Solution equilibrium calculations were performed in this study to understand the impact of contaminant metal ions on the precipitation efficiency of selected rare earth elements (Ce3+, Nd3+, and Y3+) ...using oxalic acid as a precipitant. Trivalent metal ions, Al3+ and Fe3+, are found to considerably affect the precipitation efficiency of REEs. When Al3+ and Fe3+ concentrations are increased by 1 × 10−4 mol/L, in order to achieve an acceptable cerium recovery of 93% from solutions containing 1 × 10−4 mol/L Ce3+, oxalate dosage needs to increase by 1.2 × 10−4 and 1.68 × 10−4 mol/L, respectively. Such great impacts on the required oxalate dosage are also observed for Nd3+ and Y3+, which indicates that oxalic acid consumption and cost will be largely increased when the trivalent metal ions exist in REE-concentrated solutions. Effects of the divalent metal ions on the oxalate dosage are minimal. Furthermore, solution equilibrium calculation results show that the precipitation of Fe3+ and Ca2+ (e.g., hematite and Ca(C2O4)∙H2O(s)) likely occurs during the oxalate precipitation of REEs at relatively high pH (e.g., pH 2.5), which will reduce rare earth oxalate product purity. In addition to the metal ions, anionic species, especially SO42−, are also found to negatively affect the precipitation recovery of REEs. For example, when 0.1 mol/L SO42− occurs in a solution containing 1 × 10−4 mol/L Ce3+ and 4 × 10−4 mol/L oxalate, the pH needs to be elevated from 2.0 to 3.3 to achieve the acceptable recovery. Overall, findings from this study provide guidance for the obtainment of high-purity rare earth products from solutions containing a considerable amount of contaminant metal ions by means of oxalic acid precipitation.
During the selective precipitation process of rare earths using oxalic acid, consumption of the precipitant is largely increased by trivalent metal ions, such as Al3+ and Fe3+, while divalent metal ions impose minor impact. Display omitted
Abstract
Accurate identification of microRNA (miRNA) targets at base-pair resolution has been an open problem for over a decade. The recent discovery of miRNA isoforms (isomiRs) adds more complexity ...to this problem. Despite the existence of many methods, none considers isomiRs, and their performance is still suboptimal. We hypothesize that by taking the isomiR–mRNA interactions into account and applying a deep learning model to study miRNA–mRNA interaction features, we may improve the accuracy of miRNA target predictions. We developed a deep learning tool called DMISO to capture the intricate features of miRNA/isomiR–mRNA interactions. Based on tenfold cross-validation, DMISO showed high precision (95%) and recall (90%). Evaluated on three independent datasets, DMISO had superior performance to five tools, including three popular conventional tools and two recently developed deep learning-based tools. By applying two popular feature interpretation strategies, we demonstrated the importance of the miRNA regions other than their seeds and the potential contribution of the RNA-binding motifs within miRNAs/isomiRs and mRNAs to the miRNA/isomiR–mRNA interactions.
Gamma-delta (γδ) T cells are a subset of T cells that promote the inflammatory responses of lymphoid and myeloid lineages, and are especially vital to the initial inflammatory and immune responses. ...Given the capability to connect crux inflammations of adaptive and innate immunity, γδ T cells are responsive to multiple molecular cues and can acquire the capacity to induce various cytokines, such as GM-CSF, IL-4, IL-17, IL-21, IL-22, and IFN-γ. Nevertheless, the exact mechanisms responsible for γδ T cell proinflammatory functions remain poorly understood, particularly in the context of the central nervous system (CNS) diseases. CNS disease, usually leading to irreversible cognitive and physical disability, is becoming a worldwide public health problem. Here, we offer a review of the neuro-inflammatory and immune functions of γδ T cells, intending to understand their roles in CNS diseases, which may be crucial for the development of novel clinical applications.
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•Ultrasound-assisted leaching (UAL) of various metals is detailedly discussed.•Detailed discussions on the enhanced leaching mechanisms of ultrasound are proposed.•The development of ...the novel UAL techniques in the future are put forward.•Quantum chemical modeling point on the UAL process and its challenges are proposed.•The main obstacles for the industrial applications of UAL are proposed.
