Copper Release Research Articles

Flame emission spectroscopy of single droplet micro explosions.

Nanoparticles exhibit superior physical and chemical properties, making them highly desirable for various applications. Flame spray pyrolysis (FSP) is a versatile technique for synthesizing size and composition-controlled metal oxide/sulfide nanoparticles through a gas-phase reaction. To understand the fundamental mechanisms governing nanoparticle formation in FSP, simplified single-droplet experiments have proven to unravel the physicochemical mechanisms of liquid metal precursor combustions. This work introduces a novel method using flame emission spectroscopy and high-speed imaging to analyze combustion species and metal release during metalorganic single droplet combustions, with the example of the 2-ethylhexanoci acid (EHA)-tetrahydrothiophene (THT)-mesitylcopper (MiCu) precursor system. The method enables the tracing of precursor components released from droplet into the flame by spatial and temporal resolved emission tracking from combustion species (OH*, CH*, C2*, CS*, CS2*) and atomic spectral lines (Cu I). The tracking of metal emission enables the direct observation of the particle formation route, offering novel insights into the metalorganic precursor combustions. The findings of this work show a direct correlation between micro-explosions and nanoparticle formation through the gas-to-particle route. The release of copper emissions is observed with the micro-explosion event, marking the micro-explosions as the critical mechanism for the metal release and subsequent nanoparticle formation during the combustion process. The results indicate a metalorganic viscous shell formation (THT + MiCu) leading to the micro explosion. The EHA/THT ratio significantly affects the combustion behavior. Lower ratios lead to a gradual copper release before the micro explosion; higher ratios shorten the copper release and delay the micro explosion - the highest ratio results in two distinct burning stages.

A structured risk scenario analysis framework and case study of reserve regulation in non-ferrous metal markets

Reserve regulation in non-ferrous metal markets is crucial for stabilizing the market supply and demand relationship and ensuring a stable supply and demand relationship. This study proposes a “Background-Action-Response” (BAR) framework for structured risk scenario analysis in metal markets. The copper release event by China’s National Food and Strategic Reserves Administration in 2021 is used as a case study to analyze the effectiveness of the release behavior on market stability. The framework and methodology provided in this study offer decision-makers a systematic approach to identify and respond to risk scenarios in stockpiling and release decision analysis.

Biomimetic Gradient Hydrogels with High Toughness and Antibacterial Properties.

Traditional hydrogels, as wound dressings, usually exhibit poor mechanical strength and slow drug release performance in clinical biomedical applications. Although various strategies have been investigated to address the above issues, it remains a challenge to develop a simple method for preparing hydrogels with both toughness and controlled drug release performance. In this study, a tannic acid-reinforced poly (sulfobetaine methacrylate) (TAPS) hydrogel was fabricated via free radical polymerization, and the TAPS hydrogel was subjected to a simple electrophoresis process to obtain the hydrogels with a gradient distribution of copper ions. These gradient hydrogels showed tunable mechanical properties by changing the electrophoresis time. When the electrophoresis time reached 15 min, the hydrogel had a tensile strength of 368.14 kPa, a tensile modulus of 16.17 kPa, and a compressive strength of 42.77 MPa. It could be loaded at 50% compressive strain and then unloaded for up to 70 cycles and maintained a constant compressive stress of 1.50 MPa. The controlled release of copper from different sides of the gradient hydrogels was observed. After 6 h of incubation, the hydrogel exhibited a strong bactericidal effect on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with low toxicity to NIH/3T3 fibroblasts. The high toughness, controlled release of copper, and enhanced antimicrobial properties of the gradient hydrogels make them excellent candidates for wound dressings in biomedical applications.

