Two-dimensional chiral metal-organic framework nanosheets L-hyp-Ni/Fe@SiO2 composite for HPLC separation.

In this study, we have synthesised a chiral l-hyp-Ni/Fe@SiO2 composite as a chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) for the first time. This was achieved by coating two-dimensional (2D) chiral metal-organic framework nanosheets (MONs) l-hyp-Ni/Fe onto the surface of activated SiO2 microspheres using the "wrapped in net" method. The separation efficiency of the l-hyp-Ni/Fe chromatographic column was systematically evaluated in normal-phase HPLC (NP-HPLC) and reversed-phase HPLC (RP-HPLC) configurations, employing various racemates as analytes. The findings revealed that 16 chiral compounds were separated using NP-HPLC, and five were separated using RP-HPLC, encompassing alcohols, amines, ketones, esters, alkanes, ethers, amino acids and sulfoxides. Notably, the resolution (Rs) of nine chiral compounds exceeded 1.5, indicating baseline separation. Furthermore, the resolution performance of the l-hyp-Ni/Fe@SiO2-packed column was compared with that of Chiralpak AD-H. It was observed that certain enantiomers, which either could not be resolved or were inadequately separated on the Chiralpak AD-H column, attained separation on the 2D chiral MONs column. These findings suggest a complementary relationship between the two columns in racemate separation, with their combined application facilitating the resolution of a broader spectrum of chiral compounds. In addition, baseline separation was achieved for five positional isomers on the l-hyp-Ni/Fe@SiO2-packed column. The effects of the analyte mass and column temperature on the resolution were also examined. Moreover, during HPLC analysis, the l-hyp-Ni/Fe columns demonstrated commendable repeatability, stability and reproducibility in enantiomer separation. This research not only advances the utilisation of 2D chiral MONs as CSPs but also expands their applications in the separation sciences.

Assessment of bioremediation potential of Calotropis procera and Nerium oleander for sustainable management of vehicular released metals in roadside soils.

Land transportation is a major source of heavy metal contamination along the roadside, posing significant risks to human health through inhalation, oral ingestion, and dermal contact. Therefore, this study has been designed to determine the concentrations of vehicular released heavy metals (Cd, Pb, Ni, and Cu) in roadside soil and leaves of two commonly growing native plant species (Calotropis procera and Nerium oleander).Two busy roads i.e., Lahore-Okara road (N-5) and Okara-Faisalabad roads (OFR) in Punjab, Pakistan, were selected for the study. The data were collected from five sites along each road during four seasons. Control samples were collected ~ 50 m away from road. The metal content i.e. lead (Pb), cadmium (Cd) nickel (Ni) and copper (Cu) were determined in the plant leaves and soil by using Atomic Absorption Spectrophotometer (AAS). Significantly high amount of all studied heavy metals were observed in soil and plant leaves along both roads in contrast to control ones. The mean concentration of metals in soil ranged as Cd (2.20-6.83 mg/kg), Pb (4.53-15.29 mg/kg), Ni (29.78-101.26 mg/kg), and Cu (61.68-138.46 mg/kg) and in plant leaves Cd (0.093-0.53 mg/kg), Pb (4.31-16.34 mg/kg), Ni (4.13-16.34 mg/kg) and Cu (2.98-32.74 mg/kg). Among roads, higher metal contamination was noted along N-5 road. Significant temporal variations were also noted in metal contamination along both roads. The order of metal contamination in soil and plant leaves in different seasons was summer > autumn > spring > winter. Furthermore, the metal accumulation potential of Calotropis procera was higher than that of Nerium oleander. Therefore, for sustainable management of metal contamination, the plantation of Calotropis procera is recommended along roadsides.

A dual recognition-based strategy employing Ni-modified metal-organic framework for in situ screening of SIRT1 inhibitors from Chinese herbs.

