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Rare earth elements and yttrium (REY) have attracted considerable attention over the last decade because of their vital roles in clean energy, consumer product, national defense and security applications, among other uses. Due to the retention of REY during coal burning, coal combustion ash is considered as potential alternative sources for REY. Understanding the content, speciation, retention and/or transformation behavior of REY during coal combustion not only expands our knowledge of the combustion behavior of the trace elements in coal, but also provides basis for modeling REY partitioning during coal combustion and for developing economically viable REY recovery technologies. This review makes a critical summary of recent progress in the study of REY in coal ash. The contents and the extraction potentials of REY in coal ash derived from 15 major coal-producing countries worldwide were summarized and evaluated. Various analytical methods for determining REY bulk contents and speciation, together with the solid sample pretreatment, analytical accuracy and precision, advantages and disadvantages were summarized and compared. Modern analytical approaches combined indirect methods (e.g., sequential extraction) shed light on the physical distribution, mineralogy, and the chemical state of REY in coal ash. Three types of REY occurrences in coal ash, including Si-Al glassy association, discrete minerals or compounds, and organic association (bound with unburned carbon) were defined in the review. The glassy association can be further divided into REY minerals closely bound to glass phases and dispersed throughout the glassy structure. REY partitioning in various emission streams, the size distribution, and their enrichment behavior in coal ash were discussed. Thermal behavior and transformation of various REY forms in coal during combustion process, including organic-associated REY, REY phosphates, REY carbonates, clay-bound REY and among others were summarized. Two possible retention mechanisms of REY by aluminosilicate glass at boiler temperature were proposed: the incorporation of the individual REY phases into the glass as inclusions and the diffusion of REY phases throughout Si-Al glass structures in the melting process. Feed coal mineral types, mineral-mineral associations, boiler conditions, and other factors control the retention process. After coal combustion, the speciation of REY in fly ash may be modified by the reactions of REY phases with flue gas components. Further, an overview of REY transformation mechanisms during coal combustion was deeply discussed. Finally, current extraction techniques for REY recovery from coal combustion ash were introduced. Future outlooks and research problems were also identified.

Leaching recovery of rare earth elements (REEs) from two natural kaolinite samples were investigated in this study. Using standard leach conditions without pretreatment, only 10% and 56% of the total REEs were leached from the raw samples, respectively. However, pretreatment by calcination at temperatures between 500 °C and 900 °C increased the leaching recovery of total REEs to values as high as 93% for both samples. Mineralogical characterization and acid leaching results suggested that the decomposition of the kaolinite structure occurs as a function of calcination temperature. Comparisons between the REEs and the major constituent elements of kaolinite showed that their leaching characteristics contrasted. Moreover, sequential chemical extraction results suggested that the fractions of REEs occurring in an ion-adsorption form were negligible. Therefore, the REEs were primarily associated with REE-bearing minerals of which, a portion was encapsulated in kaolinite aggregates while the remaining existed as liberated particles. These association characteristics were proven through SEM-EDX analysis. Based on the mineralogy characterization, acid leaching, and sequential chemical extraction results, it was concluded that the REEs have complicated modes of occurrence and association characteristics with kaolinite. The positive impacts of calcination on the leaching recovery of REEs are likely due to two mechanisms, i.e., (1) liberation of the encapsulated REE-bearing minerals through expansion of the kaolinite aggregates, and (2) conversion of the REE-bearing minerals into more soluble forms.

The emergence of additive manufacturing technology opens up avenues for developing manufacturing industries, and a clear future direction for additive manufacturing is 4D printing. As a young field, it is full of new elements to be researched. In a summary and overview of the current state of research and trends, existing studies are generally manually reviewed and organized. It is susceptible to subjective thinking and knowledge blindness, making it difficult to reflect the current state of research in 4D printing in a comprehensive manner. This paper constructs a visualizing technology identification framework for the global 4D printing research field for manufacturing regarding basic information, technology evolution paths, knowledge structures, and emerging trends through bibliometric techniques and Gephi and CiteSpace software. The purpose of this paper was to provide a systematic, comprehensive, dynamic, quantitative, and objective analysis of the 4D printing research field in order to deepen and refine research in the field, as well as to reveal the overall existing knowledge structure and potential emerging trends. Researchers can use it to understand current research gaps and best practice pathways.

In this investigation, the fine-grained bauxite ore flotation was conducted in a plate-packed flotation column. This paper evaluated the effects of packing-plates on recovering fine bauxite particles and revealed the fundamental mechanisms. Bubble coalescence and break-up behaviors in the packed and unpacked flotation columns were characterized by combining Computational Fluid Dynamics (CFD) and Population Balance Model (PBM) techniques. Flotation experiments showed that packing-plates in the collection zone of a column can improve bauxite flotation performance and increase the smaller bauxite particles recovery. Using packing-plates, the recovery of Al2O3 increased by 2.11%, and the grade of Al2O3 increased by 1.85%. The fraction of &minus, 20 &mu, m mineral particles in concentrate increased from 47.31% to 54.79%. CFD simulation results indicated that the packing-plates optimized the bubble distribution characteristics and increased the proportion of microbubbles in the flotation column, which contributed to improving the capture probability of fine bauxite particles.

An innovative self-designed medium was packed in a bench-scale flotation column to study its influence on the flotation recovery of bauxite. Computational fluid dynamics (CFD) simulation was conducted to reveal the impact of the packing medium on the turbulent characteristics of collection zone in the column. Simulation results show that multilayer packing of the medium divides the collection zone into small units having different turbulent intensities, which is more suitable for flotation separation. The packing medium decreases the turbulence kinetic energy (from 1.08 &times, 10&minus, 2 m2/s2 to 2.1 &times, 3 m2/s2), turbulence eddy dissipation (from 3.71 &times, 2 m2/s3 to 9.8 &times, 3 m2/s3) and axial fluid velocity of fluid in the column. With three layers of packing, the recovery of Al2O3 increased by 2.11% and the aluminum to silicon content ratio of the concentrate improved from 5.16 to 9.72.

