of HLB-affected citrus. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

The foliar application of zinc (Zn) has been regarded as a practical and economical way to reduce grain cadmium (Cd) accumulation and enhance grain quality in crops. Herein, a two-year field experiment was carried out to examine the efficacy of different application rates of the foliar Zn fertilizer in Cd reduction and microelement biofortification in wheat (Triticum aestivum L.) grains. The results show that the T4 and T5 treatments, 500 and 250-fold dilution of the foliar Zn fertilizer, respectively, increased the grain yield to varying degrees in the two years. When compared with controls and based on the average of the two years' results, spraying with the foliar Zn fertilizer remarkably decreased grain Cd concentrations (44.5%), Cd translocation from stem to grain (TFStem/Grain) (4.92%), the H R I values of Cd (45.5%), PA/Ca (27.8%), PA/Fe (21.4%) and PA/Mn (5.81%) under the T2 treatment (1000-fold dilution). Furthermore, the T2 treatment significantly increased the Zn (37.8%), Ca (48.9%), Fe (37.6%), Mn (14.8%) and total protein (7.92%) contents and the estimated Zn bioavailability (28.9%) in wheat grains after two years. All these findings suggest that the foliar Zn fertilizer holds considerable promise as a safe crop production technique and a means of mitigating "hidden hunger" in developing countries. [ABSTRACT FROM AUTHOR]

Iron (Fe) is an important essential micronutrient and its deficiency is a widespread micronutrient malnutrition problem for human being in the world. Iron biofortification of staple food crop is regarded as an effective way to solve this problem. Rice is the most important food crop in the world feeding over half of the global population; therefore, a small increase in Fe concentration in rice grain can greatly improve human health. However, the mechanisms of Fe dense accumulation in rice grain are not fully understood, which limits the advance of high Fe-dense rice breeding. In this paper, the characteristics of Fe re-utilization in the dense rice genotype (IR68144) were studied, as compared with the indense rice genotype (IR64). The results showed that the ability of iron remobilization from “source” to “sink” was much greater in IR68144 than in IR64, i.e. from root, the 1st, 2nd, and 3rd leaf, as well as leaf sheath to the new growing leaves and tillers at vegetative stage, and from root, stem, and flag leaf to grain at reproductive stage. It was estimated that the re-mobilization of Fe in the dense genotype IR68144 accounted for 28.5% of total Fe of the plant at the 4th leaf stage, which was 1.6-fold higher than that of the in-dense genotype IR64. At the reproductive growth stage, the re-translocation of Fe from leaves and stems to grain was found to be much greater in the dense than in the indense rice genotype, and the re-translocation of Fe depended greatly on Fe pretreatment levels before anthesis and Fe/Zn nutritional status after anthesis. The dense genotype remobilized about 10-time more Fe from stem with low Fe pretreatment, and exported around 6-time more Fe from roots and 10-time more Fe from the flag leaf with adequate Fe pretreatment, as compared to the indense genotype. The remobilization of Fe from the vegetative organs to grain was greater at low Fe supply than at higher Fe supply, and greater re-translocation of Fe was noted in IR68144 than in IR64 when pretreated with low Fe. After stopped Fe supply at anthesis, the Fe export from the flag leaf decreased with increasing Fe pretreatment levels in IR68144, but Fe input in the flag leaf was noted in IR64. After anthesis, the contribution of remobilized Fe to brown rice Fe accumulation was greater in IR68144 than in IR64 with low, adequateand high Fe pretreatments. The results indicate that the Fe-dense rice genotype has greater ability of reutilizing Fe in the source tissues than the indense genotype, and the remobilization ability of Fe from older leaf to the new growing leaves could be used for predicting grain Fe accumulation ability.

Zinc (Zn) is an essential micronutrient for plant and human, and over 40% of children in the world are suffering from Zn malnutrition. Zinc deficiency in human is mainly caused from low Zn concentration and bioavailability in foods or edible parts of crop plants. Biofortification appears to be a most sustainable and cost-effective approach to solve human micronutrient malnutrition. Zinc deficiency is a widespread problem in rice, causing decreased crop yields and nutritional quality. Increasing Zn density in rice grain is important for improving crop yield and human nutrition. Large genotypic differences in Zn concentration in rice grains have been observed, however, the mechanisms of Zn dense acumulation in rice grain is not fully understood. In this paper, 68Zn stable isotope tracing technique was used to compare the translocation of 68Zn absorbed at different growth stages to grain and Zn remobilization between Zn-dense and Zn-indense rice genotype. The results showed that the Zn-dense rice genotype (IR68144) had greater translocation of 68Zn absorbed during early (from seedling to tillering stage) and late (from grain filling to harvest stage)growth stages, as compared with the indense genotype (IR64). More than half of Zn distributed in grains was translocated from those absorbed by rice plant before anthesis, accounting for 63% and 52% of the total for IR68144 and IR64, respectively. Even after grain filling, plenty of Zn could be transported into grains, with a two fold higher distribution rate to brown rice for IR68144 than for IR64. The Zn-indense rice genotype IR64 contained more 68Zn in roots whereas the Zn-dense rice genotype IR68144 contained more 68Zn in stems, leaves, and grains when 68Zn was supplied at all stages. The remobilization of 68Zn within the plant varied greatly between the two genotypes. When stopping 68Zn supplying at tillering stage, we found that more 68Zn was retranslocated into the new growing leaves and tillers, and more 68Zn was exported from the full-expanded leaf in the dense genotype than in the indense genotype. When stopping 68Zn supply at Anthesis stage, it was observed that more 68Zn was retranslocated into the growing grain, and more 68Zn remobilized from stem and flag leaf in IR68144 than in IR64. The retranslocation of 68Zn from the flag leaf to grain was found to be twice greater in IR68144 than in IR64 when applying 68Zn on the flag leaf either at booting stage or anthesis stage. These results indicated that the Zn-density in rice grain is closely associated with the ability of Zn translocation from “the source” to “the sink” at both early and late growth stages and phloem mobility of Zn, especially from stem to grain.

Unmanned aerial vehicles (UAVs) have gained considerable attention in the research community due to their exceptional agility, maneuverability, and potential applications in fields like surveillance, multi-access edge computing (MEC), and various other domains. However, efficiently providing computation offloading services for concurrent Internet of Things devices (IOTDs) remains a significant challenge for UAVs due to their limited computing and communication capabilities. Consequently, optimizing and managing the constrained computing, communication, and energy resources of UAVs are essential for establishing an efficient aerial network infrastructure. To address this challenge, we investigate the collaborative computation offloading optimization problem in a UAV-assisted MEC environment comprising multiple UAVs and multiple IODTs. Our primary objective is to obtain efficient offloading strategies within a multi-heterogeneous UAV environment characterized by limited computing and communication capabilities. In this context, we model the problem as a multi-agent markov decision process (MAMDP) to account for environmental dynamics. We employ a multi-agent deep deterministic policy gradient (MADDPG) approach for task offloading. Subsequently, we conduct simulations to evaluate the efficiency of our proposed offloading scheme. The results highlight significant improvements achieved by the proposed offloading strategy, including a notable increase in the system completion rate and a significant reduction in the average energy consumption of the system. [ABSTRACT FROM AUTHOR]