In recent two decades, ultrasound has been broadly applied to the hydrometallurgical leaching process to recover valuable metals within raw materials, aiming to solve the shortcomings of the conventional leaching process, including relatively low leaching recovery, long leaching duration, high reagent usage, high energy consumption and so on. The present work focuses on a comprehensive overview of the ultrasound-enhanced leaching of various metals, such as common nonferrous and ferrous metals, rare metals, rare earth elements, and precious metals, from raw metal ores and secondary resources. Moreover, the enhanced leaching mechanisms by ultrasound are discussed in detail and summarized based on the improvement of leaching kinetics, enhancement of the mass transfer and diffusion of lixiviants, and promotion of the oxidative conversion of metals from insoluble to soluble states. Lastly, the challenges and outlooks of future research on the leaching recovery for valuable metals with the assistance of ultrasound irradiation are proposed.
Follicular regulatory T cells (Tfr) have critical functions in inflammatory and autoimmune disorders. The main purpose of the current work was to assess Tfr cell frequency in patients with dilated ...cardiomyopathy (DCM). Flow cytometry showed that, compared with normal controls, DCM cases showed markedly reduced Tfr cell rates and Tfr/Tfh ratios, but significantly increased follicular helper T cell (Tfh) rates. Correlation analysis showed that the Tfr rate in DCM patients was positively correlated with left ventricular ejection fraction (LVEF), and negatively correlated with N-terminal brain natriuretic peptide (NT-proBNP) levels. Lower Foxp3 and higher Bcl-6, ICOS, and PD-1 mRNA expression levels were found in patients with DCM. In addition, plasma interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and IL-21 levels were significantly increased in DCM cases. Moreover, IgG and IgG3 levels were also elevated in individuals with DCM. Correlation analysis showed that the Tfr rate in DCM patients was negatively correlated with IgG and IgG3, while the Tfh rate was positively correlated with IgG and IgG3. Changes in circulating Tfr levels may have a critical immunomodulatory function in DCM and may become a new therapeutic target for DCM. Key words: Dilated cardiomyopathy; Follicular regulatory T cells; Immune response; Heart failure
Shape memory polymers (SMP) are the smart materials that have received the most attention and are the most commonly employed. SMP can be 4D printed to create prefabricated components with transform ...shapes, properties, or functions under different external excitations. Although smart equipment assembled from these prefabricated components is extensively used in various fields, a systematic overview summary of their design ideas still needs to be provided. This paper briefly analyzes current trends in the design ideas and application of SMP-based prefabricated components. By summarizing two different design ideas: structural combination and material modification, it demonstrates the application of smart equipment assembled from SMP-based prefabricated components in medical, industrial, and aerospace fields. Furthermore, current challenges with both design ideas are discussed.
Pay-for-performance (P4P) schemes are commonly used to incentivize primary healthcare (PHC) providers to improve the quality of care they deliver. However, the effectiveness of P4P schemes can vary ...depending on their design. In this study, we aimed to investigate the preferences of PHC providers for participating in P4P programs in a city in Shandong province, China.
We conducted a discrete choice experiment (DCE) with 882 PHC providers, using six attributes: type of incentive, whom to incentivize, frequency of incentive, size of incentive, the domain of performance measurement, and release of performance results. Mixed logit models and latent class models were used for the statistical analyses.
Our results showed that PHC providers had a strong negative preference for fines compared to bonuses (- 1.91; 95%CI - 2.13 to - 1.69) and for annual incentive payments compared to monthly (- 1.37; 95%CI - 1.59 to - 1.14). Providers also showed negative preferences for incentive size of 60% of monthly income, group incentives, and non-release of performance results. On the other hand, an incentive size of 20% of monthly income and including quality of care in performance measures were preferred. We identified four distinct classes of providers with different preferences for P4P schemes. Class 2 and Class 3 valued most of the attributes differently, while Class 1 and Class 4 had a relatively small influence from most attributes.