Many studies have been published in recent years focusing on the recovery of rare earth elements (REEs) from coal-related materials, including coal, coal refuse, coal mine drainage, and coal combustion byproducts particularly fly ash. The scientific basis and technology development have been supported by coal geologists and extractive metallurgists, and through these efforts, the concept has progressed from feasibility assessment to pilot-scale production over the last five years. Physical beneficiation, acid leaching, ion-exchange leaching, bio-leaching, thermal treatment, alkali treatment, solvent extraction, and other recovery technologies have been evaluated with varying degrees of success depending on the feedstock properties. In general, physical beneficiation can be a suitable low-cost option for preliminary upgrading; however, most studies showed exceedingly low recovery values unless ultrafine grinding was first performed. This finding is largely attributed to the combination of small RE-bearing mineral particle size and complex REE mineralogy in coal-based resources. Alternatively, direct chemical extraction by acid was able to produce moderate recovery values, and the inclusion of leaching additives, alkaline pretreatment, and/or thermal pretreatment considerably improved the process performance. The studies reviewed in this article revealed two major pilot plants where these processes have been successfully deployed along with suitable solution purification technologies to continuously produce high-grade mixed rare earth products (as high as +95%) from coal-based resources. This article presents a systematic review of the recovery methods, testing outcomes, and separation mechanisms that are involved in REE extraction from coal-related materials. The most recent findings regarding the modes of occurrence of REEs in coal-related materials are also included.

In this paper, the effect of sodium alginate (SA) on the flotation separation of molybdenite (MoS2) from chalcopyrite using kerosene as collector was systematically investigated. The results of single-mineral micro-flotation tests indicated that SA exhibited strong depression on chalcopyrite flotation while it imposed no impact on the floatability of molybdenite. However, in the chalcopyrite–molybdenite mixed-mineral flotation system, the presence of chalcopyrite significantly increased the depressing effect of SA on molybdenite flotation, leading to a considerable reduction in the flotation selectivity. The negative impact of chalcopyrite on the performance of SA in molybdenite flotation was eliminated by adding a certain dosage of kerosene prior to SA. A concentrate containing 53.43% of molybdenum (Mo) was obtained at 76.90% of recovery using 19 mg/L kerosene and 40 mg/L SA at pH 5.4. Zeta potential measurements indicated that the adsorption of SA on chalcopyrite surfaces was stronger than that on molybdenite surfaces, which agreed with the single-mineral flotation test results. The adsorption of SA on chalcopyrite was further confirmed to be chemisorption by Fourier-transform infrared spectroscopy (FTIR) spectra analyses. When Cu2+ appeared in solution, the flotation of molybdenite was strongly depressed by SA. Mechanism analyses indicated that more active sites were generated on molybdenite surfaces after the addition of Cu2+, thus promoting the adsorption of SA. Published version

Acute myocardial infarction (AMI) induced by ischemia hypoxia severely threatens human life. Cell apoptosis of neurocytes was identified to mediate the pathogenesis, while the potential mechanism was still unclear. Sprague Dawley (SD) rats were used to establish the AMI rat model. Real-time polymerase chain reaction (PCR) and Western blot were performed to detect gene expression in mRNA and protein levels, respectively. A TUNEL assay was carried out to determine cell apoptosis. The relationship between SRY-related HMG-box (SOX7) and miR-128 was verified using luciferase reporter assay. The expression of SOX7 was decreased, while miR-128 was increased in AMI rats and ischemia hypoxia (IH) induced H9c2 cells. Hypoxia induction significantly promoted the expression of interleukin (IL)-33 and soluble ST2 (sST2), and also promoted cell apoptosis. MiR-128 targets SOX7 to regulate its expression. Down-regulated miR-128 reversed the effects of IH on expression of SOX7, sST2 and cell apoptosis, while down-regulated sST2 abolished the effects of miR-128 inhibitor. In addition, overexpressed IL-33 abolished the effects of miR-128 inhibitor that induced by IH on the expression of SOX7 and cell apoptosis. In vivo experiments validated the expression of miR-128 on cell apoptosis. The present study indicated that miR-128 modulated cell apoptosis by targeting SOX7, which was mediated by IL-33/sST2 signaling pathway.

Background Metaphors may provide clarity or identify hidden similarities between two ideas, and their use in cognitive restructuring can help maximise the effect of therapy information. This study aimed to determine whether metaphorical cognitive restructuring would produce a greater intervention effect in targeted mood and cognition than non-metaphorical restructuring. Methods Eighty-eight participants chose 25 problems of interest and wrote a self-report distress problem and were then randomly divided into a metaphorical restructuring group (N = 29), a literal restructuring group (N = 30), or a no restructuring problem restating group (N = 29). Participants first read a description of psychological distress ("problem") and then read a solution within one micro-counseling scenario. They were asked to evaluate their insightfulness during the intervention and evaluated mental distress and self-efficacy before and after the intervention. Results The mental distress of the metaphorical restructuring group significantly decreased after the intervention. Further, this group had greater insightfulness during the intervention, and this insightfulness could predict the reduction of negative affect after the intervention. Conclusions The use of metaphors can be of great value in eliciting a salient cognitive restructuring process and in alleviating mental distress.

