Identification of key lncRNAs in age-related macular degeneration through integrated bioinformatics and experimental validation.

This study aimed to identify key long noncoding RNAs (lncRNAs) in age-related macular degeneration (AMD) patients and to identify relevant pathological mechanisms of AMD development. We identified 407 differentially expressed mRNAs and 429 differentially expressed lncRNAs in retinal pigment epithelium (RPE) and retina in the macular region of AMD patients versus controls (P < 0.05 and |log2FC| > 0.585) from GSE135092. A total of 14 key differentially expressed mRNAs were obtained through external data validation from GSE115828. A miRNA-mRNA and miRNA-lncRNA network containing 52 lncRNA nodes, 49 miRNA nodes, 14 mRNA nodes and 351 edges was constructed via integrated analysis of these components. Finally, the LINC00276-miR-619-5p-IFIT3 axis was identified via protein-protein network analysis. In the t-BH-induced ARPE-19 senescent cell model, LINC00276 and IFIT3 were downregulated. Overexpression of LINC00276 could accelerate cell migration in combination with IFIT3 upregulation. This compelling finding suggests that LINC00276 plays an influential role in the progression of AMD, potentially through modulating senescence processes, thereby setting a foundation for future investigative efforts to verify this relationship.

Evaluation of Nanopore Sequencing for Diagnosing Pulmonary Tuberculosis Using Negative Smear Clinical Specimens.

Purpose: This study aimed to evaluate the efficacy of nanopore sequencing for diagnosing pulmonary tuberculosis (PTB) using smear-negative clinical specimens. Methods: We conducted a retrospective study based on a review of patient medical records to assess the accuracy of nanopore sequencing as a diagnostic tool for smear-negative PTB. Compared with clinical diagnosis, we determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of nanopore sequencing. Results: A total of 647 patients were evaluated. Nanopore sequencing demonstrated an overall sensitivity of 91.7%, specificity of 85.3%, PPV of 95.1%, NPV of 76.4%, and AUC of 0.88. Notably, the overall diagnostic accuracy of nanopore sequencing was significantly higher than that of Mycobacterium tuberculosis (MTB) culture technique. Conclusion: Nanopore sequencing exhibited satisfactory overall diagnostic accuracy for smear-negative PTB, regardless of MTB culture status. Therefore, if conditions permit, nanopore sequencing is recommended as a diagnostic method for smear-negative PTB.

Diagnostic validity of MRI for central nervous system tuberculosis: protocol for a systematic review and meta-analysis.

INTRODUCTION: Central nervous system tuberculosis (CNSTB) is a severe condition, sometimes associated with a poor prognosis. Early diagnosis of CNSTB remains challenging, considering that conventional methods lack sensitivity or might lead to certain side effects. Herein, we presented a protocol for a systematic review and meta-analysis to assess the diagnostic efficacy of MRI for CNSTB. METHODS AND ANALYSIS: SinoMed, Wanfang database, China National Knowledge Infrastructure, Embase, the Cochrane Library and PubMed will be searched to identify studies reporting on the use of MRI in the diagnosis of CNSTB from database inception to December 2023. The following keywords will be applied: 'Intracranial tuberculosis', 'Cerebral tuberculosis', 'Central nervous system tuberculosis', 'Spinal tuberculous arachnoiditis' and 'Magnetic Resonance Imaging'. Studies that evaluate the diagnostic accuracy of MRI for the diagnosis of CNSTB and report clear reference criteria will be included. Studies from which full true positive, false positive, false negative and true negative values cannot be extracted, those published in languages other than English or Chinese, abstracts not reporting the full text, and case reports will be excluded. Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) will be used to evaluate the methodological quality of each included study. Stata V.15.0 and RevMan V.5.3 will be used to perform a meta-analysis and generate forest plots and summary receiver operating characteristic curves. In case of significant heterogeneity between studies, possible sources of heterogeneity will be explored through subgroup and meta-regression analyses. ETHICS AND DISSEMINATION: This research is based on public databases and does not require ethical approval. Results will be submitted for publication in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42023415690.

