The locational marginal price (LMP) methodology has been discussed for distribution networks/systems under the smart grid initiative. In this paper, a new distribution LMP (DLMP) formulation is ...presented which includes reactive power prices and voltage constraints. To solve DLMP, three modeling tools, namely, linearized power flow for distribution (LPF-D), loss factors for distribution (LF-D), and linear optimal power flow for distribution (LOPF-D) are proposed. LPF-D solves not only voltage angles but also magnitudes through linear expression between bus injections and bus voltages, specifically for distribution systems. LF-D is solved recursively based on the radial topology of typical distribution systems. With the integration of LPF-D and LF-D, conventional optimal power flow (OPF) can be reformulated as LOPF-D which is essentially a linear programming model. Test results on various systems show that: 1) LPF-D efficiently yields very close results if compared with AC power flow; 2) LOPF-D provides very close dispatch results in both real and reactive power if compared with ACOPF; and 3) the proposed DLMPs calculated with LF-D and LOPF-D give accurate price information if compared with the prices from ACOPF. Further, these three tools are not limited to DLMP but can be potentially applied to other distribution analyses.
•Current knowledge on pyrethroids in sediment is reviewed on a global scale.•Toxicity of sediment-associated pyrethroids to benthic invertebrates is evaluated.•Potential risk of pyrethroids to ...benthic community is simulated based on SQC.•Sediment-bound pyrethroids exhibited potential risk to benthic organisms globally.•Factors influencing sediment risk assessment of pyrethroids is discussed.
Pyrethroids are the third most applied group of insecticides worldwide and are extensively used in agricultural and non-agricultural applications. Pyrethroids exhibit low toxicity to mammals, but have extremely high toxicity to fish and non-target invertebrates. Their high hydrophobicity, along with pseudo-persistence due to continuous input, indicates that pyrethroids will accumulate in sediment, pose long-term exposure concerns to benthic invertebrates and ultimately cause significant risk to benthic communities and aquatic ecosystems. The current review synthesizes the reported sediment concentrations of pyrethroids and associated toxicity to benthic invertebrates on a global scale. Geographically, the most studied area was North America, followed by Asia, Europe, Australia and Africa. Pyrethroids were frequently detected in both agricultural and urban sediments, and bifenthrin and cypermethrin were identified as the main contributors to toxicity in benthic invertebrates. Simulated hazard quotients (HQ) for sediment-associated pyrethroids to benthic organisms ranged from 10.5±31.1 (bifenthrin) to 41.7±204 (cypermethrin), suggesting significant risk. The current study has provided evidence that pyrethroids are not only commonly detected in the aquatic environment, but also can cause toxic effects to benthic invertebrates, and calls for better development of accurate sediment quality criteria and effective ecological risk assessment methods for this emerging class of insecticides.
This study aimed to explore how cold acclimation (CA) modulates cold stress in tobacco leaves and reveal the relationship between CA and cold stress resistance, and the mechanism of CA-induced plant ...resistance to cold stress. This study examined the effects of CA treatment (at 8-10℃ for 2 d) on the cold tolerance of tobacco leaves under 4°C cold stress treatment using seedlings without CA treatment as the control (NA). In both CA and NA leaves, cold stress treatment resulted in a decrease in maximum photochemical efficiency of PSII (F
v
/F
m
), increase in relative variable fluorescence (V
J
) at 2 ms on the standardized OJIP curve, inhibition of PSII activity, and impairment of electron transfer on the acceptor side. Besides increasing the malondialdehyde (MDA) content and electrolyte leakage rate, the cold stress exacerbated the degree of membrane peroxidation. The CA treatment also induced the accumulation of reactive oxygen species (ROS), including superoxide anion (O
2
·
−
) and H
2
O
2,
and increased the activities of antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbic acid peroxidase (APX). The CA treatment also enhanced the accumulation of soluble sugar (SS) and soluble protein (SP), cyclic electron flow (CEF), and the proportion of regulatory energy dissipation Y(NPQ). Moreover, CA+ cold stress treatment significantly reduced CEF and Y(NPQ) in tobacco leaves than under NA+ cold stress treatment, thus significantly alleviating the degree of PSII photoinhibition. In conclusion, CA treatment significantly alleviated PSII photoinhibition and oxidative damage in tobacco leaves under cold stress treatment. Improvement in cold resistance of tobacco leaves is associated with the induction of antioxidant enzyme activity, accumulation of osmoregulation substances, and initiation of photoprotective mechanisms.