Recovery of rare earth elements (REEs), especially heavy and critical REEs, from alternative resources such as coal refuse has recently become increasingly important. A natural leachate containing 6.14 ppm of REEs with a pH value of 2.70 was collected from a coal coarse refuse pile and utilized as a feedstock for REE recovery tests. The pH value of the natural leachate was gradually increased in a step-wise manner using a sodium hydroxide solution which produced several precipitates. A precipitate containing about 1.1% total REEs was obtained in the pH range of 4.85–6.11 while recovering >80% of the REEs contained in the original leachate. The leaching and staged precipitation process enriched both the critical and heavy REE fractions. The ratios of heavy-to-light (H/L) and critical-to-uncritical (C/UC) REEs in the precipitate were much higher than the coarse refuse material (H/L: 1.54 vs 0.21, C/UC: 1.51 vs 0.34). Additionally, the precipitate contained 18.4% Al, 1.7% Zn, 1.4% Cu, 1.1% Mn, 0.5% Ni and 0.2% Co. A solution chemistry study indicated that the hydroxide and hydroxysulphate precipitates of Al, Si and Cu produced in the pH range of 4.85–6.11 contributed to the fractionation of the REEs and other metal ions such as Zn, Mn and Co to the precipitate. The iron hydroxide precipitates formed at lower pH values did not contain a significant amount of REEs. An explanation may be the competitive adsorption between Al, which was present at higher solution concentrations, and REEs on the iron hydroxide and/or hydroxysulphate precipitate surfaces as proven by results of precipitation tests conducted on model solutions. A product containing 94% of a rare earth oxide mix was obtained by re-dissolution of the REE enriched precipitates followed by selective precipitation using oxalic acid. The overall results including an economic assessment indicate that leachate solutions generated naturally from coarse coal refuse may be a valuable source of critical and heavy REEs that can be effectively recovered and concentrated using staged precipitation.

Objective: To determine the underlying mechanism of miR-34b/c in regulating doxorubicin (Dox)-induced myocardial cell injury. Methods: The viability of mouse myocardial cells HL-1 was detected by MTT assay. The apoptosis of HL-1 cells was detected by TUNEL assay. mRNA expressions of ITCH, TNF-α and IL-6 were measured by qRT-PCR. Protein levels of ITCH, NF-κB, TNF-α and IL-6 were measured by western blot. Dual luciferase assay was performed to detect the regulation of miR-34b/c on ITCH. Mouse model of cardiomyopathy was induced by intraperitoneal injection of Dox. Results: Dox reduced HL-1 cell viability and activated NF-κB pathway in HL-1 cells. miR-34b/c expressions were gradually up-regulated and ITCH expression was gradually down-regulated in Dox-treated HL-1 cells. miR-34b/c expression had negative correlation with the mRNA expression of ITCH. Besides, ITCH was a target of miR-34b/c. miR-34b/c mimic reduced cell viability, suppressed ITCH expression, increased TNF-α and IL-6 level, and promoted NF-κB expression in nucleus and cytoplasm of HL-1 cells. Whereas silencing miR-34 protected HL-1 cells through regulating ITCH. Finally, we demonstrated miR-34 antagomir-protected myocardial cells in mouse model of cardiomyopathy. Conclusion: miR-34b/c decreased HL-1 cell viability and promoted the secretion of proinflammatory cytokines in Dox-induced myocardial cells through ITCH/NF-κB pathway.

Cardiac remodeling is a major early event of heart failure, which is regulated by multiple signaling pathways. Here, we demonstrate that TBC1D25 is upregulated during pathological cardiac remodeling. The aim of this study is to determine the role of TBC1D25 in cardiac remodeling and to illustrate the underlying molecular mechanism. Specifically, cardiac remodeling was induced in TBC1D25-KO mice and their wild-type control mice through partial transverse aortic constriction (TAC) of aortic arch. Knockout TBC1D25 exacerbated cardiac hypertrophy, fibrosis and dysfunction. Meanwhile, TBC1D25 overexpression in both H9C2 cells and NRCMs alleviate Angiotensin II-induced cardiomyocyte hypertrophy in vitro. Moreover, TBC1D25 deficiency increases the phosphorylation levels of TAK1 and its downstream molecular (JNK and p38), whereas overexpressed TBC1D25 inhibits phosphorylation of TAK1, JNK and p38. And TAK1 is the key molecule in this process. Furthermore, we demonstrated that TBC1D25 could directly interacts with TAK1 by immunoprecipitation assay and GST pull-down assay, and the interaction needs the amino acids from at least 138 to 226 in the C-terminal region of TBC1D25 and from 1 to 300 in the C-terminal region of TAK1. We conclude that TBC1D25 suppresses pathological cardiac remodeling via regulating TAK1-JNK/p38 signaling pathway, which suggests that TBC1D25 will likely become a promising therapeutic target for heart failure.

The majority of rare earth elements (REEs) existing in the feed to coal preparation plants report to the coarse refuse streams which are transported for permanent storage in contained piles. In this study, an integrated flowsheet was developed based on laboratory test data which combines physical separation, pyrite bio-oxidization, heap leaching, selective precipitation and solvent extraction processes. The test data was obtained from (1) characterization of a number of natural leachate and solid samples collected from different preparation plants which process coals from a number of coal seams and (2) laboratory acid leaching and selective precipitation tests results. The highly-valued critical REEs (i.e., Y, Nd, Eu, Tb and Dy) were selectively leached from the refuse samples in the natural environment due to the acid generated by pyrite oxidization. The leachate samples were evaporated to remove water and obtain residual solids (i.e., dissolved solids in the leachates). The total REE content in the dissolved solids from a given leachate sample was 380 ppm, which was higher than the REE content of the coarse refuse material that generated the leachate (322 ppm). Acid leaching tests recovered as much as 80% of the total REEs from the coarse refuse samples using a 1.2 M sulfuric acid solution. Afterwards, the pH of the leachate was increased in a step-wise fashion which resulted in the production of precipitates containing 0.3–1.1% total REEs. A significant amount of contaminants, such as Fe, Al, and Ca, were eliminated in the sequential precipitation process, which allowed further upgrading using oxalic acid precipitation and/or solvent extraction. In the proposed flowsheet, the coarse refuse is arranged in heap leach pads and the acid needed for REE leaching is primarily produced from pyrite bio-oxidization, which enhances the selectivity of REE recovery and significantly reduces the cost. The successful application of the flowsheet would result in significant benefits to both the coal and rare earth industries.

