The effect of extracellular polymeric substances on MICP solidifying rare earth slags and stabilizing Th and U.

Microbially induced carbonate precipitation (MICP) has been used to cure rare earth slags (RES) containing radionuclides (e.g. Th and U) and heavy metals with favorable results. However, the role of microbial extracellular polymeric substances (EPS) in MICP curing RES remains unclear. In this study, the EPS of Lysinibacillus sphaericus K-1 was extracted for the experiments of adsorption, inducing calcium carbonate (CaCO3) precipitation and curing of RES. The role of EPS in in MICP curing RES and stabilizing radionuclides and heavy metals was analyzed by evaluating the concentration and morphological distribution of radionuclides and heavy metals, and the compressive strength of the cured body. The results indicate that the adsorption efficiencies of EPS for Th (IV), U (VI), Cu2+, Pb2+, Zn2+, and Cd2+ were 44.83%, 45.83%, 53.7%, 61.3%, 42.1%, and 77.85%, respectively. The addition of EPS solution resulted in the formation of nanoscale spherical particles on the microorganism surface, which could act as an accumulating skeleton to facilitate the formation of CaCO3. After adding 20 mL of EPS solution during the curing process (Treat group), the maximum unconfined compressive strength (UCS) of the cured body reached 1.922 MPa, which was 12.13% higher than the CK group. The contents of exchangeable Th (IV) and U (VI) in the cured bodies of the Treat group decreased by 3.35% and 4.93%, respectively, compared with the CK group. Therefore, EPS enhances the effect of MICP curing RES and reduces the potential environmental problems that may be caused by radionuclides and heavy metals during the long-term sequestration of RES.

Selection of optimal models for predicting growth stress in Artemisia desertorum by comparison of linear regression and multiple neural networks: Take the construction of a green mine in the Bayan Obo mine as an example.

In recent years, more and more countries are focusing on the control of mining sites and the surrounding ecological environment, and the new environmental concept of green mines has been proposed. By investigating the ecological background of a mine site, pollution and ecological imbalances in the mine can be predicted, managed or transformed. This study investigated the effects of rare earth elements on plant growth in the Baotou Bayan Obo Rare Earth Mine and evaluated soil contamination and subsequent remediation through the measured plant height. Using linear regression, BP(Back Propagation) neural networks, GA-BP(Genetic Algorithm- Back Propagation) neural networks, ELM(Extreme Learning Machine) and GA-ELM(Genetic Algorithm- Extreme Learning Machine) model prediction instruments, the different rare earth solution concentrations were set as input values and the heights of Artemisia desertorum, which as the model plant, were set as output values in the prediction. The results showed that the linear regression predicted the standard error of single La(III), Ce(III) solution and compound La(III) + Ce(III) solution for Artemisia desertorum growth stress was on the high side, 7.02%- 8.92%; the efficiency range of each group of models under BP neural network, GA-BP neural network and ELM neural network were 1.15%- 2.53%, 0.85%- 1.28%, 1.76%- 3.53%; while the efficiency range under GA-ELM neural network was 0.59%- 0.68%, with average error values and predicted values close to the true values. Among them, the MAPE of GA-ELM neural network are significantly lower than other models, and the error decreases with increasing concentration of the compound solution. So GA-ELM neural network can be used as an efficient, fast and reasonable optimal model for predicting the growth stress of Artemisia desertorum in Bayan Obo mining area. The experimental results can provide a theoretical basis for assessing the risk of soil rare earth contamination in the area, evaluating the expectation of later remediation, and provide a degree of new ideas for the construction of green mines.

High-frequency vibration of beveled crystal plates by using subregional geometric fitting method.

The beveling process is an important process in the manufacturing of resonators, which has a significant impact on the frequency stability of resonators. Without understanding the frequency characteristics of the resonator after beveling, it is impossible to accurately design the beveled resonators. Thus, in order to investigate the vibration characteristics of AT-cut beveled resonators, we investigated the high-frequency vibration in this work by using the subregional geometric fitting method (SGFM) based on Mindlin's plate theory. Quartz crystal plates with nonuniform thicknesses are partitioned into three regions and each region is fitted by using the polynomial functions based on the measured geometric morphology data. The governing equations are obtained based on Mindlin's two-dimensional theory and the coupled vibrations are further solved using the partial differential equation module of COMSOL. In the numerical calculation, we compare the results obtained by the SGFM with those obtained by the global fitting method and the measured data. The accuracy and effectiveness of the SGFM are also verified. It is found that the frequencies obtained by the SGFM are slightly higher than the frequencies obtained by the global fitting method, and the results of SGFM are closer to the measured results. Meanwhile, as the beveling time increases, the frequency increases and the energy trapping effect becomes more significant. The proposed method can significantly improve the computational efficiency of thickness-shear vibration while ensuring accuracy. It is expected to provide a new geometric fitting method for the analysis of beveled crystal resonators.