Assessment of the Initial Result of Screw Fixation for Proximal Crescentic Metatarsal Osteotomy with Distal Soft Tissue Reconstruction in Severe Hallux Valgus Treatment.

INTRODUCTION: Proximal crescentic metatarsal osteotomy and distal soft tissue reconstruction have been introduced to correct severe HV. The intrinsically unstable proximal first crescentic osteotomy depends on enough force fixation for stability. It is necessary to judge the number of fixation screws for osteotomy. METHOD: Fifty-two feet of 50 adult patients with severe HV were included in this study. The treatment was proximal crescentic metatarsal osteotomy with a single screw and distal soft tissue reconstruction in Group 1 and the fixation with two screws with distal soft tissue reconstruction in Group 2. Clinical and radiological follow-ups were assessed after 4 and 12 months of operation. In Group 1, HVA decreased from 46.4 ±3.28 to 19.9 ±4.70 after 12 months of operation and from 45.1 ±3.45 to 19.1 ±4.70 in Group 2. Regarding the intermetatarsal angle (IMA) in Group 1, it was changed from 18.5 ±1.98 to 9.25 ±1.11 after 12 months of operation. For group 2, it decreased from 18.3 ±1.81 to 9.53 ±1.70. Meanwhile, the AOFAS score improved from 63.1 to 83.9 after 12 months of operation in Group 1 and improved from 64.3 to 82.8 in Group 2. RESULTS: Furthermore, the VAS score reduced from 4.5±1.01 to 1.7± 0.43 in Group 1 and from 4.7±0.92 to 1.7±0.55 in Group 2 after 12 months of operation. There were no significant differences identified between Group 1 and Group 2 in terms of VAS and AOFAS scores and HVA and IMA measurements. CONCLUSION: There is less complication in two-screw fixation for crescentic osteotomy compared to a single-screw fixation.

The value of histopathology combined with CapitalBio Mycobacterium real-time polymerase chain reaction test for diagnosing spinal tuberculosis.

Purpose: To evaluate the diagnostic efficacy of CapitalBio Mycobacterium real-time polymerase chain reaction assay (CapitalBio test) in spinal tuberculosis (STB). The value of histopathology combined with the CapitalBio test in diagnosing STB was also assessed. Methods: We retrospectively analyzed the medical information of suspected STB. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of histopathology, CapitalBio test, and histopathology combined with CapitalBio test were calculated to evaluate their diagnostic efficacy compared with a composite reference standard. Results: A total of 222 suspected STB patients were included in the study. The sensitivity, specificity, PPV, NPV, and AUC of histopathology for STB were recorded to be 62.0, 98.0, 97.4, 68.3%, and 0.80, respectively. The sensitivity, specificity, PPV, NPV, and AUC of the CapitalBio test were 75.2, 98.0, 97.9, 76.7%, and 0.87, respectively, while that of histopathology combined with the CapitalBio test was 81.0, 96.0, 96.1, 80.8%, and 0.89, respectively. Conclusion: Histopathology and CapitalBio test exhibited high accuracy and are recommended in diagnosing STB. Histopathology combined with the CapitalBio test might give the best efficacy in STB diagnosis.

Comparison of a minimally invasive osteosynthesis technique with conventional open surgery for transverse patellar fractures.

PURPOSE: The study aims to compare the efficacy and safety of a new minimally invasive osteosynthesis technique with those of conventional open surgery for transverse patellar fractures. METHODS: It was a retrospective study. Adult patients with closed transverse patellar fracture were included, and with open comminuted patellar fracture were excluded. These patients were divided into minimally invasive osteosynthesis technique (MIOT) group and open reduction and internal fixation (ORIF) group. Surgical time, frequency of intraoperative fluoroscopy, visual analogue scale score, flexion, extension, Lysholm knee score, infection, malreduction, implant migration and implant irritation in two groups were recorded and compared. Statistical analysis was performed by the SPSS software package (version 19). A p < 0.05 indicated statistical significance. RESULTS: A total of 55 patients with transverse patellar fractures enrolled in this study, the minimally invasive technique was performed in 27 cases, and open reduction was performed in 28 cases. The surgical time in the ORIF group was shorter than that in the MIOT group (p = 0.033). The visual analogue scale scores in the MIOT group were significantly lower than those in the ORIF group only in the first month after surgery (p = 0.015). Flexion was restored faster in the MIOT group than that in the ORIF group at one month (p = 0.001) and three months (p = 0.015). Extension was recovered faster in the MIOT group than that in the ORIF group at one month (p = 0.031) and three months (p = 0.023). The recorded Lysholm knee scores in the MIOT group were always greater than those in the ORIF group. Complications, such as infection, malreduction, implant migration, and implant irritation, occurred more frequently in the ORIF group. CONCLUSION: Compared with the ORIF group, the MIOT group reduced postoperative pain and had less complications and better exercise rehabilitation. Although it requires a long operation time, MIOT may be a wise choice for transverse patellar fractures.