A strategy for source control of acid mine drainage by intelligent management of mine wastes

For mine site management, the release of acid and heavy metal ions from sulfur-containing waste rock or tailings (principally chalcopyrite and pyrite) under natural deposit conditions is a major environmental problem. In this study, the interaction between chalcopyrite and pyrite at different mass ratios under a simulated acid mine drainage environment was investigated. The dissolution experiments showed that a low proportion of pyrite promotes chalcopyrite dissolution, while a high proportion inhibits dissolution. However, this phenomenon is weakened by the presence of microorganisms. In addition, the combined characterization by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy indicated that a high ratio of pyrite incorporation facilitated the formation of passivation layers on the chalcopyrite surface. Scanning electron microscopy results show that many oxidation etching pits are found on the surface of the chalcopyrite residues surface in a low ratio of pyrite addition, whereas numerous islands are observed and tightly wrapped around the surface of the chalcopyrite residues surface in a high ratio of pyrite addition. The current work presents a viable, practical approach to tailings stacking that reduces the release of the heavy metal ions copper and acid through the appropriate proportioning of ores.

Dealloyed nano-porous Ti[sbnd]Cu coatings with controlled copper release for cardiovascular devices

TiCu coatings with controlled copper release and nano-porous structures were fabricated as biocompatible, blood-contacting interfaces through a two-step process. Initially, coatings with 58 % Cu were created using HiPIMS/DC magnetron co-sputtering, followed by immersion in a dilute HF solution for varying durations to achieve dealloying. The presence of Ti elements in the as-deposited TiCu coatings facilitated their dissolution upon exposure to the dilute HF solution, resulting in the formation of nanopores and increased nano-roughness. Dealloying treatment time correlated with higher Cu/(Ti + Cu) values, nanopore size, and nano-roughness in the dealloyed samples. The dealloyed TiCu coatings with 87 % Cu exhibited a controlled release of copper ions and displayed nanopores (approximately 80 nm in length and 31.0 nm in width) and nano-roughness (Ra roughness: 82 nm). These coatings demonstrated inhibited platelet adhesion and suppressed smooth muscle cell behavior, while supporting favorable endothelial cell viability and proliferation, attributed to the controlled release of copper ions and the extent of nanostructures. In contrast, the as-deposited TiCu coatings with 85 % Cu showed high copper ion release, leading to decreased viability and proliferation of endothelial cells and smooth muscle cells, as well as suppressed platelet adhesion. The TiCu coatings met medical safety standards, exhibiting hemolysis rates of <5 %. The technology presented here paves the way for the simple, controllable, and cost-effective fabrication of TiCu coatings, opening new possibilities for surface modification of cardiovascular devices such as vascular stents and inferior vena cava filters.

Harvested versus conditioned new test pieces in drinking water lead or copper corrosion testing

Abstract Corrosion monitoring apparatuses are important tools in drinking water distribution systems for empirically assessing effectiveness of corrosion treatment before application to the entire water system. They are also important for tracking lead or copper release in the distribution system before, during, and after a treatment strategy is in place. A major debate is whether to use test pieces of pipe harvested from the distribution system or to use conditioned new metal surfaces. Harvested and conditioned new test pieces were studied in multiple types of water systems using analysis of chemical scales, biofilms, and metals release data. It was found that both methods of testing are equally valid if procedures follow certain conditions: (1) apparatus configuration and operation are consistent, (2) properties of distribution system pipe wall accumulations are known, (3) dissolved and particulate metal fractions are determined, and (4) apparatus metal release data are correlated with residential data. The use of conditioned new test pieces, obtainable with relative ease, lowers corrosion control study costs, providing a tool for water systems of all sizes to select the most effective corrosion control strategy and to pro-actively track lead and copper release trends in the distribution system.

Potential of single and designed mixed cultures to enhance the bioleaching of chalcopyrite by oxidation-reduction potential control