The flotation separation of scheelite from calcite using sodium humate (SH) as a potential depressant has been studied through micro-flotation experiments, zeta potential and Fourier transform infrared (FT-IR) spectra measurements. The flotation results indicate SH exhibited selective depression effect on calcite in the presence of sodium oleate, achieving the flotation separation of scheelite from calcite. Zeta potential results indicate that SH strongly absorbed on calcite surface but negligibly on scheelite surface, which prevents the adsorption of sodium oleate on calcite surface. The FT-IR results also show that SH can be adsorb on the surface of calcite. Results shown a higher Ca density on the calcite than on scheelite surface, and that calcite can accommodate the interaction of SH.

Rare earth element (REE) recovery from coal and coal byproducts using physical and/or chemical methods has been the focus of recent investigations due to concerns over worldwide supply. In the current study, the association characteristics of REEs and the recovery of REEs from the organic and inorganic components were systematically studied for a Fire Clay seam coal source. The coal sample was ground in a stirred ball mill and treated by froth flotation in stages to obtain clean coal concentrates and tailing samples. The clean coal concentrate from the first stage was re-ground to liberate more micro-dispersed mineral matter followed by flotation. After six grinding and recovery stages, the cumulative grinding time was 110 min, which reduced the particle size from 90% passing 84.3 μm to 4.5 μm. Analyses conducted on the tailing samples collected from each stage revealed that the REEs have a strong association with micro-dispersed kaolinite. The REE content in the tailings material increased from around 580 ppm to 1200 ppm on an ash basis. The ratio of heavy-to-light REEs in both the clean coal concentrates and tailing samples increased, which indicated a stronger affinity between the heavy REEs and the finest mineral matter grains in the organic matrix. Based on these findings, REE concentration tests were performed using froth flotation, magnetic separation and acid leaching. A product containing nearly 7000 ppm of REEs was achieved from a feed containing 500 ppm REEs using a batch WHIMS unit. The elemental content indicated that the rare earth mineral in the concentrate was primarily monazite. Leaching the high ash content fractions generated from the sequential grinding and flotation steps using 1 M nitric acid resulted in recovering more than 80% of total REEs with the exception of scandium. A lower recovery value obtained for scandium indicated a unique association with the mineral matter relative to the other REEs.

In order to clarify the effect of copper contents on the corrosion resistance of stainless steel in biological environment, 316L-0Cu (wt%), 316L-1.5Cu (wt%), 316L-4.5Cu (wt%) and 316L-7.5Cu (wt%) coatings were prepared by laser melting deposition (LMD), and the microstructure and corrosion behavior in simulated body fluids (SBF) were studied. The results show that the planar growth, cellular crystal and dendritic microstructure are formed in the four kinds of LMD-produced coatings. With the increase of copper contents, the microstructure is refined, the corrosion resistance is decreased first and then is increased. This is because the copper oxide precipitates at the high-density grain boundaries, which can promote the passivation behavior. Under the combined action of Cr2O3 and Cu2O, the corrosion resistance of 316L-7.5Cu coating is closest to that of 316L-0Cu coating.

Considering the optimization problem of manned robot swarm scheduling in public environment, we constructed a demand-time-space-energy consumption scheduling model taking passenger waiting time and robot swarm energy consumption as optimization goals. This paper proposes an ant-sparrow algorithm based on the same number constraints colonies of ant and sparrow, which combines the advantages of ant colony algorithm great initial solution and the fast convergence speed of the sparrow search algorithm. After a limited number of initial iterations, the ant colony algorithm is transferred to the sparrow search algorithm. In order to increase the diversity of feasible solutions in the later stage of the ant-sparrow algorithm iteration, a divide-and-conquer strategy is introduced to divide the feasible solution sequence into the same small modules and solve them step by step. Applying it to the manned robot swarm scheduling service in the public environment, experiments show that the ant-sparrow algorithm introduced with a divide-and-conquer strategy can effectively improve the quality and convergence speed of feasible solutions.

Phosphatic clay is a waste material produced during the beneficiation of phosphate ore, which likely poses severe environmental problems. In this study, a phosphatic clay containing 258 ppm of total rare earth elements (REEs) was used as a feedstock for REE recovery. By reacting with 0.1 M HCl at 75 °C for 3 h, around 36 % of light REEs and 65 % of heavy REEs were extracted from the raw material. However, after calcination pretreatment at 600 °C for 2 h, the recovery was increased to 73 % and 81 %, respectively, which are close to the recoveries obtained from the raw material using a much higher acid concentration of 1.2 M. Based on the findings from sequential chemical extraction tests and scanning electron microscopy analysis, the positive impact was explained by the decomposition and conversion of REE-bearing minerals into more leachable species. Using a higher calcination temperature of 900 °C, recovery of both the light and heavy REEs was largely reduced relative to the raw material. Mineralogical analyses showed that the dominant minerals existing in the material, such as muscovite, were fused and sintered during the calcination at 900 °C. These reactions likely caused the decreases in the recovery. The results and findings from this study will contribute to the beneficial uses of phosphatic clay and the production of REEs.

Rare earth elements (REEs) found in coal are in the form of minerals, ion-adsorbed onto clay surfaces or inner layers, or organically bound. Rare earth minerals such as monazite exist in coal and have grain sizes smaller than 5 µm. In this study, froth flotation was successful in concentrating rare earth minerals existing in a thickener underflow material derived from Fire Clay seam coal that contained around 431 ppm of total rare earth elements (TREE) on a dry ash basis. Conditioning with fatty acid followed by processing using multiple stages of conventional flotation produced a final concentrate containing 2,300 ppm TREE. Using a laboratory flotation column to limit hydraulic entrainment, the TREE content was further enriched to around 4,700 ppm, which equated to an enrichment ratio of 10:1..