Clinical Application of the Mycobacterium tuberculosis-RNA Assay of Pericardial Tissue Specimens in the Diagnosis of Tuberculous Pericarditis.

Purpose: To assess the accuracy of the Mycobacterium tuberculosis (MTB)-RNA assay using pericardial tissue specimens for tuberculous pericarditis (TBP) diagnosis. Methods: MTB culture and MTB-RNA assay were performed for patients with suspected TBP. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of these two assays were analyzed. Results: This study included 79 patients. The sensitivity, specificity, PPV, NPV, and AUC were 28.1% (18/64), 100.0% (15/15), 100.0% (18/18), 24.6% (15/61), and 0.64 for the MTB culture and 37.5% (24/64), 100.0% (15/15), 100.0% (24/24), 27.3% (15/55), and 0.69 for the MTB-RNA assay, respectively. Patients with positive pericardial tissue culture were defined as having definite TBP; in other words, culture was the gold standard for this group of patients and had a sensitivity, specificity, PPV, and NPV of 100% and an AUC of 1.00. However, these values were found to be 72.2% (13/18), 100.0% (15/15), 100.0% (13/13), 75.0% (15/20), and 0.86 for the MTB-RNA assay, respectively. Among patients with probable TBP (culture-negative patients), the sensitivity, specificity, NPV, and AUC of MTB culture were 0.0% (0/46), 100.0% (15/15), 24.6% (15/61), and 0.50, respectively, but the PPV could not be determined. These values were found to be 23.9% (11/46), 100.0% (15/15), 100.0% (11/11), 30.0% (15/50), and 0.62 for the MTB-RNA assay, respectively. Conclusion: MTB-RNA assay using pericardial tissues had limited diagnostic efficacy for TBP. In culture-positive TBP, the diagnostic accuracy of MTB-RNA was good. In contrast, in culture-negative TBP, its diagnostic accuracy was unsatisfactory.

Enhancement of Tendon Repair Using Tendon-Derived Stem Cells in Small Intestinal Submucosa via M2 Macrophage Polarization.

(1) Background: Reconstruction of Achilles tendon defects and prevention of postoperative tendon adhesions were two serious clinical problems. In the treatment of Achilles tendon defects, decellularized matrix materials and mesenchymal stem cells (MSCs) were thought to address both problems. (2) Methods: In vitro, cell adhesion, proliferation, and tenogenic differentiation of tendon-derived stem cells (TDSCs) on small intestinal submucosa (SIS) were evaluated. RAW264.7 was induced by culture medium of TDSCs and TDSCs-SIS scaffold groups. A rat Achilles tendon defect model was used to assess effects on tendon regeneration and antiadhesion in vivo. (3) Results: SIS scaffold facilitated cell adhesion and tenogenic differentiation of TDSCs, while SIS hydrogel coating promoted proliferation of TDSCs. The expression of TGF-ß and ARG-1 in the TDSCs-SIS scaffold group were higher than that in the TDSCs group on day 3 and 7. In vivo, the tendon regeneration and antiadhesion capacity of the implanted TDSCs-SIS scaffold was significantly enhanced. The expression of CD163 was significantly highest in the TDSCs-SIS scaffold group; meanwhile, the expression of CD68 decreased more significantly in the TDSCs-SIS scaffold group than the other two groups. (4) Conclusion: This study showed that biologically prepared SIS scaffolds synergistically promote tendon regeneration with TDSCs and achieve antiadhesion through M2 polarization of macrophages.

