Iron/sulfur centers are key cofactors of proteins intervening in multiple conserved cellular processes, such as gene expression, DNA repair, RNA modification, central metabolism and respiration. ...Mechanisms allowing Fe/S centers to be assembled, and inserted into polypeptides have attracted much attention in the last decade, both in eukaryotes and prokaryotes. Basic principles and recent advances in our understanding of the prokaryotic Fe/S biogenesis ISC and SUF systems are reviewed in the present communication. Most studies covered stem from investigations in Escherichia coli and Azotobacter vinelandii. Remarkable insights were brought about by complementary structural, spectroscopic, biochemical and genetic studies. Highlights of the recent years include scaffold mediated assembly of Fe/S cluster, A-type carriers mediated delivery of clusters and regulatory control of Fe/S homeostasis via a set of interconnected genetic regulatory circuits. Also, the importance of Fe/S biosynthesis systems in mediating soft metal toxicity was documented. A brief account of the Fe/S biosynthesis systems diversity as present in current databases is given here. Moreover, Fe/S biosynthesis factors have themselves been the object of molecular tailoring during evolution and some examples are discussed here. An effort was made to provide, based on the E. coli system, a general classification associating a given domain with a given function such as to help next search and annotation of genomes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
► Fe/S assembly understanding was enhanced by structural analysis of IscU–IscS complex. ► A-type carriers allow for the delivery of preformed clusters. ► Fe/S homeostasis is controlled by IscR, Fur and RyhB. ► Metal toxicity is mediated via Fe/S proteins. ► Fe/S biosynthesis systems show diversity in both genetic organization and factors content.
Chemical doping of reduced graphene oxide (rGO) oxide has been a major trend as photocatalyst and electrocatalyst owing to large number of active sites they bring in. In the present work ternary ...copper iron sulphide (Cu5FeS4) has been successfully synthesized using hydrothermal method and incorporated with rGO, N/rGO and B/rGO. The structural, morphological and compositional changes were analyzed using XRD, XPS, SEM, TEM and EDAX results respectively. The bandgap of the materials was confirmed using UV-DRS results. The photoluminescence (PL) spectra of the samples revealed the reduction of recombination with the presence of rGO and doped rGO. The photocatalytic studies of the composites were carried out using methylene blue(MB) as a model pollutant where CFS-N/rGO shows the highest degradation rate of 70%.The electrocatalytic tests were conducted in order to study the performance of the composites as catalyst for HER where CFS-N/rGO showed an enhanced activity with higher current density and lower Tafel slope.The higher Cdl value of CFS-N/rGO indicates the increased number of exposed active sites when doped with N/rGO. The results indicate a considerable amount of change in the photocatalytic and electrocatalytic properties of CFS when doped with rGO, B/rGO and N/rGO.
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•Cu5FeS4 (CFS) catalyst was prepared via hydrothermal method.•The as-synthesized particles were added with rGO, N/rGO and B/rGO (CFS-rGO, CFS N/rGO, CFS-B/rGO).•CFS-N/rGO exhibits superior electrocatalytic activity towards HER and photocatalytic activity for dye degradation.
MotiMove is a battery‐powered general‐purpose transcutaneous functional electrical stimulator (tFES) that comes out of more than 40‐year academic research at the University of Belgrade, Serbia. ...MotiMove can be used for therapeutic intervention, clinical research, and support of fitness training in different application modes (cycling, rowing, grasping, walking, and exercising). Unlike other commercially available tFES devices, it allows real‐time open or closed‐loop control of stimulation parameters to 8 separate current sources from a multitude of sensors. Recent studies with MotiMove in healthy people and people with motor diseases have shown the applicability of the MotiMove stimulator for different users in various environments. Future development will focus on FES clothes with dry interface electrodes and integrated sensors that combined with MotiMove will make a compact easy‐donning testbed for real‐time FES control algorithms.
Applications of MotiMove multi‐channel FES stimulator for Cycling, Rowing, Walking and Grasping.
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•FeS and Fe3O4 anchoring hydrotalcites were synthesized as Fenton reagent.•Heterogeneous Fenton system showed high performance for methoxychlor degradation.•Parameters for ...methoxychlor degradation by Fenton reagent were optimized.•Degradation mechanism and reusability were studied in detail.
