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In the rapidly evolving domain of mobile edge–cloud computing (MECC), the proliferation of Internet of Things (IoT) devices and mobile applications poses significant challenges, particularly in dynamically managing computational demands and user mobility. Current research has partially addressed aspects of service migration and resource allocation, yet it often falls short in thoroughly examining the nuanced interdependencies between migration strategies and resource allocation, the consequential impacts of migration delays, and the intricacies of handling incomplete tasks during migration. This study advances the discourse by introducing a sophisticated framework optimized through a deep reinforcement learning (DRL) strategy, underpinned by a Markov decision process (MDP) that dynamically adapts service migration and resource allocation strategies. This refined approach facilitates continuous system monitoring, adept decision making, and iterative policy refinement, significantly enhancing operational efficiency and reducing response times in MECC environments. By meticulously addressing these previously overlooked complexities, our research not only fills critical gaps in the literature but also enhances the practical deployment of edge computing technologies, contributing profoundly to both theoretical insights and practical implementations in contemporary digital ecosystems. [ABSTRACT FROM AUTHOR]

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]

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]

Zinc-oxide nanoparticles (ZnO-NP) effect on crop physiology and zinc recovery remains poorly studied for acidic-sandy soils. To address this, greenhouse pot (plastic-pots, 6 kg soil, maize) experiments with ZnO-NP (50, 100, 150, 200 mg kg−1) applied via different methods (soil-drench, seed-coating and foliar-spray) was conducted in a 60 days study. Results revealed that ZnO-NP via seed-coating (100 mg kg−1) and soil-drench (150 mg kg−1) enhanced shoot and total P uptake, while ZnO-NPs (foliar) (50 mg kg−1) enhanced maize growth (6–11%), with agronomic and physiological improvements ultimately resulted in greater biomass (16–20%), Zn agronomic efficiency and uptake. Compared to ZnSO4 treatment and the control, seed-coating with 100 mg kg−1 ZnO-NP increased leaf chlorophyll and pigment content by 12–127%. Principal component analysis revealed a close association among growth traits, plant pigments, fluorescence parameters, total Zn and P concentration, and uptake with total biomass as influenced by ZnO-NPs. Thus, compared to conventional ZnSO4 and higher dosages of ZnO-NPs, foliar-spray of ZnO-NP at 50 mg kg−1, seed-coating at 100 mg kg−1, or soil-drench at 150 mg kg−1 increased maize biochemical characteristics, growth, biomass, and Zn agronomic efficiency. These elucidate important implications of ZnO-NP application for increasing plant development and Zn biofortification in acidic-sandy soils. [ABSTRACT FROM AUTHOR]

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]

Sugarcane yield in China is low because of the shallow A-horizon soil layer, or as it is commonly called by farmers, the "plow soil layer", as well as low soil organic matter and fertilizer utilization efficiency. Fenlong-ridging deep tillage (FT), also called vertical rotary tillage, and amendment with biochar have been shown to improve soil quality and crop yield. In this study, field trials were conducted with newly planted and ratoon sugarcane to evaluate the effectiveness of FT, together with amendment with biochar and nitrogen fertilization, to improve sugarcane yield. The treatments were conventional tillage with chemical fertilizer without biochar (CT-CF, which was the control of this experiment), FT with chemical fertilizer without biochar (FT-CF), conventional tillage with chemical fertilizer mixed with biochar (CT-CFB), and FT with chemical fertilizer mixed with biochar (FT-CFB). FT-CFB treatment presented higher soil porosity, as well as higher contents of available N, P, K, total N, and organic matter, and lower soil bulk density. Similarly, results showed that FT-CFB presented higher sugarcane root fresh and dry weights, higher germination percentage, higher tiller number, and higher yield with statistically significant differences among treatments for both newly planted and ratoon sugarcane plants. Significant interactions between biochar and FT were observed for these crop traits. The interactions of FT and amendment with biochar improved the soil's physical and chemical properties and increased the available nutrients, resulting in improved root growth and sugarcane yield. The statistical results of the present study imply that Fenlong-ridging deep tillage combined with chemical fertilizer mixed with biochar (FT-CFB) application is a new promising farm management practice for improving the soil's physical and chemical properties and root growth, increasing total yield in China's sugarcane belt area. [ABSTRACT FROM AUTHOR]

Modeling plants for biomass production and metal uptake from surrounding environment is strongly dependent on the moisture content of soil. Therefore, experiments were conducted to find out how soil moisture affects the phenotypic traits, photosynthetic efficiency, metabolic profile, and metal accumulation in the hyperaccumulating ecotype of Sedum alfredii (S. alfredii). A total of six water potential gradients were set: 0 ~ −15 kPa (T1), −15 ~ −30 kPa (T2), −30 ~ −45 kPa (T3), −45 ~ −60 kPa (T4), −60 ~ −75 kPa (T5), and −75 ~ −90 kPa (T6). Different water potential treatments had a significant effect on plant growth and metal uptake efficiency. Compared to T3, T2 was more effective in promoting plant growth and development, with an increase in biomass of 23% and 17% in both fresh weight (FW) and dry weight (DW), respectively. T2 and T3 had the highest cadmium (Cd) content in the shoot (280.2 mg/kg) and (283.3 mg/kg), respectively, whereas T1 had the lowest values (204.7 mg/kg). Cd availability for plants in the soil was affected by moving soil moisture cycles. Changes in soil moisture that were either too high or too low compared to the ideal soil water content for S. alfredii growth resulted in a significant reduction in Cd accumulation in shoots. Tryptophan, phenylalanine, and other amino acids were accumulated in T5, whereas only tryptophan and phenylalanine slightly increased in T1. Sugars and alcohols such as sucrose, trehalose, mannitol, galactinol, and mannobiose increased in T5, while they decreased significantly in T1. Interestingly, in contrast to T1, the two impaired metabolic pathways in T5 (galactose and starch metabolism) were identified to be glucose metabolic pathways. These findings provide scientific information (based on experiments) to improve biomass production and metal uptake efficiency in hyperaccumulating ecotype of S. alfredii for phytoremediation-contaminated agricultural fields. [ABSTRACT FROM AUTHOR]

Nitrogen, despite being essential for the growth of plants, can pose serious threats to the ecological environment when applied excessively as fertilizers. The application of nanomaterials has a catalytic effect on crop growth and a restorative effect on the environment. However, their effect on mitigating ammonium stress in crops is poorly understood. In the present study, the roles of nanoparticles of magnesium oxide (nMgO) and hydroxyapatite (nHA) with different application rates (0, 10, 100, 500, and 1000 mg L−1) on seed germination and seedling growth in water spinach (Ipomoea aquatica Forssk.) and Hami melon (Cucumis melo L.) were investigated, and the ammonium stress mitigating capacity of nanoparticles with the optimal application rate on the two crops was analyzed. The results showed that the application of nMgO and nHA at an optimal rate of 100 mg L−1 significantly promoted seed germination of water spinach, followed by the increase of germination potential, seed germination rate, and germination index, while alleviating the inhibitory effect of NH4+ stress in water spinach. As for the Hami melon, nHA reduced the ammonium stress on seedlings by promoting antioxidant enzyme activity, while nMgO was found to be involved in reducing the root growth of Hami melon seedlings. This study provided a reference on how to select the appropriate type and optimize the application method of nanomaterials that will be used in agriculture in the future. [ABSTRACT FROM AUTHOR]

