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Abstract Ionic memristors can emulate brain‐like functions of biological synapses for neuromorphic technologies. Apart from the widely studied excitatory‐excitatory and excitatory‐inhibitory synapses, reports on memristors with the inhibitory‐inhibitory synaptic behaviors remain a challenge. Here, the first biaxially inhibited artificial synapse is demonstrated, consisting of a solid electrolyte and conjugated microporous polymers bilayer as neurotransmitter, with the former serving as an ion reservoir and the latter acting as a confined transport. Due to the migration, trapping, and de‐trapping of ions within the nanoslits, the device poses inhibitory synaptic plasticity under both positive and negative stimuli. Remarkably, the artificial synapse is able to maintain a low level of stable nonvolatile memory over a long period of time (≈60 min) after multiple stimuli, with feature‐inferencing/‐training capabilities of neural node in neuromorphic computing. This work paves a reliable strategy for constructing nanochannel ionic memristive materials toward fully inhibitory synaptic devices.

BackgroundPassive safety system reliability is generally evaluated through best estimation plus uncertainty (BEPU) analysis. An important step in the evaluation process is sensitivity analysis of parameters, which is used to identify key system parameters to reduce the complexity of the model. However, local sensitivity analysis methods based on linear or monotonic assumptions may yield incorrect sensitivity results for complex nuclear power systems. Meanwhile, applying the global sensitivity method is difficult in practical engineering because of its high calculation cost.PurposeThis study aims to develop an efficient and low-cost global sensitivity analysis method for passive systems under ocean conditions.MethodsFirstly, the low-rank approximation (LRA) method was employed to improve the Sobol method based on Monte Carlo simulation. The number of unknown coefficients was significantly reduced by using the multivariate-based tensor product. Then, the LRA coefficients were used to calculate the sensitivity index, and the validity of the proposed method was verified by addressing several sensitivity analysis benchmark questions. Finally, taking an integrated pressurized water reactor including the passive residual heat removal system as the object, a simulation program for thermal-hydraulics analysis under ocean conditions was developed. And its sensitivity analysis was conducted using the proposed method.ResultsThe results show that the proposed method can accurately identify system key parameters after only 200 simulation calculations taking about 55 min, and the sensitivity ranking results are consistent with those obtained by Sobol method after 1.0×105 simulation calculations taking about 19 d.ConclusionsThe efficient global sensitivity analysis method established in this study can provide effective guidance for reliability analysis and design optimization of passive systems.

Abstract Background The Mindray BC-6800 haematology analyzer (BC-6800) provides a dedicated flag ‘Infected RBC’ (InR) and the number of InR (InR#)/the permillage of InR (InR‰) in routine blood testing as a screening tool for malaria in endemic areas. This study sought to evaluate the effectiveness of the BC-6800 flag parameter for aiding the diagnosis of malaria. Methods A total of 181 samples were tested using the Mindray BC-6800 haematology analyzer, including 117 malaria-infected samples collected from Yunnan, China, and 64 samples from healthy controls. Microscopy examination was conducted as reference when stained thick blood film revealed the presence of malaria parasites identified as Plasmodium vivax and Plasmodium falciparum. The receiver operating characteristic (ROC) curve analysis was developed using Analyse-it v4.92.3. The Kappa value was determined to evaluate the agreement between BC-6800 and light microscopy. Results The sensitivity of InR‰ generated by BC-6800 for P. vivax and P. falciparum was 88.3 and 24.1%, respectively; specificity of InR‰ for malaria parasites was 84.3 and 84.3%, respectively; positive predictive value and negative predictive value was 89.4 and 82.7% for P. vivax, and 52.8 and 60.3% for P. falciparum. There was a strong correlation between ΔWBC and InR‰ (R2 = 0.9731 for P. vivax and R2 = 0.9757 for P. falciparum). There was also a significant correlation between parasitaemia and InR# in P. vivax-infected samples (R2 = 0.734). InR# was evaluated using ROC curve analysis, the area under the ROC curve is 0.95 with a 95% confidence interval of 0.926 to 0.974, and the cut-off value is 0.01 × 109/L for P. vivax. However, the ring stage and the early trophozoite stage of Plasmodium cannot be detected easily on BC-6800, possibly because of the small size and low nucleic acid content of these stages. Conclusions The findings suggest that the flag ‘InR’ and the parameters ‘InR#/InR‰’ provided by the BC-6800 haematology analyzer could be used to screen for malaria in a clinical setting.

The electrochemical behavior of the chalcocite oxidation process in the presence and absence of microorganisms was investigated using electrochemical techniques, including cyclic voltammetry, anodic polarization curves, Tafel curves, and X-ray photoelectron spectroscopy (XPS) analysis. The research results prove the stepwise dissolution mechanism of chalcocite in the presence and absence of microorganisms. The initial stage of oxidation is initiated at low redox potentials. During the initial stage, the intermediate products of CuxS (1 ≤ x via XPS. The XPS analysis results show that the components of the passivation layer on the electrode surface are complex, including CuS, polysulfide (Sn2-), elemental sulfur (S0) and intermediate oxidation products that contain sulfate (SO42-) and that CuS is the main passivating component; therefore, the oxidation of chalcocite follows the multisulfur method.