Heterogeneous Fenton-like degradation of methoxychlor in water was studied over two FeS@LHDs and Fe3O4@LHDs catalysts prepared by anchoring hydrotalcites (LHDs) onto nano-FeS and nano-Fe3O4 particles respectively via an in situ growth method. The effects of different heterogeneous Fenton system, pH value, initial concentrations of methoxychlor, dioctylsulfosuccinate sodium (AOT) and H2O2, and temperature on the degradation of methoxychlor were systematically investigated. Typically, within the pH range studied (2.5–3.5) the maximum methoxychlor removal of 57.54% was achieved after degradation reaction time of 120 min. The methoxychlor degradation followed pseudo-second-order kinetic model, and its initial degradation efficiency was found to follow the equation of −vo = 72.627e−36.71/RT(CMethoxychlor)2. Methoxychlor was degraded by the Fenton system in two stages and the intermediates were mineralized to hexanoic acid, 3-hydroxy-4-methoxy benzoic acid, water and dioxide. The results demonstrate that heterogeneous Fenton process catalyzed by Fe3O4@LDHs and FeS@LDHs is promising in wastewater treatment.
Genome-wide association studies have discovered a link between genetic variants on human chromosome 15q26.1 and increased coronary artery disease (CAD) susceptibility; however, the underlying ...pathobiological mechanism is unclear. This genetic locus contains the
(FES proto-oncogene, tyrosine kinase) gene encoding a cytoplasmic protein-tyrosine kinase involved in the regulation of cell behavior. We investigated the effect of the 15q26.1 variants on FES expression and whether FES plays a role in atherosclerosis.
Analyses of isogenic monocytic cell lines generated by CRISPR (clustered regularly interspaced short palindromic repeats)-mediated genome editing showed that monocytes with an engineered 15q26.1 CAD risk genotype had reduced FES expression. Small-interfering-RNA-mediated knockdown of FES promoted migration of monocytes and vascular smooth muscle cells. A phosphoproteomics analysis showed that FES knockdown altered phosphorylation of a number of proteins known to regulate cell migration. Single-cell RNA-sequencing revealed that in human atherosclerotic plaques, cells that expressed
were predominately monocytes/macrophages, although several other cell types including smooth muscle cells also expressed
. There was an association between the 15q26.1 CAD risk genotype and greater numbers of monocytes/macrophage in human atherosclerotic plaques. An animal model study demonstrated that
knockout increased atherosclerotic plaque size and within-plaque content of monocytes/macrophages and smooth muscle cells, in apolipoprotein E-deficient mice fed a high fat diet.
We provide substantial evidence that the CAD risk variants at the 15q26.1 locus reduce FES expression in monocytes and that FES depletion results in larger atherosclerotic plaques with more monocytes/macrophages and smooth muscle cells. This study is the first demonstration that FES plays a protective role against atherosclerosis and suggests that enhancing FES activity could be a potentially novel therapeutic approach for CAD intervention.
Lithium-sulfur batteries are currently being explored as promising advanced energy storage systems due to the high theoretical specific capacity of sulfur. However, achieving a scalable synthesis for ...the sulfur electrode material whilst maintaining a high volumetric energy density remains a serious challenge. Here, a continuous ball-milling route is devised for synthesizing multifunctional FeS
/FeS/S composites for use as high tap density electrodes. These composites demonstrate a maximum reversible capacity of 1044.7 mAh g
and a peak volumetric capacity of 2131.1 Ah L
after 30 cycles. The binding direction is also considered here for the first time between dissolved lithium polysulfides (LiPSs) and host materials (FeS
and FeS in this work) as determined by density functional theory calculations. It is concluded that if only one lithium atom of the polysulfide bonds with the sulfur atoms of FeS
or FeS, then any chemical interaction between these species is weak or negligible. In addition, FeS
is shown to have a strong catalytic effect on the reduction reactions of LiPSs. This work demonstrates the limitations of a strategy based on chemical interactions to improve cycling stability and offers new insights into the development of high tap density and high-performance sulfur-based electrodes.
Iron sulfides have been attracting great attention as anode materials for high‐performance rechargeable sodium‐ion batteries due to their high theoretical capacity and low cost. In practice, however, ...they deliver unsatisfactory performance because of their intrinsically low conductivity and volume expansion during charge–discharge processes. Here, a facile in situ synthesis of a 3D interconnected FeS@Fe3C@graphitic carbon (FeS@Fe3C@GC) composite via chemical vapor deposition (CVD) followed by a sulfuration strategy is developed. The construction of the double‐layered Fe3C/GC shell and the integral 3D GC network benefits from the catalytic effect of iron (or iron oxides) during the CVD process. The unique nanostructure offers fast electron/Na ion transport pathways and exhibits outstanding structural stability, ensuring fast kinetics and long cycle life of the FeS@Fe3C@GC electrodes for sodium storage. A similar process can be applied for the fabrication of various metal oxide/carbon and metal sulfide/carbon electrode materials for high‐performance lithium/sodium‐ion batteries.
