Reduction Of Metal Ions Research Articles

Accelerating Small Electron Polaron Dissociation and Hole Transfer at Solid-Liquid Interface for Enhanced Heterogeneous Photoreaction.

In a photocatalysis process, quick charge recombination induced by small electron polarons in a photocatalyst and sluggish kinetics of hole transfer at the solid-liquid interface have greatly limited photocatalytic efficiency. Herein, we demonstrate hydrated transition metal ions as mediators that can simultaneously accelerate small electron polaron dissociation (via metal ion reduction) and hole transfer (through high-valence metal production) at the solid-liquid interface for improved photocatalytic pollutant degradation. Fe3+, by virtue of its excellent redox ability as a homogeneous mediator, enables the BiVO4 photocatalyst to achieve drastically increased photocatalytic degradation performance, up to 684 times that without Fe3+. The enhanced performance results from Fe(IV) species production (via Fe3+ oxidation) induced by dissociation of small electron polarons (via Fe3+ reduction), featuring an extremely low kinetic barrier (5.4 kJ mol-1) for oxygen atom transfer thanks to the donor-acceptor orbital interaction between Fe(IV) and organic pollutants. This work constructs a high-efficiency artificial photosynthetic system through synergistically eliminating electron localization and breaking hole transfer limitation at the solid-liquid interface for constructing high-efficiency artificial photosynthetic systems.

Z-scheme driven charge transfer in g-C3N4/α-Fe2O3 nanocomposites enabling photocatalytic degradation of crystal violet and chromium reduction

In this study, we demonstrated the design and fabrication of iron oxide-embedded protonated graphitic carbon nitride (α-Fe2O3/p-g-C3N4) nanocomposites for photocatalytic dye degradation and heavy metal reduction applications under sunlight irradiation. The developed nanocomposites, with varying weight percentages of α-Fe2O3, were characterized for their structural (XRD, FTIR, XPS), optical (absorption and photoluminescence), morphological (FE-SEM, TEM), and electrochemical (EIS) properties to elucidate their structure-property relationships. The synthesis method ensures the uniform dispersion of α-Fe2O3 nanoparticles, with a particle size range of 50–60 nm, onto p-g-C3N4. XPS analysis suggests the formation of an electrical layer at the interface of α-Fe2O3/p-g-C3N4, facilitating the formation of a Z-scheme heterojunction. The photoluminescence and EIS spectra of the nanocomposite indicated effective separation and transfer of photo-induced charge carriers, aided by a reduced bandgap energy of ∼2.63 eV. Notably, the optimized 10 wt% α-Fe2O3/p-g-C3N4 nanocomposite exhibited superior photocatalytic activity, degrading nearly 100 % of crystal violate dye and reducing 98 % of Cr(VI) ions, compared to bare p-g-C3N4, which degraded around 43 % of the dye and reduced 39 % of Cr(VI) ions under sunlight irradiation. Scavenger studies indicated that α-Fe2O3/p-g-C3N4 nanocomposites produce adequate superoxide anions and hydroxyl radicals for dye degradation and heavy metal ion reduction. The composite also demonstrated consistent recyclability up to 5 cycles with around 100 % cyclical efficiency. The pH-dependent photoreduction and cyclic dye degradation by the 10 wt% α-Fe2O3/p-g-C3N4 photocatalyst indicated excellent stability, making it suitable for the treatment of multi-pollutant wastewater.

One-pot synthesis of monodisperse silver-lignin particles: Enhanced antibacterial agents against antibiotic-resistant bacteria

Lignin-based supports for metal nanoparticles (NPs) have attracted significant attention due to their abundant functional groups that facilitate NPs loading. However, many studies involve a two-step process: fabricating lignin particles and then reducing metal ions to NPs using physical energy consumption or chemical reduction. A one-step in-situ reduction method for NP synthesis on carrier surfaces, eliminating energy consumption, is needed for environmentally friendly and sustainable approach. Herein, we demonstrate that poly-l-lysine (PL) controls the self-assembly kinetics of kraft lignin (KL), and reduces silver ion (Ag+) to silver nanoparticles (AgNPs), forming highly monodisperse, co-self-assembled PL-KL particles (Ag@PL-KLPs) without chemical reducing agents or energy consumption. PL facilitated rapid KL desolvation, promoting intermolecular interactions and silver ion adsorption, followed by an efficient, separate nucleation and growth process yielded Ag@PL-KLPs approximately 270 nm in size with a narrow distribution. Notably, Ag@PL-KLPs exhibited enhanced bacteriostatic and bactericidal properties against antibiotic-resistant bacteria (ARB), including both Gram-negative and Gram-positive strains, at concentrations of 250 μg/mL. Leveraging biomass-derived lignin and this cost-effective, one-step green synthesis approach offers a sustainable method for avoiding antibiotic overuse and environmental contamination.