The surface charge mechanisms of monazite were studied using electrokinetic tests, solution equilibrium calculations, crystal structure characterization, and electrostatic model predictions. The isoelectric point (IEP) of a natural monazite sample was found to occur at pH 6.0. To allow a theoretical study of the surface charge on monazite, fundamental values associated with cerium monazite (CePO 4 ) were utilized to quantify the isoelectric point (IEP) and point of zero charge (PZC) using solution equilibrium calculations and electrostatic models. The IEP and PZC of the cerium monazite were determined to be equal with a pH value of 7.2. Hydroxyl and hydrogen were found to be potential determining ions and preferential hydrolysis of the lattice ions played a minor role. The findings support the hypothesis that the charge of monazite surfaces in water is a result of protonation/deprotonation reactions. The difference in the IEP values obtained for the natural monazite and cerium monazite along with the wide range of values reported in literature may be partially explained by the amount of carbon dioxide dissolved in solution. When equilibrating with carbon dioxide at 10 –3.5 atm partial pressure, the IEP of the cerium monazite shifted to a solution pH value of 4.5.

The adsorption mechanism of octanohydroxamic acid (OHA) on monazite was studied using kinetic, isotherm, and thermodynamic adsorption tests as well as FTIR, titration, and micro-flotation experiments. The adsorption mechanism was described as a chemisorption/surface precipitation process. At low OHA concentrations, adsorption occurred by chemisorption as a result of the reaction between surface active sites and OHA molecules. With an increase in concentration and interaction time, surface precipitation occurred. For chemisorption, adsorption was an exothermic and entropy driven process and maximum adsorption was achieved at pH 9.0 due to more active sites. In an acidic environment, such as pH 3.0, adsorption was achieved via chemisorption and hydrophobic bonding. However, a strong basic and higher temperature environment contributes to surface precipitation of basic rare earth hydroxamate. FTIR tests showed the movement of CH 2 band position from 2924 cm − 1 to 2920 cm − 1 with increases in pH values from 3.0 to 6.0, 9.0, and 11.0, which corresponds to the status of chemisorbed and surface precipitated OHA, respectively.

The dissolution of minerals provides elevated concentrations of alkaline earth metal ions such as calcium (Ca 2+ ) in water which may have a significant influence on flotation performance. The effects of Ca 2+ ions dissolved from calcite surfaces on the flotation performance of a monazite-calcite system have been investigated using micro-flotation tests followed by fundamental collector adsorption studies. The results indicate that specially adsorbed CaOH + via hydrogen bonding competed with hydroxamic acid for the phosphate-oxygen active sites on the monazite surface and decreased its hydrophobicity due to hydration. Electrostatically adsorbed CaOH + on monazite increased the adsorption density of hydroxamic acid through a chelating interaction. At higher dosages of calcium and hydroxamic acid, bulk and surface precipitation of calcium-hydroxamate occurs in the monazite-calcium-hydroxamic acid system.

Although the effects of cognitive reappraisal in regulating negative emotion are generally well documented, its regulatory effects are usually not very strong because the ordinary reappraisals employed in previous studies were insufficient to overcome the mental set or response bias toward negative situations. In this study, we developed a new strategy employing creative reappraisals that provides an insightful reinterpretation of the negative stimulus. We believe this approach, through adopting a guided (creative) reappraisal rather than self-generation strategy, will greatly improve the emotion regulation effect of reappraisal through activating the neural networks representing the process of deep and structural mental representational change accompanied by the feeling of positive emotion and mental reward. The behavioral results suggested that 1) regarding the transient regulatory effect, creative reappraisal resulted in a positive rating for standardized negative pictures; 2) creative reappraisal had a long-lasting effect in reducing negative affect. In parallel with these behavioral results, the imaging data indicated that 1) creative reappraisal was specifically associated with greater engagement of the amygdala and hippocampus as well as regions in the ventral striatum, and 2) the engagement of the amygdala predicted the transient regulatory effect of creative reappraisal, while the involvement of the hippocampus and the ventral striatum predicted long-term regulatory effects. These findings suggest that the superior regulatory effect of creative reappraisal could be mediated by amygdala-based salient emotional arousal, hippocampus-based new association formation, and striatum-based mental rewarding to lead to a novel and positive experience that could be kept in long-term memory. This research indicates the key role of creative insight in reappraisal and presents a novel and highly efficient reappraisal strategy.

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Cognitive restructuring is an important strategy in cognitive behavioral therapy (CBT). The present study aimed to observe cognitive restructuring in major depressive disorder (MDD) patients using textual micro-counseling dialogue situations. A set of textual micro-counseling dialogues was used to trigger cognitive restructuring in 25 MDD patients and 27 healthy adults. The participants read descriptions ("problems") and explanations ("solutions") for psychologically distressing situations. High-, low-, and zero-restructuring solutions were randomly matched to the problems. The participants evaluated the adaptability and emotional valence of the problems and the insightfulness, adaptability, novelty, and emotional valence of the solutions. Insightfulness ratings for high-restructuring solutions were significantly higher relative to those of low-restructuring solutions in healthy adults, while adaptability ratings for low-restructuring solutions were significantly higher relative to those of high-restructuring solutions in MDD patients. Insightfulness ratings for the solutions were significantly predicted by novelty and adaptability in healthy adults and emotional valence in MDD patients. Lower insightfulness in high-restructuring solutions and higher adaptability in low-restructuring solutions in MDD patients may reflect deficits in cognitive control.

Posttraumatic stress disorder (PTSD) is linked to abnormal amygdala activities. This study measured amygdala functional connectivity using DSM-5 criteria. There were 33 participants in the PTSD group and 33 participants in a trauma-exposed control (TEC) group, who did not have PTSD according to the PTSD checklist of the DSM-5 (PCL-5). Our findings are as follows: (1) In the PTSD group, the amygdala had increased positive connectivity with the medial prefrontal cortex (mPFC) and hippocampus, and decreased positive connectivity with the inferior mPFC and insula. The amygdala had increased negative connectivity with the orbital prefrontal cortex and decreased negative connectivity with the insula in comparison with TEC group. (2) PCL of all participants was correlated with the connectivity between the amygdala and the mPFC, hippocampus, and insula. These regions overlapped with those identified in the between-group comparisons. However, there was no association between PCL of the PTSD group and connectivity in these regions. Abnormal functional connectivity between the amygdala and mPFC subdivisions, hippocampus, and insula reveals their importance in PTSD pathogenesis.