Biomining is the extraction of target metals from ores or wastes such as the dissolution of chalcopyrite for copper recovery. A key outstanding topic of study is to improve the rate and total copper released from chalcopyrite that can become ‘passivated’ by surface layers, which hinders oxidative attack on the metal sulfide bond. One strategy to increase chalcopyrite bioleaching is to control of the oxidation-reduction potential in the desired range by using ‘weak’ iron oxidizers. In this study, 15 acidophilic species were evaluated for their ability to catalyze chalcopyrite dissolution that resulted in the addition of Acidithiobacillus ferrianus, Sulfobacillus thermotolerans, and Metallosphaera sedula to the known ‘weak’ iron oxidizing species. Based upon these data, four microbial consortia were designed including mesophiles (25° and 37 °C), moderate thermophiles (49 °C), and thermophiles (70 °C) that increased copper recoveries by up to 32% compared to abiotic controls. The best performing consortium was the moderate thermophiles Sulfobacillus thermotolerans, Sulfobacillus acidophilus, and Ferroplasma acidiphilum that maintained the oxidation-reduction potential in the desired range. However, the consortia also showed evidence of synergistic interactions between ‘weak’ iron oxidizers that increased the efficiency of ferrous iron oxidation that resulted in oxidation-reduction potentials above the desired range and lower copper release. Therefore, while designing microbial consortia is a promising strategy to improve the performance of chalcopyrite bioleaching, care must be taken to ensure synergistic effects do not result in high oxidation-reduction potentials.

Soil moisture dynamics regulates the release rates and lability of copper in contaminated paddy soils

The climate changes have caused more extreme precipitation and drought events in the field and have exacerbated the severity of wet-dry events in soils, which will inevitably lead to severe fluctuations in soil moisture content. Soil moisture content has been recognized to influence the distribution of heavy metals, but how temporal changes of soil moisture dynamics affect the release rates and lability of heavy metals is still poorly understood, which precludes accurate prediction of environmental behavior and environmental risk of heavy metals in the field. In this study, we combined experimental and modeling approaches to quantify copper release rates and labile copper fractions in two paddy soils from southern China under different moisture conditions. Our kinetic data and models showed that the release rates and lability of copper were highly associated with the soil moisture contents, in which, surprisingly, high soil moisture contents effectively reduced the release rates of copper even with little changes in the reactive portions of copper in soils. A suite of comprehensive characterization on soil solid and solution components along the incubation suggested that soil microbes may regulate soil copper lability through forming microbially derived organic matter that sequestered copper and by increasing soil particle aggregation for protecting copper from release. This study highlights the importance of incorporating soil moisture dynamics into future environmental models. The experimental and modeling approaches in this study have provided basis for further developing predictive models applicable to paddy soils with varying soil moisture under the impact of climate change.

Decoupling locally enhanced electric field treatment (LEEFT) intensity and copper release by applying asymmetric electric pulses for water disinfection

Copper has well-known anti-microbial properties but is typically not considered for drinking water disinfection because of its health risk to human at efficient biocidal concentrations. Locally enhanced electric field treatment (LEEFT) is a cutting-edge technique that aims to inactivate bacteria by generating aqueous pores on the cell membrane through the application of a strong electric field. LEEFT can also increase the permeability of the cell membrane, which promotes the uptake of chemical disinfectants to reduce the required biocidal concentrations. Previously, a coaxial-electrode copper ionization cell (CECIC) was developed to combine copper disinfection with LEEFT, demonstrating superior disinfection efficiency with low effluent copper concentrations (<0.5 mg/L). However, using direct-current (DC) voltages results in a dilemma that a higher voltage is necessary for effective LEEFT disinfection, but a lower voltage is required to limit Cu release. Here, asymmetric electric pulses are employed to decouple the LEEFT intensity from copper release in the CECIC. In this case, LEEFT intensity is primarily determined by the pulse amplitude while the copper release is controlled by the pulse offset. We have demonstrated that the use of asymmetric electric pulses achieves significantly higher inactivation efficiency compared to the DC voltages with the similar level of Cu release. For the water with conductivity similar to tap water (∼100 μS/cm), a high inactivation efficiency of 4.7-log is achieved with only 0.49 mg/L copper release. These findings highlight the potential of asymmetric electric pulses as a promising alternative to DC voltages for the practical application of LEEFT-Cu systems in the future.

