Free Metal Research Articles

Thermodynamic Modeling and Research for Processing Complex Concentrate Blends in Custom Copper Smelters for Maximum Revenue

Custom copper smelters, which are dependent on purchased concentrates, are facing increasing economic pressures amid falling treatment and refining fees. With the declining availability of high-grade, low-impurity concentrates, copper demand is expected to surge to support the transition to renewable energy. This study, which is based on recent observations of Chinese custom smelters, examines their strategies to address the challenge of purchasing concentrates at record-low treatment and refining charges. By investing in slag flotation technology, smelters can enhance copper, gold, and silver recovery. By blending high-grade and low-grade concentrates, they can capitalize on the gap between the recoverable and payable metals, which are often referred to as “free metals”, while also benefiting from byproducts, mainly sulfuric acid. While this approach offers economic opportunities, it introduces operational complexities. To mitigate these, laboratory testing, combined with advanced digital predictive tools based on thermodynamics, is crucial. This study demonstrates the use of thermodynamic models supported by experimental work for analyzing furnace operations. FactSage® software and a custom database are employed to define the operating window of two common flowsheets: (1) flash smelting + flash converting and (2) bottom-blown smelting + bottom-blowing converting.

Chrome-free leather processing based on amine pendant metal-organic frameworks and dialdehyde with enhanced dye affinity.

To overcome the stringent regulations in the usage of chromium salts and dye-rich effluent let out by the tanning industry, a sustainable way of leather processing has been demonstrated utilizing amine pendant metal-organic frameworks (MOF) UiO-66-NH2 along with glyoxal. It was found that an offer of 8% (w/w) MOF along with 6% (w/w) glyoxal increased the shrinkage temperature of the leathers to 89 ± 2°C with exhaustion of MOF up to 84.3 ± 1.5%. The presence of cationic amine sites in the MOF aided in the fixation of anionic post-tanning agents and improved the adsorption of dyes from 74.3 ± 2.5% in the case of conventional leather to 91.8 ± 1.7% for experimental leather. In comparison to chrome-tanned leather, the experimental leathers were rated the highest in terms of dye fastness concerning rubbing action and against perspiration, showcasing the washable properties and better affinity and irreversible binding of dyes to the leather matrix. Mechanism studies through XPS spectroscopy revealed the interaction between the acidic amino acids of collagen and free zirconium metal sites and the imine linkage between amine pendants of MOF and basic amino acids of collagen protein. Further, the BOD5/COD ratio of 0.36 confirmed the better treatability of the wastewater emanating from the proposed process making it a sustainable tanning system. Thus, the combination of amine pendant MOFs with dialdehyde can be a promising strategy for the development of robust chrome-free leathers with excellent functional properties.

Modular Chiral Bithiophene‐2NO Ligands: Synthesis and Application in Asymmetric Palladium(II)‐Catalysed Friedel‐Crafts Alkylation

AbstractThe development of privileged thiophene‐type ligand remains highly desirable, owing to the high coordination ability of sulfur atom to most of the soft metals. Herein, a new class of C2‐symmetric rigid chiral tertiary amine‐derived dioxide ligands with a coordinating bithiophene bridge was developed in a convenient synthetic route with 25–62% overall yields. The bithiophene‐2NO‐palladium(II) catalyst system was generated in situ and found to be highly capable catalyst in the asymmetric Friedel‐Crafts alkylation of indoles. Excellent yields (up to 92%) and high enantioselectivities (up to >99% ee) are obtained for a wide range of substrates under mild conditions. Control experiments and DFT calculations revealed the origins of the enantioselectivity. This represented the first example of chiral thiophene ligands coordinating with soft metal Pd(II) in the asymmetric Friedel‐Crafts alkylation. Experiments revealed that the counteranion is involved in the stereoselectivity‐determining step in this soft palladium(II) catalysis, and the additional NO and thiophene in ligands can act as the second chelation site and thus reduce the amount of free metal ions for suppressing background reaction in the catalytic system.