Background/Aims: Myeloid-derived suppressor cells (MDSCs) are increased in inflammatory and autoimmune disorders. This study aims to evaluate the significance of MDSCs in dilated cardiomyopathy (DCM) patients. Methods: In total, 42 newly hospitalized DCM patients and 39 healthy controls were enrolled in the study. The frequencies of circulating CD14+HLA-DR-/low MDSCs were determined by flow cytometry. Then, the functional properties of MDSCs in suppressing T cell proliferation and interferon-gamma (IFN-γ) production were measured in a co-culture model. Then, mRNA expression levels of various important molecules in peripheral blood mononuclear cells were measured by real time polymerase chain reaction. Furthermore, correlation analyses between MDSC frequencies and cardiac function parameters were also performed. Results: The frequencies of circulating CD14+HLA-DR-/low MDSCs were significantly elevated in DCM patients compared with healthy controls. It showed that MDSCs from DCM patients more effectively suppressed T cell proliferation and IFN-γ production compared with those from healthy controls, which was partially mediated by arginase-1 (Arg-1). In addition, the correlation analysis suggested that MDSC frequencies were negatively correlated with left ventricular ejection fraction (LVEF), while positively with N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with DCM. Conclusions: Circulating activated MDSCs might play significant immunomodulatory roles in the pathogenesis of DCM.

The separation of carbon from fly ash significantly improves the potential end-us of combustion byproducts. Froth flotation is the most effective separation technique for ultrafine material. Diesel dosages, conditioning time, and impeller rotating speeds' influences on carbon flotation performance were studied. From flotation products, + 25 and − 25 μm fractions were screened out to study their different flotation behaviors. At a given impeller speed, carbon recovery of +25 μm fraction increased significantly from 38.46% to 74.22% over a range of diesel dosage from 0.5 to 4.5 kg/t, while that of -25 μm fraction was relatively constant at 85% over the same diesel dosage range. Morphologies and microstructures of coarse and fine carbon were studied by using scanning electron microscope. Porous structures of coarse carbon were observed. It's difficult for diesel droplets of several microns to penetrate the pores of coarse carbon particles, which increases diesel consumption. Increasing impeller speeds from 1200 to 1600 rpm during conditioning improved the carbon recovery and separation efficiency of + 25 μm fraction by 79% and 110%, respectively, which significantly reduced diesel consumption. Flotation kinetic studies indicate that increasing impeller speeds during conditioning stage can improve the flotation rate constant and maximum carbon recovery for both + 25 and − 25 μm fractions.

Acid mine leachate (AML) may be a significant source of rare earth and other critical elements needed for the manufacturing of advanced electronics and renewable energy technologies. A systematic study was performed on a natural leachate collected from a coal preparation plant that treated bituminous coal containing elevated amounts of pyrite. The leachate contained 1.96 ppm total REEs, 2.52 ppm Zn, 2.15 ppm Ni, 1.22 ppm Cu, 0.77 ppm Co, and 25 ppm Mn. Sequential precipitation using simple pH control generated a pre-concentrate containing 0.82% total REEs, 1.08% Zn, 0.91% Ni, 0.50% Cu, 0.34% Co, 7.1% Mn. The pre-concentrate was further treated by re-dissolution using a 10 M HNO3 solution, which resulted in a solution pH of 1.5. The addition of oxalic acid to selectively precipitate the REEs followed by roasting of the precipitate generated a product containing >98% rare earth oxides. More than 95% of the Cu and Zn were recovered from the residual liquid using Na2S at pH 2 and 3, respectively. The CuS and ZnS contents in the corresponding concentrates were 60% and 58%, respectively. The majority of the Co and Ni remained in the residual liquid. Based on these findings, a process flowsheet was developed to recover the REEs and critical metals from AML.

Three segments of a core sample collected from the Guxu coalfield (Sichuan Province, China) were evaluated to determine the rare earth element (REE) leachability and mineralogy. Elemental analysis of the three samples showed that the roof and floor strata contained as high as 2087 ppm of total REEs, a value much higher than other coal-based materials reported in the literature. For the floor samples, 47% to 65% of the light REEs (LREEs) were leached within 5 min of contact time using 1 M mineral acid, and prolonged contact, up to 120 min, increased the LREE recovery to as high as 75%. For the roof sample, only 25% of the LREEs were leached at extended contact times. Unlike the LREEs, heavy REE (HREE) recovery from both the roof and floor materials was less than 25%. The relatively high REE content of the feed materials facilitated detailed SEM-EDX and TEM-EDX analyses of the samples. These studies confirmed the presence of several rare earth carbonate minerals, including bastnaesite and parasite, as well as rare earth phosphate minerals such as florencite and apatite. Given the prevalence and rare earth content of the particles analyzed via SEM-EDX, the data suggests that the LREEs present in the floor and roof samples were primarily associated with carbonates and phosphates, respectively. Further SEM-EDX analysis of the leaching residues showed that florencite was the only LREE-bearing species remaining after prolonged acid leaching, indicating that florencite is less soluble relative to the other rare earth minerals. The leaching results corroborate the SEM-EDX and TEM-EDX findings, while providing critical fundamental information on the relationship between REE content, REE mineralogy, and REE leachability in coal refuse materials.