Synthesis and characterization of Selenicereus undatus extract mediated nano-Bi2O3 and its application in the adsorption of Rhodamine B dye

Betacyanins (BC) are reddish-purple pigments widely found in the peels of white-fleshed dragon fruit (Selenicereus undatus) and peels and pulps of red-fleshed dragon fruit (Selenicereus costaricensis). BC pigments are good anti-oxidants that inhibit the formation of reactive oxygen species (ROS) in plants and thereby promote the reduction of metal ions to zero-valent metals. It also acts as a good stabilizing and capping agent in the synthesis of nanoparticles. Hence, this research aims to extract, and quantize the content of BC from the peels of Selenicereus undatus, to fabricate betacyanin-rich- Selenicereus undatus (SU) modified bismuth oxide nanoparticles (Bi2O3 NPs) and characterize using UV-Vis, FTIR, XRD, SEM, EDAX, and BET. The quantity and stability of the betacyanin are optimized using various parameters like time, temperature, solvent ratio, pH, etc., through a UV-Vis spectrophotometer at 538 nm. Synthesized SU-Bi2O3 NPs aim to alleviate synthetic dye contaminants through adsorption- an efficient route for water remediation. The nano-adsorbent Bi2O3 NPs showed an increase in dye adsorption with an increase in reaction time, temperature, and Bi2O3 NPs dosage, enabling efficient removal of dyes such as Rhodamine B (RhB) dyes.

Light‐Promoted Extraction of Precious Metals Using a Porphyrin‐integrated One‐dimensional Covalent Organic Framework

Precious metals are valuable materials for the chemical industry, but they are scarce and pose a risk of supply disruption. Recycling precious metals from waste is a promising strategy, here we tactfully utilize light irradiation as an environmental‐friendly and energy‐saving adjunctive strategy to promote the reduction of precious metal ions, thereby improving the adsorption capacity and kinetics. A newly light‐sensitive covalent organic framework (PP‐COF) was synthesized to illustrate the effectiveness and feasibility of this light auxiliary strategy. The equilibrium adsorption capacities of PP‐COF with light irradiation towards gold, platinum, and silver ions are 4729, 573, and 519 mg g–1, which are 3.3, 1.9, and 1.2 times the adsorption capacities under dark condition. Significantly, a filtration column with PP‐COF can recover more than 99.8% of the gold ions in the simulated e‐waste leachates with light irradiation, and 1 gram of PP‐COF can recover gold from up to 0.15 tonne of e‐waste leachates. Interestingly, the captured precious metals by PP‐COF with light irradiation mainly exist in the micron‐sized particles, which can be easily separated by extraction. We believe this work can contribute to precious metal recovery and circular economy for recycling resources.

Light-Promoted Extraction of Precious Metals Using a Porphyrin-integrated One-dimensional Covalent Organic Framework.

Precious metals are valuable materials for the chemical industry, but they are scarce and pose a risk of supply disruption. Recycling precious metals from waste is a promising strategy, here we tactfully utilize light irradiation as an environmental-friendly and energy-saving adjunctive strategy to promote the reduction of precious metal ions, thereby improving the adsorption capacity and kinetics. A newly light-sensitive covalent organic framework (PP-COF) was synthesized to illustrate the effectiveness and feasibility of this light auxiliary strategy. The equilibrium adsorption capacities of PP-COF with light irradiation towards gold, platinum, and silver ions are 4729, 573, and 519 mg g-1, which are 3.3, 1.9, and 1.2 times the adsorption capacities under dark condition. Significantly, a filtration column with PP-COF can recover more than 99.8% of the gold ions in the simulated e-waste leachates with light irradiation, and 1 gram of PP-COF can recover gold from up to 0.15 tonne of e-waste leachates. Interestingly, the captured precious metals by PP-COF with light irradiation mainly exist in the micron-sized particles, which can be easily separated by extraction. We believe this work can contribute to precious metal recovery and circular economy for recycling resources.