Verbascum gimgimense an Endemic Turkish Plant: Evaluation of In Vitro Anticancer, Antioxidant, Enzyme Inhibitory Activities, and Phytochemical Profile.

The Verbascum genus has gained significant attention in the pharmaceutical field, particularly in recent years, due to its valuable medicinal properties, which are well-recognized in complementary and alternative medicine. Certain species within this genus contain essential compounds and exhibit a wide range of therapeutic activities. In this study, the ethanolic extract of Verbascum gimgimense (VG) was analyzed for its cytotoxic, apoptotic, antioxidant, and enzyme inhibitory properties, as well as its phenolic and lipophilic compounds. The phenolic compounds in the extract were identified using Exactive Plus Orbitrap HPLC-HRMS, while the lipophilic components were characterized by GC-MS analysis. The Neutral Red Uptake (NRU) cell viability assay and colony formation assay were performed to assess the antiproliferative and anti-colony survival effects of VG on the A549 human lung adenocarcinoma cell line. Additionally, a wound healing assay measured cell migration, and the apoptotic process was evaluated using Caspase-3 ELISA and acridine orange/ethidium bromide staining. Protein expression levels were determined by western blot analysis. DPPH, ABTS FRAP, and CUPRAC assays were used to determine free radical scavenging, reducing power, and metal chelating activities, respectively. VG was rich in dominant phenolic components, including benzoic acid (6.809 mg/g extract), phloretic acid (1.279 mg/g extract), luteolin 7-rutinoside (2.799 mg/g extract), luteoloside (3.300 mg/g extract), kuromanine (3.456 mg/g extract), and rutin hydrate (2.015 mg/g extract). Major fatty acids identified in VG included palmitic acid (17.3%), stearic acid (2.99%), linoleic acid (9.44%), and α-linolenic acid (26.48%). VG treatment significantly reduced colony formation ability, decreased wound closure, and increased both apoptotic cell count and caspase-3 activity compared to the control group. Protein levels of c-PARP, p53, and p21 were substantially elevated compared to controls. In addition to its strong free radical scavenging, reducing power and metal chelating activity, VG exhibited strong inhibitory effects on α-amylase, α-glucosidase, AChE, BChE, and tyrosinase. Our study demonstrates that VG possesses antiproliferative, apoptotic, antioxidant, and enzyme-inhibitory properties. V. gimgimense emerges as a promising natural antioxidant source with potentially significant regulatory effects on key enzymes and proteins, which could contribute to managing various human diseases and inspire the development of novel therapeutic strategies.

Electronic Feature Modification of Ni and Co Free Metal–Organic Framework Nanoparticles by Vanadium Introduction for Water Oxidation

Electronic Feature Modification of Ni and Co Free Metal–Organic Framework Nanoparticles by Vanadium Introduction for Water Oxidation

Enhanced salt content and stabilized bilayer passivation interphase toward long-life and high-safety anode-free lithium battery

Anode-free lithium batteries (AFBs) offer optimal energy density, low cost, and simple manufacturing, making them desirable for next-generation high-energy-density batteries. However, the continuous consumption of electrolyte and Li metal through the undesirably constructed solid electrolyte interphase (SEI) significantly limits the cycling and thermal stability of AFBs. To address this challenge, dual-solvent localized high-LiFSI salt concentration electrolytes (DS-LHCEs) are designed by the addition of sulfolane (SF) due to its higher LiFSI solubility and highly consistent Li+-solvent binding energy with DME. High LiFSI content increases the salt-to-solvent concentration, decreases the amount of free solvent molecules, and restricts the side reaction between the free solvent and Li metal. As a result, a flat and dense Li metal with a robust LiF-rich SEI is deposited on Cu foil. Moreover, the introduction of trioxane (TO) constructs a high-strength outer organic SEI layer, which protects the weak grain boundaries of the inner inorganic SEI layer, further enhancing the stability of the Li metal anode. This results in assembled AFB pouch cells with a superior lifetime (206 cycles with 80 % capacity retention) and a much higher onset self-heating temperature (119 °C vs. 58 °C in the DME-based baseline electrolyte).

