Improved classification of soil As contamination at continental scale: resolving class imbalances using machine learning approach.

The identification of arsenic (As)-contaminated areas is an important prerequisite for soil management and reclamation. Although previous studies have attempted to identify soil As contamination via machine learning (ML) methods combined with soil spectroscopy, they have ignored the rarity of As-contaminated soil samples, leading to an imbalanced learning problem. A novel ML framework was thus designed herein to solve the imbalance issue in identifying soil As contamination from soil visible and near-infrared spectra. Spectral preprocessing, imbalanced dataset resampling, and model comparisons were combined in the ML framework, and the optimal combination was selected based on the recall. In addition, Bayesian optimization was used to tune the model hyperparameters. The optimized model achieved recall, area under the curve, and balanced accuracy values of 0.83, 0.88, and 0.79, respectively, on the testing set. The recall was further improved to 0.87 with the threshold adjustment, indicating the model's excellent performance and generalization capability in classifying As-contaminated soil samples. The optimal model was applied to a global soil spectral dataset to predict areas at a high risk of soil As contamination on a global scale. The ML framework established in this study represents a milestone in the classification of soil As contamination and can serve as a valuable reference for contamination management in soil science.

Central hyperthyroidism due to an ectopic TSH-secreting pituitary tumor: a case report and literature review.

Ectopic thyroid-stimulating hormone (TSH)-secreting tumors are extremely rare, with only 15 reported cases in the literature. Herein, we described a 60-year-old female patient with thyrotoxicosis and elevated or unsuppressed levels of TSH. Family history and laboratory and genetic tests did not support a diagnosis of resistance to thyroid hormone (RTH). Given the unsuppressed TSH, TSH-secreting tumor was suspected, and magnetic resonance imaging (MRI) of the pituitary gland was performed. Surprisingly, the MRI scans revealed a nodule in the nasopharynx rather than a pituitary tumor in the sella region. Further evaluation using Gallium-68 DOTATATE positron emission tomography/computed tomography (68Ga-DOTATATE PET/CT) demonstrated increased DOTATATE uptake in the nasopharyngeal nodule. Additionally, an octreotide suppression test (OST) revealed an obvious reduction in TSH levels, further supporting the suspicion of the nasopharyngeal mass as the cause of inappropriate TSH secretion. To prepare for surgery, the patient received preoperative administration of octreotide, resulting in the normalization of TSH and thyroid hormone levels. The patient subsequently underwent successful surgical removal of the nasopharyngeal mass. Following the procedure, the patient experienced complete resolution of hyperthyroidism symptoms, with TSH declined and thyroid hormone levels returned to normal. Histochemistry analysis of the tumor revealed positive staining for TSH, growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), and somatostatin receptor 2 (SSTR2). We discussed differential diagnosis of hyperthyroidism due to inappropriate TSH secretion, with a particular emphasis on the importance of 68Ga-DOTATATE PET/CT in combination with OST for identifying ectopic pituitary tumors.

Artificial intelligence-based prediction model for the elemental occurrence form of tailings and mine wastes.

With the advent of the second industrial revolution, mining and metallurgical processes generate large volumes of tailings and mine wastes (TMW), which worsens global environmental pollution. Studying the occurrence of metal and metalloid elements in TMW is an effective approach to evaluating pollution linked to TMW. However, traditional laboratory-based measurements are complicated and time-consuming; thus, an empirical method is urgently needed that can rapidly and accurately determine elemental occurrence forms. In this study, a model combining Bayesian optimization and random forest (RF) approaches was proposed to predict TMW occurrence forms. To build the RF model, a dataset of 2376 samples was obtained, with mineral composition, elemental properties, and total concentration composition used as inputs and the percentage of occurrence forms as the model output. The correlation coefficient (R), coefficient of determination, mean absolute error, root mean squared error, and root mean squared logarithmic error metrics were used for model evaluation. After Bayesian optimization, the optimal RF model achieved accurate predictive performance, with R values of 0.99 and 0.965 on the training and test sets, respectively. The feature significance was analyzed using feature importance and Shapley additive explanatory values, which revealed that the electronegativity and total concentration of the elements were the two features with the greatest influence on the model output. As the electronegativity of an element increases, its corresponding residual fraction content gradually decreases. This is because the solubility typically increases with the solvent's polarity and electronegativity. Overall, this study proposes an RF model based on the nature of TMW that can rapidly and accurately predict the percentage values of metal and metalloid element occurrence forms in TMW. This method can minimize testing time requirements and help to assess TMW pollution risks, as well as further promote safe TMW management and recycling.

