Pollution control performance of solidified nickel-cobalt tailings on site: Bioavailability of heavy metals and microbial response.

There has been increasing attention given to nickel-cobalt tailings (NCT), which pose a risk of heavy metal pollution in the field. In this study, on site tests and sampling analysis were conducted to assess the physical and chemical characteristics, heavy metal toxicity, and microbial diversity of the original NCT, solidified NCT, and the surrounding soil. The research results show that the potential heavy metal pollution species in NCT are mainly Ni, Co, Mn, and Cu. Simultaneous solidification and passivation of heavy metals in NCT were achieved, resulting in a reduction in biological toxicity and a fivefold increase in seed germination rate. The compressive strength of the original tailings was increased by 20 times after solidification. The microbial diversity test showed that the abundance of microbial community in the original NCT was low and the population was monotonous. This study demonstrates, for the first time, that the use of NCT for solidification in ponds can effectively solidification of heavy metals, reduce biological toxicity, and promote microorganism diversity in mining areas (tended to the microbial ecosystem in the surrounding soil). Indeed, this study provides a new perspective for the environmental remediation of metal tailings.

Vascular complications of ProGlide versus Prostar in transcatheter aortic valve replacement (TAVR) procedures: meta-analysis.

BACKGROUND: The aim of this study was to compare the vascular complications of ProGlide and Prostar in percutaneous transfemoral transcatheter aortic valve replacement. METHODS: Electronic databases were searched in July 2022 for studies that compared the vascular complications of ProGlide and Prostar for percutaneous closure in transcatheter aortic valve replacement. The primary outcome was major vascular complications and the secondary outcomes were minor vascular complications, types of access-site vascular complications, device failure, and additional intervention. Estimates of relative effects were pooled to generate ORs and their 95 per cent c.i. using a random-effects model. The risk of bias in non-randomized comparative studies was assessed using the Risk Of Bias In Non-randomized Studies - of Interventions ('ROBINS-I') tool. RESULTS: Nine studies were identified and a total of 7529 patients were included. Among them, 4144 patients received ProGlide and 3385 received Prostar. The pooled data showed that the risk of major vascular complications was significantly lower with ProGlide versus Prostar (OR 0.50, 95 per cent c.i. 0.32 to 0.78). Regarding the types of vascular complications, vascular trauma was the most common complication and the risk was similar between groups (OR 1.02, 95 per cent c.i. 0.55 to 1.91). ProGlide had a lower risk of bleeding complications (OR 0.46, 95 per cent c.i. 0.22 to 0.94), but a higher risk of ischaemia complications (OR 1.90, 95 per cent c.i. 1.10 to 3.27). The risk of device failure was lower in the ProGlide group (OR 0.45, 95 per cent c.i. 0.21 to 0.95). Both groups had a similar risk of having additional interventions for vascular complications (OR 1.02, 95 per cent c.i. 0.75 to 1.39). The use of ProGlide was associated with a lower risk of additional surgical treatments (OR 0.52, 95 per cent c.i. 0.34 to 0.80), but a higher risk of endovascular treatments (OR 2.69, 95 per cent c.i. 1.29 to 5.63). CONCLUSION: In percutaneous transfemoral transcatheter aortic valve replacement procedures, ProGlide has superior safety and efficacy when compared with Prostar; it is associated with fewer major vascular complications and device failures. The vascular complications of ProGlide are more likely to be dealt with using endovascular treatments than surgical treatments.

Cyclic-di-AMP signalling in lactic acid bacteria.

