•Establishing a risk analysis model for multi-objective flood control operation of a complex reservoir system coupling multi-dimensional uncertainties.•Introducing the initial water level uncertainty ...to risk analysis for multi-reservoir operation.•Using copula theory to describe the correlation of the errors of reservoir initial water levels and the time-space correlation of flood forecast errors.
Many uncertainties are involved in flood control operation of a multi-reservoir system and result in risks for the system. Risk analysis for reservoir flood control operation is essential for decision making. Traditional flood control risk analysis only takes flood forecast error as the main risk source, ignoring the influence of dynamic control of flood-limited water level on reservoir initial water level for flood regulation. In this study, the spatial correlation of reservoir initial water level errors and the spatiotemporal correlation of flood forecast errors are identified via copula function. A risk analysis model considering both upstream and downstream is established for multi-objective flood control operation of a complex reservoir system, coupling multi-dimensional uncertainties of reservoir initial water levels, flood forecast errors, reservoir capacity curve errors, reservoir discharge curve errors and river flood routing errors. The impact of multiple risk sources with spatiotemporal correlations on reservoir flood control operation is then evaluated and the competitive tradeoff between flood control risks in upstream and downstream analyzed. The model is applied to a mixed four-reservoir system in Pi River Basin in China. Results indicated that 1) there is a strong correlation between the reservoir initial water level errors in space and also between the flood forecast errors in space and time, which can be effectively described by copula function, and ignoring the correlations will underestimate the flood control risk; 2) the two objective values of upstream and downstream show a clear competitive relationship, and the solution that prefers one objective has low risk marginal benefit, thus choosing a compromise solution can balance risks; 3) coupling the initial water level uncertainty reduces the flood control risk caused by the flood forecast errors to a certain extent, but also lead to the increase of extreme risk loss.
Heparin, including unfractionated heparin (UFH), low-molecular-weight heparin (LMWH) and heparin derivatives, are commonly used in venous thromboembolism treatment and reportedly have beneficial ...effects on cancer survival. Heparin can affect the proliferation, adhesion, angiogenesis, migration and invasion of cancer cells via multiple mechanisms. The main mechanisms involve inhibition of heparanase, P-/L-selectin, angiogenesis, and interference with the CXCL12-CXCR4 axis. Here we summarize the current experimental evidence regarding the anti-cancer role of heparin and its derivatives, and conclude that there is evidence to support heparin's role in inhibiting cancer progression, making it a promising anti-cancer agent.
•Establishing a stochastic programming model for floodwater utilization of a complex multi-reservoir system.•Decomposing the system into four basic subsystems and identifying the excess storage for ...each subsystem.•Integrating risk constraints into the aggregation-decomposition method.•Introducing risk hedging to offset the risks between reservoirs.
Floodwater utilization through dynamic operating flood limited water levels (FLWLs) of reservoirs plays an important role in flood control and water conservation. This study proposes a risk-based aggregation-decomposition method for floodwater utilization of a complex multi-reservoir system. The original system is decomposed into four basic configurations. For the subsystem with hydraulic connections, the upper bound of FLWL of each reservoir is identified based on a given risk level for the subsystem and risk hedging between reservoirs. A stochastic programming model to maximize hydropower generation is then established for joint operation of the multi-reservoir system to find and update the optimal operation strategy during flood seasons. The mixed cascade reservoirs in the Pi River Basin are selected as a case study. The application results are compared with those of the original design model and deterministic operation model without considering risk, which shows that joint operation and dynamic control of FLWLs: 1) significantly increases the power generation and improves the utilization rate of floodwaters compared to those of the original design model; 2) power production rate increases with the acceptable risk but the increasing rate between them decreases with higher levels of risk; 3) results in lower utilization rate of floodwaters compared to that of the deterministic model, but the difference is not significant. The proposed method provides a framework for risk-based decision-making in floodwater utilization to enhance the comprehensive benefits of a multi-reservoir system.
Motivation: Information from fully sequenced genomes makes it possible to reconstruct strain-specific global metabolic network for structural and functional studies. These networks are often very ...large and complex. To properly understand and analyze the global properties of metabolic networks, methods for rationally representing and quantitatively analyzing their structure are needed. Results: In this work, the metabolic networks of 80 fully sequenced organisms are in silico reconstructed from genome data and an extensively revised bioreaction database. The networks are represented as directed graphs and analyzed by using the‘ breadth first searching algorithm to identify the shortest pathway (path length) between any pair of the metabolites. The average path length of the networks are then calculated and compared for all the organisms. Different from previous studies the connections through current metabolites and cofactors are deleted to make the path length analysis physiologically more meaningful. The distribution of the connection degree of these networks is shown to follow the power law, indicating that the overall structure of all the metabolic networks has the characteristics of a small world network. However, clear differences exist in the network structure of the three domains of organisms. Eukaryotes and archaea have a longer average path length than bacteria. Availability: The reaction database in excel format and the programs in VBA (Visual Basic for Applications) are available upon request. Supplementary Material: Bioinformatics Online. Contact: aze@gbf.de; hwm@gbf.de * To whom correspondence should be addressed.
