A kaolinite containing 245 ppm of REEs was used as a feedstock for REE recovery. Acid leaching test results showed that less than 20% of the REEs were leached using 1.2 mol/L HCl. However, after ...thermal treatment at 600 °C, a recovery of over 80% was obtained with a much lower acid concentration (0.01 mol/L). Meanwhile, only 3.91% Al, 2.34% Fe, 8.63% K, 9.32% Mg, 0.08% Ti, and 5.34% Ca were simultaneously extracted. Therefore, high-purity rare earth products are likely produced from the kaolinite. To achieve a more comprehensive utilization of the kaolinite, the residual solid after REE recovery was subjected to a selective leaching process to prepare porous silica. Comparisons among three different types of mineral acids showed that H2SO4 provided the best performance. The effects of different factors were investigated using the response surface methodology. A porous silica with as high as 336.95 m2/g specific surface area was ultimately produced.
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•Less than 20% of total REEs were extracted from a kaolinite using 1.2 mol/L HCl.•Around 80% of total REEs were extracted using 0.01 mol/L HCl after thermal activation.•Residual solid after REEs recovery was used to prepare porous silica.•A porous silica with as high as 336.95 m2/g specific surface area was obtained.
REE recovery from a kaolinite sample was conducted in the present study. The results of mineralogical analyses, salt leaching, and acid leaching tests confirmed that REEs predominantly existed as ...florencite (REEAl3(PO4)2(OH)6) in the material, and the proportion of ion-exchangeable and ion-substituted REEs was negligible. Mechanical grinding for 4 h completely destroyed the crystal structure of the material, but the recovery of total REEs was less than 20%, indicating that insufficient liberation of the REE-bearing particles is not the only factor leading to the low recovery. Thermal treatment of the raw material at 600 °C for 2 h largely enhanced the total REE recovery to as high as 92%. The improved recovery was ascribed to the thermal decomposition of crystallized florencite into an amorphous phase, which was proved through transmission electron microscopy - energy dispersive X-ray analysis. Findings from the study will contribute to REE recovery and comprehensive utilization of kaolinite.
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•REEs were recovered from a non-ion adsorption kaolinite.•REEs predominantly existed as REE-bearing minerals (e.g., florencite).•Mechanical grinding did not largely increase the REE recovery.•Thermal treatment at 600 °C considerably improved the REE recovery.•The increases in REE recovery were due to thermal decomposition of florencite.
•Carbon flotation from fly ash was performed using an emulsified diesel collector.•Emulsification using sodium petroleum sulfonate enhanced the flotation efficiency.•Carbon recovery was improved from ...41% to 86% using the emulsified collector.•The enhanced efficiency was attributed to the sulfonate groups in the emulsifier.
It is critical to separate carbon from fly ash due to its increasing amount being produced per year and component requirements for secondary utilizations. Flotation is an efficient technique to fulfill this task. Effects of diesel emulsification using sodium petroleum sulfonate on unburned carbon flotation from a fly ash sample were studied. Flotation tests showed that carbon recovery was increased from 41% to 86% using the emulsified collector at the same dosage level (0.5 kg/ton) as diesel. Zeta potential measurements indicated that both the carbon and emulsified collector droplets carried negative charges within the studied pH range. For fly ash particles with high carbon content, adsorption bands of carbonyl bond (CO) were detected in the FTIR spectra, which agreed with the XPS characterization findings. XPS analysis indicated that the emulsified diesel (ED) collector interacted more intensively with the surface carbon-oxygen groups relative to the normal diesel collector. Finally, the improved efficiency of ED is proved to be related to its polar groups and reduced oil droplet size. The polar groups of ED (mainly sulfonate) interacted with the surface oxygen containing groups (e.g., CO and COOH) through hydrogen bonding and Lewis acid base interaction.