Fluorides immobilization through calcium aluminate cement-based backfill: Accessing the detailed leaching characterization under torrential rainfall.

Urbanization and economic development have increased the demand for fertilizers to sustain food crop yields. Huge amounts of by-products, especially phosphogypsum (PG), are generated during the wet processing of rock phosphate to produce fertilizers. Chronic exposure to fluoride in phosphogypsum in groundwater as a result of the weathering of fluoride-containing waste poses a significant health risk to millions of people. We propose a method for using calcium aluminate cement (CAC) to remediate high fluoride contents in solid waste. Column leaching tests under harsh rainfall conditions confirmed the efficient fluoride immobilization capacity of a CAC binder. Although the fluoride concentrations in leachates during the first 1-2 days (1.25 mg/L) slightly exceeded the threshold of 1.00 mg/L, the concentrations over 3-28 days (ranging from 0.98 to 0.83 mg/L) consistently remained well within the acceptable range. Furthermore, our characterization and geochemical modeling revealed the fluoride retention mechanisms of CAC-stabilized PG under laboratory-simulated conditions of torrential rainfall. During leaching, physical encapsulation prevents fluoride from contacting leachate. However, an unfavorable pH value can cause the release of fluoride from the cement matrix, which is subsequently captured by aluminate hydrate through adsorption or co-precipitation. We quantified the carbon footprint of CAC for immobilizing 1 mg of fluoride in PG, obtaining a remarkably low value of 4.4 kg of CO2, in contrast to the emissions associated with the use of ordinary Portland cement (OPC). The findings suggest a unique opportunity for extensive PG remediation. This opportunity extends the horizons of achieving zero-waste emissions in the phosphorus industry and has practical significance in the context of reducing carbon emissions.

A case of endobronchial metastasis of colon cancer mimics sarcoidosis, and a review of related literature.

PURPOSE: Endobronchial metastases (EBM) are defined as bronchoscopically visible lesions histopathologically identical to extrapulmonary tumors. We summarized the literature on endobronchial metastasis of colorectal cancer and give a brief review. METHOD: We present a rare case with an episode mistaken for sarcoidosis and unexpectedly identified as colon cancer by bronchoscopic biopsy. A 53-year-old man with dry cough and dyspnea had diffuse micro lung nodules and lymphadenopathy on CT and PET/CT. He was diagnosed with sarcoidosis and took steroid therapy, but the symptoms could not be alleviated. Bronchoscopy was suggested. He was finally identified with colon cancer by bronchoscopic biopsy, which was confirmed by endoscopic biopsy. We summarise the clinical manifestations, imaging, prognosis of EMB of colorectal cancer. RESULT: EBM are rare. Colorectal cancer is common in EBM and the frequency is increasing. CONCLUSION: EBM should be distinguished from primary lung cancer, sarcoidosis.

The comparison of three different molecular imaging methods in localization and grading of insulinoma.