Sirtuin1 (SIRT1), an NAD+-dependent histone deacetylase, plays a crucial role in regulating molecular signaling pathways. Recently, inhibition of SIRT1 rather than its activation shows the therapeutic potential for central nervous system disorder, however, the discovered SIRT1 inhibitors remains limited. In this work, a dual recognition-based strategy was developed to screen SIRT1 inhibitors from natural resources in situ. This approach utilized a Ni-modified metal-organic framework (Ni@Tyr@UiO-66-NH2) along with cell lysate containing an engineered His-tagged SIRT1 protein, eliminating the need for purified proteins, pure compounds, and protein immobilization. The high-performance Ni@Tyr@UiO-66-NH2 was synthesized by modifying the surface of UiO-66-NH2 with Ni2+ ions to specifically capture His-tagged SIRT1 while persevering its enzyme activity. By employing dual recognition, in which Ni@Tyr@UiO-66-NH2 recognized SIRT1 and SIRT1 recognized its ligands, the process of identifying SIRT1 inhibitors from complex matrix was vastly streamlined. The developed method allowed the efficient discovery of 16 natural SIRT1 inhibitors from Chinese herbs. Among them, 6 compounds were fully characterized, and suffruticosol A was found to have an excellent IC50 value of 0.95 ±â€¯0.12 µM. Overall, an innovative dual recognition-based strategy was proposed to efficiently identify SIRT1 inhibitors in this study, offering scientific clues for the development of drugs targeting CNS disorders.

Assessing the health risks of heavy metals and seasonal minerals fluctuations in Camellia sinensis cultivars during their growth seasons.

The risk assessment of heavy metals in tea is extremely imperative for the health of tea consumers. However, the effects of varietal variations and seasonal fluctuations on heavy metals and minerals in tea plants remain unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to evaluate the contents of aluminum (Al), manganese (Mn), magnesium (Mg), boron (B), calcium (Ca), copper (Cu), cobalt (Co), iron (Fe), sodium (Na), zinc (Zn), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and antimony (Sb) in the two categories of young leaves (YL) and mature leaves (ML) of tea (Camellia sinensis) cultivars throughout the growing seasons. The results showed significant variations in the contents of the investigated nutrients both among the different cultivars and growing seasons as well. Furthermore, the average concentrations of Al, Mn, Mg, B, Ca, Cu, Co, Fe, Na, Zn, As, Cd, Cr, Ni, and Sb in YL ranged, from 671.58-2209.12, 1260.58-1902.21, 2290.56-2995.36, 91.18-164.68, 821.95-5708.20, 2.55-3.80, 3.96-25.22, 37.95-202.84, 81.79-205.05, 27.10-69.67, 0.028-0.053, 0.065-0.127, 2.40-3.73, 10.57-12.64, 0.11-0.14 mg kg-1, respectively. In ML, the concentrations were 2626.41-7834.60, 3980.82-6473.64, 3335.38-4537.48, 327.33-501.70, 9619.89-13153.68, 4.23-8.18, 17.23-34.20, 329.39-567.19, 145.36-248.69, 40.50-81.42, 0.089-0.169, 0.23-0.27, 5.24-7.89, 18.51-23.97, 0.15-0.19 mg kg-1, respectively. The contents of all analyzed nutrients were found to be higher in ML than in YL. Target hazard quotients (THQ) of As, Cd, Cr, Ni, and Sb, as well as the hazard index (HI), were all less than one, suggesting no risk to human health via tea consumption. This research might provide the groundwork for essential minerals recommendations, as well as a better understanding and management of heavy metal risks in tea.

Phytoremediation of pollutants in oil-contaminated soils by Alhagi camelorum: evaluation and modeling.