Copper‐PCL/PVP virucidal nanofibers against coronavirus produced by electrospinning technology

AbstractThis work investigated the virucidal property of copper‐loaded poly(ε‐caprolactone) (PCL)/polyvinylpyrrolidone (PVP) blended nanofibers against coronavirus. Electrospinning solutions were prepared with 0.25, 0.75, and 1.50% [w/v] of copper salt and their properties of electrical conductivity, surface tension, and viscosity were measured. The copper‐PCL/PVP nanofibers produced electrospun composite membranes of 30.5–38 g m−2. IR spectra confirmed the blended PCL/PVP, and SEM/EDS images revealed the morphology of the randomly oriented nanofibers with homogeneously incorporated copper in the electrospun nanofibers. The copper quantification indicated the final incorporation of 5.50 ± 0.31, 14.00 ± 1.03, and 27.10 ± 3.00 mg g−1 of copper, as measured by atomic absorption spectrometry, into electrospun composite membranes for 0.25, 0.75, and 1.50% [w/v] copper solution formulations, respectively, and these compositions also affected the nanofibers mechanical properties. Copper release assays showed that copper‐PCL/PVP nanofibers readily release ions into aqueous media. The 0.75% copper‐PCL/PVP composite membrane was virucidal against coronavirus, reaching 99.99% inactivation in 1 hour and 99.999% inactivation in 24 h, and non‐cytotoxic to L929 cells in 24 h of exposure. This work presents a virucidal composite membrane with potential use in personal protective equipment against viral outbreaks or pandemics.

Correlating the Effect of Composition and Textural Properties on Bioactivity for Pristine and Copper-Doped Binary Mesoporous Bioactive Glass Nanoparticles.

Multifunctional substitutes for bone tissue engineering have gained significant interest in recent years in the aim to address the clinical challenge of treating large bone defects resulting from surgical procedures. Sol-gel mesoporous bioactive glass nanoparticles (MBGNs) have emerged as a promising solution due to their high reactivity and versatility. The effect of calcium content on MBGNs textural properties is well known. However, the relationship between their composition, textural properties, and reactivity has not yet been thoroughly discussed in existing studies, leading to divergent conclusions. In this study, pristine and copper-doped binary MGBNs were synthesized by a modified Stöber method, using a cationic surfactant as pore-templating agent. An opposite evolution between calcium content (12-26 wt%) and specific surface area (909-208 m2/g) was evidenced, while copper introduction (8.8 wt%) did not strongly affect the textural properties. In vitro bioactivity assessments conducted in simulated body fluid (SBF) revealed that the kinetics of hydroxyapatite (HAp) crystallization are mainly influenced by the specific surface area, while the composition primarily controls the quantity of calcium phosphate produced. The MBGNs exhibited a good bioactivity within 3 h, while Cu-MBGNs showed HAp crystallization after 48 h, along with a controlled copper release (up to 84 ppm at a concentration of 1 mg/mL). This comprehensive understanding of the interplay between composition, textural properties, and bioactivity, offers insights for the design of tailored MBGNs for bone tissue regeneration with additional biological and antibacterial effects.

Effect of organic matter on the adsorption and release of copper in some gypsiferous soils in Salah al-Din Governorate

A laboratory experiment was conducted to study the behavior of copper in gypsum soils of different organic sources through a number of experiences, and knowledge of copper adsorption and release conditions in it, and used three equations physicochemical Langmuir, Freundlich, and Temkin. It was adopted The coefficient of determination (R2 ) is a better choice equation to describe the adsorption of copper, the results showed that the Langmuir equation was enough for the description and evaluation of copper adsorption compared to the rest of the physicochemical equations used according to the highest coefficient of determination R2, and the efficiency of R2 was (92, 87, 65) % for each of the Langmuir and Freundlich equations and Temkin, respectively. The maximum adsorption values of the Langmuir equation were (61.728 - 25,906) mg.kg-1 and a bonding energy (0.731 - 0.128) L.mg-1, and Freundlech's equation showed the maximum adsorption values (1.346 - 0.855) L.mg-1 and a bonding energy (15.160 - 4.010) mg.kg-1, while the maximum adsorption values were to equation Temkin range between (35 - 29) mg.kg-1 energy connectivity ranging what between (0.495-0.185) L.kg-1, and from equation Temkin can that define type adsorption physical or a chemist and on the most chemical calendar for height valuable heat interaction bT, which ranges from (84.86 - 70.34). As for the results of liberating copper adsorbed, the highest values of liberated copper were recorded at. Levels add high from copper (50,100,150) mgkg-1 and at levels low add from copper (2,5,10) mgkg-1 be valuable Liberation copper zero (nill).