Biomass-Derived Organonanomaterials as Contrast Agents for Efficient Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) is a popular imaging tool that is valuable for the early detection and monitoring of malignancies because it does not involve radiation and is noninvasive. Metal-based contrast agents (CAs) are commonly used in clinical settings despite concerns about the toxicity of free metals. Therefore, finding alternative nontoxic imaging probes is vital. In this work, we have synthesized and effectively utilized sustainable biomass lignin-based all-organic nanoconjugates linked with nitroxide radicals as MRI CAs. Lignin grafted with poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (LPGT) exhibits a longitudinal relaxivity of 0.54 mM-1 s-1. LPGT shows exceptional characteristics, including resistance to reduction and nontoxicity toward living organisms. LPGT displays enhanced MRI contrast in the BALB/c mouse model for a duration exceeding 4.35 h. Our primary goal is to design MRI agents that are exceptionally effective sustainable biomass-derived materials and do not require the use of metals. Nicely, LPGT offers adequate contrast enhancement at 5-fold lower (0.020 mmol/kg) than the standard dose (0.1 mmol/kg), easing worries about toxic metal buildup. Consequently, LPGT shows promise as a feasible CA for metal-free MRI.

A stable dual-function lanthanum MOF: Simultaneous CO2 capture and catalysis

Carbon dioxide (CO2) capture has become a hot topic in recent years because of global warming issues. However, most research has focused primarily on gas capture, with limited methods available for achieving both CO2 capture and conversion within a single material. Here, we synthesized FMU-101, a metal-organic framework (MOF) with metal-open sites, through the self-assembly of [1,1′-Biphenyl]-3,3′,5-tricarboxylic acid and lanthanide ions in a solvothermal environment. FMU-101 features hexagonal one-dimensional pores with a diameter of 1.4 nm. The presence of free dimethylamine cations and metal open sites in the channel contributes to its remarkable capability for selectively enriching CO2 from CO2/CH4 mixtures in dynamic breakthrough experiments. Furthermore, the metal-open sites in FMU-101 play a crucial role in CO2 fixation, serving as effective catalytic sites for converting the adsorbed CO2 into high-value chloropropylene carbonate, a versatile chemical intermediate. The segregation and conversion mechanisms were further elucidated through density-functional theory (DFT) calculations and Grand Canonical Monte Carlo (GCMC) simulations, which highlighted the critical role of metal-open sites in CO2 adsorption and transformation.

Green tea (Camellia sinensis L.) potential to liver of hyperuricemia rats (Rattus norvegicus) fed with high purine diet

Uric acid is produced in tissues containing xanthine oxidases, like the small intestine and liver, as involved in the purine metabolism of adenine and guanine. High uric acid levels cause damage to cell membranes due to the lipid peroxidase chain reaction. Foods containing high purines will activate the xanthine oxidase (XOD), causing an increase in free radicals. Free radicals attack polyunsaturated fatty acids (PUFA) by forming lipid peroxides. PUFA molecules contain multiple double bonds, which make them susceptible to oxidation by reactive oxygen species (ROS), such as free radicals. PUFA will be broken into simple compounds such as pentane, ethane, and aldehydes, leading to malondialdehyde (MDA) formation. High MDA levels illustrate the process of cell membrane oxidation leading to cell membrane damage. Hyperuricemia is often treated using synthetic drugs such as allopurinol; however, it can cause side effects. Some people will choose medicinal plants with minimal side effects. Green tea (Camellia sinensis L.) contains many polyphenol antioxidants, especially flavonoids, which also have a strong antioxidant effect by exerting multiple mechanisms such as inhibiting several enzymes, including antiphospholipid peroxidase, free radical scavengers, metal bonds, and xanthine oxidase (XOD). Statistical analysis results proved that green tea with a dose of 600 mg/kg BW could decrease the level of MDA in the liver by 84.87% (p 0.01) and reduce the activity of XOD by 35.36% (p 0.01). Taken together, green tea can improve liver histopathology.