Influenza A virus (IAV) has evolved various strategies to counteract the innate immune response using different viral proteins. However, the mechanism is not fully elucidated. In this study, we ...identified the PB1 protein of H7N9 virus as a new negative regulator of virus- or poly(I:C)-stimulated IFN induction and specifically interacted with and destabilized MAVS. A subsequent study revealed that PB1 promoted E3 ligase RNF5 to catalyze K27-linked polyubiquitination of MAVS at Lys362 and Lys461. Moreover, we found that PB1 preferentially associated with a selective autophagic receptor neighbor of BRCA1 (NBR1) that recognizes ubiquitinated MAVS and delivers it to autophagosomes for degradation. The degradation cascade mediated by PB1 facilitates H7N9 virus infection by blocking the RIG-I-MAVS-mediated innate signaling pathway. Taken together, these data uncover a negative regulatory mechanism involving the PB1-RNF5-MAVS-NBR1 axis and provide insights into an evasion strategy employed by influenza virus that involves selective autophagy and innate signaling pathways.
Step changes in the curve of locational marginal prices (LMP) under load variation have been known characteristics given its present formulation. Identifying LMP intervals under wind uncertainty is ...important for market participants to assess and mitigate their risks when price forecast is needed. This work proposes a bi-level optimization model to calculate the LMP intervals under wind uncertainty without the repetitive Monte Carlo (MC) simulation. The specific bus LMP maximization (or minimization) is the upper level problem, while the ISO's economic dispatch is the lower level problem. Case studies are presented to demonstrate the proposed methodology.
A novel aptamer-based label-free assay for sensitive and selective detection of ATP was developed. This assay employs a new aptamer/fluorescent probe system that shows resistance to exonuclease I ...(Exo I) digestion upon binding to ATP molecules. In the absence of ATP, the complex between the ATP-binding aptamer (ATP–aptamer) and a DNA binding dye, berberine, is digested upon the addition of exonuclease I, leading to the release of berberine into solution and consequently, quenched berberine fluorescence. In the presence of ATP, the ATP-binding aptamer folds into a G-quadruplex structure that is resistant to Exo I digestion. Accordingly, berberine is protected in the G-quadruplex structure and high fluorescence intensity is observed. As such, based on the fluorescence signal change, a label-free fluorescence assay for ATP was developed. Factors affecting the analysis of ATP including the concentration of ATP-binding aptamer, reaction time, temperature and the concentration of Exo I were comprehensively investigated. Under optimal conditions, the fluorescence intensity of the sensing system displayed a response for ATP in a wide range up to 17.5mM with a detection limit of 140nM.
•Biosensing ATP with a new berberine/exonuclease I probe system is demonstrated.•Exonuclease I is used to recognize and digest ATP-bound aptamers.•The aptasensor gives low background unparalleled by non-enzyme-based assays.•Sensitive and selective detection of ATP is achieved.•A response for ATP in a wide range from 0.5μM to 17.5mM is obtained.
Extensive use of neonicotinoid insecticides has raised great concerns about their ecological risk. A reliable method to measure trace neonicotinoids in complicated aquatic environment is a premise ...for assessing their aquatic risk. To effectively remove matrix interfering substances from field water samples before instrumental analysis with HPLC/MS/MS, a multi-sorbent solid phase extraction method was developed using Box-Behnken design. The optimized method employed 200mg HLB/GCB (w/w, 8/2) as the sorbents and 6mL of 20% acetone in acetonitrile as the elution solution. The method was applied for measuring neonicotinoids in water at a wide range of concentrations (0.03–100μg/L) containing various amounts of matrix components. The recoveries of acetamiprid, imidacloprid, thiacloprid and thiamethoxam from the spiked samples ranged from 76.3% to 107% while clothianidin and dinotefuran had relatively lower recoveries. The recoveries of neonicotinoids in water with various amounts of matrix interfering substances were comparable and the matrix removal rates were approximately 50%. The method was sensitive with method detection limits in the range of 1.8–6.8ng/L for all target neonicotinoids. Finally, the developed method was validated by measurement of trace neonicotinoids in natural water.