Cyclic dimeric adenosine monophosphate (cyclic-di-AMP) is a nucleotide second messenger present in Gram-positive bacteria, Gram-negative bacteria and some Archaea. The intracellular concentration of cyclic-di-AMP is adjusted in response to environmental and cellular cues, primarily through the activities of synthesis and degradation enzymes. It performs its role by binding to protein and riboswitch receptors, many of which contribute to osmoregulation. Imbalances in cyclic-di-AMP can lead to pleiotropic phenotypes, affecting aspects such as growth, biofilm formation, virulence, and resistance to osmotic, acid, and antibiotic stressors. This review focuses on cyclic-di-AMP signalling in lactic acid bacteria (LAB) incorporating recent experimental discoveries and presenting a genomic analysis of signalling components from a variety of LAB, including those found in food, and commensal, probiotic, and pathogenic species. All LAB possess enzymes for the synthesis and degradation of cyclic-di-AMP, but are highly variable with regards to the receptors they possess. Studies in Lactococcus and Streptococcus have revealed a conserved function for cyclic-di-AMP in inhibiting the transport of potassium and glycine betaine, either through direct binding to transporters or to a transcriptional regulator. Structural analysis of several cyclic-di-AMP receptors from LAB has also provided insights into how this nucleotide exerts its influence.

Submicron tourmaline enhanced the solidification of municipal solid waste incineration fly ash by chemical structure reorganization and stabilized heavy metals.

Municipal solid waste incineration fly ash (MSWIFA) exsits in large quantitities and contains pollutants such as heavy metal. While solidification is one of the most effective methods for treating MSWIFA, this application is limited by cost, subsequent treatment, and simultaneous immobilization of anions and cations. This research demonstrated that under a certain initial pressure (20 MPa), a gelation reaction involving ball milling-modified tourmaline powder, a small amount of cement clinker, and MSWIFA forms a stable consolidated body and significantly reduces the risk of heavy metal dissolution. The consolidated MSWIFA can easily be formed into unfired bricks in large-scale pilot production, and a response surface model was used to optimize the experimental parameters. When the mass ratio of tourmaline: cement clinker: MSWIFA was 15:15:200 (mixed with a moisture content of 13 to 15 %), the compressive strength of the consolidated body reached 13 MPa, and the amounts of Cr and Pb leached decreased from 12 mg/L to 0.1 mg/L and 25 mg/L to 0.3 mg/L, respectively. The consolidated form contained a new mineral phase (Ca3Si2O7·3H2O, Ca10Mg0.8(SiO4)0.6O2Cl, and CaCl2∙Ca(OH)2·H2O) with a high compressive strength. Notably, the soluble PbSO4 in the MSWIFA was converted into relatively stable PbSiO3, and Cr(VI) was lattice-wrapped. This study was the first to demonstrate that tourmaline synchronously passivates Pb(II) and Cr(VI) in fly ash in the solid phase, with a low cost and requires no subsequent treatment. This study provided a novel technical path for recycling MSWIFA. Eventually, leaching of the heavy metals Pb, Cr, Cu, Cd, and Zn from the solids achieved concentrations less than 0.25, 1.5, 0.5, 0.15, and 100 mg/L.

Use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers increases the risk of postoperative acute kidney injury after elective endovascular abdominal aortic aneurysm repair.

BACKGROUND: Endovascular abdominal aortic aneurysm repair (EVAR) is the major treatment for abdominal aortic aneurysm (AAA); however, EVAR still carries a considerable risk of acute kidney injury (AKI). The present study aimed to investigate the risk factors for AKI after elective EVAR procedures. METHODS: This was a retrospective observational study. Eligible patients who underwent EVAR from September 2011 to March 2019 in West China Hospital were included. The primary outcome was the occurrence of AKI within two days after EVAR, which was defined by the Kidney Disease Improving Global Outcomes Clinical Practice Guideline. Demographics, comorbidities, medications, laboratory tests, anatomical parameters of AAA, and relative operative details were collected as variables. Univariable and multivariable logistic regression analyses were applied to identify the risk factors among variables, and covariate interactions were further assessed. RESULTS: A total of 679 eligible patients were included. The incidence of postoperative AKI was 8.2% (56/679) in the whole cohort, and it was associated with a lower 5-year survival rate (63.5% vs . 80.9%; χ 2  = 4.10; P  = 0.043). The multivariable logistic regression showed that chronic kidney disease (OR, 5.06; 95% CI: 1.43-17.95; P  = 0.012), angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) (OR, 2.60; 95% CI: 1.17-5.76; P  = 0.019), and short neck (OR, 2.85; 95% CI: 1.08-7.52; P  = 0.035) were independent risk factors for postoperative AKI. In the covariate interaction analysis, the effect of ACEIs/ARBs use on postoperative AKI was similar across all subgroups ( P  > 0.05), thereby suggesting a robust effect of ACEIs/ARBs use in all patients undergoing elective endovascular abdominal aortic aneurysm repair. CONCLUSIONS: Postoperative AKI was associated with lower survival rate, and the use of ACEIs/ARBs was the only adjustable independent risk factor. Clinicians should consider withdrawing ACEIs/ARBs in high-risk patients undergoing elective endovascular abdominal aortic aneurysm repair to prevent postoperative AKI.