P4P schemes that offer bonuses rather than fines, monthly rather than annual payments, incentive size of 20% of monthly income, paid to individuals, including quality of care in performance measures, and release of performance results are likely to be more effective in improving PHC performance. Our findings also highlight the importance of considering preference heterogeneity when designing P4P schemes.
Aiming at the problem of unmanned reconfiguration and docking of ground vehicles under complex working conditions, we designed a piece of docking equipment composed of an active mechanism based on a ...six-degree-of-freedom platform and a locking mechanism with multi-sensors. Through the proposed control method based on laser and image sensor information fusion calculation, the six-dimensional posture information of the mechanism during the docking process is captured in real time so as to achieve high-precision docking. Finally, the effectiveness of the method and the feasibility of the 6-DOF platform are verified by the established model. The results show that the mechanism can meet the requirements of smooth docking of ground unmanned vehicles.
Exploring the transformation of spatial mechanisms from their unfolded to controlled folding states to meet the requirements of various application scenarios has long been a hot topic in mechanical ...structure research. Although conventional spatial mechanisms can be designed to meet almost any application scenario, the design’s complex and excessive combinations of structural components, kinematic pairs, and drive units are unavoidable. It introduces many problems, such as poor reliability, drive complexity, and control difficulties. Based on 4D printing technology, the design of self-folding spatial mechanisms that use pre-stressed response properties under predetermined thermal excitation to achieve different shrinkage ratios integrates the control and drive system and the structural components and kinematic pairs. It brings novel features of self-folding while effectively avoiding many problems associated with conventional mechanical design. Further, the pre-stressed response model introduces the self-folding spatial mechanisms’ excitation, morphing, and driving investigation. Self-folding spatial mechanisms with different shrinkage ratios were prepared via fused deposition modeling, which verified the theoretical analysis and pre-stress response model and the design’s correctness and feasibility by experiments. The existing 4D printing technology lacks a paradigmatic design method in the application field. Contrarily, this work organically combined the conventional mechanical structure design with materials and fabrication via fused deposition modeling. A systematic study of self-folding spatial mechanisms from structural design to morphing control was carried out. This design is expected to introduce a novel paradigm of 4D printing technology in conventional mechanical design and has considerable application prospects in spherical radar calibration mechanisms.
•Coal refuse has the potential to be used as a resource of critical metals.•Calcination significantly enhanced the leaching recoveries of critical metals.•80–90% of the rare earth elements were ...leached using 1.2 M HCl under 75 °C.•The modes of occurrence of the critical metals were quantified.•Insoluble rare earth minerals were decomposed into soluble species by calcination.
The impacts of calcination on the leaching recovery of rare earth elements (REEs) and other critical metals from a Baker seam coal refuse material were investigated in this study. Acid leaching test results showed that leaching recovery of the REEs, especially the light REEs, was increased significantly from around 24% to 80–90% after calcination under 600–750 °C for two hours. By considering the major element leaching kinetics and the mineralogical changes of the dominant minerals caused by calcination, two mechanisms were proposed for the improved leaching performance: (1) decomposition of difficult-to-dissolve REE-bearing minerals into soluble forms; and (2) liberation of REE-bearing minerals encapsulated in clays after calcination due to the dehydration and disintegration of the layered clay structure. Sequential chemical extraction tests showed that a significant fraction (around 75%) of the REEs in the raw material were present in an insoluble form. After calcination under proper temperatures (600–800 °C), the majority of the insoluble light REEs (LREEs) were converted into soluble forms. Changes in the modes of occurrence of the LREEs and phosphorous based on leaching rate and sequential leaching correlated well as a function of the calcination temperature. This finding in addition to SEM-EDX results tends to indicate the potential that the LREEs occur primarily as rare earth phosphates such as monazite in the untreated coal refuse material. The acid leaching and sequential chemical extraction results show that co-extraction of REEs and other critical metals such as Co, Mn, and Li is possible using a calcination-acid leaching procedure.
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