Activation of low-grade phosphate rocks such as dolomite phosphate rock (DPR) with organic molecules of humic acid (HA) and sodium lignosulfonate (SLS) holds promise for developing slow release P fertilizers. Consequently, activated DPR fertilizers also contains multiple essential plant elements, including P, Ca, Mg, Zn, and Fe, while minimizing leaching losses of nutrients and heavy metals. Greenhouse experiments were conducted to examine the availability of Ca, Mg, and trace metals in soils applied with activated DPR fertilizers and subsequent response of lettuce (Lactuca Sativa L.) as compared with original DPR and water-soluble P fertilizers including superphosphates (SP) and diammonium phosphates (DAP). Application of activated DPR fertilizers stimulated the uptake of Ca, Mg, Zn, Fe, B by lettuce plants relative to original DPR and DAP. Potential toxic elements such as Cr, Cd, Ni, Pb, and Cu were mostly immobilized in soil without uptake by lettuce when applied with activated DPRs primarily due to increased soil pH, as compared with water soluble fertilizers such as DAP and SPs. Apparently, the activated DPR fertilizers offer advantages over original DPR materials and water-soluble P fertilizers in providing multiple nutrients with minimal adverse effects on soil and environmental quality. [ABSTRACT FROM AUTHOR]

Rationally designing highly active oxygen evolution reaction (OER) electrocatalysts with robust stability is critical for industrial electrochemical water splitting. Hierarchical iron–nickel oxyhydroxide nanosheets directly grown on porous TiFe2-based intermetallics are designed and prepared as OER catalysts. The best-performing nanosheets only need 295 mV to achieve 100 mA cm−2, along with exceptional durability at a high current density of 1000 mA cm−2. This work introduces a scalable strategy for producing robust OER catalysts that have potential for industrial applications. [ABSTRACT FROM AUTHOR]

Application of crop residues and chemical nitrogen (N) fertilizer is a conventional practice for achieving high yield in a rice system. However, the fallacious combination of N fertilizers with crop straw not only significantly reduces the N use efficiencies (NUEs) but also leads to serious environmental problems. The present study employed five treatments including no N fertilization and no straw incorporation (ck), N fertilization incorporation only (S0), N fertilization with 40% straw (S40), N fertilization with 60% straw (S60), and N fertilization with 100% straw (S100) to improve N use efficiency as well as reduced Cd distribution in rice. The crop yields were largely enhanced by fertilization ranging from 13 to 52% over the straw addition treatments. Compared with ck, N fertilizer input significantly decreased soil pH, while DOC contents were raised in response to straw amendment, reaching the highest in S60 and S100 treatments, respectively. Moreover, straw addition substantially impacted the Cd accumulation and altered the bacterial community structure. The soil NH4+-N concentration under S0 performed the maximum in yellow soil, while the minimum in black soil compared to straw-incorporated pots. In addition, the soil NO3−-N concentration in straw-incorporated plots tended to be higher than that in straw-removed plots in both soils, indicating that crop straw triggering the N mineralization was associated with native soil N condition. Furthermore, the NUE increased with 15 N uptake in the plant, and the residual 15 N in soil was increased by 26.8% with straw addition across four straw application rates. Overall, our study highlights the trade-offs between straw incorporation with N fertilizer in eliminating potential Cd toxicity, increasing fertilizer-N use efficiencies and help to provide a feasible agricultural management. [ABSTRACT FROM AUTHOR]

Purpose: Improving crop yields by increasing fertilizer-use-efficiency is essential to minimizing agriculture's environmental impact. Water-dispersible carbon nanomaterials (CNM) have emerged as an innovative material to improve crop yields by increasing nutrient utilization and enhancing crop physiological processes. However, the optimum dose of CNM, performance on crop growth, and impact on soil biochemical properties remain poorly understood. Methods: A greenhouse pot experiment (55 days) was conducted to evaluate the effect of three CNM rates, applied basally as a soil drench amendment, on the growth of two lettuce varieties and soil biochemical properties. We compared three CNM rates (200, 400 & 800 mg kg−1; C200F, C400F & C800F) along with a negative control (C0F0; no fertilizer or CNM) and a positive control (C0F; fertilizer at recommended doses like CNM treatments, no CNM applied). Results: We found that nitrogen (N), phosphorus and potassium (K) accumulation by lettuce and availability in soil were enhanced with CNM application, with 31% (C200F) and 34% (C400F) increases in shoot N accumulation compared to C0F, and K accumulation peaking at C800F (230% increase over C0F). Compared to C0F, soil microbial biomass carbon was 67–180% (C200F) or 42–150% (CF400) higher, phosphatase enzyme activity was 29–32% higher with C200F, and urease enzyme activity was 37–38% higher at C400F, indicating greater soil biological activity at lower application rates. Conclusion: Overall, CNM (200–400 mgkg−1 soil) promoted lettuce growth, enhanced soil fertility and soil biological activity, elucidating that water-dispersible CNM can be an alternative soil amendment to improve crop growth and soil biochemical quality. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting offers an appealing method to produce hydrogen as we attempt to achieve global carbon neutrality. However, the lack of earth-abundant, low-cost, active, and stable catalysts at large current densities severely hinders its industrial applications. TiNi3-based intermetallics as porous monolith catalysts (PMCs) exhibit an efficient hydrogen evolution reaction (HER) performance (an overpotential of 244 mV to afford 200 mA cm−2) and excellent stability in 1 M KOH. Theoretical calculations demonstrate that the synergetic effect between Ni and Mo can enhance HER activity. PMCs provide a new strategy to design catalysts with efficient and stable performance for industrial applications. [ABSTRACT FROM AUTHOR]

Soil pollution caused by potentially toxic metals has become a worldwide environmental issue. Geogenic processes and anthropogenic activities are two important sources of soil pollution. Soils may inherit toxic metals from parent materials; however, soil pollution mostly results from industrial and agricultural activities. Contamination by metals can be indicated by the changes in chemical, biochemical, and microbial properties of soils and plant responses. The total concentration of toxic metals in soil is still the most widely used indicator for risk assessment although extractable amounts have been reported to be more closely related to plant uptake. Several models have been proposed for assessing soil contamination by toxic metals, but none of them are commonly accepted for application to a wide range of soils. This review paper highlights how toxic metal contamination negatively affects soil and environmental quality, impacts food quality and security, and poses a threat to human health. Further research is needed to not only improve soil contamination diagnosis, modeling, and regulatory standards but also for remediation efficiency. [ABSTRACT FROM AUTHOR]

In this study, micro Coix lacryma-jobi L. vertical flow constructed wetlands with 0, 10 and 30 mg/L Cr6+ (in the form of K2Cr7O2) in the water sources were constructed to study the purification efficiency of chromium-contaminated wastewater, bacterial community diversity, chromium chemical speciation distribution and other indicators. The results showed that the constructed wetlands had high purification efficiency for chromium-contaminated wastewater. The removal rate of Cr6+ reached 99.61% and 95.45% in 10 and 30 mg/L Cr6+ treatment. The bacterial diversity index was unaffected by Cr6+ treatment; however, the bacterial richness index declined dramatically as Cr6+ treatment concentration increased. The bacterial community structure was influenced by the substrates pH, moisture content, organic matter and total chromium content. The abundance of Burkholderiaceae (uncultured) and Saccharimonadales (uncultured) were positively correlated with non-residual chromium content. The results contributed to understand the effect of chromium on bacterial community structure by considering the chromium chemical speciation. [ABSTRACT FROM AUTHOR]