In order to study the effect of soil salt content on the corrosion of buried metal by the stray current in urban rail transit, a small experimental platform for the buried metal corrosion is built. ...The corrosion rate and mass loss of buried carbon steel specimens in soil samples with or without DC stray current are measured and calculated when different content of NaCl is added into the soil samples, respectively. The experimental results show that the corrosion rate and mass loss of the buried metal increase with the increase of soil salt content. DC stray current will aggravate the corrosion of the buried metal. The corrosion degree of buried metal will be seriously aggravated under the coupling action of DC stray current and salt. When there is no DC stray curren, the corrosion degree of buried metal is relatively small, and the influence of soil salt content on the buried metal corrosion is also relatively small. Finally, a multiphysics simulation model corresponding to the experiment is established to verify the experimental results. The simulation results are basically consistent with the experimental results, which proves the accuracy of the experimental results. The research results can provide a theoretical basis for the corrosion protection design of subway stray current.
Backgrounds
Although drug-eluting stents are the most common interventional devices for patients with coronary disease, drug-coated balloons (DCBs) represent a novel therapeutic alternative in ...certain scenarios. This prospective, observational all-comers study explored the clinical outcomes of DCB use in patients with coronary lesions.
Methods and results
All patients treated with DCBs were enrolled in this study, including patients with in-stent restenosis (ISR) or de novo lesions. The primary outcome was the target lesion revascularization (TLR) rate at one year.
We enrolled 2306 patients with 2660 lesions and performed DCB angioplasty in 399 patients (17.3%) with ISR and 1907 patients (82.7%) with de novo lesions. During follow-up (366 ± 46 days), the TLR rate was lower in the de novo lesion group (1.31%) compared to the ISR group (7.02%) odds ratio (OR) 0.176, 95% confidence interval (CI) 0.101–0.305,
p
< 0.001. Patients with de novo lesions had a lower yearly incidence of MACE compared to ISR patients (2.73 vs. 9.27%, respectively, OR 0.274, 95% CI 0.177–0.424,
p
< 0.001) and a lower incidence of any revascularization (5.09 vs. 13.03%, OR 0.358, 95% CI 0.251–0.510,
p
< 0.001). No significant differences between groups were observed in the rates of cardiac death (OR 0.783, 95% CI 0.258–2.371,
p
= 0.655) or MI (OR 0.696, 95% CI 0.191–2.540,
p
= 0.573).
Conclusions
DCB angioplasty in this all-comers, real-world, prospective study was safe and efficient with low TLR and MACE rates. Thus, DCB appears to be an attractive alternative for the stent-less treatment of de novo coronary lesions.
Graphic abstract
ISR in-stent restenosis; OR odds ratio; CI confidence interval; TLR target lesion revascularization; MACE major adverse cardiovascular events; MI myocardial infraction. MACE defined as the composite outcome of cardiac death, myocardial infarction, and target vessel revascularization. Any revascularization includes any percutaneous coronary intervention, and coronary artery bypass grafting.
•Acid mine drainage (AMD) contains critical elements (e.g., Co, Mn, and Ni).•A flowsheet was developed to recover and purify Co, Mn, and Ni from AMD.•Co and Ni products with 94% and 100% purity were ...generated, respectively.•A Mn product containing 30 wt.% Mn was generated.
The rapid development of advanced technologies has increased the demand for critical elements, such as Mn, Co, and Ni. A systematic study was conducted to develop a process for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). As major contaminants, Fe and Al in the solution were sequentially precipitated and eliminated by elevating the pH to around 4.00 and 6.50, respectively. After that, a pre-concentrated slurry containing 3,794 mg/L Mn, 59 mg/L Co, 127 mg/L Ni, and 300 mg/L Zn was obtained by collecting the precipitates formed in the pH range of 6.50 to 10.00. The pH of the pre-concentrated slurry was decreased to around 5.00 by adding HCl to re-dissolve Co, Ni, and Zn for further purification. At this pH, greater than 50% of Mn remained undissolved, and filtration of the undissolved material resulted in a product with around 30 wt.% Mn. Sodium sulfide was added into the re-dissolved solution to selectively precipitate Co, Ni, and Zn while remaining Mn in the solution. Almost 100% of Co, Ni, and Zn but only around 15% of Mn were precipitated using a sulfur to metal molar ratio of 1 at pH 4.00. The sulfide precipitate was calcined at 200 °C for 2 h and then completely dissolved in 1.2 M HCl. The critical elements existing in the dissolved solution were efficiently separated using a two-stage solvent extraction process. Ultimately, Co and Ni products with almost 94% and 100% purity were obtained by sulfide and alkaline precipitation, respectively.