Aims: This cross-sectional study compared the value of molecular imaging (Exendin-4 positron emission tomography/computed tomography [PET/CT], 68Ga-DOTATATE PET/CT, 18F- fluorodeoxyglucose [FDG] PET/CT) in insulinoma localization by stratified tumor size and grading, and explored the correlation of the related the maximum standardized uptake value (SUVmax) with insulinoma grading, Ki-67, maximum tumor diameter, and glucose metabolism. Methods: In 28 insulinoma patients, the sensitivity of three types of PET/CT for localizing insulinoma was calculated according to tumor size and grade. We compared the SUVmax for different insulinoma grades and analyzed the correlation of SUVmax with Ki-67, maximum tumor diameter, and glucose metabolism indicators. Results: The study included 12 grade (G) 1 and 16 G2 cases, with maximum tumor diameters ranging from 9 to 40 mm. Without differentiation by size and grade, the sensitivity of Exendin-4 PET/CT to localize insulinoma was 100%, which significantly exceeded that of 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT (75% and 57%, respectively). In tumors with a maximum diameter ≤ 20 mm and ≤ 15 mm, the sensitivity of Exendin-4 (both 100%) significantly exceeded that of 68Ga-DOTATATE PET/CT (74% and 64%, respectively) and 18F-FDG PET/CT (54% and 50%, respectively). In G1 tumors, the sensitivity of Exendin-4 PET/CT was significantly higher than that of 18F-FDG PET/CT, but not that of 68Ga-DOTATATE PET/CT, while in G2 tumors, the sensitivity of Exendin-4 PET/CT was significantly higher than that of both other types. However, all three PET/CT types missed a metastatic lymph node in one patient. The 18F-FDG PET/CT SUVmax was significantly lower than that of the other PET/CT types and that of 68Ga-DOTATATE PET/CT was significantly lower in G2 than in G1. 68Ga-DOTATATE PET/CT SUVmax correlated negatively with Ki-67. A receiver operating characteristic (ROC) curve suggested that 68Ga-DOTATATE PET/CT SUVmax > 19.9 could predict G1 tumors. Conclusion: Exendin-4 PET/CT was superior to 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT for insulinoma localization, particularly small and G2 tumors, but its diagnostic value in small metastatic lymph nodes requires further exploration. 68Ga-DOTATATE PET/CT SUVmax could be used as an adjunct to pathology, and a value > 19.9 could predict G1 tumors. No PET/CT SUVmax could predict tumor maximum diameter and glucose metabolism.

Mechanistic insights into Pb and sulfates retention in ordinary Portland cement and aluminous cement: Assessing the contributions from binders and solid waste.

Identifying immobilization mechanisms of potentially toxic elements (PTEs) is of paramount importance in the field application of solidification/stabilization. Traditionally, demanding and extensive experiments are required to better access the underlying retention mechanisms, which are usually challenging to quantify and clarify precisely. Herein, we present a geochemical model with parametric fitting techniques to reveal the solidification/stabilization of Pb-rich pyrite ash through conventional (ordinary Portland cement) and alternative (calcium aluminate cement) binders. We found that ettringite and calcium silicate hydrates exhibit strong affinities for Pb at alkaline conditions. When the hydration products are unable to stabilize all the soluble Pb in the system, part of the soluble Pb may be immobilized as Pb(OH)2. At acidic and neutral conditions, hematite from pyrite ash and newly-formed ferrihydrite are the main controlling factors of Pb, coupled with anglesite and cerussite precipitation. Thus, this work provides a much-needed complement to this widely-applied solid waste remediation technique for the development of more sustainable mixture formulations.

Evaluating the metal recovery potential of coal fly ash based on sequential extraction and machine learning.

Given the depletion of metal resources and the potential leaching of toxic elements from solid waste, secondary recovery of metal from solid waste is essential to achieve coordinated development of resources and the environment. In this study, hybrid models combining the gradient boosting decision tree and particle swarm optimization algorithm were constructed and compared based on two different datasets. Additionally, a new, quantitative evaluation index for metal recovery potential (MRP) was proposed. The results showed that the model constructed using more elemental properties could more accurately predict metal fractions in coal fly ash (CFA) with an R2 value of 0.88 achieved on the testing set. The MRP index revealed that the DAT sample had the greatest recovery potential (MRP = 43,311.70). Ca was easier to recover due to its high concentration and presence mostly in soluble fractions. Model post-analysis highlighted that the elemental properties and total concentrations generally exerted a greater influence on the metal fractions. The innovative evaluation strategy based on machine learning and sequential extraction presented in this work provides an important reference for maximizing metal recovery from CFA to achieve environmental and economic benefits with the goal of sustainable development.

In-situ remediation of phosphogypsum in a cement-free pathway: Utilization of ground granulated blast furnace slag and NaOH pretreatment.