Purpose: Salinity and drought are the main abiotic stresses which affect agricultural crop production worldwide. Various approaches and beneficial amendments are used to increase crop stress tolerance and production under world prevailing water deficit and saline conditions. Methods: Our experiment was planned to assess the beneficial role of silicon under water deficient and natural saline condition for increasing wheat crop growth, yield and production. Four levels of silicic acid i.e. 50 kg ha− 1, 100 kg ha− 1, 150 kg ha− 1 and 200 kg ha− 1 were applied with three irrigation levels i.e. one irrigation, two irrigation and four irrigation in moderately saline soil of ECe 7.34 under field conditions using RCBD split plot experimental design. Results: Different growth (i.e. plant height, no. of tillers, spike length, thousand grain weight, biological yield and grain yield), physiological (i.e. chlorophyll contents, relative water contents, membrane stability index and osmolality), antioxidant activity (i.e. SOD, POD and CAT) and elemental analysis (i.e. nitrogen, phosphorus, potassium, zinc, sodium and silicon concentration) were checked in our study. Salinity stress and lower irrigation levels significantly reduced all tested parameters except of osmolality and Na + concentration while antioxidant enzymatic activity remained similar in different levels of irrigation with no silica application i.e. Control. Si fertilization in higher doses i.e. 200 kg ha− 1 increased growth parameters maximum by 61%, physiological parameters by 45%, antioxidant activity by 36% and nutrients concentration by 46% decreasing the osmolality by 26% and Na concentration by 48% in wheat. Conclusions: It was concluded that inclusion of Si fertilization in plant nutrition increases wheat crop growth and production by improving plant stress tolerance attributes, nutrients balance and minimizing negative effect of osmotic and oxidative stress under naturally prevailing water deficit saline conditions. [ABSTRACT FROM AUTHOR]

Mato Grosso do Sul State in Brazil is characterized by the 'Cerrado' ecoregion, which is the most biologically rich Savannah globally. In agricultural terms, the region produces several commodities that are exported around the world. This level of productivity has been achieved through the large-scale use of synthetic fertilizers, which has created several economic and environmental concerns. New approaches in soil fertility management are required to avoid environmental degradation, pollution, and socio-environmental damages. A field experiment, lasting two years, was conducted to investigate the composted sewage sludge (CSS) effects on an infertile acidic soil (Oxisol) planted to maize (Zea mays L.). The following complete randomized complete block design with a 4 × 2 + 2 factorial scheme (four replications) was applied: four CSS increasing rates (from 5.0 to 12.5 Mg ha−1, w.b.) following two application methods (whole area and between crop rows). A control, without CSS or synthetic fertilizers, and conventional synthetic fertilization without CSS were also investigated. Evaluated parameters were: (i) soil and leaf micronutrient concentrations; (ii) maize development, yield, and production. The CSS application increased: (i) the concentration of micronutrients in both soil and leaves; and (ii) the crop yield. Both were particularly true at the higher CSS applied rates. Such organic fertilizer can be safely used as a source of micronutrients for crops as an important low-cost and environmentally friendly alternative to mineral fertilizers, thus safeguarding soil health. [ABSTRACT FROM AUTHOR]

As the power density of modern CPUs is gradually increasing, thermal management has become one of the primary concerns for multicore systems, where task scheduling and dynamic voltage/frequency scaling (DVFS) play a pivotal role in effectively managing the system temperature. In this article, we propose CARTAD, a new reinforcement learning (RL)-based task scheduling and DVFS method for temperature minimization and latency guarantee on multicore systems. The novelty of CARTAD framework is that we exploit the machine learning technique to analyze the applications’ intermediate representations (IRs) generated by a compiler and identify an important feature which is critical for predicting the application’s performance. With the newly explored feature, we construct an RL-based scheduler with the more effective state representation and reward function such that the system temperature can be minimized while guaranteeing applications’ latency. We implement and evaluate CARTAD on real platforms in comparison with the state-of-the-art approaches. Experimental results show CARTAD can reduce the maximum temperature by up to 16 °C and the average temperature by up to 10 °C. [ABSTRACT FROM AUTHOR]

Straw residues, as one of the conservation farming practices, are being strongly encouraged in China, including some cadmium-polluted areas. Nowadays, a portion of this plant residue is promoted to be removed for reducing excess metal(loid) in the soil and to be used for bioenergy production. Nevertheless, the possible influences of contaminated straw or the burial of its derived biochars on Cd accumulation in soil and data based on health risk assessment associated with different status and extent of soil contamination were relatively unknown. Thus it is important to provide a more systematical understanding of contaminated straw burial at specific contamination zones, which may provide useful guidance for straw utilization. In this study, we harvested two genotypes of rice straw from 6 contaminated levels among three soil types to comprehensively study the total Cd contents in straws and its derived biochars and correlate the sets of straw characteristics and Cd contents in three different contamination zones. The total Cd concentration in straws grew at a steady rate relatively with increasing soil Cd contamination levels, compared to those in biochars which performed more fluctuate due to the strong burning. According to correlational analyses, three-way ANOVA showed that the moisture, ash, volatile and fixed carbon were all significantly affected by straw CdTotal contents (p < 0.001). Such relationships were attributed to guide straw removal portions for gasification. Meanwhile, there was a significant correlation between straw Cd concentration and soil types (p < 0.001), confirming that it might be worth determining soil remediation by straw removal according to site-specific farmland conditions. This work will help to assess efforts toward predicting Cd concentration in the paddy soils related to kinds of contamination status and would also give useful guidance to make sustainable management strategies for crop straws in polluted regions. Novelty statement This work provided data on how much rice straw is needed to remove to ensure the minimal amount to control soil contamination and reduce costs according to site-specific conditions and soil Cd contamination status. It also explains the correlations between straw characteristics related to bioenergy use and soil conditions which would give guidance to balance using crop straw for increased bioenergy production and the need to also protect, preserve, and enhance soil resources. [ABSTRACT FROM AUTHOR]

Composted sewage sludge (CSS) contains large amounts of organic matter and nutrients and can be used as an organic fertilizer to improve growth, yield, and quality of sugarcane. However, there is a lack of information regarding the impact of CSS application on sugarcane seedling performance in nursery environments. A field study was conducted using a randomized complete block design to evaluate the development, nutritional status, productivity, and technological quality of sugarcane seedlings after CSS application with or without mineral fertilizer. Morphological variables (stem height, diameter, and number, as well as leaf area), technological attributes (total recoverable sugar: ATR; quantity of sucrose in sugarcane juice: Pol; Brix: percentage (weight/weight) of soluble solids contained in juice; TAH: tons of sugar per hectare), nutritional status, and sugarcane productivity were evaluated. Treatments did not influence morphological and technological variables except for TAH but did positively alter nutritional status and seedling productivity. The application rates of 5.0 and 7.5 Mg ha−1 of CSS with or without mineral fertilizers (MF) provided the greatest increase in crop productivity. Our results indicate that CSS can be a sustainable nutritional management option in sugarcane seedling nurseries, resulting in greater crop productivity at lower mineral fertilization rates. [ABSTRACT FROM AUTHOR]