A thermodynamically stable O2-type cathode with reversible O2-P2 phase transition for advanced sodium-ion batteries.

Low-cost sodium-ion batteries (SIBs) have shown very promise in the applications of renewable energy and low-speed electric vehicles. The development of a new O2-type cathode in SIBs is very challenging in that this compound is only stable as an intermediate product of P2-type oxides during redox reactions. Here, we report a thermodynamically stable O2-type cathode obtained by Na/Li ion exchange from P2-type oxide in a binary molten salt system. It is demonstrated that the as-prepared O2-type cathode exhibits a highly reversible O2-P2 phase transition during Na+ de-intercalation. The unusual O2-P2 transition has a low volume change of ∼11%, much lower than that of 23.2% for P2-O2 transformation in the P2-type cathode. The lowered lattice volume change of this O2-type cathode gives rise to superior structural stability upon cycling. Therefore, the O2-type cathode possesses a reversible capacity of about 100 mAh/g with a good capacity retention of 87.3% even after 300 cycles at 1C, indicating outstanding long-term cycling stability. These achievements will promote the development new class of cathode materials with high capacity and structural stability for advanced SIBs.

Developing Smart Nanoparticles Responsive to the Tumor Micro-Environment for Enhanced Synergism of Thermo-Chemotherapy With PA/MR Bimodal Imaging.

With the development of nanotechnology, a theranostics nanoplatform can have broad applications in multimodal image-guided combination treatment in cancer precision medicine. To overcome the limitations of a single diagnostic imaging mode and a single chemotherapeutic approach, we intend to combat tumor growth and provide therapeutic interventions by integrating multimodal imaging capabilities and effective combination therapies on an advanced platform. So, we have constructed IO@MnO2@DOX (IMD) hybrid nanoparticles composed of superparamagnetic iron oxide (IO), manganese dioxide (MnO2), and doxorubicin (DOX). The nano-platform could achieve efficient T2-T1 magnetic resonance (MR) imaging, switchable photoacoustic (PA) imaging, and tumor microenvironment (TME)-responsive DOX release and achieve enhanced synergism of magnetic hyperthermia and chemotherapy with PA/MR bimodal imaging. The results show that IMD has excellent heating properties when exposed to an alternating magnetic field (AMF). Therefore, it can be used as an inducer for tumor synergism therapy with chemotherapy and hyperthermia. In the TME, the IMD nanoparticle was degraded, accompanied by DOX release. Moreover, in vivo experimental results show that the smart nanoparticles had excellent T2-T1 MR and PA imaging capabilities and an excellent synergistic effect of magnetic hyperthermia and chemotherapy. IMD nanoparticles could significantly inhibit tumor growth in tumor-bearing mice with negligible side effects. In conclusion, smart IMD nanoparticles have the potential for tumor diagnosis and growth inhibition as integrated diagnostic nanoprobes.

Pupal Diapause Termination and Transcriptional Response of Antheraea pernyi (Lepidoptera: Saturniidae) Triggered by 20-Hydroxyecdysone.

The pupal diapause of univoltine Antheraea pernyi hampers sericultural and biotechnological applications, which requires a high eclosion incidence after artificial diapause termination to ensure production of enough eggs. The effect of pupal diapause termination using 20-hydroxyecdysone (20E) on the eclosion incidence has not been well-documented in A. pernyi. Here, the dosage of injected 20E was optimized to efficiently terminate pupal diapause of A. pernyi, showing that inappropriate dosage of 20E can cause pupal lethality and a low eclosion incidence. The optimal ratio of 20E to 1-month-old pupae was determined as 6 µg/g. Morphological changes showed visible tissue dissociation at 3 days post-injection (dpi) and eye pigmentation at 5 dpi. Comprehensive transcriptome analysis identified 1,355/1,592, 494/203, 584/297, and 1,238/1,404 upregulated and downregulated genes at 1, 3, 6, and 9 dpi, respectively. The 117 genes enriched in the information processing pathways of "signal transduction" and "signaling molecules and interaction" were upregulated at 1 and 3 dpi, including the genes involved in FOXO signaling pathway. One chitinase, three trehalase, and five cathepsin genes related to energy metabolism and tissue dissociation showed high expression levels at the early stage, which were different from the upregulated expression of four other chitinase genes at the later stage. Simultaneously, the expression of several genes involved in molting hormone biosynthesis was also activated between 1 and 3 dpi. qRT-PCR further verified the expression patterns of two ecdysone receptor genes (EcRB1 and USP) and four downstream response genes (E93, Br-C, ßFTZ-F1, and cathepsin L) at the pupal and pharate stages, respectively. Taken together, these genes serve as a resource for unraveling the mechanism underlying pupal-adult transition; these findings facilitate rearing of larvae more than once a year and biotechnological development through efficient termination of pupal diapause in A. pernyi in approximately half a month.