Phytoremediation is a cost-effective and environmentally friendly method, offering a suitable alternative to chemical and physical approaches for the removal of pollutants from soil. This research explored the phytoremediation potential of Alhagi camelorum, a plant species, for total petroleum hydrocarbons (TPHs) and heavy metals (HMs), specifically lead (Pb), chromium (Cr), nickel (Ni), and cadmium (Cd), in oil-contaminated soil. A field-scale study spanning six months was conducted, involving the cultivation of A. camelorum seeds in a nursery and subsequent transplantation of seedlings onto prepared soil plots. Control plots, devoid of any plants, were also incorporated for comparison. Soil samples were analyzed throughout the study period using inductively coupled plasma-optical emission spectroscopy (ICP‒OES) for HMs and gas chromatography‒mass spectrometry (GC‒MS) for TPHs. The results showed that after six months, the average removal percentage was 53.6 ± 2.8% for TPHs and varying percentages observed for the HMs (Pb: 50 ± 2.1%, Cr: 47.6 ± 2.5%, Ni: 48.1 ± 1.6%, and Cd: 45.4 ± 3.5%). The upward trajectory in the population of heterotrophic bacteria and the level of microbial respiration, in contrast to the control plots, suggests that the presence of the plant plays a significant role in promoting soil microbial growth (P < 0.05). Moreover, kinetic rate models were examined to assess the rate of pollutant removal. The coefficient of determination consistently aligned with the first-order kinetic rate model for all the mentioned pollutants (R2 > 0.8). These results collectively suggest that phytoremediation employing A. camelorum can effectively reduce pollutants in oil-contaminated soils.

Selective production of phenolic monomer via catalytic depolymerization of lignin over cobalt-nickel-zirconium dioxide catalyst.

The utilization of lignin, an abundant and renewable bio-aromatic source, is of significant importance. In this study, lignin oxidation was examined at different temperatures with zirconium oxide (ZrO2)-supported nickel (Ni), cobalt (Co) and bimetallic Ni-Co metal catalysts under different solvents and oxygen pressure. Non-catalytic oxidation reaction produced maximum bio-oil (35.3 wt%), while catalytic oxidation significantly increased the bio-oil yield. The bimetallic catalyst Ni-Co/ZrO2 produced the highest bio-oil yield (67.4 wt%) compared to the monometallic catalyst Ni/ZrO2 (59.3 wt%) and Co/ZrO2 (54.0 wt%). The selectively higher percentage of vanillin, 2-methoxy phenol, acetovanillone, acetosyringone and vanillic acid compounds are found in the catalytic bio-oil. Moreover, it has been observed that the bimetallic Co-Ni/ZrO2 produced a higher amount of vanillin (43.7% and 13.30 wt%) compound. These results demonstrate that the bimetallic Ni-Co/ZrO2 catalyst promotes the selective cleavage of the ether ß-O-4 bond in lignin, leading to a higher yield of phenolic monomer compounds.

Divergent roles of IREG/Ferroportin transporters from the nickel hyperaccumulator Leucocroton havanensis.

In response to our ever-increasing demand for metals, phytotechnologies are being developed to limit the environmental impact of conventional metal mining. However, the development of these technologies, which rely on plant species able to tolerate and accumulate metals, is partly limited by our lack of knowledge of the underlying molecular mechanisms. In this work, we aimed to better understand the role of metal transporters of the IRON REGULATED 1/FERROPORTIN (IREG/FPN) family from the nickel hyperaccumulator Leucocroton havanensis from the Euphorbiaceae family. Using transcriptomic data, we identified two homologous genes, LhavIREG1 and LhavIREG2, encoding divalent metal transporters of the IREG/FPN family. Both genes are expressed at similar levels in shoots, but LhavIREG1 shows higher expression in roots. The heterologous expression of these transporters in A. thaliana revealed that LhavIREG1 is localized to the plasma membrane, whereas LhavIREG2 is located on the vacuole. In addition, the expression of each gene induced a significant increase in nickel tolerance. Taken together, our data suggest that LhavIREG2 is involved in nickel sequestration in vacuoles of leaf cells, whereas LhavIREG1 is mainly involved in nickel translocation from roots to shoots, but could also be involved in metal sequestration in cell walls. Our results suggest that paralogous IREG/FPN transporters may play complementary roles in nickel hyperaccumulation in plants.