Sugarcane demands large amounts of nutrients to reach a high level of productivity. Nutrients are generally supplied by mineral fertilizers, but their high costs and negative environmental impacts have generated interest in greater use of organic nutrient sources such as composted sewage sludge (CSS). In this study, we evaluated changes in soil chemical properties after the application of CSS or CSS/mineral fertilizer (MF) combinations to soil containing sugarcane seedlings under nursery conditions. Treatments included: T1: conventional mineral fertilization (MF) without application of CSS, T2: 100% of the recommended MF (06–30–24); T3: application of 2.5 Mg−1 CSS; T4: 5.0 Mg−1 CSS, T5: 7.5 Mg−1 CSS, T6: 2.5 Mg−1 CSS and 50% MF, T7: 5.0 Mg−1 CSS and 50% MF, T8: 7.5 Mg−1 CSS and 50% MF, T9: 2.5 Mg−1 CSS and 100% MF, T10: 5.0 Mg−1 CSS and 100% MF, T11: 7.5 Mg−1 CSS and 100% MF. Soil chemical properties were evaluated from the soil surface (0.0–0.25 m) and subsurface (0.25–0.50 m) horizons. The results showed that the increase in CSS application did not affect soil organic matter content at either depth, while Zn concentrations increased in the soil subsurface horizon. The application of CSS at 5.0 Mg ha−1 with or without 50% MF resulted in the highest pH values, sum of bases, cation-exchange capacity, P, K, Ca, Mg, Cu, and Zn in surface horizons. The use of CSS as an organic fertilizer in sugarcane nurseries improves soil fertility, reduces mineral fertilizer requirements, and, thus, facilitates the sustainable disposal of sewage sludge. [ABSTRACT FROM AUTHOR]

With its accumulation in upland rice, cadmium (Cd) can easily enter the human food chain, which poses a global health threat considering nearly half of the human population depends on rice as a staple food source. A study was conducted to (1) evaluate Cd accumulation by rice cultivars, grown in Cd-polluted Tropical Oxisols, with different levels of Cd tolerance; (2) quantify Cd transfer from soil to rice shoots and grain; and (3) estimate daily Cd intake by humans. Three rice cultivars, characterized by low (Cateto Seda–CS), medium (BRSMG Talento–BT), and high (BRSMG Caravera–BC) Cd uptake capacity, were investigated. Rice cultivars were exposed to increasing soil Cd concentrations (0.0, 0.7, 1.3, 3.9, 7.8, and 11.7 mg kg−1). Analysis was performed on soil, shoots, and grain. Shoot biomass and grain yield decreased with increasing Cd supply, suggesting the following Cd tolerance: CS > BT > BC. Cadmium concentrations in shoots and grain increased when exposed to Cd. Only CS did not exceed the maximum Cd limit permitted in food (0.40 mg kg−1), when rates up to 1.3 mg kg−1 of Cd were applied to soil. Considering daily rice consumption levels in Brazil, Cd intake often exceeds maximum tolerable levels. Continuous monitoring of soil Cd concentrations is a pivotal step in avoiding hazards to humans. Such monitoring is important on a global scale since outside of Asia, Brazil is the leading rice-producing and rice-consuming country. [ABSTRACT FROM AUTHOR]

Before service providers build up an mobile edge computing (MEC) platform, an important issue that needs to be considered is the configuration of computing resources on edge servers. Since the computing resources on an edge server are limited compared with a cloud server and the service provider's deployment budget is limited, it would be unrealistic to equip all edge servers with abundant computing resources. In addition, the edge servers have different computation demands due to their different geographies. Therefore, this article investigates the problem of server configuration optimization in an MEC environment based on a given computation demand statistics of the selected deployment locations. Our strategy is to treat each edge server as an M/M/m queueing model, and then establish the performance and cost models for the system. Two optimization problems, including cost constrained performance optimization, and performance constrained cost optimization are formulated based on our models and solved by a series of fast numerical algorithms. We also conduct extensive numerical simulation examples to show the effectiveness of the proposed algorithms. MEC service providers can use our strategy to get the appropriate type of processor and obtain the optimal processor number for each edge server to achieve two different goals: (1) deliver the highest‐quality services with a given cost constraint; (2) minimize the investment cost with a service‐quality guarantee. Our research is of great significance for service providers to control the tradeoff between investment cost and service quality. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) pollution in cultivated soils has posed a great risk to human health through the soil-plant-human pathway. Therefore, it is important to derive soil thresholds for the low-Cd accumulating genotype of wheat (Triticum aestivum L.) to promote its application in agricultural production on Cd-contaminated sites. Here, a pot experiment was performed to explore the transfer characteristics of Cd in two contrasting wheat genotypes at three different soils and the effect of soil parameters together with soil safety Cd thresholds derivation. Generally, grain Cd highly accumulating wheat genotype (Zhenmai10, HT) showed higher Cd accumulation in grains than grain Cd weakly accumulating wheat genotype (Aikang58, LT). Stepwise multiple linear regression (SMLR) analysis (log-transformed Freundlich-type) indicated that Cd accumulation in wheat grains was strongly related to soil total Cd concentration and pH for both genotypes (R2 = 0.907*** for HT; R2 = 0.910*** for LT). Combining the simple regression model of soil-plant transfer system with the risk assessment method based on human health, soil total Cd thresholds for three soils were calculated with the values of 0.62, 0.82, and 0.62 mg kg-1 in LT genotype and 0.31, 0.77, and 0.49 mg kg-1 in HT genotype. Therefore, we suggested that when deducing soil thresholds, the ability of wheat genotypes to accumulate Cd and soil properties should be considered because of the large differences in soil thresholds between different genotypes and types of soils. We believe our results will promote the application of low-Cd wheat genotypes to agricultural production, thereby ensuring the safety of their products. [ABSTRACT FROM AUTHOR]

Fluorosis is a chronic systemic disease induced by excessive intake of fluoride (F−). Fluoride in water and foods has been widely concerned, while limited reports focused on F− in soils and tobacco leaves which could transfer to human body. In the present study, we mainly focused on the distribution of F− in tobacco-planted soils and tobacco leaves in Bijie City, Southwest China. Soil total F− concentration ranged from 443.7 to 5,979 mg kg−1. The level of F− extracted by water (FH2O) and KCl solution (FKCl) ranged from 0.58 to 25.55 mg kg−1 and from 0.67 to 21.35 mg kg−1, respectively; hence, FH2O could be used to indicate the bioavailability of soil F− in the study area. The sequential extraction of F− show that the residual and exchangeable F− was the highest (97.44–99.73% of the total F−) and lowest (less than 0.25%) fractions of collected soil samples, respectively. According to the distribution of total and soluble F− in the soil profiles at the depth of 0–100 cm, soils were polluted mainly at the 0–40 cm layer. The soluble F− content in rhizosphere soils were higher than that in bulk soils, and tobacco leaves accumulated F− ranged from 16.73 to 111.3 mg kg−1 which was affected by soil pH and Ca content. Tobacco leaves F− level was related to the maturity of the leaves, with the F−content of medium leaves being higher than that of top leaves. More attention should be paid to tobacco with high F− content since F− pollution may transfer to human body via tobacco smoking. [ABSTRACT FROM AUTHOR]