In-situ remediating phosphogypsum (PG) for cemented paste backfill (CPB) in the contaminated site is economic management for promoting sustainable developments in the phosphate industry. This study concerns the combined use of NaOH pretreatment and ground-granulated blast furnace slag (GGBFS) additives to promote the solidification/stabilization of PG with a lower carbon footprint pathway. According to physico-chemical analyses, the NaOH pretreatment effectively removed approximately 95% of F within the PG, which may originally be present as sparingly soluble fluorides or coexisting with silicates. The micro mineralogical characterization illustrates that the pretreatment can accelerate the early age hydration, with more hydration products observed, including calcium silicate hydrates and ettringite, effective F and P retention candidates. Whereas the incorporation of GGBFS plays an essential role in promoting the generation of additional cement hydrates at the following stages. The macro mechanical performance analysis indicates that the mixtures of pretreated-PG-OPC-GGBFS exhibit an excellent mechanical performance satisfying the design criteria. Subsequent elemental mapping and toxicity characteristic leaching procedures demonstrate that this combined approach has a competitive F and P immobilization ability compared to the typical OPC binder and individual GGBFS addition. The newly formed phases effectively controlled the concentration of F and P through adsorption, incorporation, or encapsulation. Objectively, the proposed methodology can be a promising candidate pathway for extrapolating the in-situ immobilization of PG. This study opens up new perspectives for synergetically recycling PG and GGBFS in a profitable and low carbon footprint way.

The Phosphorus Transport in Groundwater from Phosphogypsum-Based Cemented Paste Backfill in a Phosphate Mine: A Numerical Study.

Stacked phosphogypsum (PG) can not only cause a waste of resources but also has a serious negative impact on the surface environment. Phosphogypsum backfilling (PGB) in the underground goaf is a useful approach to effectively address the PG environmental problems. However, the effects of this approach on the groundwater environment have not been studied. Therefore, the present study aims to assess the spatiotemporal evolution mechanism of total phosphorus (TP) in groundwater to solve the diffusion regular pattern of TP in PGB bodies, as well as to manage and mitigate the impacts of TP on the groundwater system. In this study, leaching toxicity experiments and a numerical groundwater simulation software (GMS10.4) were combined to develop a three-dimensional conceptual model for predicting the groundwater flow and contaminant transport under steady-state conditions in a phosphorus mine in Anhui. The results showed a lower TP concentration than the TP standard concentration (0.2 mg/L) at a source concentration of 0.59 mg/L. However, groundwater TP source concentrations of 1.88 and 2.46 mg/L in the study area were found to exceed the standard concentration for a certain time and areas. In addition, the transport and dispersion of TP are influenced not only by the groundwater flow field, drainage ditches, rivers, and wells but also by the adsorption and attenuation effects of the soil that occur during the transport process, affecting the dispersion distance and distribution of groundwater TP concentrations. The results of the present study can promote the development of groundwater-friendly PGB technology, providing a great significance to the construction of green mines and the promotion of ecological civilization.

The Slope Safety, Heavy Metal Leaching, and Pollutant Diffusion Prediction Properties under the Influence of Unclassified Cemented Paste Backfill in an Open Pit.

Open-pit unclassified cemented paste backfilling (OPUCPB) methods have not only addressed the disposal problems of tailings but also eliminated geological hazards of high and steep open pit slopes and created conditions for ecological restoration of the open pit in the future. In this paper, slope safety simulations, heavy metal leaching, groundwater monitoring, and pollutant diffusion predictions were examined to evaluate the slope safety pattern and environmental protection enabled by OPUCPB. The results showed that: (1) The safety factor of the open pit slope was proportional to the height of OPUCPB operation. Under the condition of seismic force and seepage field, the safety factor of slope B was increased from 1.188 to 1.574 by OPUCPB. (2) The toxic and harmful components in tailings were significantly stabilized by the OPUCPB. Under the conditions of acid leaching and water leaching, the quality of the leaching solution met the requirements of the class III limit of groundwater (GB/T14848-2017). (3) The monitoring results of groundwater quality around the open pit showed that the OPUCPB had no effect on groundwater, and the water quality met the requirements of the class III limit of groundwater (GB/T14848-2017). (4) Considering the diffusion prediction of pollutants and groundwater under extreme conditions, it was found that the pollution process is slow, and the shortest time required for pollutants to reach the standard limit is 232 d at a distance of 50 m from the leakage point. Therefore, the influence of OPUCPB can be controlled, and this method can achieve improved reclamation of open pits and safety treatment of tailings. It was worth popularizing and applying in mining enterprises.

Highly-efficient fluoride retention in on-site solidification/stabilization of phosphogypsum: Cemented paste backfill synergizes with poly-aluminum chloride activation.