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•Non-calcined coal and combustion byproducts contain high amounts of insoluble REEs.•Calcined coal contains more soluble REEs as metal oxides.•Rare earth oxides can be readily extracted under mild ...acid conditions.•Ammonium sulfate prevents the re-adsorption of REEs on clay surfaces.•Selective leaching of heavy REEs resulted in 65% recovery at pH 4 using 1 M (NH4)2SO4.
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 ℃.
Our previous study showed that placebo expectations can develop in a transferable manner; for example, a placebo expectation developed within an analgesic experience may lead to reduced anxiety. ...Considering that activities in such emotion‐responsive areas as the amygdala and insula can be detected through functional magnetic resonance imaging (fMRI), we used fMRI to further study the transferable placebo anxiolytic effect. A main‐effect analysis showed that activity in the amygdala and insula was reduced in the placebo condition, whereas an interaction analysis showed activity in the two regions was selectively attenuated in the placebo condition when unpleasant pictures were viewed. We also observed greater activity in the subgenual anterior cingulate cortex under placebo conditions when either emotionally negative or neutral pictures were viewed. These data suggest that the anxiety‐relieving placebo effect arose from a reward‐related response underpinned by the participants' expectations.
Tendon is a major component of musculoskeletal system connecting the muscles to the bone. Tendon injuries are very common orthopedics problems leading to impeded motion. Up to now, there still lacks ...effective treatments for tendon diseases.
Tendon stem/progenitor cells (TSPCs) were isolated from the patellar tendons of SD rats. The expression levels of genes were evaluated by quantitative RT-PCR. Immunohistochemistry staining was performed to confirm the presence of tendon markers in tendon tissues. Bioinformatics analysis of data acquired by RNA-seq was used to find out the differentially expressed genes. Rat patellar tendon injury model was used to evaluate the effect of U0126 on tendon injury healing. Biomechanical testing was applied to evaluate the mechanical properties of newly formed tendon tissues.
In this study, we have shown that ERK inhibitor U0126 rather PD98059 could effectively increase the expression of tendon-related genes and promote the tenogenesis of TSPCs in vitro. To explore the underlying mechanisms, RNA sequencing was performed to identify the molecular difference between U0126-treated and control TSPCs. The result showed that GDF6 was significantly increased by U0126, which is an important factor of the TGFβ superfamily regulating tendon development and tenogenesis. In addition, NBM (nonwoven-based gelatin/polycaprolactone membrane) which mimics the native microenvironment of the tendon tissue was used as an acellular scaffold to carry U0126. The results demonstrated that when NBM was used in combination with U0126, tendon healing was significantly promoted with better histological staining outcomes and mechanical properties.
Taken together, we have found U0126 promoted tenogenesis in TSPCs through activating GDF6, and NBM loaded with U0126 significantly promoted tendon defect healing, which provides a new treatment for tendon injury.
The present study compared learning-based placebo effect and cognition-based reappraisal, to reveal the common and unique neural mechanisms between the two emotion regulations. First, the ...anxiety-relieving effect was tested by conducting a behavioral experiment. Next, the participants with the highest placebo or reappraisal effect were selected for the functional magnetic resonance imaging experiments. The results indicated that: (1) they both attenuated activity in the right amygdala and right insula, and (2) placebo effect activated the left subgenual cingulate whereas reappraisal activated the right dorsal prefrontal cortex (PFC) and the left inferior PFC. Our results show that learning-based placebo effect and cognition-based reappraisal have common anxiety-relieving effects. The placebo effect mainly depends on direct pathway subgenual cingulate–amygdala to regulate emotions, whereas the reappraisal may rely on both indirect pathways, such as the dorsal PFC–subgenual cingulate–amygdala, and direct pathways, such as the ventral lateral PFC–amygdala to regulate emotions.
► We compared learning-based placebo effect and cognition-based reappraisal strategies .► The participants showing the highest placebo or reappraisal effect were selected. ► Two strategies both attenuated activity in the amygdala and right insula. ► Placebo may rely on direct but reappraisal on both direct and indirect PFC path.
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