An integrated constructed wetland (ICW) with six subsystems has been operated for six years (60,000 Ton day−1) and exhibited strong stability and high efficiency for removing conventional pollutants in tail water. This study was aimed to characterize the removal efficiency of antibiotics in relation to bacterial community structure and composition in this integrated constructed wetland. Water samples were taken from different ICW sites in two distinct seasons (i.e. winter and summer). The results showed that concentrations of antibiotics in ICW decreased from influent to effluent with varying removal rates among the different antibiotics (quinolones, ulfonamides and macrolides). The pyrosequencing of 16S ribosomal DNA revealed that the composition of dominant phyla could be grouped into four bacterial clusters and the key discriminant phyla, family or genera from each cluster was strongly associated with the specific physicochemical parameters of water or type of antibiotics. Members of the key phyla (Proteobacteria, Bacteroidetes, Parcubacteria, and Actinobacteria) appeared to play an important role in antibiotics removal. In general, both the concentration of antibiotics and physicochemical parameters of water shaped the bacterial communities. These results improve our understanding of the interactions between antibiotics or water physiochemical parameters and bacterial communities in the integrated constructed wetland. [ABSTRACT FROM AUTHOR]

Environmental context: Nano-enabled agriculture holds the promise of enhancing crop production while reducing the environmental impacts of agrochemicals. We review recent developments in the use of nano-fertilisers, nano-additives, nano-pesticides, nano-sensors, nano-cleansers and nano-delivery systems in agriculture. The review highlights the need for systematic studies on nanotoxicity and the development of cost-effective and eco-friendly nanomaterials for future applications. To keep pace with the ever-increasing demand of world population (nearly 9.8 billion), worldwide food production will need to increase by 50 % by 2050. Nanotechnology innovations show great promise for combating this challenge by delivering a more sustainable, efficient and resilient agricultural system, while promoting food security. Further exploration of nanotechnology applications in agriculture is necessary to realise its potential in manufacturing innovative agrochemicals and novel delivery platforms to enhance crop production and quality. Here, we review the fundamentals of nanotechnology and focus on its potential in agricultural applications. Progress has been made in the development of nano-fertilisers, nano-additives, nano-pesticides, nano-herbicides, nano-bactericides, nano-cleansers and nano-sensors to improve agrochemical efficiency, reduce runoff, enhance plant growth, and diagnose plant nutrition deficiencies and diseases. In addition, nano-delivery systems have been designed to deliver effective components to targeted sites within a plant to provide potential solutions to some devastating crop diseases which cannot be effectively managed with conventional methods. However, nano-enabled agriculture is still in its infancy and its applications are mostly theoretical. Therefore, more research is needed to develop biodegradable, cost-effective and safe nanomaterials for future application. Moreover, systematic studies are crucial to safeguard our food production system, while making efforts to raise public awareness of nanotechnology. Environmental context. Nano-enabled agriculture holds the promise of enhancing crop production while reducing the environmental impacts of agrochemicals. We review recent developments in the use of nano-fertilisers, nano-additives, nano-pesticides, nano-sensors, nano-cleansers and nano-delivery systems in agriculture. The review highlights the need for systematic studies on nanotoxicity and the development of cost-effective and eco-friendly nanomaterials for future applications. [ABSTRACT FROM AUTHOR]

Folates are one of the essential micronutrients for all living organisms. Due to inadequate dietary intake, folate deficiency remains prevalent in humans. Genetically diverse germplasms can potentially be used as parents in breeding programs and also for understanding the folate regulatory network. Therefore, we investigated the natural genetic diversity of folates and their physiological regulation in pak choi (Brassica rapa subsp. Chinensis) germplasm. The total folate concentration ranged from 52.7 μg 100 gFW–1 to 166.9 μg 100 gFW–1, with 3.2-fold variation. The main folate vitamer was represented by 5-CH3-H4folate, with 4.5-fold variation. The activities of GTP cyclohydrolase I and aminodeoxy chorismate synthase, the first step of folate synthesis, were high in high folate accessions and low in low folate accessions. Analysis of the transcription levels of 11 genes associated with folate metabolism demonstrated that the difference in folate concentrations may be primarily controlled at the post-transcriptional level. A general correlation between total folate and their precursors was observed. Folate diversity and chlorophyll content were tightly regulated through the methyl cycle. The diverse genetic variation in pak choi germplasm indicated the great genetic potential to integrate breeding programs for folate biofortification and unravel the physiological basis of folate homeostasis in planta. [ABSTRACT FROM AUTHOR]

Submerged aquatic vegetation (SAV) enhances assimilation efficiency of nutrients in wetlands, and improves the water quality, but may serve as secondary sources when their litter residues are decomposed. A laboratory incubation was conducted to investigate the biomass decay rate of four common SAV species: Hydrilla (Hydrilla verticillata), Naiad (Najas guadalupensis), Potamogeton (P. illinoensis), and Chara (Chara spp). Plant biomass samples were collected from the stormwater treatment areas in south Florida, USA and incubated in water at 40 °C for 126 days. At the end of incubation, the mixtures were passed through a 1 m sieve, and the plant debris above the screen were rinsed, oven-dried, and weighed. Biomass (dry matter) was measured and the decay rate was calculated, and total concentration of carbon (C), nitrogen (N), phosphorus (P) and other elements (K, Na, Ca, Mg, Al, Fe, and Mn) in the SAV plants were determined. Subsamples (5 mL) of the suspension (representing floc solution) were used for bacteria and fungi colony counting. The relationships between the decay rate and nutrient features or chemical components were analyzed. The results showed that Hydrilla had the highest decay rate (0.007930 d−1), and Chara had the lowest (0.002798 d−1). Concentrations of N, P, C and cations (K, Na, and Mn), and the ratio (K + Na)/(Ca + Al) in the SAVs had positive correlations with the biomass decay rate, whereas concentrations of Ca and Al, and the ratios of C/N and C/P in the plants were negatively correlated with the decay rate. However, the effect of microorganisms in the biomass decay rate of SAVs was not significant. These results suggest that high C concentration and more Ca and Al in the plant tissues can retard SAV biomass decomposition. [ABSTRACT FROM AUTHOR]

Information is needed for comparative assessment and agronomic practices for phytoavoidation in multi-pollutant field. A field study was conducted to explore 97 Brassica pekinensis L. genotypes with permissible limit of contaminants growing in a severely Cd, moderately nitrate and slightly Pb multi-polluted field. Thirteen genotypes, i.e. KGZY, CXQW, CAIB, JINL, JQIN, JFEN, WMQF, XLSH, TAIK, BJXS, JUKA, XYJQ and GQBW, were identified with permissible limit for nitrate, Cd and Pb based on their resistance to heavy metal and nitrate accumulation in leaves when grown in co-contaminated soils. Furthermore, the correlation between essential and toxic elements concentrations in plant of B. pekinensis were inconsistent. Generally speaking, application of increasing Ca, K and S fertilizers in appropriate forms and dosages tended to increase the yield and quality of B. pekinensis cultivated in multi-pollutant field. [ABSTRACT FROM AUTHOR]

Seawater intrusion (SI) is thought to be a significant threat to groundwater and soil quality in arid costal ecosystems, causing a reduction in freshwater availability and soil productivity. This study investigated the effects of seawater intrusion on soil and groundwater quality in the Nile Delta region at 16 sites located at distances of 5–45 km from the coast. We found that groundwater and soil quality were significantly affected by seawater intrusion. Results from the investigations indicated that: (1) the salinity and alkalinity of groundwater and soil pore-water decreased with increasing distances towards the inland, and showed significant positive correlations for EC, SAR, Na+ and Cl− by 0.80, 0.46, 0.78 and 0.66 respectively offshore (45 km); (2) there were significant positive correlations between salinity and alkalinity of both groundwater and soil pore-water inland up to 15 km distance from the coast;(3) mixing ratio values (F%) of seawater and groundwater were 9.30 to 37.56% in different sites, recording a maximum value close to the sea (5 km), while a minimum value was observed offshore (45 km); and (4) increasing seawater intrusion had negative impacts on the quality of groundwater and soil up to 15 km from the sea, providing the possibility of exploiting irrigated land in Nile delta up to 15 km from the Mediterranean sea. [ABSTRACT FROM AUTHOR]