Phosphogypsum (PG) is a massively generated hazardous by-product in the phosphorus industry. Large-scale, efficient, profitable on-site recycling is an emerging topic for promoting sustainable phosphorus circularity and mitigating potential human exposure. In this work, we integrated a green and low-cost additive polymeric aluminum chloride (PAC) into the binder design of PG immobilization. The overall experimental results illustrate that the incorporation of PAC can efficiently promote the cement hydration reaction, with amorphous phases increased from 25.9 wt% (control group) to 27.5 wt% (with 2 g/L PAC). The macro-investigations indicate that the PAC optimized the porosity and mechanical properties of specimens, facilitating a mechanically stable solidified matrix for extrapolating its field engineering application. The detailed micrographs and elemental mapping demonstrate that apart from co-existing with the hydration products, the PAC agent plays a role in the immobilization of fluoride. Herein, the combined optimization enhanced the fluoride retention capacity due to the precipitated additional hydration products, comparable encapsulation, and high adsorption ability of PAC agents. Therefore our design of PAC-augmented binders can open up a new field of PG on-site solidification/stabilization application that ensures efficient fluoride retention in a technically feasible and financially profitable methodology.

Ab initio calculations of CO2 adsorption on ß-C2S(100) and M3-C3S(001) surfaces: An exploration of early CO2 sequestration pathways.

Investigating CO2 sequestration in cement-based materials is significant for achieving carbon neutrality in the cement and concrete industries. The early CO2 sequestration pathways on cement-based materials are fundamental for CO2 sequestration, which is not clear. Towards this, the adsorption behavior of CO2 on ß-C2S(100) and M3-C3S(001) was investigated at the atomic level using density functional theory calculations, which were then compared with water adsorption results. The molecular adsorption configurations of CO2 on both ß-C2S(100) and M3-C3S(001) were tilted from their initial configurations due to the influence of surface Ca and O atoms. The CO2 adsorption energy on M3-C3S(001) and ß-C2S(100) were -0.458 eV and -0.426 eV, respectively, indicating adsorption on M3-C3S(001) was more energetically favorable. After CO2 adsorption, electrons were transferred from the surface to the CO2 molecule. Furthermore, the Ca-O bond orders of ß-C2S(100) and M3-C3S(001) after CO2 adsorption were maximally decreased by 2.79% and 6.99%, respectively. A more significant adsorption influence on surfaces was found for H2O, with more negative adsorption energy, more evident electron transfer, and a greater decrease in bond order. The CO2 adsorption on ß-C2S(100) and M3-C3S(001) were still spontaneous at 298 K and 1 atm. This study provides important theoretical insights into early CO2 sequestration at the atomic level, which has practical implications for the design of efficient CO2 sequestration technologies.

The carbon uptake and mechanical property of cemented paste backfill carbonation curing for low concentration of CO2.

Large volumes of carbon dioxide are released during mining and ore resource development, and cemented paste backfill (CPB) materials are placed in the mined-out stopes where can be discharged from polluted air containing CO2. The construction of green mines and the goal of achieving carbon neutrality have become an inevitable choice for the mining industry to achieve the harmonious development of rational exploitation of resources and environmental protection. Against this background, to minimize the carbon emissions from the mining industry and promote the efficient utilization of CPB, this study investigated the carbon-uptake characteristics and mechanical property of CPB in underground mined-out stopes with 1.5 % concentration CO2. The results show that the carbonation curing (CC) increased the carbonation rate by nearly 4 times compared to natural curing, while the samples exhibited total carbonation within 28 days. This indicates that CO2 uptake could occur within the CPB. The CO2 was absorbed as calcium carbonate minerals, and each ton of CPB can ideally absorb about 78.4 kg CO2 and treat 2600 m3 of dirty air in the mined-out stopes. The increase in early uniaxial compressive strength (UCS) during CC required a higher cement concentrate, and the CC would retard the development of later compressive strength. Microstructure analysis indicated that the CC refined the pore structure and reduced the porosity of the CPB. It also affected the crystal growth and distribution of hydration and carbonation products, further influencing the difference in strength. In summary, CPB technology can potentially be useful during carbon uptake and may assist in mitigating carbon emissions from the mining industry and promoting environment friendly development.