Impact of gender on the prognosis of carotid body tumor after surgical resection.

BACKGROUND: Carotid body tumors (CBTs) are rare neuroendocrine neoplasms, but the prognosis of patients with resected CBTs has seldom been elucidated. This study was conducted to investigate the association between variables, especially sex, and the prognosis of carotid body tumor resection. METHODS: This was a large-volume single-center retrospective cohort study. Patients who were diagnosed with CBTs between 2009 and 2020 at our center were analyzed retrospectively. Their preoperative, surgical, and follow-up data were collected, and the association between variables and outcomes of CBT resection was assessed by correlation analysis, multivariate logistic regression, and multivariate Cox regression as appropriate. RESULTS: A total of 326 patients (66.6% were females) were included. Males developed larger CBTs than females (4.3 ± 1.8 cm vs. 3.8 ± 1.4 cm, P = .003). Males were more likely to develop succinate dehydrogenase B (SDHB) mutations (P = .019) and had worse relapse-free survival rates (P = .024). Although tumor size and Shamblin classification had positive relationships with neurological complications and intraoperative blood loss, they did not affect the overall survival rate of patients, which was only influenced by remote metastasis (P = .007) and local recurrence (P = .008). CONCLUSIONS: Compared to females, males with CBT resection were found to have more SDHB mutations and worse relapse-free survival rates, which may lead to the deterioration of prognosis. Tumor size and Shamblin classification cannot predict the overall survival rate of patients with excised CBTs.

Cyclic di-AMP Oversight of Counter-Ion Osmolyte Pools Impacts Intrinsic Cefuroxime Resistance in Lactococcus lactis.

The broadly conserved cyclic di-AMP (c-di-AMP) is a conditionally essential bacterial second messenger. The pool of c-di-AMP is fine-tuned through diadenylate cyclase and phosphodiesterase activities, and direct binding of c-di-AMP to proteins and riboswitches allows the regulation of a broad spectrum of cellular processes. c-di-AMP has a significant impact on intrinsic ß-lactam antibiotic resistance in Gram-positive bacteria; however, the reason for this is currently unclear. In this work, genetic studies revealed that suppressor mutations that decrease the activity of the potassium (K+) importer KupB or the glutamine importer GlnPQ restore cefuroxime (CEF) resistance in diadenylate cyclase (cdaA) mutants of Lactococcus lactis Metabolite analyses showed that glutamine is imported by GlnPQ and then rapidly converted to glutamate, and GlnPQ mutations or c-di-AMP negatively affects the pools of the most abundant free amino acids (glutamate and aspartate) during growth. In a high-c-di-AMP mutant, GlnPQ activity could be increased by raising the internal K+ level through the overexpression of a c-di-AMP-insensitive KupB variant. These results demonstrate that c-di-AMP reduces GlnPQ activity and, therefore, the level of the major free anions in L. lactis through its inhibition of K+ import. Excessive ion accumulation in cdaA mutants results in greater spontaneous cell lysis under hypotonic conditions, while CEF-resistant suppressors exhibit reduced cell lysis and lower osmoresistance. This work demonstrates that the overaccumulation of major counter-ion osmolyte pools in c-di-AMP-defective mutants of L. lactis causes cefuroxime sensitivity.IMPORTANCE The bacterial second messenger cyclic di-AMP (c-di-AMP) is a global regulator of potassium homeostasis and compatible solute uptake in many Gram-positive bacteria, making it essential for osmoregulation. The role that c-di-AMP plays in ß-lactam resistance, however, is unclear despite being first identified a decade ago. Here, we demonstrate that the overaccumulation of potassium or free amino acids leads to cefuroxime sensitivity in Lactococcus lactis mutants partially defective in c-di-AMP synthesis. It was shown that c-di-AMP negatively affects the levels of the most abundant free amino acids (glutamate and aspartate) in L. lactis Regulation of these major free anions was found to occur via the glutamine transporter GlnPQ, whose activity increased in response to intracellular potassium levels, which are under c-di-AMP control. Evidence is also presented showing that they are major osmolytes that enhance osmoresistance and cell lysis. The regulatory reach of c-di-AMP can be extended to include the main free anions in bacteria.