Over the last decade, human population has been facing great challenges in ensuring appropriate supply of food free from cadmium (Cd) contamination. Selection of genetically low-Cd wheat (Triticum aestivum L.) genotypes, with a large biomass and high accumulation of Cd in straw but low-Cd concentration in grains, is an inventive approach of phytoremediation while keeping agricultural production in moderately contaminated soils. In this study, variations in Cd uptake and translocation among the 30 wheat genotypes in two different sites were investigated in field experiments. Significant differences in grain Cd concentration were observed between the two sites, with averaged values of 0.048 and 0.053 mg kg−1 DW, respectively. Based on straw Cd accumulation, grain Cd concentration, and TFrs, Bainong207 and Aikang58 for site A and Huaimai23 and Yannong21 for site B are promising candidates of low-Cd genotypes, which have considerable potential in achieving phytoremediation while keeping agricultural production on moderately or slightly Cd-polluted soil. The results indicate that it is possible to select the optimal low-Cd genotypes of wheat for different soil types by taking consideration of the effect of soil-wheat genotype interaction on grain Cd concentration. [ABSTRACT FROM AUTHOR]

Soil degradation due to global warming, water scarcity and diminishing natural resources negatively impacts food security. Soil fertility deterioration, particularly phosphorus (P) deficiency, remains a challenge in the arid and semi-arid regions. In this study, field experiments were conducted in different geographical locations to investigate the effects of organic amendments coupled with P fertilization and irrigation on soil physical-chemical properties, and the growth, yield and quality of wheat. Application of P fertilizers combined with organic amendments mitigated soil salinity, increased organic matter content, available water, hydraulic conductivity and available macronutrients, but decreased soil bulk density. Application of organic amendments slightly increased total Cd, Ni and Pb in soil, but Cd and Ni concentration was below allowable limits whilst Pb reached a hazardous level. Soil P fractions were significantly increased with the combined application of mineral P and organic amendments irrespective of salinity and irrigation. Crop growth yield and quality of wheat improved significantly in response to the integrated application of mineral P and organic amendments. In conclusion, the combination of mineral P sources with organic amendments could be successfully used as a cost-effective management practice to enhance soil fertility and crop production in the arid and semi-arid regions stressed with water scarcity and natural resource constraints. [ABSTRACT FROM AUTHOR]

Coal fly ash (FA) is a solid waste produced in coal combustion. This study focused on the removal of Cd2+ from wastewater by a newly synthesized adsorbent material, the low-temperature and sodium hydroxide–modified fly ash (SHM-FA). The SEM and BET analyses of SHM-FA demonstrated that the adsorbent was porous and had a huge specific surface area. The XRF, XRD, FTIR and TGA characterization showed that SHM-FA has an amorphous structure and the Si–O and Al–O in the fly ash dissolved into the solution, which improved the adsorption capacity of Cd. The results indicated that SHM-FA has desired adsorption performance. The adsorption performance was significantly affected by the dosage, starting pH, Cd2+ initial concentrations, and temperature, as well as adsorption time. In the optimal conditions, the removal efficiency and adsorption capacity of Cd2+ by SHM-FA were 95.76% and 31.79 mg g−1, respectively. The experiment provided clearly explained adsorption kinetics and isotherms. And the results confirmed that the adsorption behavior was well described by the pseudo-second-order kinetic and Langmuir isotherm model, which means that the adsorption of Cd2+ was controlled by SHM-FA through surface reaction and external diffusion process. In addition, the recycling of SHM-FA for reuse after Cd2+ adsorption showed high removal efficiency up to six times of use. Therefore, it can be concluded that SHM-FA is a low-cost adsorbent for Cd2+ removal from wastewater. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in soils has become an important concern for human health. Therefore, it is vital to develop suitable remediation strategies for contaminated soils. Oilseed rape tolerates high concentrations of heavy metals and is a promising candidate for the phytoextraction of cadmium (Cd) and lead (Pb) from metal-contaminated soils. A field experiment was conducted to evaluate 28 oilseed rape cultivars including Brassica napus L. and Brassica juncea L. for their ability to accumulate Cd and Pb. These cultivars were grown in a field co-contaminated with Cd (0.78 mg kg−1) and Pb (330 mg kg−1). The results showed that concentrations in shoots ranged from 1.22 to 3.01 mg kg−1 for Cd and from 10.8 to 29.5 mg kg−1 for Pb. Cadmium and Pb accumulations in shoots could reach 83.4 and 799 μg plant−1, respectively. The majority of translocation factors (TFs) for Cd (> 1.0) were higher than for Pb (≤ 1.0). However, concentrations of Cd and Pb in seeds were much lower, in the range of 0.04 to 0.21 mg kg−1 and 0.04 to 0.51 mg kg−1, respectively. The seed yields of oilseed rape varied from 1238 to 2904 kg ha−1, with a mean value of 2289 kg ha−1. Among the cultivars, three (OS-9, OS-12, and OS-15) were selected as Cd and Pb potential accumulators, with Cd accumulation in shoots being 2.74–3.70 times higher and Pb accumulation in shoots being 3.37–5.23 times higher as compared with the lowest accumulating cultivar. These selected cultivars (B. napus) have application potential for phytoextraction of Cd and Pb from polluted soils without stopping agricultural activities and accompanying food safety issues. [ABSTRACT FROM AUTHOR]

Despite the high specific capacities, the practical application of transition metal oxides as the lithium ion battery (LIB) anode is hindered by their low cycling stability, severe polarization, low initial coulombic efficiency, etc. Here, we report the synthesis of the NiO/Ni2N nanocomposite thin film by reactive magnetron sputtering with a Ni metal target in an atmosphere of 1 vol.% O2 and 99 vol.% N2. The existence of homogeneously dispersed nano Ni2N phase not only improves charge transfer kinetics, but also contributes to the one-off formation of a stable solid electrolyte interphase (SEI). In comparison with the NiO electrode, the NiO/Ni2N electrode exhibits significantly enhanced cycling stability with retention rate of 98.8% (85.6% for the NiO electrode) after 50 cycles, initial coulombic efficiency of 76.6% (65.0% for the NiO electrode) and rate capability with 515.3 mA·h·g−1 (340.1 mA·h·g−1 for the NiO electrode) at 1.6 A·g−1. [ABSTRACT FROM AUTHOR]