Comparison of the Accuracy of Two Different Molecular Tests for the Diagnosis of Tuberculous Lymphadenitis Using Core Needle Biopsy Specimens: A Diagnostic Accuracy Study.

Purpose: To evaluate the diagnostic accuracy of the CapitalBio Mycobacterium real-time polymerase chain reaction assay (CapitalBio test) testing of core needle biopsy (CNB) specimens for tuberculous lymphadenitis (TBL) and to compare it with Xpert MTB/RIF. Methods: We retrospectively analyzed the medical data on patients with suspected peripheral TBL. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of the CapitalBio test, Xpert MTB/RIF, and parallel test (positive result for either of these two tests) were calculated to evaluate their diagnostic efficacy compared with the final clinical diagnosis. Results: The study included 114 patients. For diagnosing TBL using CNB samples, the sensitivity, specificity, PPV, NPV, and AUC were 65.0%, 100.0%, 100.0%, 28.6%, and 0.83, respectively, for the CapitalBio test; 72.0%, 100.0%, 100.0%, 33.3%, and 0.86, respectively, for Xpert MTB/RIF; and 82.0%, 100.0%, 100.0%, 43.8%, and 0.91, respectively, for the parallel test. Conclusion: The accuracy of the CapitalBio test and Xpert MTB/RIF for diagnosing TBL using CNB specimens was moderate, while the sensitivity and NPV of these two tests were relatively low. The diagnostic accuracy of the CapitalBio test was slightly lower than that of Xpert MTB/RIF, but the difference between the two was not statistically significant. Parallel test might improve the diagnostic accuracy but not substantially over a single test.

Ultrasound-guided interscalene block versus intravenous analgesia and sedation for reduction of first anterior shoulder dislocation.

PURPOSE: This study aims to compare the efficacy of ultrasound-guided interscalene block (US-ISB) with that of intravenous analgesia and sedation (IVAS) in reducing first shoulder dislocation. MATERIAL AND METHODS: A prospective study was performed in 66 patients with first anterior shoulder dislocation in emergency department. The patients were divided into a US-ISB (n = 32) group and an IVAS (IVAS n = 34) group. The procedure time (anesthesia, reduction, and hospital times), pain score (before, during, and after reduction), reduction attempts, complications, and patient satisfaction were recorded and compared between the two groups. RESULTS: The anesthesia time (P < 0.01) and reduction time (P < 0.01) were shorter and the hospital time (P < 0.01) was longer in the IVAS group than in the US-ISB group. No significant differences in preoperative (P = 0.18) and postoperative (P = 0.27) pain scores were found between the two groups, but the intraoperative score of the US-ISB group was significantly higher than that of the IVAS group. More reduction attempts (P < 0.01) were recorded in the US-ISB group than that in the IVAS group. Complications (P < 0.01) such as nausea, vomiting, headache, and hypoxia occurred more frequently in the IVAS group than in the US-ISB group. No significant difference in patient satisfaction was observed between two groups (P = 0.96). CONCLUSION: Compared with IVAS group, US-ISB group reduces the time to discharge and achieves lesser complication. The pain score and reduction attempt are lower in the IVAS group than in the US-ISB group.

Development and Prospect of Esophageal Tissue Engineering.

Currently, patients with esophageal cancer, especially advanced patients, usually use autologous tissue for esophageal alternative therapy. However, an alternative therapy is often accompanied by serious complications such as ischemia and leakage, which seriously affect the prognosis of patients. Tissue engineering has been widely studied as one of the ideal methods for the treatment of esophageal cancer. In view of the complex multi-layer structure of the natural esophagus, how to use the tissue engineering method to design the scaffold with structure and function matching with the natural tissue is the principle that the tissue engineering method must follow. This article will analyze and summarize the construction methods, with or without cells, and repair effects of single-layer scaffold and multi-layer scaffold. Especially in the repair of full-thickness and circumferential esophageal defects, the flexible design method and the binding force between the layers of the scaffold are very important. In short, esophageal tissue engineering technology has broad prospects and plays a more and more important role in the treatment of esophageal diseases.