A bottleneck occurs in the application of bioleaching technology to fluoride-containing ore. The reason for this is that fluorine has a strong inhibitory effect on leaching bacteria with the dissolution of fluorine-containing gangue minerals. In this study, we use the chemical properties of fluorine to convert F ions by adding substances that can form stable complexes with F-, which enables the leaching bacteria to tolerate high fluoride environments. In this research, we studied the inhibition mechanism of fluorine on bacteria, and identified its true toxic form (HF). We found that fluoride exhibited a transmembrane inhibitory effect on bacteria. Under fluoride stress conditions, the concentration of intracellular fluoride was significantly higher than that of a non-fluorinated control group, which was about 18% dry cell. We selected common Fe3+ ions in the bioleaching system, and studied the competitive complex detoxification of Fe3+ to F-. Our thermodynamic analysis results show that Fe3+ can compete with HF in first-order competitive complexation reactions whereby the HF complex structure is converted to FeFn3-n. In the presence of ferric ions, we found that the bacteria could tolerate F-concentrations up to 1.0 g·L-1. Our analysis of the Fe and F complex species indicates that bacteria could grow normally when the concentration of Fe3+ ions was five times greater than that of F- ions. Correspondingly, the proportion of FeF2+ components in the solution was ≥ 45%, and the concentration of free fluoride was 2.87×10-5 mol·L-1. The complexation mechanism shows that as the ratio of F--Fe3+ decreases, the concentration of the ligand is relatively lower. Based on the coordination chemistry, the complex of fluoride and iron moves in a lower coordination direction, and the Fe and F complex species can be controlled by adjusting the concentration ratio of F- and Fe3+ in the medium, therefore making it possible for bacteria to grow in a high-fluorine environment.

The preparation of high-quality iron concentrate from pyrite cinder by means of desulphurization has potential industrial applications. On one hand, the comprehensive utilization of pyrite cinder can be achieved, while on the other hand, the environmental problems that it causes can be solved effectively. In this study, the desulfurization technology and its process flowsheet, as well as recent advances, were summarized in detail. There are mainly three desulfurization methods, namely, chemical leaching, combined process, and bioleaching method. Chemical leaching mainly involves the acid leaching and alkali leaching processes. The combined process contains the alkali-acid leaching process, flotation-magnetic separation, gravity separation-flotation, magnetic roasting-magnetic separation, etc. The technical features of these methods were introduced, and it is concluded that bioleaching has a potential application value. The research areas of bioleaching method in a future will be included as:the breeding of effective desulfurization bacteria, cyclic utilization of desulfurization water, synergistic recovery of valuable metals, and basic investigation and engineering technology research in the bioleaching desulfurization process.

Agglomeration technology is one of the most effective measures to enhance the poor heap permeability of ores caused by the presence of fine particles. Selecting the proper acid resistant binder is key to the successful heap leaching of copper ore. The agglomeration of oxide-sulfide mixed copper ore was studied in this paper, and results show that Biometek-WLAG001 is an ideal acid resistant binder. The effects of binder amount, water spray amount, rotational speed, curing time, aging acid addition amount, and aging time on the compressive and wet strengths of agglomerated pellets were investigated in single-factor experiments. The effects of binder amount, curing time, aging acid addition amount, and aging time on the wet strength of agglomerated pellet were further studied via a response surface methodology, and results were optimized and analyzed by Design-Expert 8.0 software. The interaction mechanism between the binder and the ore was investigated by Fourier transform infrared spectroscopy analysis and Zeta potential measurements. Results reveal that the binder and ore undergo chemical adsorption but not electrostatic attraction.

Sucrose is a commonly utilized nutritive sweetener in food and beverages due to its abundance in nature and low production costs. However, excessive intake of sucrose increases the risk of metabolic disorders, including diabetes and obesity. Therefore, there is a growing demand for the development of nonnutritive sweeteners with almost no calories. d‐Allulose is an ultra‐low‐calorie, rare six‐carbon monosaccharide with high sweetness, making it an ideal alternative to sucrose. In this study, we developed a cell factory for d‐allulose production from sucrose using Escherichia coli JM109 (DE3) as a chassis host. The genes cscA, cscB, cscK, alsE, and a6PP were co‐expressed for the construction of the synthesis pathway. Then, the introduction of ptsG‐F and knockout of ptsG, fruA, ptsI, and ptsH to reprogram sugar transport pathways resulted in an improvement in substrate utilization. Next, the carbon fluxes of the Embden‐Meyerhof‐Parnas and the pentose phosphate pathways were regulated by the inactivation of pfkA and zwf, achieving an increase in d‐allulose titer and yield of 154.2% and 161.1%, respectively. Finally, scaled‐up fermentation was performed in a 5 L fermenter. The titer of d‐allulose reached 11.15 g/L, with a yield of 0.208 g/g on sucrose. [ABSTRACT FROM AUTHOR]