3D interconnected FeS@Fe3C@graphitic carbon networks are constructed via a chemical vapor deposition method followed by a sulfuration process. The unique nanostructure endows the FeS@Fe3C@GC composite with high discharge capacity, good rate capability, and excellent cycling stability as anode for sodium‐ion batteries. The strategy can be extended to the fabrication of other metal oxide/carbon and metal sulfide/carbon electrode materials.
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•Better photodegradation activity of FeS-Fe2S3 than the monocomponent systems.•Using of visible light decreases cost of the method.•Red shift in band gap energy of FeS-Fe2S3 than the ...monocomponent systems.•Zeolite support increased the charge separation in photoexcited FeS-Fe2S3 and degradation activity.
FeS and Fe2S3 semiconductors were coupled and supported onto clinoptilolite nanoparticles (CN) via sulfidizing of Fe(II) and Fe(III) exchanged CN. The composite was characterized by X-ray diffraction (XRD), scanning electron microscope-energy dispersive x-ray (SEM-EDX), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS) techniques. To study of the synergistic effects of supporting and coupling, the photocatalytic activities of FeS-CN, Fe2S3-CN and FeS-Fe2S3-CN catalysts were evaluated in the photodegradation of ciprofloxacin (CIP) aqueous solution. The ratio of FeS/Fe2S3 played an important role in the photocatalytic activity of the coupled systems, so the catalyst FF1 which ion exchanged in a solution containing 0.1 mol L−1 Fe(II) and 0.15 mol L−1 Fe(III) showed the best activity in the degradation of CIP. To study the interactions of the experimental variables on the photocatalytic activity of the FeS-Fe2S3-CN catalyst, experiments were designed using response surface methodology (RSM) approach. The best results were obtained in the run with the following conditions: pH 3.7, catalyst dose of 2.8 g L−1, 3.8 mg L−1 of CIP during 102 min irradiation of the suspension. The satisfactory correlation coefficient (R2 = 0.9480) for the second order polynomial model, confirmed that the predicted data by RSM well agree with the experimental results.
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•A novel MXenes based composite material was successfully constructed.•Waterenvironment conditions played a vital role in adsorption of U(VI)/Cr(VI).•U(VI)/Cr(VI) adsorbed on ...Ti3C2@FeS-PDA/PEI was chemically controlled.•Removal mechanism was associated with surface complexation reaction.
Herein, a MXenes decorated nanoscale FeS composites were developed via electrostatic self-assembly strategy to achieve efficient U(VI)/Cr(VI) adsorption-reduction. Different analytical techniques were applied to adequately characterize all as-prepared materials to determine the formation of species with the desired morphology and properties. Results revealed that the special chemical structure of MXenes could improve the dispersion of FeS nano-particles and suppress its aggregation. Meanwhile, the adsorption data closely well tailored with the Langmuir isotherm and Pseudo-second-order equation, and the maximum removal efficiencies were 88.5 and 107.2 mg/g for uranium(VI) and chromium(VI). It was also found that the presence of other cations and anions had no obvious influence on removal of U(VI)/Cr(VI), whereas the elimination process was a spontaneous endothermic reaction. More importantly, according to the spectroscopic analysis and DFT calculation, both FeS and surface functional groups on Ti3C2@FeS-PDA/PEI exhibited strong chemical affinities to the targeted pollutants, while FeS could effectively reduce Uranium(VI) to Uranium(IV) and Chromium(VI) to Chromium(III). This work facilitated the omnidirectional improvement of MXenes-based materials for the de-pollution of practical radionuclide or heavy metals wastewater.
Developing low cost, long life, and high capacity rechargeable batteries is a critical factor towards developing next-generation energy storage devices for practical applications. Therefore, a simple ...method to prepare graphene-coated FeS
embedded in carbon nanofibers is employed; the double protection from graphene coating and carbon fibers ensures high reversibility of FeS
during sodiation/desodiation and improved conductivity, resulting in high rate capacity and long-term life for Na
(305.5 mAh g
at 3 A g
after 2450 cycles) and K
(120 mAh g
at 1 A g
after 680 cycles) storage at room temperature. Benefitting from the enhanced conductivity and protection on graphene-encapsulated FeS
nanoparticles, the composites exhibit excellent electrochemical performance under low temperature (0 and -20 °C), and temperature tolerance with stable capacity as sodium-ion half-cells. The Na-ion full-cells based on the above composites and Na
V
(PO
)
can afford reversible capacity of 95 mAh g
at room temperature. Furthermore, the full-cells deliver promising discharge capacity (50 mAh g
at 0 °C, 43 mAh g
at -20 °C) and high energy density at low temperatures. Density functional theory calculations imply that graphene coating can effectively decrease the Na
diffusion barrier between FeS
and graphene heterointerface and promote the reversibility of Na
storage in FeS
, resulting in advanced Na
storage properties.
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