Folic Acid Functionalized Chlorin e6-Superparamagnetic Iron Oxide Nanocarriers as a Theranostic Agent for MRI-Guided Photodynamic Therapy.

Imaging-guided cancer theranostic is a promising strategy for cancer diagnostic and therapeutic. Photodynamic therapy (PDT), as an approved treatment modality, is limited by the poor solubility and dispersion of photosensitizers (PS) in biological fluids. Herein, it is demonstrated that superparamagnetic iron oxide (SPIO)-based nanoparticles (SCFs), prepared by conjugated with Chlorin e6 (Ce6) and modified with folic acid (FA) on the surface, can be used as versatile drug delivery vehicles for effective PDT. The nanoparticles are great carriers for photosensitizer Ce6 with an extremely high loading efficiency. In vitro fluorescence imaging and in vivo magnetic resonance imaging (MRI) results indicated that SCFs selectively accumulated in tumor cells. Under near-infrared laser irradiation, SCFs were confirmed to be capable of inducing low cell viability of RM-1 cells In vitro and displaying efficient tumor ablation with negligible side effects in tumor-bearing mice models.

Coordination-driven self-assembly of a molecular figure-eight knot and other topologically complex architectures.

Over the past decades, molecular knots and links have captivated the chemical community due to their promising mimicry properties in molecular machines and biomolecules and are being realized with increasing frequency with small molecules. Herein, we describe how to utilize stacking interactions and hydrogen-bonding patterns to form trefoil knots, figure-eight knots and [2]catenanes. A transformation can occur between the unique trefoil knot and its isomeric boat-shaped tetranuclear macrocycle by the complementary concentration effect. Remarkably, the realization and authentication of the molecular figure-eight knot with four crossings fills the blank about 41 knot in knot tables. The [2]catenane topology is obtained because the selective naphthalenediimide (NDI)-based ligand, which can engender favorable aromatic donor-acceptor π interactions due to its planar, electron-deficient aromatic surface. The stacking interactions and hydrogen-bond interactions play important roles in these self-assembly processes. The advantages provide an avenue for the generation of structurally and topologically complex supramolecular architectures.

Reduced Dynamic Interactions Within Intrinsic Functional Brain Networks in Early Blind Patients.

Neuroimaging studies in early blind (EB) patients have shown altered connections or brain networks. However, it remains unclear how the causal relationships are disrupted within intrinsic brain networks. In our study, we used spectral dynamic causal modeling (DCM) to estimate the causal interactions using resting-state data in a group of 20 EB patients and 20 healthy controls (HC). Coupling parameters in specific regions were estimated, including the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and inferior parietal lobule (IPC) in the default mode network (DMN); dorsal anterior cingulate cortex (dACC) and bilateral anterior insulae (AI) in the salience network (SN), and bilateral frontal eye fields (FEF) and superior parietal lobes (SPL) within the dorsal attention network (DAN). Statistical analyses found that all endogenous connections and the connections from the mPFC to bilateral IPCs in EB patients were significantly reduced within the DMN, and the effective connectivity from the PCC and lIPC to the mPFC, and from the mPFC to the PCC were enhanced. For the SN, all significant connections in EB patients were significantly decreased, except the intrinsic right AI connections. Within the DAN, more significant effective connections were observed to be reduced between the EB and HC groups, while only the connections from the right SPL to the left SPL and the intrinsic connection in the left SPL were significantly enhanced. Furthermore, discovery of more decreased effective connections in the EB subjects suggested that the disrupted causal interactions between specific regions are responsive to the compensatory brain plasticity in early deprivation.