Lithium recovery from the density fractions of Baker (namely West Kentucky No. 13) seam coal was investigated in this study. Proximate and elemental analyses showed that lithium contents in the 1.8–2.2 SG and 2.2 SG sink fractions were 185 ppm and 150 ppm, respectively, which are significantly higher than the average content of coal sources (12 ppm) and coal ashes (66 ppm) worldwide. Moreover, due to the high lithium contents and mass distribution, nearly 90% of the lithium present in the Baker coal sample was distributed in the two density fractions. Direct leaching using a HCl solution resulted in less than 10% lithium recovery, which was due to nearly 90% of the lithium being associated with insoluble solids as determined by the results from sequential extraction tests. Calcination of both density fractions under 600 °C for two hours followed by leaching resulted in recovery increases in the range of 70% to 80%. The pyro-metallurgical pretreatment step converted most of the associated lithium minerals to more easy-to-leach forms such as carbonate and metal oxide. Based on mineralogy characterization and leaching test results, it was concluded that the positive effects of calcination on lithium leachability resulted from the dehydration and disintegration of kaolinite as well as dehydroxylation and expansion of muscovite/illite. An analysis of the leaching kinetics revealed that the leaching rate of lithium was controlled by interface transfer and diffusion across the product layer and was negatively impacted when the calcination temperature exceeded 600 °C due to sintering of the kaolinite.

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.

The modes of occurrence associated with rare earth elements (REEs) in bituminous coal sources were evaluated along with their potential recovery by calcination treatment at 600 ℃ followed by sequential extraction. The coal samples were collected from three different resources, i.e., Fire Clay, West Kentucky No. 13, and Illinois No. 6 seams. Sequential extraction tests indicated that the majority of REEs in the calcined samples occurred as metal oxides especially for the West Kentucky No. 13 calcined material (54% of total REEs), which is distinct from untreated coal and combustion byproducts from pulverized coal boilers reported in literature. In addition, heavy REEs were more likely associated with easily dissolvable forms (i.e., ion-exchangeable, carbonates, and metal oxides). The calcined samples were leached under weak acidic conditions with and without adding ammonium sulfate to recover REEs. About 13%, 24%, and 20% of the REEs were extracted from the Fire Clay, West Kentucky No. 13, and Illinois No. 6 materials, respectively, by leaching at pH 4.0. The addition of 1 M ammonium sulfate further increased the recovery values to 18%, 45%, and 32%, respectively. In addition, about 64% of HREEs were extracted from the West Kentucky No. 13 calcined material under this condition. As such, a significant portion of the REEs can be easily extracted from the samples obtained by calcining the coals at 600 ℃.

Rare earth elements (REEs) contained in coal and associated mineral matter exist in several forms including micro-dispersed minerals, ion adsorption onto clay surfaces, and chemically bound. Tests found that REEs can be effectively recovered from certain components of three coal sources by leaching under mild conditions followed by solvent extraction. A range of pH values were evaluated at solution temperatures of 25 and 75 ℃. When using 1.2 M of sulfuric acid, nearly 85% recovery of the REEs was extracted from the middlings material collected from an operating plant. Acid leaching of a second middling source from another plant resulted in 60% of the total REEs being recovered under the same leaching conditions. Solvent extraction treatment of the leachate produced from six different coal sources resulted in products containing up to 50% total REEs from feedstocks starting with around 300 ppm.

Physicochemical Problems of Mineral Processing; ISSN 2084-4735

Flotation separation of scheelite from calcite is difficult due to the similarities in their surface properties. In this work, the flotation behavior of scheelite and calcite using oxidized paraffin soap(OPS), benzohydroxamic acid(BHA) and the mixed OPS/BHA collectors was investigated through micro-flotation experiments. The flotation results of single mineral experiments demonstrated a higher selectivity for the flotation of scheelite from calcite at pH 9 than individual OPS and BHA when using water glass as depressant. In order to probe the validity of the findings, mixed binary minerals experiments, contact angle and zeta potential experiments were also carried out successfully. Accepted version

Insight is a salient psychotherapeutic progress but has rarely been measured in a controlled experimental setting. This study aimed to assess whether textual micro-counseling dialogue could validly evoke insight and to explore the characteristics of insight. The guessing riddle of cognitive psychology was used as a reference of the experimental paradigm. Specifically, textual micro-counseling dialogues applying cognitive restructuring techniques were presented. The participant first read a description of a psychological distress ("problem") and then an explanation ("solution"). Zero-, low-, and high-restructuring solutions were randomly matched to the problems and it was expected that they would trigger different levels of insight experiences. Experts and students evaluated the adaptability and emotional valence of problems, and the insightfulness, novelty, adaptability, and emotional valence of solutions. For both experts and students, different intensities of insightfulness were produced across high-, low- and zero-restructuring solutions. Novelty significantly discriminated the high-restructuring solutions from the other two solution types. Adaptability and emotional valence could discriminate the high- and low-restructuring solutions types from the zero-restructuring solution. Insightfulness had high correlations with novelty and adaptability. These results indicated that textual micro-counseling dialogues with a high-restructuring solution could validly produce the greatest insightfulness and the features of high-restructuring solutions may have reference meaning for improving psychotherapeutic effect.

Previous research indicates that coal and coal by-products are a potential source of critical elements including rare earth elements (REE) with estimated amounts in the range of 50 million metric tons. Despite the proven presence of elevated REE concentrations, commercial extraction and recovery have not been realized. This article provides a review of the abundance, mode of occurrence, and recovery methods of rare earth elements in coal and coal by-products. The feasibility of using established REE extraction and recovery technologies is discussed along with issues associated with their use with coal resources.

Background: The placebo effect in relieving negative emotion arousal is poorly understood.Aims: We examined whether placebo expectation established with noise stimuli could have a transferable anxiolytic effect on negative emotion arousal.Methods: In Experiment 1, noise intensity was surreptitiously lowered during placebo condition in the preconditioning phase to reinforce placebo expectation, and the noise-relieving placebo effect was assessed in the testing phase. In Experiment 2, the same manipulation as in Experiment 1 was administered in the preconditioning phase, but the anxiolytic placebo effect was assessed in the testing phase using negative pictures.Results: Intensity and annoyance by the noise in Experiment 1 were significantly reduced, and unpleasantness in Experiment 2 was also significantly reduced in the placebo condition.Conclusion: Direct noise-relieving placebo effects and transferred anxiolytic placebo effects were found. The present study provides evidence that the placebo effect can be transferred from noise to emotion.