Dermal and oral exposure risks to heavy metals from 3D printing metal-fill thermoplastics

Manufacturing advancements in polymer printing now allow for the addition of metal additives to thermoplastic feedstock up to 80–90 % by weight and subsequent printing on low-cost desktop 3D printers. Particles associated with metal additives are not chemically bound to the plastic polymer, meaning these particles can potentially migrate and become bioavailable. This study investigated the degree to which two human exposure pathways, oral (ingestion) and dermal (skin contact), are important exposure pathways for metals (copper, chromium, and tin) from metal-fill thermoplastics used in consumer fused filament fabrication (FFF). We found that dermal exposure to copper and bronze filaments presents the highest exposure risk due to chloride (Cl−) in synthetic sweat driving copper (Cu2+) release and dissolution. Chromium and tin were released as micron-sized particles < 24 μm in diameter with low bioaccessibility during simulated oral and dermal exposure scenarios, with potential to undergo dissolution in the gastrointestinal tract based on testing using synthetic stomach fluids. The rate of metal particle release increased by one to two orders of magnitude when thermoplastics were degraded under 1 year of simulated UV weathering. This calls into question the long-term suitability of biodegradable polymers such as PLA for use in metal-fill thermoplastics if they are designed not to be sintered. The greatest exposure risk appears to be from the raw filaments rather than the printed forms, with the former having higher metal release rates in water and synthetic body fluids for all but one filament type. For brittle feedstock that requires greater handling, as metal-fill thermoplastics can be, practices common in metal powder 3D printing such as wearing gloves and washing hands may adequately reduce metal exposure risks.

Biocidal activity of multifunctional cuprite-doped anion exchanger – Influence of bacteria type and medium composition

The study presents unconventional, bifunctional, heterogeneous antimicrobial agents – Cu2O-loaded anion exchangers. The synergetic effect of a cuprous oxide deposit and polymeric support with trimethyl ammonium groups was studied against the reference strains of Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 27853. Biological testing (minimum bactericidal concentration, MBC), time- and dose-dependent bactericidal effect (under different conditions – medium composition and static/dynamic culture) demonstrated promising antimicrobial activity and confirmed its multimode character. The standard values of MBC, for all studied hybrid polymers and bacteria, were similar (64–128 mg/mL). However, depending on the medium conditions, due to the copper release into the bulk solution, bacteria were actively killed even at much lower doses of the hybrid polymer (25 mg/mL) and low Cu(II) concentrations in solution (0.01 mg/L). Simultaneously, confocal microscopic studies confirmed the effective inhibition of bacterial adhesion and biofilm formation on their surface. The studies conducted under different conditions showed also the influence of the structure and physical properties of studied materials on the biocidal efficacy and an antimicrobial action mechanism was proposed that could be significantly affected by electrostatic interactions and copper release to the solution. Although the antibacterial activity was also dependent on various strategies of bacterial cell resistance to heavy metals present in the aqueous medium, the studied hybrid polymers are versatile and efficient biocidal agents against bacteria of both types, Gram-positive and Gram-negative. Therefore, they can be a convenient alternative for point-of-use water disinfection systems providing water quality in medical devices such as dental units, spa equipment, and aesthetic devices used in the cosmetic sector.

Temperature-Responsive Nanoassemblies for Self-Regulated Photothermal Therapy and Controlled Copper Release to Accelerate Chronic Wound Healing.

Photothermal therapy (PTT) is an effective therapeutic method against multidrug-resistant bacteria. The heating temperature is of great significance to completely eliminate bacteria but not damage surrounding healthy tissue. To meet the need for chronic wound management, a pH and temperature dual-responsive copper-gold nanoassembly (sCuAu NAs) was constructed by cross-linking the CuAu nanoparticles (CuAu NPs) with small molecules involved in the Edman degradation reaction. At room temperature, the sCuAu NAs could quickly heat up to eliminate the biofilm upon laser irradiation due to the surface plasmon resonance coupling effect. On arriving at the degradation temperature of around 50 °C, the sCuAu NAs are disassembled into CuAu NPs in the wound infection site, which not only prevents overheating but also promotes deep penetration and accelerates copper-ion release to remove residual bacteria and promote wound healing. This study not only provides an effective treatment that can simultaneously alleviate wound infection and accelerate wound healing but also brings up an idea on the development and application of temperature self-regulated photothermal agents in various diseases.