•A deep convolutional generative adversarial network (DCGAN) combined with Wasserstein generative adversarial network (WGAN) called DC-WGAN is proposed as a runoff generation model.•A runoff ...generation method based on Copula function is developed.•The applicability of DC-WGAN in the field of runoff stochastic generation for a reservoir system is verified.•The spatial–temporal correlation of runoff samples of DC-WGAN compared with the Copula function is analyzed.
The implicit stochastic optimization (ISO) model is a methodology that has been extensively employed in the mid-long term optimal operation of a reservoir system. The generation of runoff series is the key technology to make up for the poor representativeness and reliability of historical runoff samples and is the premise to guarantee the accuracy of the ISO model. However, the traditional methods are not suitable for the stochastic generation of runoff series, among reservoirs with spatial–temporal correlation. In this work, the generative adversarial network called DC-WGAN is developed as a runoff generation model. DC-WGAN is based on a data-driven model and can capture the correlation of runoff series in time and space dimensions simultaneously. The proposed method is applied to the downstream Jinsha river cascade and Three Gorges cascade reservoirs in China to generate ten-day runoff series and is compared with the stochastic generation method based on Copula function. The focus of this paper is the model's performance in replicating the spatial–temporal correlation of ten-day runoff series. Results are as follows. (1) DC-WGAN has strong learning and generalization ability, which can learn the correct distribution of original runoff samples and generate runoff series similar to that from the validation set. (2) The runoff series among reservoirs with spatial–temporal correlation can be generated through DC-WGAN without assuming the probability distribution of samples in advance. (3) DC-WGAN is better than Copula function in capturing the spatial–temporal correlation, especially the moderate and weak correlation. The proposed methodology has a high practical value and application prospect for the stochastic generation of runoff series with spatial–temporal correlation.
Due to the wide use of atrazine (ATR), the concern has increased regarding the negative impact of ATR on reproduction. Nevertheless, the reproductive effects caused by different exposure ...concentrations and the severity of toxic damage are poorly understood. In organisms, ATR is metabolized and degraded through phase II enzyme systems, and changes in cytochrome P450 (CYP) enzymes may have a regulatory role in the harm of ATR. However, less information is available on the induction of CYPs by ATR in avian organisms, and even less on its effects on the testis. Birds are exposed to ATR mainly through food residues and contaminated water, the purpose of this study was to examine reproductive toxicity by different exposure concentrations and elaborate metabolic disorders caused by ATR in European quail (Coturnix coturnix). In this study, the quail were given ATR at 50 mg/kg, 250 mg/kg and 500 mg/kg by oral gavage for 45 days, and the testicular weight coefficients, histopathology and ultrastructure of testes, primary biochemical functions, sex steroid hormones, critical protein levels in the testosterone synthesis pathway, the expression of genes involved CYPs, gonad axis and nuclear receptors expression were investigated. Altogether, testicular coefficient decreased significantly in the high-dose group (1.22%) compared with the control group (3.03%) after 45 days of ATR exposure, and ATR is a potent CYP disruptor that acts through the NXRs and steroid receptor subfamily (APND, CAR, ERND and ERα) without a dose-dependent manner. Notably, ATR interfered with the homeostasis of hormones by triggering the expression of hormones on the gonad axis (LH and E2). These results suggest that exposure to ATR can cause testicular toxicity involving accommodative disorder of phase II enzyme and testosterone synthesis in European quail.
The streamflow process is an crucial information resource for the joint optimal operation of reservoirs. As the length and representativeness of historical streamflow samples are insufficient for ...practice projects, streamflow stochastic generation approaches are usually used to expand the streamflow series. For the joint operation and management of the multi-reservoir system, the multisite streamflow stochastic generation (MSSG) with high-dimensional temporal-spatial correlation poses a challenge. This paper develops the generative adversarial network as a novel MSSG model. In contrast to the existing literature on MSSG, which solely focuses on a specific case study and provides a comparatively one-sided assessment, this paper evaluates multiple characteristics of streamflow at various time scales from three MSSG models in two instances. Specifically, three MSSG models, namely the seasonal autoregression (SAR) model coupled with the master station method, the Copula model coupled with the master station method, and the deep convolutions generative adversarial network (DCGAN) model, are employed to generate monthly, ten-daily, and daily streamflow series of the two-reservoir and eight-reservoir systems. This study aims to examine the performance of three models and provide recommendations for implementing MSSG approaches in practice. Results show that: (1) the priority should be given to the maximum iterations on the DCGAN model at a large time scale, while at a smaller time scale, the training of the model is directly linked to the setting of batch size; (2) the Copula model is capable for better retaining statistical characteristics of streamflow series for similarity; (3) the SAR model excels in simulating the extremes of streamflow; and (4) the DCGAN model possesses a significant advantage in capturing the temporal-spatial higher-order correlation, especially in systems comprising more than two reservoirs and with small time scales (e.g., daily streamflow). Furthermore, this study presents comprehensive and multi-scale recommendations for selecting MSSG approaches, thereby providing a theoretical foundation and practical value for MSSG in diverse scenarios.