Selective recovery of manganese from electrolytic manganese residue by using water as extractant under mechanochemical ball grinding: Mechanism and kinetics.

This research aimed to address the issue of residual manganese in electrolytic manganese residue (EMR), which is difficult to recycle and can easily become an environmental hazard and resource waste. This research developed a method for the efficient and selective recovery of manganese from EMR and the removal of ammonia nitrogen (ammonium sulfate) under the combined action of ball milling and oxalic acid. The optimum process parameters of this method were obtained through single-factor experiment and response-surface model. Results showed that the recovery rate of manganese can exceed 98%, the leaching rate of iron was much lower than 2%, and the leaching rates of manganese and ammonia nitrogen after EMR ball grinding were 1.01 and 13.65 mg/L, respectively. Kinetics and mechanism studies revealed that ammonium salts were primarily removed in the form of ammonia, and that insoluble manganese (MnO2) was recovered by the reduction of FeS and FeS2 in EMR under the action of oxalic acid. Iron was solidified in the form of Fe2O3 and Fe2(SiO3)3. The technology proposed in this research has great industrial application value for the recycling and harmless treatment of EMR.

Short communication: Dynamic changes in bacterial diversity during the production of powdered infant formula by PCR-DGGE and high-throughput sequencing.

Microorganisms such as thermophilic and psychrotrophic bacteria cause spoilage of milk and milk products [e.g., powdered infant formula (PIF)], mainly because they produce heat-stable extracellular enzymes. However, the dynamic changes in microbial diversity during PIF production are still not well understood. We used denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing (HTS) to investigate bacterial community structure and distribution during the major stages of PIF production: raw milk, pasteurization, mixing, evaporation, and spray-drying. Our PCR-DGGE analysis indicated that Lactobacillus and Pseudomonas spp. were the dominant bacteria at the raw milk and pasteurization stages; Lactococcus, Streptococcus, Enterococcus, and Lactobacillus spp. were abundant during mixing, evaporation, and spray-drying. Our HTS analysis showed that Pseudomonas had an abundance of 96.79% at the raw milk stage. Lactobacillus, Streptococcus, Thermus, Acinetobacter, and Bacteroides spp. were most common after pasteurization. The index of bacterial diversity was highest at the evaporation stage, suggesting a high potential risk of microbial contamination. The results from DGGE and HTS were consistent in reflecting changes in dominant flora, but different in reflecting the richness of bacterial communities present during PIF production: HTS revealed a much higher richness of bacterial species than DGGE. Our findings from DGGE and HTS showed that psychrophilic and thermophilic bacteria were the main flora present during PIF production: psychrophilic bacteria were mainly Pseudomonas spp. and thermophilic bacteria were mainly Lactobacillus, Streptococcus, and Bacillus spp. To our knowledge, this is the first study to report dynamic changes in microbial communities during PIF production. Our results provide insight into bacterial communities and identify potential contamination sources that could serve as a guide for reducing microbial risk.