Effective MOF-derived electrocatalysts based on nitrogen and different transient metal doped (M: Ni, Co, and Fe) for oxygen reduction reaction toward direct ethanol fuel cell

Non-precious metal catalysts (NPMCs) doped with nitrogen were derived from MOFs. Appropriate ligand and framework order in the precursor ensured the presence of various nitrogenous species and high surface area in the NPC, Ni-NPC, Co-NPC, and Fe-NPC electrocatalysts. Electrochemical properties of the as-prepared electrocatalysts were examined in 0.1 M KOH solution to investigate the effects of metal and doped nitrogen on the oxygen reduction reaction (ORR). The free metal electrocatalyst (NPC) displayed poor ORR activity with an onset potential of 0.87 VRHE. The presence of nickel in the Ni-NPC catalyst could not create more active sites in comparison with the NPC catalyst, while onset potential of the Co-NPC catalyst shifted to 21 mV more positive (Compare to NPC). The investigation of doping active transient metals indicated that Fe-doping could be effective. It was because of the improved ORR activity of the Fe-NPC electrocatalysts with an onset potential of 0.99 VRHE. Furthermore, in a long-term stability test, this optimum electrocatalyst could retain more than 92% of its initial current density and experienced just 57 mV loss in its half-wave potential in an accelerated degradation test. Direct ethanol fuel cell test reveals maximum power density of 19.2 mW cm−2 at ambient temperature.

An Evaluation of Metal Binding Constants to Cell Surface Receptors in Freshwater Organisms, and Their Application in Biotic Ligand Models to Predict Metal Toxicity

Biotic ligand models (BLMs) predict the toxicity of metals in aquatic environments by accounting for metal interactions with cell surface receptors (biotic ligands) in organisms, including water chemistry (metal speciation) and competing cations. Metal binding constants (log KMBL values), which indicate the affinity of metals for cell surface receptors, are fundamental to BLMs, but have only been reported for a few commonly investigated metals and freshwater species. This review evaluated literature toxicity and uptake data for seven key metals (cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), uranium (U), and zinc (Zn)) and four key competing cations (protons (H), calcium (Ca), magnesium (Mg), and sodium (Na)), to derive average metal binding constants for freshwater organisms/taxa. These constants will improve current BLMs for Cd, Cu, Ni, Pb, and Zn, and aid in developing new BLMs for Co and U. The derived metal binding constants accurately predicted metal toxicity for a wide range of freshwater organisms (75–88% of data were within a factor of two and 88–98% of data were within a factor of three of the ideal 1:1 agreement line), when considering metal speciation, competing cations and the fraction of cell receptors ((fC)M50%) occupied by the metal at the median (50%) effect concentration (EC50). For many organisms, toxicity occurs when 50% of cell surface receptors are occupied by the metal, though this threshold can vary. Some organisms exhibit toxicity with less than 50% receptor occupancy, while others with protective mechanisms show reduced toxicity, even with similar log KMBL values. For Cu, U, and Pb, the toxic effect of the metal hydroxide (as MOH+) must be considered in addition to the free metal ion (M2+), as these metals hydrolyse in circumneutral freshwaters (pH 5.5 to 8.5), contributing to toxicity.

Non-consumable gamma-cyclodextrin additive constructing anti-solvation interphase realizing dendrites free and high-performance lithium metal batteries

Relying on surpassing high theoretical capacity (3,865 mAh/g) and the lowest relative electrode potential (0 V vs. metallic Li), lithium metal batteries (LMBs) have been regarded as the “holy grail” of next-generation energy storage technology. Whereases, the instability of pristine solid electrolyte interphase (SEI) layers and the disorderly growth of lithium dendrites are still significant challenges to the commercialisation of LMBs. In this study, a novel approach is introduced to homogenise Li deposition by incorporating an environmentally friendly electrolyte additive, gamma-cyclodextrin (γ-CD), in ether-based electrolytes. Through host-guest interactions, γ-CD additives not only form inclusion complexes to improve Li+ transference number to 0.86 but also encapsulate TFSI- anions and other solvent molecules within the “cavity effect” to relieve unfavourable solvent effect. Electrochemical characterisations demonstrate that introducing 1 wt% γ-CD elevates the oxidation decomposition voltage of ether electrolytes to 4.15 V, thereby inhibiting the decomposition of ether electrolytes and reducing the fracture of SEI layers. According to reduce the nucleate potential, the Li//Cu half battery exhibits improved stability for 100 cycles, with an improved average Coulombic efficiency (CE) maintained above 98.4 %. Even if applied at high current densities of 5.0 mA cm−2 for a capacity of 1.0 mAh cm−2, the Li//Li symmetric battery can cycle for over 800 h, and the Li//Li4Ti5O12 (LTO) full battery retains 98.8 % of the initial capacity after 1,400 cycles.