Determination of interactions of ferrihydrite-humic acid-Pb (II) system.

Ferrihydrite often precipitates with humic acid in natural ways, affecting the fate of lead ions, the stabilization of humic acid, and the aging process of ferrihydrite. A series of 2-line ferrihydrite-humic (Fh-HA) acid with varying C loadings has been prepared, the morphology and surface properties of Fh-HA organo-minerals have been characterized, and the adsorption property of Pb ions onto Fh-HA has been studied. The results indicated that a strong interference of HA to ferrihydrite 2-line Fh dominated mineral phase in all samples, but with increasing C/Fe molar ratios, the crystallinity gradually weakened, particles became smaller, and SSA decreased significantly. The data of Mössbauer spectra confirmed C loadings changed the unit structure of ferrihydrite. Fh-HA performed good adsorption properties to Pb (II): high efficiency and big capacity, especially Fh-HA_2.0. pH had great effect on Pb (II) sorption, the pH change affects not only the amounts of competitive ions in solutions, but also the dissociation and protonation of functional groups on the surface of Fh-HA. Sorption kinetics can be well modeled by a pseudo-second-order model, and the process was controlled by film and intraparticle adsorption simultaneously. The adsorption isotherms can be well described by Freundlich isotherm model. The detailed determination results of Fe 2p, O 1 s, and Pb 4f spectra before and after lead adsorption showed mononuclear bidentate or binuclear bidentate ligands occurring on Fh-HA surface, forming stable inner-sphere complex. By comparison of Mössbauer spectra and TEM images, with aging time, a slower evolution of iron oxide/oxyhydroxide phases in Fh-HA-Pb system happened compared to pure ferrihydrite. Ferrihydrite has transformed to a combination of ferrihydrite, goethite, and hematite phases. In this study, the determination of C-Fe interaction, Pb fate influenced by Fh-HA, and transformation of ferrihydrite would have a great implication to application of Fh-HA precipitates in remediation for surface water or groundwater polluted by heavy metals.

Neoadjuvant immunotherapy for resectable esophageal cancer: A protocol of meta-analysis.

BACKGROUND: Esophageal cancer is a highly malignant cancer with a very poor prognosis. For resectable esophageal cancer, neoadjuvant treatment could improve the prognosis of esophageal cancer. However, current clinical neoadjuvant treatment options for esophageal cancer are still limited. The application of immunotherapy is a potentially beneficial new neoadjuvant treatment option for esophageal cancer. The objective of this meta-analysis is to evaluate the efficacy and safety of immunotherapy for the neoadjuvant treatment of esophageal cancer. METHODS: We will search Wanfang Database, SinoMed, China National Knowledge Infrastructure, Embase, Web of Science, Pubmed, and Cochrane Library for relevant articles published before July, 2021. We will also search the unpublished clinical trials of neoadjuvant immunotherapy in esophageal cancer in preprint website (such as bioRXiv and medRxiv) up to July, 2021. We will perform a meta-analysis to evaluate the efficacy and safety of neoadjuvant immunotherapy for resectable esophageal cancer. Randomized controlled trials (RCTs) will be included in this study. The risk of bias will be evaluated for each included study using the Cochrane Handbook for Systematic Reviews of Interventions. We will use RevMan 5.3 software for statistical analysis of the data. RESULTS: The results of this study will provide evidence of immunotherapy using as neoadjuvant treatment for esophageal cancer. This meta-analysis will be submitted to a peer-reviewed journal seeking for publication. CONCLUSION: The results of this study will provide a reliable basis for clinicians and patients to formulate the best pre-surgical treatment plan for resectable esophageal cancer. SYSTEMATIC REVIEW REGISTRATION: INPLASY202120026.

Spatial-temporal analysis and background value determination of molybdenum concentration in basins with high molybdenum geochemical background - A case study of the upper Yi River basin.