The concentration, distribution and pollution status caused by toxic metals, i.e. (Hg, Cd, Cr, Cu, Mn, Pb, Cd and Zn) were measured in sediments from two water reservoir (Tong reservoir and Yang reservoir) in southeast coastal area in China by using enrichment factor (EF), potential ecological risk index , total potential ecological risk (PER) and principal component analysis. Results showed that most of the sediment samples collected from both water reservoirs were moderately to heavily polluted by Cu, Cr, Cd, Hg, Pb and Zn. In Tong reservoir mean concentrations of the various toxic metals, i.e. (Hg, Cd, Cr, Cu, Mn, Pb and Zn) were 0.26, 1.64, 81.04, 46.68, 208.81, 88.43 and 165.27 mg kg−1, respectively while in Yang reservoir mean concentrations of the various toxic metals, i.e. (Hg, Cd, Cr, Cu, Mn, Pb and Zn) were 0.28, 0.51, 21.38, 24.44, 322.37, 47.72 and 70.84 mg kg−1, respectively. Results of EF showed that in Tong reservoir Cu, Hg and Pb ranged from moderately enrichment to moderately severe enrichment while Cr and Zn were in the range of moderately enrichment. Similarly, cadmium (Cd) was found in the range of severe enrichment. While in Yang reservoir; Cu, Cr, Pb and Zn has no enrichment but Cd and Hg were characterised as moderately enriched. Moreover, PER in Tong reservoir was ranged, 142.71–415.07 with an average of 234.67 in all the core sediments, which showed that PER of Tong reservoir is in the range of considerable risk. While total PER of Yang reservoir was in the range of moderate risk to considerable risk. Among both water reservoirs, sediments samples collected from the Tong reservoir were more contaminated than Yang reservoir. The extent of pollution caused by toxic metals in both water reservoirs indicates that condition is much alarming for biota and for residents in surrounding area of both reservoirs. Sediments samples of both reservoirs were extensively polluted by mainly two toxic metals, i.e. (Cd and Hg) while moderately less polluted by other toxic metals. Accumulation of Cd and Hg in both reservoirs was predominantly influenced by agricultural practices, human activities, residential run-off and soil erosion. [ABSTRACT FROM AUTHOR]

Purpose: Rapid industrialization in China accelerated environmental pollution by xenophores and trace metals particularly cadmium. Numerous studies have been conducted to address soil contamination using organic and inorganic amendments under pot or incubation conditions, but few were performed under field conditions, particularly in the wheat-growing areas. This study aims to investigate the effectiveness of pre-applied soil amendments for Cd immobilization, changes in soil pH, and metal uptake by wheat. Materials and methods: In this study, 12 treatments, i.e., control (CK), lime, DaSan Yuan (DASY), DiKang No. 1 (DEK1), biochar, Fe-biochar, Yirang, CaMgP, and green stabilizing agents (GSA-1, GSA-2, GSA-3, and GSA-4), were evaluated for Cd immobilization in incubation and field experiments. Changes in soil pH and available metal content with amendments were monitored from 30 to 150 days of incubation. Single extraction method and DTPA-extractable and sequential extraction procedures were employed to assess the variations in available Cd contents of field soil. The impact of soil amendments on Cd uptake and bioaccumulation in food part of wheat was measured at harvesting stage in a contaminated site. Results and discussion: Lime treatment increased soil pH by 32% and reduced available Cd to 0.213 mg kg−1, as compared to CK (control) in the incubation experiment (0.343 mg kg−1). Effects of the amendments on wheat growth, soil pH, and Cd phytoavailability were reported. Wheat biomass was highest in treatment GSA-2 (13,880 kg ha−1) and GAS-4 resulted in an increase in grain yield (5350 kg ha−1). Soil pH of the treated field at harvesting stage increased up to 6.50, 6.50, and 6.47 by application of GSA-4, GSA-2, and lime, respectively. Cadmium contents in wheat grain were declined significantly in the treatments of GSA-2, GSA-4, and lime. Conclusions: Results of this study revealed a significant decrease in available Cd concentration with the application of amendments. Composite amendments were more effective in terms of metal uptake and bioaccumulation in wheat. In addition, our results indicate the effectiveness of composite amendments in stabilizing Cd in contaminated soil. [ABSTRACT FROM AUTHOR]

Purpose: The increasing land application of sewage sludge and animal manure has accelerated the input of 17α-ethynylestradiol (EE2) into soils and environment, which would influence the health of vegetables and also the hormonal system of animals. In order to remove EE2 from soils, one possible option is bioremediation by using EE2-degrading microorganism or/and EE2-accumulating plants. The study attempted to isolate EE2-degrading microorganism from soils, and investigate the effect of this microorganism and/or organic pollutant removable plant Lolium perenne on the removal of EE2 from soil.Materials and methods: EE2-degrading bacteria Hyphomicrobium sp. GHH was obtained from farmland soil. Pot experiments were taken to investigate the inoculation of Hyphomicrobium sp. GHH, cultivation of L. perenne, and inoculation of Hyphomicrobium sp. GHH + cultivation of L. perenne on the EE2 removal from soil. The plant biomass, EE2 concentration in plant root and shoot, phytoremediation efficiency, and the soil urease activity and dehydrogenase activity were determined to evaluate the interaction of plant and microbe on EE2 removal from soil.Results and discussion: The inoculation of Hyphomicrobium sp. GHH significantly increased root length of L. perenne as well as EE2 concentrations in root and shoot (P < 0.05). On days 14, 28, and 42 after the treatment with l. perenne cultivation alone, the phytoextraction efficiency of EE2 was 16.5, 25.2, and 29.8%, respectively, while this phytoextraction efficiency was improved by 82.0, 44.0, and 41.0%, respectively, with the inoculation of Hyphomicrobium sp. GHH. On days 28 and 42, the combination of Hyphomicrobium sp. GHH with l. perenne removed 94.0 and 99.0% of EE2, respectively, from the soil. EE2 was mainly stored in the root of L. perenne, with all the translocation factor (TF) values < 1. The promoting effect of different treatments on the removal efficiency of EE2 decreased in the order: L. perenne + Hyphomicrobium sp. GHH > L. perenne alone > Hyphomicrobium sp. GHH. This was consistent with the changing trend of the activities of soil urease and dehydrogenase, indicating that plant cultivation stimulated the growth of rhizospheric microorganisms.Conclusions: Application of Hyphomicrobium sp. GHH in combination with L. perenne has great potential for remediating EE2-contaminated soil, and plant-microbe interaction has synergistic effect on the EE2 removal. [ABSTRACT FROM AUTHOR]

For various applications of negative temperature coefficient (NTC) thermistors, it is useful to develop a material system to achieve different room-temperature resistivities (ρ25) and temperature sensitivity (B value) by adjusting slightly the chemical composition. Here, B3+/Na+-modified NiO-based ceramics (denoted as xB/yNa-NiO, 0 ≤ x ≤ 0.04 and 0 ≤ y ≤ 0.07) were prepared for NTC thermistors. The phase component and microstructure of the ceramics were detected respectively by using X-ray diffraction and scanning electron microscope. The related electrical properties and temperature sensitivity were investigated by analyzing the resistivity-temperature characteristic and related complex impedance spectra. The results show that all the prepared ceramics have a cubic crystalline structure and present typical NTC characteristics. By changing the concentrations of B3+- and Na+-ions in the compounds, ρ25 from 47.94 Ω cm to 1.024 MΩ cm and B values from 2582 to 8019 K were achieved. The analysis of complex impedance spectra reveals that both grain effect and grain boundary effect contribute to the electrical conduction and NTC feature. The conduction mechanisms combining with band conduction and polaron hopping model are proposed for the NTC effect in xB/yNa-NiO thermistors. [ABSTRACT FROM AUTHOR]