Ab initio calculation of the adsorption of As, Cd, Cr, and Hg heavy metal atoms onto the illite(001) surface: Implications for soil pollution and reclamation.

Elucidating the mechanisms of heavy metal (HM) adsorption on clay minerals is key to solving HM pollution in soil. In this study, the adsorption of four HM atoms (As, Cd, Cr, and Hg) on the illite(001) surface was investigated using density functional theory calculations. Different adsorption configurations were investigated and the electronic properties (i.e., adsorption energy (Ead) and electron transfer) were analyzed. The Ead values of the four HM atoms on the illite(001) surface were found to be As > Cr > Cd > Hg. The Ead values for the most stable adsorption configurations of As, Cr, Cd, and Hg were -1.8554, -0.7982, -0.3358, and -0.2678 eV, respectively. The As atoms show effective chemisorption at all six adsorption sites, while Cd, Cr, and Hg atoms mainly exhibited physisorption. The hollow and top (O) sites were more favorable than the top (K) sites for the adsorption of HM atoms. The Gibbs free energy results show that the illite(001) surface was energetically favorable for the adsorption of As and Cr atoms under the influence of 298 K and 1 atm. After adsorption, there was a redistribution of positions and reconfiguration of the chemical bonding of the surface atoms, with a non-negligible influence around the upper surface atoms. Bader charge analysis shows electrons were transferred from the surface to the HM atoms, and a strong correlation between the valence electron variations and the adsorption energy was observed. HM atoms had a high electronic state overlap with the surface O atoms near the Fermi energy level, indicating that the surface O atoms, though not the topmost atoms around the surface, significantly influence HM adsorption. The above results show illite(001) preferentially adsorbed As among all four investigated HM atoms, indicating that soils containing a high proportion of illite might be more prone to As pollution.

Retention of phosphorus and fluorine in phosphogypsum for cemented paste backfill: Experimental and numerical simulation studies.

The solidification/stabilization of phosphogypsum using cemented paste backfill (OCPB) provides a low-cost and alternative in-situ technique for recycling phosphogypsum stockpiles. But the OCPB is far from obtaining steady states in which the pollutants would redistribute as a response to dynamic environmental conditions. Further, the associated chemical interactions and the mineralogy information of the solubility-controlling phases of contaminants (fluorine and phosphorus) have not been thoroughly studied or fully understood. In this study, a framework coupling the chemical, mineralogical, and morphological analyses is used to determine the fluoride and phosphate retention mechanisms of immobilized OCPB. Then the pH-dependent leaching tests and numerical simulation is applied as a useful tool to identify the minerals controlling stabilized OCPB leaching behavior. The overall findings proved that aluminate-rich calcium silicate hydrates play an essential role in fluoride and phosphate retention. Both experimental and simulational acid neutralization and leaching curves indicate that the cementitious matrix works as a strong buffering material ensuring high pH conditions that are necessary for fluorine and phosphorus retention. Although discrepancies were observed in absolute fluorine and phosphorus leaching values at highly acidic conditions, the simulations are able to describe highly amphoteric leaching behavior. The simulation suggests that the aluminum species and calcium phosphates governed the solubility of fluorine and phosphorus, respectively. The results of this work would have implications for predicting the leaching behavior of OCPB in detrimental and multiple environments.

Hydration and Mechanical Properties of Blended Cement with Copper Slag Pretreated by Thermochemical Modification.

The application of granulated copper slag (GCS) to partially replace cement is limited due to its low pozzolanic activity. In this paper, reconstituted granulated copper slag (RGCS) was obtained by adding alumina oxide (Al2O3) to liquid copper slag. Blended cement pastes were formulated by a partial substitute for ordinary Portland cement (OPC) with the RGCS (30 wt%). The pozzolanic activity, mechanical development, and the microstructure were characterized. The results show that 5-10 wt% Al2O3 contributes to the increase in magnetite precipitation in RGCS. The addition of Al2O3 alleviates the inhibition of C3S by RGCS and accelerates the dissociation of RGCS active molecules, thus increasing the exothermic rate and cumulative heat release of the blended cement pastes, which are the highest in the CSA10 paste with the highest Al2O3 content (10 wt%) in RGCS. The unconfined compressive strength (UCS) values of blended cement mortar with 10 wt% Al2O3 added to RGCS reach 27.3, 47.4, and 51.3 MPa after curing for 7, 28 and 90 d, respectively, which are the highest than other blended cement mortars, and even exceed that of OPC mortar at 90 d of curing. The pozzolanic activity of RGCS is enhanced with the increase in Al2O3 addition, as evidenced by more portlandite being consumed in the CSA10 paste, forming more C-S-H (II) gel with a higher Ca/Si ratio, and a more compact microstructure with fewer pores than other pastes. This work provided a novel, feasible, and clean way to enhance the pozzolanic activity of GCS when it was used as a supplementary cementitious material.