Rooibos tea waste binary oxide composite: An adsorbent for the removal of nickel ions and an efficient photocatalyst for the degradation of ciprofloxacin.

In this study, rooibos tea waste (RTW) incorporated with a binary oxide (BO; Fe2O3-SnO2) has been reported for the first time as a highly efficient adsorbent material for the elimination of Ni(II) ions. The as-synthesised rooibos tea waste-binary oxide (RWBO) composite adsorbent was characterised using miscellaneous techniques such as FTIR, XRD, SEM, EDX, TGA, BET, and XPS. The RWBO was then tested for the removal of Ni(II) in a batch adsorption experiment. The composite adsorbent showed a great removal efficiency of about 99.75% for Ni(II) ions at 45 °C, 180 min agitation time, pH 7, and dosage of 250 mg. The adsorption process was found to be endothermic and spontaneous. Also, the spent adsorbent [RWBO-Ni(II)] was found to be solar light active with a narrow band gap of 1.4 eV. It was further used as a photocatalyst for the photocatalytic abatement of 10 mg/L ciprofloxacin with an extent of degradation of 83% obtained after 150 min. In addition, the extent of mineralisation of the ciprofloxacin by the spent adsorbent as obtained from the TOC data was found to be 64%. Overall, the RWBO composite adsorbent lends itself as an efficient, eco-friendly and promising material for environmental remediation.

Risk assessment and strontium isotopic tracing of potentially toxic metals in creek sediments around a uranium mine, China.

The contamination of creek sediments near industrially nuclear dominated site presents significant environmental challenges, particularly in identifying and quantifying potentially toxic metal (loid)s (PTMs). This study aims to measure the extent of contamination and apportion related sources for nine PTMs in alpine creek sediments near a typical uranium tailing dam from China, including strontium (Sr), rubidium (Rb), manganese (Mn), lithium (Li), nickel (Ni), copper (Cu), vanadium (V), cadmium (Cd), zinc (Zn), using multivariate statistical approach and Sr isotopic compositions. The results show varying degrees of contamination in the sediments for some PTMs, i.e., Sr (16.1-39.6 mg/kg), Rb (171-675 mg/kg), Mn (224-2520 mg/kg), Li (11.6-78.8 mg/kg), Cd (0.31-1.38 mg/kg), and Zn (37.1-176 mg/kg). Multivariate statistical analyses indicate that Sr, Rb, Li, and Mn originated from the uranium tailing dam, while Cd and Zn were associated with abandoned agricultural activities, and Ni, Cu, and V were primarily linked to natural bedrock weathering. The Sr isotope fingerprint technique further suggests that 48.22-73.84% of Sr and associated PTMs in the sediments potentially derived from the uranium tailing dam. The combined use of multivariate statistical analysis and Sr isotopic fingerprint technique in alpine creek sediments enables more reliable insights into PTMs-induced pollution scenarios. The findings also offer unique perspectives for understanding and managing aqueous environments impacted by nuclear activities.

Elucidating hepatoprotective potential of Cichorium intybus through multimodal assessment and molecular docking analysis with hepatic protective enzymes.

This study employed a comprehensive approach to validate the hepatoprotective potential of phytoconstituents from Cichorium intybus leaves. In vitro, in vivo and in silico techniques were used to confirm the protective effects on liver enzymes. In vitro antioxidant assessment revealed the highest potential in the hydroethanolic leaf extract compared to aqueous and methanolic extracts. The study further investigated the ameliorative efficacy of the hydro-ethanolic extract (HECL) in male Wistar rats exposed to lead (50 mg/kg b wt.) and nickel (4.0 mg/kg b wt.) individually and in combination for 90 days. HECL at 250 mg/kg b wt. mitigated hepatic injury, oxidative stress, DNA fragmentation, ultrastructural and histopathological alterations induced by lead and nickel. Molecular docking explored the interaction of 28 phytoconstituents from C. intybus with hepatoprotective protein targets. Cyanidin and rutin exhibited the highest affinity for liver corrective enzymes among the screened phytoconstituents. These findings underscore the liver corrective potential of C. intybus leaf phytoconstituents, shedding light on their molecular interactions with hepatoprotective targets. This research contributes valuable insights into the therapeutic applications of C. intybus in liver protection.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway.