Plant uptake of cadmium (Cd) is affected by soil and environmental conditions. In this study, hydroponic experiments were conducted to investigate the effects of elevated CO2 coupled with inoculated endophytic bacteria M002 on morphological properties, gas exchange, photosynthetic pigments, chlorophyll fluorescence, and Cd uptake of S. alfredii. The results showed that bio-fortification processes (elevated CO2 and/or inoculated with endophytic bacteria) significantly (p < 0.05) promoted growth patterns, improved photosynthetic characteristics and increased Cd tolerance of both ecotypes of S. alfredii, as compared to normal conditions. Net photosynthetic rate (Pn) in intact leaves of hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) were increased by 73.93 and 32.90%, respectively at the low Cd (2 μM), 84.41 and 57.65%, respectively at the high Cd level (10 μM). Superposition treatment increased Cd concentration in shoots and roots of HE, by 50.87 and 82.12%, respectively at the low Cd and 46.75 and 88.92%, respectively at the high Cd level. Besides, superposition treatment declined Cd transfer factor of NHE, by 0.85% at non-Cd rate, 17.22% at the low Cd and 22.26% at the high Cd level. These results indicate that elevated CO2 coupled with endophytic bacterial inoculation may effectively improve phytoremediation efficiency of Cd-contaminated soils by hyperaccumulator, and alleviate Cd toxicity to non-hyperaccumulator ecotype of Sedum alfredii. [ABSTRACT FROM AUTHOR]

The semiconductors based on simple oxide have unique features with controllable electrical property by element doping. Y3+ doped NiO (Ni1−xYxO, x ≤ 0.01) and Mg2+ substituted Ni0.995Y0.005O (Ni0.995−yY0.005MgyO, y ≤ 0.5) powders were synthesized by a wet chemical method. The related ceramics were obtained by conventional ceramic processing. Phase component, microstructure, electrical property and temperature sensitivity of the prepared ceramics were investigated. All ceramics have a rock‐salt type crystalline structure. The room‐temperature resistivity of the ceramics can be widely adjusted from 254 to 12 322 Ω·cm by changing the concentrations of Y3+ and Mg2+ ions. The samples show typical characteristics of negative temperature coefficient of resistivity and have high temperature sensitivity with material constants higher than 4745 K. The analysis of impedance spectra indicates that the electrical properties resulted from both grain effect and grain boundary effect. Both band conduction and small polaron hopping were proposed as possible conduction mechanisms in the studied ceramics. Y3+‐ion concentration dependence of B25/85 and ?25 in Y‐doped NiO (Ni1‐xYxO) ceramics, and the inset is the plots of Mg2+ concentration dependence of B25/85 and ?25 in Ni0.995‐yY0.005MgyO ceramics [ABSTRACT FROM AUTHOR]

The Mo modified MnFeO (MnFeMoO, x ≤ 0.05) powders were prepared by using a wet-chemical synthesis method and the related ceramics were obtained by a traditional ceramic sintering technology. The effect of Mo contents on the phase component and related electrical properties of the ceramics were investigated. The results show that the prepared ceramics have a spinel-type cubic crystalline structure, and show a typical characteristic of negative temperature coefficient (NTC) of resistivity. The thermal sensitivity constants are around 6100 K over a wide temperature range from 25 to 250 °C. The analysis of impedance spectra reveals that both grain effect and grain boundary effect contribute to the NTC feature. The conduction mechanisms for the ceramics are mainly proposed to be the electron hopping conduction inside the grains and the thermally activated charge carrier transport by overcoming the energy barrier for the grain boundary conduction. [ABSTRACT FROM AUTHOR]

Agricultural application of sewage sludge (SS) after carbonization is a plausible way for disposal. Despite its benefits of improving soil fertility and C sequestration, heavy metals contained in sewage sludge biochars (SSB) are still a concern. In this study, two types of heavy metal stabilizers were chosen: fulvic acid (FA) and phosphogypsum (with CaSO4, CS, as the main component). The two stabilizers were incorporated into SS prior to 350°C carbonization for 1 h at the rates of 1%, 2%, or 4%. The obtained SSBs were then analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Total and available concentrations of four heavy metals, i.e., Zn, Pb, Cd, and Ni, in the SSBs were determined. In addition, a series of pot soil culture experiments was conducted to investigate the effects of stabilizers incorporation into SSB on heavy metal bioavailability and the uptake by plants (corn as an indicator) and plant biomass yield, with SS and SSB (no stabilizers) as controls. The results showed that incorporation of both FA and CS increased functional groups such as carboxyl, phenol, hydroxyl, amine and quinine groups in the SSBs. The percentage of heavy metals in sulfuric and oxidizable state and residual state of SSBs were significantly increased after carbonization, and hence the mobility of the heavy metals in SSBs was decreased. The introduction of the stabilizers (i.e., FA or CS) significantly lowered the total and available concentrations of Zn, Pb, Cd, and Ni. The reduction in available heavy metal concentration increased with incorporation rate of the stabilizers from 1% to 4%. In the treatments with FA or CS incorporated SSB, less heavy metals were taken up by plants and more plant biomass yields were obtained. The mitigating effects were more pronounced at higher rates of FA or CS stabilizer. These findings provide a way to lower bioavailability of heavy metals in SS or SSB for land application or horticulture as a peat substitute. [ABSTRACT FROM AUTHOR]

Phytoremediation coupled with crop rotation (PCC) is a feasible strategy for remediation of contaminated soil without interrupting crop production. The objective of this study was to develop a PCC technology system for greenhouse fields co-contaminated with Cd and nitrate using hyperaccumulator Sedum alfredii. In this system, endophytic bacterium M002 inoculation, CO fertilization, and fermentation residue were continuously applied to improve the growth of S. alfredii, and low-accumulator Ipomoea aquatica and low-accumulator Brassica chinensis were rotated under reasonable water management. These comprehensive management practices were shown to increase S. alfredii biomass and Cd uptake and reduce Cd and nitrate concentration in I. aquatica and B. chinensis. This crop rotating system could remove 56.5% total Cd, 62.3% DTPA extractable Cd, and 65.4% nitrate, respectively, from the co-contaminated soil in 2 years of phytoremediation, and is an effective way of remediating moderately co-contaminated soil by Cd and nitrate. [ABSTRACT FROM AUTHOR]

Composts are considered one of major sources that contribute heavy metals to the environment. The objective of this study was to investigate historical changes and spatial variation of metal concentrations in Chinese composts by analysing representative compost samples and published data from 2002 to 2013. Mean concentrations of cadmium (Cd), chromium (Cr), lead (Pb), arsenic (As), mercury (Hg), zinc (Zn), nickel (Ni), and copper (Cu) in the composts were 2.42, 35.52, 32.38, 16.33, 0.32, 258.1, 9.71, and 72.24 mg kg, respectively. The percentages of samples with metal concentration exceeding critical levels of Chinese standards for organic fertilizers (NY525-2012) were 28.7, 18.3, 9.6, 1.7, and 0.9%, respectively, for Cd, As, Pb, Cr, and Hg. Modelling predicts that it would take 18, 24, 29, and 48 years for Cu, Zn, Hg, and Cd to reach Category I Environmental Capacity of China (GB15618-1995) according to current application rate. During the 2002-2013 period, concentration of Cd in composts tended to decrease with time, whereas those of Zn, Cu, and As were opposite, which is likely due to less or no control for these elements. Concentrations of Cu, Zn, As, and Cd were generally higher in composts from the economically developed regions in China, where more commercial farms were built that use metal-spiked feeds. Manures from the commercial farms generally had higher metal concentration, as compared to the subsistence farms. Further research is needed to monitor metal concentrations from source materials to composts and assess long-term impact of compost application on soil quality. [ABSTRACT FROM AUTHOR]