Cuproptosis‐Driven Enhancement of Thermotherapy by Sequentially Response Cu2‐xSe via Copper Chemical Transition

AbstractActivation of cuproptosis pathway has been reported to hold great potential in the application of tumor treatment. But the efficacy of cuproptosis seriously limited by the insufficient accumulation in the tumor sites. Therefore, herein based on the strong stabilization effects of the metalloid element selenium (Se) on copper (Cu), a photothermic Cu2‐xSe nanoparticle encapsulated with bioresponsive dimethyl maleic anhydride (DMMA@Cu2‐xSe) as a copper‐carrier to improve the copper accumulation in tumor is constructed, thus achieving cuproptosis‐driven enhancement of thermotherapy. This nanosystem exhibits the enhancement of tumor cellular uptake by a weak acid‐triggered charge‐switching ability. Next step, the exposed Cu2‐xSe is oxidized and releases divalent copper by high‐level oxide. Then, the abundant copper induces more dihydrolipoamide S‐acetyltransferase oligomerization to down‐regulate FDX1 and tricarboxylic acid cycle‐related proteins, which leads to inhibiting aerobic respiration. Cuproptosis‐induced mitochondrial damage further improves thermotherapy by up‐regulating reactive oxygen species (ROS). In addition, the generated ROS also promotes copper release to strengthen cuproptosis, and eventually improves tumor thermotherapy in turn. In general, DMMA@Cu2‐xSe with sequentially triggered copper‐release, efficient cuproptosis, and appropriate photothermal is a self‐enhanced nanoplatform for cuproptosis‐driven enhancement of thermotherapy.

Floating photovoltaic systems: photovoltaic cable submersion testing and potential impacts

Background: Floating photovoltaics (FPV) is an emerging technology that is gaining attention worldwide. However, little information is still available on its possible impacts in the aquatic ecosystems, as well as on the durability of its components. Therefore, this work intends to provide a contribution to this field, analysing possible obstacles that can compromise the performance of this technology, adding to an increase of its reliability and assessing possible impacts. The problem under study is related to the potential submersion of photovoltaic cables, that can lead to a degradation of its electrical insulation capabilities and, consequently, higher energy production losses and water contamination. Methods: In the present study, the submersion of photovoltaic cables (with two different insulation materials) in freshwater and artificial seawater was tested, in order to replicate real life conditions, when FPV systems are located in reservoirs or in the marine environment. Electrical insulation tests were carried out weekly to assess possible cable degradation, the physical-chemical characteristics of the water were also periodically monitored, complemented by analysis to detect traces of copper and microplastics in the water. Results: The results showed that the submersion of photovoltaic cables with rubber sheath in saltwater can lead to a cable accelerated degradation, with reduction of its electrical insulation and, consequently, copper release into the aquatic environment. Conclusions: The test results pointed a probable relationship between submersion of cables with rubber outer shell and water freezing temperatures and the occurrence of accelerated degradation of the cable insulation layer. Reduced insulation resistance values were measured in this cable type after the occurrence of such temperatures, both in salt and freshwater, the cable presented visible exterior degradation signs. For this case copper residues were detected in the water.

Bioactive Phenolate Salts: Thymol Salts.