Green synthesis of bimetallic Ag-ZnO nanocomposite using polyherbal extract for antibacterial and anti-inflammatory activity

The current research has involved to develop nanoparticles (NPs) of zinc oxide (ZnO) doped with silver (Ag) through an eco-friendly method. Eclipta prostrate (EP), Eclipta alba (EA), and Tridax procumbans (TP) are subjected to Soxhlet extraction using ethyl acetate. Alkaloids, flavonoids, and phenols were quantified using standard methods. Polyherbal extract was used to synthesize silver-zinc oxide nanocomposites (Ag-ZnO NCs) via the sol-gel method. The reduction of metal ions was confirmed by UV–visible spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Polyherbal plants are found to have higher concentrations of phenols, flavonoids, and alkaloids than indigenous plants. Ag-ZnO NCs functional group has been identified using Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. UV–vis spectroscopy revealed the surface plasmon resonance (SPR) of silver nanoparticles at 463–477 nm and zinc oxide nanoparticles at 266–267 nm. For Ag-ZnO NCs, the SPR peak was observed at 450 nm. Scanning electron microscopy confirmed the spherical morphology of the Ag-ZnO NCs. The anti-microbial activity of the formulated Ag-ZnO NCs was more effective than the extract against all tested pathogens. The most effective antimicrobial activities are achieved for Ag-ZnO NCs at 50 µg and 200 µg for extract. Biosynthesized nanoparticles exhibit a significant anti-inflammatory effect of 68% at a low concentration of 500 µg/mL, greater than the efficacy of diclofenac sodium. Additionally, the synthesized Ag-ZnO nanoparticle demonstrated its stability for 90 days and showed strong antimicrobial properties.

Green synthesis of Titanium dioxide nanoparticle using combination of plants and its antimicrobial study with their characterization

Abstract The characteristics and biological qualities of the nanomaterial rely heavily on how it was made. Green nanoparticle production has been developed to minimize pollution, cut expenses, and enhance safety for both human health and the environment by reducing metal ions using plant extracts as opposed to industrial chemical agents. The goal of the current work is to synthesize titanium dioxide nanoparticles in an environmentally friendly manner by using an extract from the combined shells of Stone apples (Aegle marmelos) and Wood apples (Limonia acidissima). Titanium dioxide nanoparticle formation was verified using various characterization techniques. Well diffusion was used to measure the antimicrobial activity. The fungal strains that were employed were Aspergillus Niger, Candida Albicans, and Aspergillus Flavus. All fungul strains were successfully inhibited by both the crudely prepared extract and the biosynthesized titanium dioxide nanoparticles; however, the biosynthesized titanium dioxide nanoparticles exhibited a high zone of inhibition ranging from 25 to 30 mm, while the crudely prepared extract had a low zone of inhibition ranging from 13 to 19 mm. A moderately sized zone of inhibition was observed in both the crude produced extract and the biosynthesized Titanium dioxide nanoparticles at a dilution of 100 μg/ml. Lower dilutions demonstrated less noticeable inhibition. Overall, these results showed that treatment with biosynthesized titanium dioxide nanoparticles significantly slowed the growth of many microorganisms.

Phytosynthesis of titanium dioxide nanoparticles using Cynodon dactylon leaf extract and their antibacterial activity

Due to use of nanoparticles, nanotechnology has become an important area of research penetrating in all the fields of science and technology including medicinal chemistry. Titanium dioxide nanoparticles (TiO2 NPs) play an important role in biotechnology and nanomedicine because of their antimicrobial effect against many pathogens such as bacteria, fungus, viruses and yeast. In this article, we propose an eco-friendly phytosynthesis method of TiO2 NPs using aqueous leaf extract of Cynodon dactylon herbal plant as a reducing agent. The formation of TiO2 NPs by plant bio-molecules involved in the reduction of metal ions to nanoparticles is demonstrated. The synthesized TiO2 NPs are analyzed using X-ray diffraction analysis, Fourier transform infrared spectroscopy, laser Raman spectroscopy and field emission scanning electron microscopy. The antibacterial activity of the TiO2 NPs against gram-positive bacterial pathogens like Bacillus subtilis and Staphylococcus aureus as well as gram-negative bacterial pathogen like Escherchia coli is tested. The obtained results demonstrate potent bactericidal activity of the TiO2 NPs.