Photo-assisted Fenton degradation of tetracycline hydrochloride with magnetic Fe3S4/CuS composite

In recent years, semiconductor materials have gradually become popular through photodegradation of organic pollutants, and the semiconductor materials Fe3S4 and CuS have their own shortcomings. To make both materials useful, Fe3S4/CuS composites were prepared by hydrothermal method and degradation experiments were carried out using tetracycline hydrochloride (TCH) as a simulated pollutant. The effects of factors such as the mass ratio of Fe3S4 to CuS, temperature, pH changes, the consume of H2O2, and the amount of catalyst added on the degradation of TCH were explored. At room temperature, the Fe3S4/CuS composites exhibit good Fenton degradation efficiency. The F1C1.5 composite (mass ratio of Fe3S4 to CuS is 1:1.5) achieved 74.60 % at pH 4.0 within one hour. Subsequently, the free radical capture experiments and metal leaching experiments were conducted, and it was found that the active substance h+ played a major role. At the same time, the F1C1.5 composite shows stability, allowing for a lower concentration of iron leaching and having high catalytic activity after 5 cycles. These degradation properties, together with the ease of fabrication of the catalyst, will facilitate the practical application of this system in the continuous removal of TCH.

Antioxidant, antiacetylcholinesterase and apoptotic effects of essential oil of Isodon wightii (Bentham) H. Hara

Isodon wightii (Bentham) H. Hara is well known for aromatic essential oil. This is the first study aimed to evaluate antioxidant, antiacetylcholinesterase and apoptotic potential of I. wightii oil. DPPH scavenging, metal ion chelation and antiacetylcholinesterase activities were carried out for the extracted essential oil from the leaves of I. wightii. Cytotoxic effect on HeLa cells was studied by MTT assay and its apoptotic potential was determined by Acridine Orange/Ethidium Bromide and Hoechst33258 stains. A significant free radical scavenging and metal ion chelation were determined for oil. Acetylcholinesterase inhibition was recorded with IC50 value of 7.864 µg/mL. The cytotoxic effect of oil on HeLa cells was calculated with IC50 value of 13.264 µg/mL. High level of apoptosed cells were observed at 100 µg/mL oil treated cells. The results of the study emphasise the medicinal importance of I. wightii essential oil which could be a prominent plant based cancer therapeutic agent.

Transcriptome signature of juvenile Litopenaeus vannamei cultured under different salinity levels in response to Vibrio harveyi infection

Although the widely cultured Litopenaeus vannamei is highly tolerant to varying salinity levels, the rapid fluctuation of abiotic and biotic factors due to climatic changes may become stressors to the shrimp's physiology, resulting in impaired immunity and increased disease susceptibility. This study aimed to investigate the combined effects of both factors towards L. vannamei at transcriptomic level. L. vannamei were cultured at three different salinity levels (5 ppt, 20 ppt and 30 ppt) for 60 days and were challenged with Vibrio harveyi. RNA-seq analysis was conducted on the hepatopancreas to assess the differential expressed genes (DEGs) in both control and V. harveyi infected groups. Our results revealed 5,725 DEGs was observed in shrimp reared at 5 ppt, 3,643 DEGs at 20 ppt and 1,560 DEGs at 30 ppt. Most DEGs were identified to be associated with osmoregulation and transport activities, immune and stress regulation, nutrient metabolism, growth, chitin binding, gonadal development, and metal ion binding and toxicity. We identified that shrimp cultured at intermediate salinity of 20 ppt exhibits the greatest immunity level after infection by V. harveyi, given that low salinity (5 ppt) may augment the free ion metal toxicity, resulting in higher disease susceptibility. Both V. harveyi and salinity stress function together or separately to activate a wide range of immune and stress regulatory genes, which could be potential candidate markers for future RNAi and knockdown research in developing efficient prophylactic management strategies for L. vannamei.