The environmental background value of the river section is important. It can be used to evaluate the effect of pollution control of the upstream of that river section, analyze the trend of environmental pollution, and assist the government to make decisions. Yi river is the main tributary of the Yellow River. In the headwaters of the Yi river, there are two very large molybdenum mines with a history of mining and smelting of many years. This area is also a region with a high molybdenum geochemical background. Using the collected regional molybdenum geochemical map, historical monitoring data, sampling data, remote sensing image, and spatial information of mineral enterprises, we found two reasons of why the molybdenum concentration is unusual in the basin. The first reason is the area is a high molybdenum region. The second reason is that the inherent solubility of molybdenum in the soil is changed due to human engineering activities. In this paper, we did a linear fitting on the soil samples and water samples collected from the natural areas and areas affected by human mining activities, and established a leaching model. By comparing the leaching capability of molybdenum in the soil of different areas, we found that the molybdenum release capability in areas affected by human mining was much higher than that in natural areas. Finally, this paper proposed a method to analyze the contribution rate of molybdenum concentration of this river section, using a combination of the leaching model and the D8 algorithm. The experimental results showed that the contribution rate of natural factors and human influence factors at the exit section of Yi River was 81.38% and 18.62% respectively. The background molybdenum concentration in this section was 0.16 mg/L.

A comparison of the accuracy of the CapitalBio Mycobacterium real-time polymerase chain reaction and the Xpert MTB/RIF assay for the diagnosis of tuberculous meningitis.

OBJECTIVES: We aimed to compare the efficiency of the CapitalBioMycobacterium real-time polymerase chain reaction (PCR) detection test with the standard Xpert MTB/RIF assay for the diagnosis of tuberculous meningitis (TBM). METHODS: We analyzed cerebrospinal fluid (CSF) from 163 patients with suspected TBM that were collected between January 1, 2018, and December 31, 2019. For both tests, we determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC). Next, we compared the diagnostic accuracy of the two techniques using clinical diagnosis as a reference standard. RESULTS: The sensitivity, specificity, PPV, NPV, and AUC, of the CapitalBio Mycobacterium detection test were 48.5%, 100%, 100%, 29.6%, and 0.74, respectively, when used for the diagnosis of TBM. In comparison, the Xpert MTB/RIF assay returned values of 47.0%, 100%, 100%, 29.0%, and 0.74, respectively. Our analysis showed that the diagnostic accuracies of the CapitalBio Mycobacterium detection test and the Xpert MTB/RIF assay were very similar; the accuracy of both tests for detecting mycobacteria was significantly higher than that associated with acid-fast staining. CONCLUSIONS: The CapitalBio Mycobacterium real-time PCR detection test has moderate sensitivity and very high specificity for TBM; results are very similar to those generated by the Xpert MTB/RIF assay. We recommend that the CapitalBio PCR test should be used as an initial screening method for TB.

Initial assessment of treatment of talar posterior process fractures with open reduction and percutaneous fixation.

The purpose of this study was to provide an initial assessment of treatment for talar posterior process fractures using open reduction and internal fixation (ORIF) through posteromedial approach and percutaneous screw fixation. From January 2014 to December 2018, 12 cases with displaced fracture of talar posterior process were treated in our department. The clinical and radiological results were assessed after 4 and 12 months of operation with Visual Analog Scale (VAS) pain and American Orthopedic Foot and Ankle Society (AOFAS) scores. ORIF was performed in four of the cases and percutaneous screw fixation was performed in eight of the cases. The average follow-up period was 13 months. Complications such as wound infection, nerve injury, screw loosening, malunion or nonunion of fracture were absent. For clinical assessment, considerable mprovements were observed for the AOFAS and VAS scores at 4 and 12 months postoperatively for both techniques. There was no significant difference for AOFAS scores and VAS scores between the two techniques (p > 0.05). Both techniques showed good functional outcome and were performed for posterior talar process fracture following the fracture displacement guidelines. Percutaneous screw fixation treatment with computer-assisted three-dimensional evaluation shortened the operation time and reduced incidences of surgical complications.

Synthesis and Hydration Characteristic of Geopolymer Based on Lead Smelting Slag.