C60 Fullerene-Induced Reduction of Metal Ions: Synthesis of C60-Metal Cluster Heterostructures with High Electrocatalytic Hydrogen-Evolution Performance.

Metal clusters, due to their small dimensions, contain a high proportion of surface atoms, thus possessing a significantly improved catalytic activity compared with their bulk counterparts and nanoparticles. Defective and modified carbon supports are effective in stabilizing metal clusters, however, the synthesis of isolated metal clusters still requires multiple steps and harsh conditions. Herein, we develop a C60 fullerene-driven spontaneous metal deposition process, where C60 serves as both a reductant and an anchor, to achieve uniform metal (Rh, Ir, Pt, Pd, Au and Ru) clusters without the need for any defects or functional groups on C60. Density functional theory calculations reveal that C60 possesses multiple strong metal adsorption sites, which favors stable and uniform deposition of metal atoms. In addition, owing to the electron-withdrawing properties of C60, the electronic structures of metal clusters are effectively regulated, not only optimizing the adsorption behavior of reaction intermediates but also accelerating the kinetics of hydrogen evolution reaction. The synthesized Ru/C60-300 exhibits remarkable performance for hydrogen evolution in an alkaline condition. This study demonstrates a facile and efficient method for synthesizing effective fullerene-supported metal cluster catalysts without any pretreatment and additional reducing agent.

Preparation of electroless deposition of NiTiZr(P) quaternary alloy and their properties

The exceptional super elasticity and corrosion-resistance of Ni-Ti alloys have attracted a lot of attention and interest lately for a wide range of applications, and complex alloy components could be prepared effectively by different preparation techniques. Ni(P), Ni-Ti(P), Ni-Zr(P), and Ni-Ti -Zr(P) binary, ternary, and quaternary alloys were coated on mild steel by electroless deposition which is a method of plating metallic films on a substrate by the reduction of metallic complex ions in solution with the aid of reducing agent from an alkaline bath. The ternary Ni-Ti-Zr(P) alloy is considered to be one of the most promising high-temperature SMAs. SEM, XRD and EDS were used to examine the morphology, phase composition and elemental composition which demonstrate the microstructure of the deposits. The mechanical characteristics of the samples were examined through scratch test and micro hardness analysis and the value increased from 261 HV200 to 405 HV200 and that the coefficient of friction raised significantly from 0.23 to 3.5 owing to the presences of added elements in Ni(P) matrix. Polarization analysis and EIS were tested to evaluate the corrosion properties of coated samples in a non-deaerated 3.5 %wt. (NaCl) solution. The outcomes indicate that as the amount of Ti-Zr elements in the bath raised, the corrosion potential became more positive and the corrosion current density decreased to 14.903 μA/cm2. Furthermore, Ni-Ti-Zr(P) alloy coating strengthens corrosion resistance in comparison to Ni(P).

Phytochemical constituents, extraction and pharmacological activity of vitex agnus-Castus nanoparticle

As a participant of the Verbenaceae family, Vitex agnus-castus comprises a wide range of chemical machineries, including flavonoids, phenolic compounds, iridoid glycosides, and essential oils. Because of its hormonal effects, it is primarily used to treat PMS, menstrual disorders, and menopausal difficulties. Green synthesis, which services plant extracts convert into metal ions into nanoparticles, its process used to make Vitex negundo nanoparticles, also denoted as nano formulations or nanoscale versions of Vitex negundo extract. This process comprises heating or ultrasonicating the plant extract after it has been jointing with a solution containing metal ions, such as silver, gold, copper oxide, or zinc oxide. This allows the phytochemicals in the extract to reduce metal ions into nanoparticles. The green synthesis experiments are both environmentally kind and sustainable. Vitex linn leaf extract is the starting point for silver and gold nanoparticles, which has some indication in pharmacological properties because of their nanoscale features, which gives antimicrobial, anti-inflammatory property, antitumor, and wound-healing abilities.