Phenolate salts of bioactive agents have been reported only scarcely. This is the first report on the formation and characterization of thymol phenolate salts as representatives of phenol-containing bioactive molecules. Thymol has been used in medicine and agriculture for decades owing to its excellent therapeutic properties. However, in light of its poor aqueous solubility, thermal instability, and especially its high chemical volatility, the utility of thymol is hampered. The present work focuses on tuning the physicochemical properties of thymol by modifying its chemical structure through salt formation. In this context, a series of metal (Na, K, Li, Cu, and Zn) and ammonium (tetrabutylammonium and choline) salts of thymol were synthesized and characterized using IR, NMR, CHN elemental analysis, and DSC analyses. The molecular formulae of thymol salts were determined based on CHN analysis and thymol quantification studies from UV-Vis spectrometric analysis. In most cases, the thymol phenolate was prepared as a 1 : 1 molar ratio with metal/ammonium ion. Only the Cu salt of thymol was isolated at a ratio of two phenolate units per copper ion. Most of the synthesized thymol salts were found to have increased thermal stability relative to thymol. The physicochemical properties such as solubility, thermal stability, and evaporation rate of thymol salts were thoroughly studied in comparison with thymol. The in vitro release studies of Cu from the copper salt of thymol is pH-dependent: rapid release of copper was observed in the lower pH release medium (100 % release at pH 1 for 12 days) and the rates of release were slower at higher pH values (5 % release at pH 2, and <1 % release at pH 4, 6, 8, and 10) over a period of about three weeks.

Enhanced catalytic stability of non-stoichiometric Cu–Al spinel catalysts for dimethyl ether synthesis from syngas: Effect of coordination structure

Cu–Al spinel catalysts were synthesized by various preparation methods, and its CO hydrogenation performance was evaluated. Characterization results showed that different preparation methods can effectively regulate the coordination distribution of cations in surface spinel structure. The sustained release property of Cu–Al spinel was related to its coordination structure. The catalyst containing a large amount of octahedral spinel Cu2+ ions was capable of delaying the reduction of copper, and small Cu nanoparticles (Cu NPs) were produced and highly dispersed on the defective spinel surface, which may be that the vacancy derived on the surface of defective spinel anchored small Cu NPs, which was the key to improve catalytic stability. We also discussed the real reason for poor catalytic stability, and this was due to that the easily-reducible spinel possessed extensive tetrahedral spinel Cu2+, which accelerated the reduction and release of copper, resulting in that the formed copper was unstable and aggregated readily. The Cu–Al spinel catalyst prepared by the solid phase method included octahedral coordination Cu2+ ratio as high as 59%, and the corresponding average size of Cu particles produced from spinel was measured as about 11.3 nm by N2O titration method, exhibiting enhanced stability and excellent catalytic performance.

Benefits and drawbacks of current copper chelators in Wilson disease

Background. Wilson disease (WD) is an autosomal-recessive disorder of copper metabolism, caused by mutations in the ATP7B gene, which codes for a membrane-bound copper-binding ATPase. This leads to progressive copper accumulation in the liver, with hepatic injury and subsequent copper release into the blood. Aim. To analyze the efficacy and side-effects of the current copper chelating agents used in treatment of Wilson disease. Material and methods. Retrospective study of 37 adult patients diagnosed with Wilson disease at the Gastroenterology and Neurology Departments of Fundeni Clinical Institute between 2012-2017. Patients were grouped into three categories: (a) those with isolated liver disease, (b) those with isolated neurologic (or psychiatric) involvement and (c) those with both liver and neurologic involvement. Results. There were 54% females (n=20). Mean age at diagnosis was 23 ± 10 years-old. Liver cirrhosis was diagnosed in 54% of cases. Neurologic involvement was described in 65% of patients. Dysarthria was the most common neurologic feature (43%), followed by parkinsonism (41%). D-Penicillamine was used as initial treatment in 89% of patients, but was interrupted in 27% of them (n=9) due to its adverse reactions. Keyser-Fleischer rings were absent in a significant proportion (40%) of patients with neurologic involvement. Both Trientine and D-Penicillamine were associated with improved or stationary liver fibrosis, however results were slightly better for Trientine. D-Penicillamine appeared to be a better option than Trientine in patients with neurologic involvement. Conclusions. Based on our study, we recommend treatment with D-Penicillamine as first-line therapy in patients with neurologic involvement. However, due to the frequent side-effects of D-Penicillamine, Trientine could be considered firstline treatment in patients with isolated hepatic involvement.