N-doped polyacrylonitrile carbon fiber interlayer for uniform and dendrite free Zn metal battery

The aqueous zinc-ion battery’s (AZBs) inherent safety and inexpensive cost make it an attractive prospect for next-generation energy storage. Nevertheless, AZBs are presently troubled by the formation of Zn dendrites and unwanted side-reactions, which can lead to cycling instability and premature collapse. This study demonstrates the fabrication of an N-doped polyacrylonitrile (PAN) carbon fiber (PCF) network with ionic conductivity using the electrospinning of a PAN solution followed by thermal treatment. Zn plating and stripping behavior can be controlled by using a three-dimensional PCF with a polar functional group as an interlayer covering on the zinc anode. This allows for partially deposited zinc to be accommodated, which ultimately results in zinc dendrite-free deposition on the zinc anode. This phenomenon is initially proven in Zn@PCF symmetric cells, and then it is demonstrated further in Zn@PCF/MnO2 whole cells, where the dendritic Zn anode surfaces become completely smooth and devoid of any features. This results in a charging and discharging cycle that is far longer than one would normally experience. The findings of this study offer a viable path toward the development of dendrite-free AZBs with great performance.

Rooted in therapeutics: comprehensive analyses of Cannabis sativa root extracts reveals potent antioxidant, anti-inflammatory, and bactericidal properties.

Following the legalization of recreational Cannabis in Canada in 2018, the associated waste, including Cannabis roots, has significantly increased. Cannabis roots, comprising 30%-50% of the total plant, are often discarded despite their historical use in Ayurvedic medicine for treating inflammatory and infectious disorders. This study evaluates the phytochemical and therapeutic properties of Cannabis root extracts from a high tetrahydrocannabinolic acid, low cannabidiolic acid cultivar (variety Alien Gorilla Glue). We performed ultra high-performance liquid chromatography coupled with mass spectrometry (UPLC-QTOF-MS) to identify the chemical components of the Cannabis roots. Extracts using water, ethanol and acid-base solvents were tested for antioxidant activity through free radical scavenging, metal chelation, and lipoperoxidation inhibition assays. Mitochondrial membrane protection was assessed using flow cytometry with the MitoPerOx probe in THP-1 monocytic leukemia cells. Anti-inflammatory potential was evaluated by measuring interleukin-6 levels in lipopolysaccharide-stimulated THP-1 cells. Bactericidal/fungicidal efficacy against Escherichia coli, Staphylococcus aureus, and Candida albicans was determined using the p-iodonitrophenyltetrazolium assay. Additionally, we investigated the anticholinesterase activity of Cannabis root extracts, given the potential role of plant alkaloids in inhibiting cholinesterase, an enzyme targeted in Alzheimer's disease treatments. UPLC-QTOF-MS analysis suggested the presence of several phenolic compounds, cannabinoids, terpenoids, amino acids, and nitrogen-containing compounds. Our results indicated significant antioxidant, bactericidal, and anticholinesterase properties of Cannabis root extracts from both soil and hydroponic cultivation. Extracts showed strong antioxidant activity across multiple assays, protected mitochondrial membrane in THP-1 cells, and exhibited anti-inflammatory and bactericidal/fungicidal efficacy. Notably, soil-cultivated roots displayed superior anti-inflammatory effects. These findings demonstrate the remarkable antioxidant, anti-inflammatory, and anti-microbial activities of Cannabis roots, supporting their traditional uses and challenging their perception as mere waste. This study highlights the therapeutic potential of Cannabis roots extracts and suggests avenues for further research and application.