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of "nil to shallow," signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be "zero to very low degree of contamination" at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Synthesis of Bioactive Nickel Nanoparticles Using Bacterial Strains from an Antarctic Consortium.

Marine microorganisms have been demonstrated to be an important source for bioactive molecules. In this paper we report the synthesis of Ni nanoparticles (NiSNPs) used as reducing and capping agents for five bacterial strains isolated from an Antarctic marine consortium: Marinomonas sp. ef1, Rhodococcus sp. ef1, Pseudomonas sp. ef1, Brevundimonas sp. ef1, and Bacillus sp. ef1. The NiSNPs were characterized by Ultraviolet-visible (UV-vis) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopic analysis. The maximum absorbances in the UV-Vis spectra were in the range of 374 nm to 422 nm, corresponding to the Surface plasmon resonance (SPR) of Nickel. DLS revealed NiSNPs with sizes between 40 and 45 nm. All NiSNPs were polycrystalline with a face-centered cubic lattice, as revealed by XRD analyses. The NiSNPs zeta potential values were highly negative. TEM analysis showed that the NiSNPs were either spherical or rod shaped, well segregated, and with a size between 20 and 50 nm. The FTIR spectra revealed peaks of amino acid and protein binding to the NiSNPs. Finally, all the NiSNPs possess significant antimicrobial activity, which may play an important role in the management of infectious diseases affecting human health.

Utilization of nickel-graphite electrode as an electron donor for high-efficient microbial removal of solved U(VI) mediated by Leifsonia sp.

Enzymatically catalyzed reduction of metals by bacteria has potential application value to uranium-mine wastewater. However, its practical implementation has long been restricted by its intrinsic drawbacks such as low efficiency and long treatment-time. This study aims to explore the effect of electrodes on U (VI) removal efficiency by a purified indigenous bacteria isolated from a uranium mining waste pile in China. The effects of current intensity, pH, initial U (Ⅵ) concentration, initial dosage of bacteria and contact time on U (Ⅵ) removal efficiency were investigated via static experiments. The results show that U(VI) removal rate was stabilized above 90% and the contact time sharply shortened within 1 h when utilized nickel-graphite electrode as an electron donor. Over the treatment ranges investigated maximum removal of U (Ⅵ) was 96.04% when the direct current was 10 mA, pH was 5, initial U (Ⅵ) concentration was 10 mg/L, and dosage of Leifsonia sp. was 0.25 g/L. In addition, it is demonstrated that U (VI) adsorption by Leifsonia sp. is mainly chemisorption and/or reduction as the quasi-secondary kinetics is more suitable for fitting the process. FTIR results indicated that amino, amide, aldehyde and phosphate -containing groups played a role in the immobilization of U (VI) more or less. SEM and EDS measurements revealed that U appeared to be more obviously aggregated on the surface of cells. A plausible explanation for this, supported by XPS, is that U (VI) was partially reduced to U (IV) by direct current then precipitated on the cells surface. These observations reveal that Nickel-graphite electrode exhibited good electro-chemical properties and synergistic capacity with Leifsonia sp. which potentially provides a new avenue for uranium enhanced removal/immobilization by indigenous bacteria.

The association between trace metals in both cancerous and non-cancerous tissues with the risk of liver and gastric cancer progression in northwest China.