Lead smelting slag (LSS) has been identified as general industrial solid waste, which is produced from the pyrometallurgical treatment of the Shuikoushan process for primary lead production in China. The LSS-based geopolymer was synthesized after high-energy ball milling. The effect of unconfined compressive strength (UCS) on the synthesis parameters of the geopolymer was optimized. Under the best parameters of the geopolymer (modulus of water glass was 1-1.5, dosage of water glass (W(SiO2+Na2O)) was 5% and water-to-binder ratio was 0.2), the UCS reached 76.09 MPa after curing for 28 days. The toxicity characteristic leaching procedure (TCLP) leaching concentration of Zn from LSS fell from 167.16 to 93.99 mg/L after alkali-activation, which was below the limit allowed. Meanwhile, C-S-H and the geopolymer of the hydration products were identified from the geopolymer. In addition, the behavior of iron was also discussed. Then, the hydration process characteristics of the LSS-based geopolymer were proposed. The obtained results showed that Ca2+ and Fe2+ occupied the site of the network as modifiers in the glass phase and then dissociated from the glass network after the water glass activation. At the same time, C-S-H, the geopolymer and Fe(OH)2 gel were produced, and then the Fe(OH)2 was easily oxidized to Fe(OH)3 under the air curing conditions. Consequently, the conclusion was drawn that LSS was an implementable raw material for geopolymer production.

Effect of simulated acid rain on stability of arsenic calcium residue in residue field.

In recent years, acid rain had a serious negative impact on the leaching behavior of industrial waste residue. Researches were mainly focused on the environmental hazards of heavy metal in the leachate, but ignored the effects of heavy metal speciation on the stability of waste residue in the subsequent stabilization process. In this study, the unstable calcium-arsenic compounds in the arsenic calcium residue were firstly removed by leaching process; subsequently, the crystallization agent was added to treat the remaining calcium-arsenic mixture. The results of the leaching process demonstrated that the decrease in particle size and pH value directly affected the increase in the cumulative leaching amount of arsenic, and the cumulative leaching ratio reached 1.55%. In addition, the concentration of arsenic decreased from 3583 to 49.1 mg L-1. After the crystallization process, the arsenic concentration was lower than the limit value of Identification Standards for Hazardous Wastes (GB 5085.3-2007). The SEM analysis showed the bulk structures, and XRD pattern confirmed that they were the stable compounds. Moreover, the result of XRD and SEM illustrated that acid concentration, chloride ions and sulfate ions were contributed to the transformation and growth of stable calcium arsenate compounds. Therefore, effective control of the acidity of acid rain, the type of anions in acid rain, and the particle size of residues would contribute to adjusting the arsenic speciation to be more stable. The leaching-crystallization process was of great significance to improve the stability of the arsenic-containing residue.

Effect of humic acid on the stabilization of cadmium in soil by coprecipitating with ferrihydrite.

Coprecipitation of humic acid (HA) with ferrihydrite (Fh) has been proposed to reduce the activity of heavy metals in aqueous solutions. The effect of the amount of HA added to the coprecipitates on the stabilization of Cd in soil is unclear. In this research, five different Fh-HA coprecipitates were synthesized to study the impact of different HA additions on the fractionation of Cd in the soil and the optimal addition ratio of C/Fe. Characterization technique as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), specific surface area analyzer, and scanning electron microscopy (SEM) was used in order to test and analyze of the microstructure and physicochemical property of the coprecipitates. The results showed that the Fh-HA coprecipitate is mainly combined by the coordination exchange of -OH on the surface of the Fh with the carboxyl group of the HA. Adding HA could stabilize Fh and increase its surface roughness. Changes in the fractionation of the Cd were used to evaluate the stabilization effect of the coprecipitate. Before treatment, Cd in different contaminated soils was existed only a small amount of residual fraction. After the addition of the Fh-HA coprecipitate, the proportion of residual Cd in each contaminated soil increased. When the C/Fe ratio was 1.5, the maximum residual fraction were 62.94%, 55.67%, and 52.99% respectively. Residual Cd could remain relatively stable indicating that the Fh-HA coprecipitate is a promising amendment for repairing Cd-contaminated soil. The addition of HA has strengthened the active role of Fh on stabilizing heavy metals.