Polyoxometalate-Ionic Liquids for Mitigating the Effects of Iron Gall Ink Corrosion on Cellulosic Supports.

Iron gall ink (IGI), renowned for its indelibility, was the most important writing ink in the Western world from the 15th to the late 19th century. However, it is now known that IGIs induce acid-catalyzed hydrolysis and iron-catalyzed oxidation of the cellulose in historical paper documents. These mechanisms of deterioration cause significant damage to the writing support materials, including color alteration and burn-through appearance, and in the worst scenarios, physical disintegration of the supports. Minimally invasive, long-term effective conservation treatments that tackle the underlying mechanisms of IGI degradation and their corrosion effects are yet to be developed. This study introduces the deployment of hydrophobic and anticorrosive polyoxometalate-ionic liquids (POM-ILs) as colorless coatings to counteract IGI-corrosion of cellulosic supports. Model IGI-containing papers (mockups) were prepared, coated with POM-ILs, and artificially aged to assess the compatibility of POM-ILs with IGI-containing documents. Comprehensive monitoring using colorimetric and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM/EDS) analyses showed minimal interference with the aesthetic properties and morphology of the IGI mockups. In addition, polyoxometalates (POMs) with vacant metal atom sites in the cluster shell can be used to coordinate free transition metal ions. The ability of a monolacunary Keggin-type polyoxotungstate to coordinate free Fe(II) from IGI solution was demonstrated using UV-vis analysis. This led to the formation of a dimeric species, [(SiW11O39Fe)2O]K12·28H2O, which was characterized by single-crystal X-ray diffraction. Altogether, this study points to POM-ILs as promising protective coatings for effectively preserving historical IGI-written heritage.

Structure and dimerization properties of the plant-specific copper chaperone CCH

Copper chaperones of the ATX1 family are found in a wide range of organisms where these essential soluble carriers strictly control the transport of monovalent copper across the cytoplasm to various targets in diverse cellular compartments thereby preventing detrimental radical formation catalyzed by the free metal ion. Notably, the ATX1 family in plants contains two distinct forms of the cellular copper carrier. In addition to ATX1 having orthologs in other species, they also contain the copper chaperone CCH. The latter features an extra C-terminal extension whose function is still unknown. The secondary structure of this extension was predicted to be disordered in previous studies, although this has not been experimentally confirmed. Solution NMR studies on purified CCH presented in this study disclose that this region is intrinsically disordered regardless of the chaperone’s copper loading state. Further biophysical analyses of the purified metallochaperone provide evidence that the C-terminal extension stabilizes chaperone dimerization in the copper-free and copper-bound states. A variant of CCH lacking the C-terminal extension, termed CCHΔ, shows weaker dimerization but similar copper binding. Computational studies further corroborate the stabilizing role of the C-terminal extension in chaperone dimerization and identify key residues that are vital to maintaining dimer stability.

Transition Metal Oxide/Sulfide on the Ni Foam for Electrocatalytic UOR & OER

Water electrolysis is an important technology related to the energy conservation, is a promising technology. Currently, one of the key efforts is to improve the efficiency and reduce the cost of water electrolysis, in particular, the anodic oxygen evolution reaction (OER). Nobel-metal free OER catalyst or alternative urea oxidation reaction (UOR) is thus favored. Due to the advantages of enhance charge transfer and desirable charge redistribution, we have investigated nobel-metal free transition metal oxide/sulfide heterostructure UOR electrocatalyst. Co-Ni based metal heterostructure is synthesized using a simple two-step hydrothermal method. The resulting samples are examined using X-ray diffractometer, Scanning electron microscopy, X-ray photoelectron spectroscopy and the Inductively coupled plasma will used as the material analysis. Electrochemical performance is evaluated using linear sweep voltammetry, electrochemical impedance spectroscopy, cyclic voltammetry, and electrochemical active surface area. Moreover, the electrocatalyst is also evaluated as OER catalysts. The relation between the material characteristics and the electrochemical performance is discussed.