Improved lifetime of a pulsed electric field (PEF) system-using laser induced surface oxidation

In this research, we explore the possibility and effectiveness of using laser-induced surface oxidation methods to enhance the durability and effectiveness of PEF (Pulsed Electric Field) systems. Despite advantages over thermal pasteurisation, PEF faces challenges like electrode corrosion and biofouling, hindering its adoption. This research introduces laser-induced oxidation to mitigate metal ion release during PEF, directly targeting electrode alteration. Our examination adopts a comprehensive method, integrating Design of Experiments (DoE) parameter sets for PEF trials, morphological analysis, evaluation of metal ion release via Inductively Coupled Plasma Quadrupole Mass Spectrometry (ICP-QMS), waveform capture utilizing a Data Acquisition (DAQ) system, electrochemical assessment via impedance spectroscopy, and examination of oxide layer composition employing X-ray photoelectron spectroscopy. Pulse waveform characteristics shows the intricate relationship between PEF processing parameters with metal ion release, alongside XPS analysis providing insights into surface chemistry. Optimized results show a three-fold reduction in metal ion release post-PEF, with laser-treated samples outperforming untreated stainless steel due to selective surface chemistry alteration, notably an increased Cr/Fe ratio, reducing harmful elements. This study highlights laser-induced oxidation as a practical solution for enhancing PEF electrode performance and reducing metal ion release, addressing key challenges in PEF technology. It advances sustainable food processing, promising extended PEF system lifespan while maintaining efficiency and product quality.

Harnessing the chromium reduction potential of Pseudomonas aeruginosa JRHM33: A comprehensive study on bioinformatics, phenotype microarray, and CCD-RSM optimization

Large amounts of wastewater are generated due to overpopulation and industrialization, The bioavailability, toxicity, and permanence of metals make heavy metal contamination a big environmental hazard. In order to maximize chromium (Cr+6) removal efficiency, the current investigation was carried out from industrial wastewater using Pseudomonas aeruginosa JRHM33.35 bacterial strains were discovered based on their physical, and biochemical properties and resistance towards chromium (Cr+6) heavy metal. The most significant bacterial strain JRHM33 found the highest-level of 1000 mg/L of chromium (Cr+6) resistance. The bacterial strain JRHM33, which has 99 % similarity to Pseudomonas aeruginosa, was found using 16 S rRNA sequencing and is employed in subsequent steps. Sequencing and study of conserved domains indicate that JRHM33 contains the laccase gene and belongs to the multicopper oxidase superfamily, which is known for its ability to reduce metal ions. Analysing phenotype microarray (PM) technology sheds light on Pseudomonas aeruginosa JRHM33 metabolic profile of microbial cells. Additionally, a series of process parameter optimizations were tried using the central composite design of response surface methodology (CCD-RSM) in an effort to reduce the amount of chromium (Cr+6) in the effluent as much as possible. At 6.8 pH, 90 min of incubation, inoculum size is 3.8 ml, and agitation is 104 rpm, a maximum 71 % Cr+6 reduction was attained. The model constructed has an R2 score of 0.983 indicates a very statistically significant outcome from the analysis of variance. The experimental outcomes and the predicted results were remarkably similar, according to the validation experiment. Studies have revealed that bacterial strains obtained from effluent containing high levels of metals utilize their inherent capability to change harmful heavy metals into less dangerous or harmless forms.

Composition Heterogeneity of Metal Ions Bound at the Oxygen-Evolving Center of Photosystem II in Living Cells.