Liver cancer and gastric cancer have extremely high morbidity and mortality rates worldwide. It is well known that an increase or decrease in trace metals may be associated with the formation and development of a variety of diseases, including cancer. Therefore, this study aimed to evaluate the contents of aluminium (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) in cancerous liver and gastric tissues, compared to adjacent healthy tissues, and to investigate the relationship between trace metals and cancer progression. During surgery, multiple samples were taken from the cancerous and adjacent healthy tissues of patients with liver and gastric cancer, and trace metal levels within these samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS). We found that concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn in tissues from patients with liver cancer were significantly lower than those in healthy controls (P < 0.05). Similarly, patients with gastric cancer also showed lower levels of Cd, Co, Cr, Mn, Ni, and Zn-but higher levels of Cu and Se-compared to the controls (P < 0.05). In addition, patients with liver and gastric cancers who had poorly differentiated tumours and positive lymph node metastases showed lower levels of trace metals (P < 0.05), although no significant changes in their concentrations were observed to correlate with sex, age, or body mass index (BMI). Logistic regression, principal component analysis (PCA), Bayesian kernel regression (BKMR), weighted quantile sum (WQS) regression, and quantile-based g computing (qgcomp) models were used to analyse the relationships between trace metal concentrations in liver and gastric cancer tissues and the progression of these cancers. We found that single or mixed trace metal levels were negatively associated with poor differentiation and lymph node metastasis in both liver and gastric cancer, and the posterior inclusion probability (PIP) of each metal showed that Cd contributed the most to poor differentiation and lymph node metastasis in both liver and gastric cancer (all PIP = 1.000). These data help to clarify the relationship between changes in trace metal levels in cancerous liver and gastric tissues and the progression of these cancers. Further research is warranted, however, to fully elucidate the mechanisms and causations underlying these findings.

Trace element levels: How Substance Use Disorder (SUD) contributes to the alteration of urinary essential and toxic element levels.

Increasing illicit drug use is one of the main problems in most countries or societies. Monitoring heavy metals and trace elements in this vulnerable group seems to be necessary. Therefore, we assessed the urinary trace element and toxic metals/metalloids concentrations (Zinc (Zn), Iron (Fe), Copper (Cu), Chromium (Cr), Lead (Pb), Cadmium (Cd), Arsenic (As), Nickel (Ni), and Mercury (Hg)) in opium, tramadol, and cannabis users compared to healthy subjects. In this cross-sectional study, patients with substance use disorder (SUD) (n = 74) were divided into four groups: cannabis, tramadol, opium, and mixed (simultaneous use of more than one of the three studied substances), along with a healthy group (n = 60). Urine samples were prepared by dispersive liquid-liquid microextraction method so that heavy metals/metalloids could be measured by ICP-MS. The mean urinary concentration of Cu (48.15 vs. 25.45; 89.2%, p<0.001), Hg (1.3 vs. 0.10; 1200%, p < 0.001), and Zn (301.95 vs. 210; 43.8%, p < 0.001) was markedly lower among patients with SUD. The mean urinary concentration of other elements including As (1.9 vs. 4.1; 115.8%), Cd (0.1 vs. 1.10; 1000%), Cr (6.80 vs. 11.65; 71.3%), Ni (2.95 vs. 4.95; 67.8%), and Pb (1.5 vs. 7.9; 426.6%) were significantly higher among patients with SUD compared to healthy subjects. When sub-groups were compared, no significant differences were observed between their trace element levels (Kruskal-Wallis test, p > 0.05). This can be an indication that regardless of the type of drug, the levels of trace elements are changed with respect to healthy individuals. Our results showed that illicit drug use causes changes in urinary trace element/heavy metal/metalloid levels and highlights the need for monitoring heavy metals and trace elements in individuals with substance use disorder. Assessment of different elements in biological samples of drug dependents may be useful for implementing new prevention and treatment protocols. In case of changes in their levels, complementary recommendations, attention to diet, and periodic assessment of toxic metal levels within treatment programs will be needed.