Resistance Loss in Cemented Paste Backfill Pipelines: Effect of Inlet Velocity, Particle Mass Concentration, and Particle Size.

Cemented paste backfill (CPB), a technology placing the solid waste into mined-out stopes in the mine through pipeline transportation, has been widespread all over the world. The resistance loss is an important parameter for pipeline transport, which is significantly affected by the slurry characteristics. However, the coupling effect of inlet velocity (IV), particle mass concentration (PMC), and particle size (PS) has not been well evaluated and diagnosed. Hence, the CFD-based three-dimensional network simulation of CPB slurry flow in an L-shaped pipe at different combinations of the three parameters was developed using COMSOL Multiphysics software, and the findings were validated through a loop experiment. The results show that increasing IV and reducing PS will contribute to the homogeneity of the slurry in the pipeline, while the PMC presents little effect. The pipe resistance loss is positively correlated with IV and PMC and negatively correlated with PS. The sensitivity to the three parameters is IV > PS > PMC. In particular, the resistance loss is minimal at IV of 1.5 m/s, PMC of 72%, and PS of 1000 um. The calculation model of resistance loss regressed from simulation presented a high accuracy with an error of 8.1% compared with the test results. The findings would be important for the design of the CPB pipeline transportation and provide guidance in the selection of transfer slurry pumps, prepreparation of backfill slurry, and pipe blockage, which will improve the safety and economic level of a mine.

Use of Pralsetinib as Neoadjuvant Therapy for Non-Small Cell Lung Cancer Patient With RET Rearrangement.

RET rearrangements are rare, and occur in 1%-2% of all non-small cell lung cancer (NSCLC) patients. Pralsetinib has a significant anti-tumor effect in patients with advanced NSCLC and a RET rearrangement. Previous studies have confirmed the efficiency of neoadjuvant target therapy for NSCLC. Herein we present a case involving a female patient who was diagnosed with stage IIIA lung adenocarcinoma and harbored a KIF5B-RET rearrangement based on next-generation sequencing. Radiologic downstaging was indicated after pralsetinib treatment. Therefore, a right lower lobectomy and systemic lymphadenectomy were successfully performed. The postoperative pathologic results revealed a response rate of 74% for primary tumor and no residual viable tumor cells were observed in lymph nodes. The tumor, nodes, and metastases (TNM) stage was ypT1cN1M0. The tumor micro-environment (TME) of the primary tumor was also assessed.

The rheological, mechanical and heavy metal leaching properties of cemented paste backfill under the influence of anionic polyacrylamide.

Anionic polyacrylamide (APAM) has widely been employed in backfill mining to accelerate the sedimentation of fine tailings particles and increase the concentration of tailings slurry. However, APAM inevitably remains in thickened tailings, leading to a nonnegligible influence on the rheological, mechanical, and heavy metal leaching properties of tailings-based cemented paste backfill (CPB). In an effort to solve these issues, the influences of APAM on CPB properties were examined in the present study. Experimental tests such as rheology, uniaxial compressive strength (UCS), toxicity leaching, and microscopy were conducted. The results showed that the presence of APAM first significantly increased the yield stress and viscosity of CPB slurry. APAM slightly improved the early UCS of CPB curing for 7 days but hindered the UCS development of samples cured for 28 days. Moreover, the presence of APAM restrained the hydration reaction, reduced the amounts of hydrated products, increased pore size, and loosed the microstructure of the test samples. Finally, the addition of APAM effectively reduced the leaching of Ag and As, while incremented that of Cu and slightly affected the leaching of Ba. In sum, these findings look promising for the safe production and environmental protection of the mining industry.