Certain Central Appalachian coals, most notably the Fire Clay coal with a REY-enriched volcanic ash fall tonstein, are known to be enriched in rare earth elements. The Fire Clay tonstein has a greater contribution to the total coal + parting REY than would be inferred from its thickness, accounting for about 20%–35% of the REY in the coal + parting sequence. Underground mining, in particular, might include roof and floor rock and the within-seam partings in the mined product. Beneficiation, necessary to meet utility specifications, will remove some of the REY from the delivered product. In at least one previously published example, even though the tonstein was not present in the Fire Clay coal, the coal was enriched in REY. In this case, as well as mines that ship run-of-mine products to the utility, the shipped REY content should be virtually the same as for the mined coal. At the power plant, however, the delivered coal will be pulverized, generally accompanied by the elimination of some of the harder rock, before it is fired into the boiler. Overall, there are a wide range of variables between the geologic sample at the mine and the power plant, any or all of which could impact the concentration of REY or other critical materials in the coal combustion products. Published version

Aim: The aim of this study was to explore whether the circulating frequency and function of myeloid-derived suppressor cells (MDSCs) are altered in patients with acute coronary syndrome (ACS). Methods: The frequency of MDSCs in peripheral blood was determined by flow cytometry, and mRNA expression in purified MDSCs was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). The suppressive function of MDSCs isolated from different groups was also determined. The plasma levels of certain cytokines were determined using Bio-Plex Pro™ Human Cytokine Assays. Results: The frequency of circulating CD14+HLA-DR-/low MDSCs; arginase-1 (Arg-1) expression; and plasma levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-33 were markedly increased in ACS patients compared to stable angina (SA) or control patients. Furthermore, MDSCs from ACS patients were more potent suppressors of T-cell proliferation and IFN-γ production than those from the SA or control groups at ratios of 1:4 and 1:2; this effect was partially mediated by Arg-1. In addition, the frequency of MDSCs was positively correlated with plasma levels of IL-6, IL-33, and TNF-α. Conclusions: We observed an increased frequency and suppressive function of MDSCs in ACS patients, a result that may provide insights into the mechanisms involved in ACS.

Getting magnetite concentrate with extremely high Fe grade using reverse flotation method has become increasingly important due to the enhanced requirement of iron making industry. The coagulation in magnetite-concentrate flotation system may impose negative effect on flotation performance. This paper combined the DLVO calculation and microscope observation to study the coagulation behavior in the system. The result shows that the coagulation between fine magnetite and coarse silica particle is very likely to occur with energy barrier 1.5 × 10 −18 J at pH 10.0, which is much smaller than 1.6 × 10 −17 J and 3.3 × 10 −17 J for fine magnetite and fine magnetite-coarse magnetite particles. The coating of fine magnetite particle on silica surface was observed under microscope. Mechanical scrubbing increases the concentrate Fe grade and recovery by 1.5% and 8.5% respectively. Magnetite concentrate of 67.9% Fe grade and 71.5% Fe recovery was finally obtained.

The IL-33/ST2 signaling pathway plays an important role in coronary artery disease (CHD), however, few studies have explored how variants in IL-33/ST2 genes influence CHD risk. Here, we examined the association between genetic variants in IL-33, ST2, and IL-1RAcP of the IL-33/ST2 axis and the risk of CHD. We conducted a case-controlled study with 1146 CHD cases and 1146 age- and sex-frequency-matched controls. Twenty-eight single nucleotide polymorphisms (SNPs) in IL-33, ST2, and IL-1RAcP were genotyped by Sequenom MassArray and TaqMan assay. Logistic regression was used to analyze these associations. The SNP rs4624606 in IL-1RAcP was nominally associated with CHD risk. The AA genotype was associated with a 1.85-fold increased risk of CHD (95% confidence interval (CI) = 1.01–3.36, p = 0.045) compared to the TT genotype. Further analysis showed that AA carriers also had a higher risk of CHD than TT + TA carriers (odds ratio (OR) = 1.85, 95% CI = 1.85–3.35, p = 0.043). However, no significant association was observed between variants in IL-33/ST2 genes and CHD risk. Further studies are needed to replicate our results in other ethnic groups with larger sample size.

The influence of conditioning on the flotation of pyrrhotite in the presence of chlorite was investigated through flotation tests, sedimentation tests, and X-ray photoelectron spectroscopy (XPS) analysis. The flotation results show that chlorite slimes dramatically impair the flotation of pyrrhotite. Sedimentation and flotation tests reveal that conditioning can effectively remove chlorite slimes from pyrrhotite surfaces, resulting in an enhanced flotation recovery of pyrrhotite. When mixed minerals were conditioned under the natural atmosphere, a faster conditioning speed and longer conditioning time decreased the flotation recovery of pyrrhotite. However, when mixed minerals were conditioned under a nitrogen atmosphere, a more intensive conditioning process provided better flotation results. XPS analyses illustrate that a faster conditioning speed and longer conditioning time under the natural atmosphere accelerates the oxidation of pyrrhotite, leading to a decrease in the flotation recovery of pyrrhotite. Published version

The activation mechanism of Pb(II) on the flotation of wolframite was systematically investigated. Micro-flotation test results showed that Pb(II) effectively improved the flotation of wolframite in the presence of benzyl hydroxamic acid (BHA). Maximum floatability of wolframite was achieved at approximately pH 8.5. Adsorption of the hydrolyzed species of Pb(II) occurred at this pH value, which provided more activated sites on the wolframite surface. As such, BHA-Pb complexes were formed on the wolframite surface, which increased the BHA adsorption. In addition, BHA-Pb complexes were also formed in solution, which replaced the Fe and interacted with the Mn on the wolframite surface. These findings were proved by the results of zeta-potential measurements, adsorption measurements, solution chemistry calculations, Fourier transform infrared spectroscopy (FTIR) analysis, and X-ray photoelectron spectroscopy (XPS) characterization. Accepted version