Influence of casein phosphopeptide-amorphous calcium phosphate on the surface topography and composition of nickel-titanium archwires during orthodontic treatment with fixed appliances.

PURPOSE: To investigate the surface topography and nickel content of nickel-titanium (NiTi) archwires exposed to either routine oral hygiene or a prophylactic regimen with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) during orthodontic treatment. METHODS: This in vivo study involved 40 orthodontic patients with fixed appliances, who were randomly assigned to either a routine oral hygiene group or a CPP-ACP supplementary regimen group. Twenty new NiTi archwires served as controls. All archwires underwent scanning electron microscopy and energy-dispersive spectroscopy to evaluate their surface topography and elemental composition. The nickel content was quantified as a percentage of total weight and the Ni/Ti ratio, and statistical comparisons were made using pairwise tests. RESULTS: Wires exposed to fluoride toothpaste showed signs of pitting corrosion, deep grooves, and corrosion debris. In contrast, wires exposed to supplementary CPP-ACP exhibited smooth surface areas interspersed with microdefects and deposits. Statistically significant differences in nickel content were found between the new and retrieved archwires, as well as between wires exposed to routine oral hygiene and CPP-ACP (P < 0.001). The archwires exposed to CPP-ACP had the lowest nickel content (P < 0.001). CONCLUSION: The use of CPP-ACP holds promise for application as a safe anticariogenic agent with possible protective properties during orthodontic treatment.

Nickel uptake in leafy greens from contaminated soil: an investigation into phytoavailability and health risk assessment using in vitro digestion model.

Nickel (Ni) is a toxic metal that not only pollutes the environment but also causes harmful impacts on plant growth and human health. Therefore, it is crucial to assess the relationship between the phytoavailability of Ni in soil and its accumulation in edible and non-edible parts of vegetables. A pot experiment was conducted to investigate Ni uptake in three different leafy vegetables, spinach (Spinacia oleracea L.), lettuce (Lactuca sativa L.), and fenugreek (Trigonella foenum-graecum L.), grown in soil artificially contaminated with Ni at three different treatment levels (100 mg kg-1, 200 mg kg-1, and 300 mg kg-1). The potential dietary toxicity of these vegetables in humans was examined by using an in vitro digestion model. The lowest and highest chlorophyll contents were detected in lettuce at 300 mg kg-1 of Ni concentration and in control plants of spinach. Their values were 34.16 ± 3.01 (SPAD unit) and 53 ± 3.7673 (SPAD unit), respectively. Among the three vegetables, lettuce and spinach at 300 mg kg-1 exhibited the highest accumulation of Ni, with 43 mg kg-1 in edible parts and 182 mg kg-1 in non-edible parts. Furthermore, health risk index (HRI) values were found to be > 1 for lettuce and fenugreek at Ni concentrations of 200 and 300 mg kg-1 for both children and adults. The average bioaccessibility of Ni in lettuce, fenugreek, and spinach during the gastrointestinal phase was 32-23%, 24-10%, and 45-37%, respectively, at a Ni concentration of 300 mg kg-1. All three vegetables grown on Ni-contaminated soil may potentially contribute to food chain toxicity. The HRI values being > 1 suggest that these vegetables are unsafe for consumption. Monitoring of Ni concentration in leafy vegetables is essential to minimize human health risks associated with food chain contamination.

Circular economy strategies for mitigating metals shortages in electric vehicle batteries under China's carbon-neutral target.