We show a new method to differentiate conductivities from the surface states and the coexisting bulk states in topological insulators using a four-probe transport spectroscopy in a multiprobe ...scanning tunneling microscopy system. We derive a scaling relation of measured resistance with respect to varying interprobe spacing for two interconnected conduction channels to allow quantitative determination of conductivities from both channels. Using this method, we demonstrate the separation of 2D and 3D conduction in topological insulators by comparing the conductance scaling of Bi2Se3, Bi2Te2Se, and Sb-doped Bi2Se3 against a pure 2D conductance of graphene on SiC substrate. We also quantitatively show the effect of surface doping carriers on the 2D conductance enhancement in topological insulators. The method offers a means to understanding not just the topological insulators but also the 2D to 3D crossover of conductance in other complex systems.
Monodisperse poly(acrylic acid)‐modified Fe3O4 (PAA@Fe3O4) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated. The PAA polymer was encapsulated into the ...inner cavity of Fe3O4 hollow spheres by a vacuum‐casting route and photo‐initiated polymerization. TEM images show that the samples consist of monodisperse porous spheres with a diameter around 200 nm. The Fe3O4 spheres, after modification with the PAA polymer, still possess enough space to hold guest molecules. We selected doxorubicin (DOX) as a model drug to investigate the drug loading and release behavior of as‐prepared composites. The release of DOX molecules was strongly dependent on the pH value due to the unique property of PAA. The HeLa cell‐uptake process of DOX‐loaded PAA@Fe3O4 was observed by confocal laser scanning microscopy (CLSM). After being incubated with HeLa cells under magnet magnetically guided conditions, the cytotoxtic effects of DOX‐loaded PAA@Fe3O4 increased. These results indicate that pH‐responsive magnetic PAA@Fe3O4 spheres have the potential to be used as anticancer drug carriers.
Dual response: Monodisperse poly(acrylic acid)‐modified Fe3O4 (PAA@Fe3O4) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated (see figure). The drug release behavior was strongly dependent on pH value due to the unique properties of PAA. Furthermore, doxorubicin (DOX)‐loaded PAA@Fe3O4 composites show an enhanced magnetically guided anticancer effect.
The prevention of fungal proliferation in postharvest grains is critical for maintaining grain quality and reducing mycotoxin contamination. Fumigation with natural gaseous fungicides is a promising ...and sustainable approach to protect grains from fungal spoilage. In this study, the antifungal activities of (
E
)-2-alkenals (C
5
-C
10
) on
Aspergillus flavus
were tested in the vapor phase, and (
E
)-2-heptenal showed the highest antifungal activity against
A. flavus
. (
E
)-2-Heptenal completely inhibited
A. flavus
growth at 0.0125 µL/mL and 0.2 µL/mL in the vapor phase and liquid contact, respectively. (
E
)-2-Heptenal can disrupt the plasma membrane integrity of
A. flavus
via leakage of intracellular electrolytes. Scanning electron microscopy indicated that the mycelial morphology of
A. flavus
was remarkably affected by (
E
)-2-heptenal. Metabolomic analyses indicated that 49 metabolites were significantly differentially expressed in
A. flavus
mycelia exposed to 0.2 µL/mL (
E
)-2-heptenal; these metabolites were mainly involved in galactose metabolism, starch and sucrose metabolism, the phosphotransferase system, and ATP-binding cassette transporters. ATP production was reduced in (
E
)-2-heptenal-treated
A. flavus
, and Janus Green B staining showed reduced cytochrome
c
oxidase activity. (
E
)-2-Heptenal treatment induced oxidative stress in
A. flavus
mycelia with an accumulation of superoxide anions and hydrogen peroxide and increased activities of superoxide dismutase and catalase. Simulated storage experiments showed that fumigation with 400 µL/L of (
E
)-2-heptenal vapor could completely inhibit
A. flavus
growth in wheat grains with 20% moisture; this demonstrates its potential use in preventing grain spoilage. This study provides valuable insights into understanding the antifungal effects of (
E
)-2-heptenal on
A. flavus
.
Key points
•
(E)-2-Heptenal vapor showed the highest antifungal activity against A. flavus among (C
5
-C
10
) (E)-2-alkenals
.
•
The antifungal effects of (E)-2-heptenal against A. flavus were determined
.
•
The antifungal actions of (E)-2-heptenal on A. flavus were revealed by metabolomics and biochemical analyses
.
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