Recent resolution advancement of in situ cryo-electron tomography (cryo-ET) and cryo-electron microscopy (cryo-EM) enables us to visualize large enzymes-in-action in atomic detail in their native environments inside living cells, such as photosystem II (PSII) and the ribosome. A variety of crystallographic and cryo-EM structures of PSII have been published for the purified PSII dimeric core complexes by itself, in supercomplexes with photosystem I (PSI) and light-harvesting complexes (LHC), and in megacomplexes with phycobilisome (PBS). In the latter case, two or five copies of asymmetric dimeric PSII molecules are present in highly asymmetric environments that differ from other 2-fold symmetric structures. Previous systematic analysis of X-ray free-electron laser (XFEL) crystal structures of PSII has shown different degrees of composition heterogeneity of metal ion cofactor bound at the oxygen-evolving center (OEC), including between two monomers of the same PSII dimer. This study analyzed the metal ions bound at four OECs in two asymmetric dimeric PSII molecules within in situ cryo-ET structures reported for an asymmetric PBS-PSII-PSI-LHC megacomplex determined in a living organism without purification and shows that composition heterogeneity with reduced metal ion occupancies at the OEC of PSII is a general phenomenon. This finding could have profound implications for spectroscopic interpretations of unpurified PSII samples.

Deciphering the Mechanisms and Biotechnological Implications of Nanoparticle Synthesis Through Microbial Consortia.

Nanomaterial synthesis is a growing study area because of its extensive range of uses. Nanoparticles' high surface-to-volume ratio and rapid interaction with various particles make them appealing for diverse applications. Traditional physical and chemical methods for creating metal nanoparticles are becoming outdated because they involve complex manufacturing processes, high energy consumption, and the formation of harmful by-products that pose major dangers to human health and the environment. Therefore, there is an increasing need to find alternative, cost-effective, dependable, biocompatible, and environmentally acceptable ways of producing nanoparticles. The process of synthesizing nanoparticles using microbes has become highly intriguing because of their ability to create nanoparticles of varying sizes, shapes, and compositions, each with unique physicochemical properties. Microbes are commonly used in nanoparticle production because they are easy to work with, can use low-cost materials, such as agricultural waste, are cheap to scale up, and can adsorb and reduce metal ions into nanoparticles through metabolic activities. Biogenic synthesis of nanoparticles provides a clean, nontoxic, ecologically friendly, and sustainable method using renewable ingredients for reducing metals and stabilizing nanoparticles. Nanomaterials produced by bacteria can serve as an effective pollution control method due to their many functional groups that can effectively target contaminants for efficient bioremediation, aiding in environmental cleanup. At the end of the paper, we will discuss the obstacles that hinder the use of biosynthesized nanoparticles and microbial-based nanoparticles. The paper aims to explore the sustainability of microorganisms in the burgeoning field of green nanotechnology.

Tunable optical properties of isoreticular UiO-67 MOFs for photocatalysis: a theoretical study.

A theoretical study of the reported photocatalytic systems based on Zr-based MOF (UiO-67) with biphenyl-4,4'-dicarboxylic acid (bpdc) and 2,2'-bipyridine-5,5'-dicarboxylic acid (bpydc) as linkers was performed. Quantum chemical calculations were carried out to understand the optical properties of the materials and to facilitate the rational design of new UiO-67 derivatives with potentially improved features as photocatalysts under ambient conditions. Hence, the effect of the structural modifications on the optical properties was studied considering different designs based on the nature of the linkers: in 1 only the bpdc linker was considered, or the mixture 1 : 1 between bpdc and bpydc linkers (labeled as 1A). Also, substituents R, -NH2, and -SH, were included in the 1A MOF only over the bpdc linker (labeled as 1A-bpdc-R) and on both bpdc and bpydc linkers (labeled as 1A-R). Thus a family of six isoreticular UiO-67 derivatives was theoretically characterized using Density Functional Theory (DFT) calculations on the ground singlet (S0) and first excited states (singlet and triplet) using Time-Dependent Density Functional Theory (TD-DFT), multiconfigurational post-Hartree-Fock method via Complete Active Space Self-Consistent Field (CASSCF). In addition, the use of periodic DFT calculations suggest that the energy transfer (ET) channel between bpdc and bpydc linkers might generate more luminescence quenching of 1A when compare to 1. Besides, the results suggest that the 1A-R (R: -SH and NH2) can be used under ambient conditions; however, the ET exhibited by 1A, cannot take place in the same magnitude in these systems. These ET can favor the photocatalytic reduction of a potential metal ion, that can coordinate with the bpydc ligand, via LMCT transition. Consequently, the MOF might be photocatalytically active against molecules of interest (such as H2, N2, CO2, among others) with photo-reduced metal ions. These theoretical results serve as a useful tool to guide experimental efforts in the design of new photocatalytic MOF-based systems.