Concerns over supply risks of critical metals used in electric vehicle (EV) batteries are frequently underscored as impediments to the widespread development of EVs. With the progress to achieve carbon neutrality by 2060 for China, projecting the critical metals demand for EV batteries and formulating strategies, especially circular economy strategies, to mitigate the risks of demand-supply imbalance in response to potential obstacles are necessary. However, the development scale of EVs in the transport sector to achieve China's carbon neutrality is unclear, and it remains uncertain to what extent circular economy strategies might contribute to the reduction of primary raw materials extraction. Consequently, we explore the future quantity of EVs in China required to achieve carbon neutrality and quantify the primary supply security levels of critical metals with the effort of battery cascade utilization, technology substitutions, recycling efficiency improvement, and novel business models, by integrating dynamic material flow analysis and national energy technology model. This study reveals that although 18%-30% of lithium and 20%-41% of cobalt, nickel, and manganese can be supplied to EVs through the reuse and recycling of end-of-life batteries, sustainable circular economy strategies alone are insufficient to obviate critical metals shortages for China's EV development. However, the supplementary capacity offered by second-life EV batteries, which refers to the use of batteries after they have reached the end of their first intended life, may prove adequate for China's prospective novel energy storage applications. The cumulative primary demand for lithium, cobalt, and nickel from 2021 to 2060 would reach 5-7 times, 23-114 times, and 4-19 times the corresponding mineral reserves in China. Substantial reduction of metals supply risks apart from lithium can be achieved by the cobalt-free battery technology developments combined with efficient recycling systems, where secondary supply can satisfy the demand as early as 2054.

Effect of copper, arsenic and nickel on pyrite-based autotrophic denitrification.

Pyritic minerals generally occur in nature together with other trace metals as impurities, that can be released during the ore oxidation. To investigate the role of such impurities, the presence of copper (Cu(II)), arsenic (As(III)) and nickel (Ni(II)) during pyrite mediated autotrophic denitrification has been explored in this study at 30 °C with a specialized microbial community of denitrifiers as inoculum. The three metal(loid)s were supplemented at an initial concentration of 2, 5, and 7.5 ppm and only Cu(II) had an inhibitory effect on the autotrophic denitrification. The presence of As(III) and Ni(II) enhanced the nitrate removal efficiency with autotrophic denitrification rates between 3.3 [7.5 ppm As(III)] and 1.6 [7.5 ppm Ni(II)] times faster than the experiment without any metal(loid) supplementation. The Cu(II) batches, instead, decreased the denitrification kinetics with 16, 40 and 28% compared to the no-metal(loid) control for the 2, 5 and 7.5 ppm incubations, respectively. The kinetic study revealed that autotrophic denitrification with pyrite as electron donor, also with Cu(II) and Ni(II) additions, fits better a zero-order model, while the As(III) incubation followed first-order kinetic. The investigation of the extracellular polymeric substances content and composition showed more abundance of proteins, fulvic and humic acids in the metal(loid) exposed biomass.

Optimizing biogas methanation over nickel supported on ceria-alumina catalyst: Towards CO2-rich biomass utilization for a negative emissions society.

Biogas methanation emerges as a prominent technology for converting biogas into biomethane in a single step. Furthermore, this technology can be implemented at biogas plant locations, supporting local economies and reducing dependence on large energy producers. However, there is a lack of comprehensive studies on biogas methanation, particularly regarding the technical optimization of operational parameters and the profitability analysis of the overall process. To address this gap, our study represents a seminal work on the technical optimization of biogas methanation obtaining an empirical model to predict the performance of biogas methanation. We investigate the influence of operational parameters, such as reaction temperature, H2/CO2 ratio, space velocity, and CO2 share in the biogas stream through an experimental design. Based on previous research we selected a nickel supported on ceria-alumina catalyst; being nickel a benchmark system for methanation process such selection permits a reliable data extrapolation to commercial units. We showcase the remarkable impact of studied key operation parameters, being the temperature, the most critical factor affecting the reaction performance (ca. 2 to 5 times higher than the second most influencing parameter). The impact of the H2/CO2 ratio is also noticeable. The response surfaces and contour maps suggest that a temperature between 350 and 450 °C and an H2/CO2 ratio between 2.5 and 3.2 optimize the reaction performance. Further experimental tests were performed for model validation and optimization leading to a reliable predictive model. Overall, this study provides validated equations for technology scaling-up and techno-economic analysis, thus representing a step ahead towards real-world applications for bio-methane production.