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•A SPE-HPLC/MS/MS method for measuring trace neonicotinoids in water were established.•Box-Behnken design was applied to optimize the extraction conditions.•The use of multi-sorbent of HLB/GCB effectively reduced matrix substances.•Recovery was from 76.3% to 107% for neonicotinoids in a wide concentration range.
The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air–water flux, ...including air–water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air–water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data.
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•Transport fluxes of chlorpyrifos and pyrethroids were assessed in Guangzhou, China.•Sediment acted as a sink for chlorpyrifos and pyrethroids.•Air-to-water transport decreased the exposure risk of atmospheric chlorpyrifos.•Dynamic transport might increase the risk of pyrethroids in air and sediment.•Flux-based pesticide concentrations provide a way to estimate sediment toxicity.
Regional risk assessment could be improved by integrating dynamic flux information derived from inter-compartmental models.
The soil environment is responsible for sustaining most terrestrial plant life, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. ...Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere, and how it responds to agricultural management such as crop rotations and soil tillage, is vital for improving global food production.
This study establishes an in-depth soil microbial gene catalogue based on the living-decaying rhizosphere niches in a cropping soil. The detritusphere microbiome regulates the composition and function of the rhizosphere microbiome to a greater extent than plant type: rhizosphere microbiomes of wheat and chickpea were homogenous (65-87% similarity) in the presence of decaying root (DR) systems but were heterogeneous (3-24% similarity) where DR was disrupted by tillage. When the microbiomes of the rhizosphere and the detritusphere interact in the presence of DR, there is significant degradation of plant root exudates by the rhizosphere microbiome, and genes associated with membrane transporters, carbohydrate and amino acid metabolism are enriched.
The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the detritusphere microbiome in determining the metagenome of developing root systems. Modifications in root microbial function through soil management can ultimately govern plant health, productivity and food security.
The purpose of this study was to assess the effectiveness of intervention with Yingyangbao (YYB) on hemoglobin (Hb) and anemia status among infants and young children (IYC) aged 6-23 months (mo) ...through a large-scale Nutrition Improvement Program for Children in Poor Areas (NIPCPA) in China from 2015 to 2020. Five rounds of cross-sectional surveys were conducted using a stratified and multi-stage probability proportional to size sampling of IYC in 2015, 2017, 2018, 2019 and 2020. Multivariable regression analyses were fitted to determine the effectiveness of the YYB intervention on Hb and anemia, respectively. A total of 36,325, 40,027, 43,831, 44,375 and 46,050 IYC aged 6-23 mo were included, and the prevalence of anemia was 29.7%, 26.9%, 24.1%, 21.2% and 18.1% in 2015, 2017, 2018, 2019 and 2020, respectively. Compared with the results in 2015, the Hb concentrations significantly improved and anemia prevalence significantly decreased among IYC in 2017, 2018, 2019, and 2020 (
< 0.001). Regression analysis showed that higher YYB consumption was significantly associated with the increment in Hb concentration and reduction in anemia stratified by age group (
< 0.001). The most significant increment in Hb concentration of 2.189 mg/L and the most significant reduction in odds of anemia were observed among IYC aged 12-17 mo who consumed 270 to 359 sachets of YYB (OR: 0.671; 95% CI: 0.627, 0.719;
< 0.001). This study suggests that YYB intervention is a successful public health strategy for reducing the risk of anemia among IYC when delivered through a large-scale NIPCPA in China. It is necessary to continue to advance the program and increase the adherence of YYB.
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