Fusarium oxysporum mediated synthesis of nitrogen-doped carbon supported platinum nanoparticles for supercapacitor device and dielectric applications

A scalable method has been developed for synthesizing nitrogen-doped carbon-supported platinum nanoparticles. Fusarium oxysporum was utilized as reducing and stabilizing agent, and calcination was employed to produce the carbon support. The unique properties of Fusarium oxysporum facilitate the reduction of metal ions while preventing agglomeration and maintaining nanoparticle stability. An extensive investigation of the electrochemical supercapacitor and temperature-dependent dielectric properties of the nanoparticles demonstrates their suitability for supercapacitor applications. Electrochemical analysis showed N-doped C/Pt NPs with high specific capacitance, 482.77F/g at 2.0 A/g, retaining 94 % capacitance even under 20 A/g after 10,000 cycles. The symmetric supercapacitor device displayed 275F/g at 2 A/g, maintaining 61.10 Wh/kg energy density at 1000 W/kg power density, with ∼ 92 % capacitance retention after 10,000 cycles. Dielectric properties of N-doped C/Pt NPs were analyzed at both ambient (300 K) and elevated (450 K) temperatures, revealing temperature-dependent characteristics and alternating current conductivity. At 0.75 MHz, the dielectric permittivity (ɛ’) was measured at 31, with tangent loss at 2.01 and a.c. conductivity at 2.597 × 10-3 O−1 m−1. Increasing the frequency to 6.0 MHz resulted in a 2.38-fold rise in dielectric permittivity and a decrease in tangent loss to 0.77, demonstrating the temperature-sensitive nature of dielectric relaxation.

Revision of metal-on-metal hip replacements with dual-mobility bearings and acetabular component retention.

In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component. Between 2012 and 2020, across two centres, 94 patients underwent revision of Birmingham MoM hip arthroplasties or resurfacings. Mean age was 65.5 years (33 to 87). In 53 patients (56.4%), the acetabular component was retained and dual-mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). Patients underwent follow-up of minimum two-years (mean 4.6 (2.1 to 8.5) years). In the DM group, two (3.8%) patients underwent further surgery: one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (9.8%) underwent further procedures: two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operating time (68.4 vs 101.5 mins, p < 0.001), postoperative drop in haemoglobin (16.6 vs 27.8 g/L, p < 0.001), and length of stay (1.8 vs 2.4 days, p < 0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p < 0.001), although there was no difference between groups for this reduction (p = 0.674 (cobalt); p = 0.186 (chromium)). In selected patients with Birmingham MoM hips, where the acetabular component is well-fixed and in a satisfactory position with no surface damage, the metal head can be exchanged for polyethylene ADM/MDM bearings with retention of the acetabular prosthesis. This presents significant benefits, with a shorter procedure and a lower risk of complications.

One-pot approach for acoustic directed assembly of metallic and composite microstructures by metal ion reduction

Acoustic-directed assembly is a modular and flexible bottom-up technique with the potential to pattern a wide range of materials. Standing acoustic waves have been previously employed for patterning preformed metal particles, however, direct patterning of metallic structures from precursors remains unexplored. Here, we investigate utilization of standing waves to exert control over chemical reaction products, while also exploring their potential in the formation of multi-layered and composite micro-structures. Concentric micro-structures of gold and silver were obtained by introducing a metal precursor salt and a reducing agent into a cylindrical piezoelectric resonator that also served as a reservoir. In addition, we introduce an innovative approach to directly fabricate metallic multi-layer and composite structures by reducing different metal ions or adding nanoparticles during the reduction step. We showcased our method through the fabrication of layered structures, incorporating a combination of gold and silver, as well as structures composed of silver and hematite nanoparticles. The produced structures were characterized through both surface and cross-sectional analyses, revealing the influence of the acoustic field on the mesostructure as well. This innovative approach is promising for production of complex microstructures with enhanced functionality and controlled properties.