Endovascular Treatment Versus Open Surgery for Isolated Iliac Artery Aneurysms: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim of this review was to compare the outcomes of endovascular treatment (ET) versus open surgery (OS) for patients with isolated iliac artery aneurysms (IIAAs). METHODS: Studies that reported ET and OS for IIAAs were searched in databases until December 5, 2018. Studies were included for reporting both ET and OS for patients with IIAAs, and at least one of the following outcomes: postoperative mortality, postoperative ischemic complications (PIC), wound complications, blood transfusion, and length of hospital stay (LHS). We adopted Inverse Variance method to calculate the mean difference (MD) of LHS, and adopted Mantel-Haenszel method for odds ratios (ORs) of postoperative mortality, PICs, wound complications, and blood transfusion. RESULTS: Nine studies were included, and all of them were observational studies, 7 studies were available for meta-analysis. When compared with OS, ET was associated with a higher risk of PICs (OR: 3.24, 95% confidence interval [CI]: 1.05-10.02), a lower risk of blood transfusion (OR: 0.22, 95% CI: 0.08-0.58), and a much shorter LHS (MD: -4.39, 95% CI: -6.18 to -2.60). The postoperative mortality and wound complication were similar between groups. CONCLUSION: Both ET and OS were safe and effective methods to repair IIAAs with similar postoperative mortality. Compared with OS, ET can reduce the need for transfusion and the time of LHS, but it was associated with a higher risk of PICs. The comparisons of primary patency and reintervention rates were still unclear between the 2 groups.

Barrier effect of coal bottom ash-based geopolymers on soil contaminated by heavy metals.

Coal bottom ash (CBA) was modified on the basis of the engineering problems of low resource utilization of CBA and difficulty in treating HMS through alkali activation to synthesize geopolymers and solidify heavy metal-contaminated soil (HMS). The optimal values of geopolymers were selected through response surface methodology. Their mineral compositions, microstructure, and binding energy were determined through X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy tests, respectively. The stress-strain curve, the leaching concentration and fraction of heavy metals, and the solidifying mechanism for remolded soil were determined through unconfined compressive strength, leaching toxicity, sequential chemical extraction, and infrared (IR) spectroscopy tests, respectively. Based on these experiments, the following conclusions were presented. The optimum ratios of CBA-based geopolymers were n(Si) : n(Al) = 2.666, n(Na) : n(Al) = 0.687, and n(water) : n(binder) = 2.422. The X-ray curves of the geopolymers were obvious hump-like protuberances at diffraction angles of 20-35° and had a dense amorphous structure on the surface. The maximum binding energies of Si 2p and Al 2p decreased to 101.03 and 72.89 eV, respectively. A 3D network polymerized because of strong geopolymerization. The maximum axial stress of the remolded soil was 104.91% higher than that of the undisturbed soil, and the leaching concentration decreased by more than 45.88%. The leaching toxicity met the requirements of standard GB 5085.3-2007. The proportion of the acid-extractable fraction of heavy metals in the remolded soil decreased, whereas the proportion of residual fraction increased. The stretching vibration of Si-O-Si (Al) and the bending vibration of Si-O-Si appeared in the IR spectrum. The soil particles were completely encapsulated by a hardened geopolymer structure, thereby forming a multilayer space-skeleton barrier structure that could greatly improve the mechanical properties.

The strategies and outcomes of left subclavian artery revascularization during thoracic endovascular repair for type B aortic dissection.

This study was to analyze the outcomes of left subclavian artery (LSA) revascularization during thoracic endovascular repair (TEVAR) for type B aortic dissections (TBAD). From 2011 to 2017, TBAD patients who underwent LSA revascularization during TEVAR were enrolled. Technical success, endoleaks, mortality, complication, reintervention, and patency of target vessels were analyzed. 38 patients were included, 14 underwent carotid-subclavian bypass (CSB), and 24 underwent chimney graft (CG) implantation. Technical success rates were 92.9% and 100% in CSB and CG group. Eleven immediate type I endoleak (EL-I) was detected, including one from CSB group and ten from CG group. Three immediate type II endoleak (EL-II) was detected in CSB group. Perioperative complications showed no difference, but CSB group had longer intensive care unit (ICU) stay time. Median follow-up time was 26.2 months, and overall mortality was 14.3% and 0% in each group. Three EL-I and one EL-II underwent reintervention. All the LSA showed good patency, except one suffered from CG collapse. Both CSB and CG were feasible strategies to preserve the antegrade blood flow of LSA, and each strategy had its advantages and disadvantages. Based on our current experience, we preferred CG for high-risk patients. However, the evidence was still not strong enough, further well-designed studies are necessary to identify the criteria for LSA revascularization strategy during TEVAR.