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Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 x 100 x 1 (l x b x h) mm(3)., QC 20240116

Transparent wood composites (TWs) offer the possibility of unique coloration effects. A colored transparent wood composite (C-TW) with enhanced fire retardancy was impregnated by metal ion solutions, followed by methyl methacrylate (MMA) impregnation and polymerization. Bleached birch wood with a preserved hierarchical structure acted as a host for metal ions. Cobalt, nickel, copper, and iron metal salts were used. The location and distribution of metal ions in C-TW as well as the mechanical performance, optical properties, and fire retardancy were investigated. The C-TW coloration is tunable by controlling the metal ion species and concentration. The metal ions reduced heat release rates and limited the production of smoke during forced combustion tests. The potential for scaled-up production was verified by fabricating samples with a dimension of 180 × 100 × 1 (l × b × h) mm3.

The present study aims to reveal horizontal sporadic E (Es) movements driven by atmospheric diurnal/semi-diurnal tides using a three-dimensional (3D) ionospheric model. Horizontal Es movements have been investigated since the mid-twentieth century, using a variety of 1D/2D observational techniques. However, there are no comprehensive studies that explain the different results asserted by the observations. Herein, we performed 3D Es simulations at mid- and low-latitudes. This is the first study to investigate horizontal Es movements from a 3D perspective. We found that the Es layers are constrained at the zonal-wind shear nodes above ∼110 km, but transported by horizontal winds below ∼110 km. The Es layers that descend with the downward tidal phases move southward. The descending Es layers move westward as they lag behind the zonal-wind shear nodes. The Es layers that stagnate at ∼100 km are transported by the semi-diurnal tides. In general, the descending and stagnating Es layers do not move eastward. This is because the Es layers diffuse vertically in the eastward/northward wind region or in the early stage of formation in the eastward/southward wind region. The horizontal Es movement tendency in the simulations agreed with and provided a general explanation for previous observations.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics., SCOPUS: ar.j, info:eu-repo/semantics/published

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.

The fabrication of reusable, sustainable adsorbents from low-cost, renewable resources via energy efficient methods is challenging. This paper presents wet-stable, carboxymethylated cellulose nanofibril (CNF) and amyloid nanofibril (ANF) based aerogel-like adsorbents prepared through efficient and green processes for the removal of metal ions and dyes from water. The aerogels exhibit tunable densities (18-28 kg m-3), wet resilience, and an interconnected porous structure (99% porosity), with a pH controllable surface charge for adsorption of both cationic (methylene blue and Pb(II)) and anionic (brilliant blue, congo red, and Cr(VI)) model contaminants. The Langmuir saturation adsorption capacity of the aerogel was calculated to be 68, 79, and 42 mg g-1for brilliant blue, Pb(II), and Cr(VI), respectively. Adsorption kinetic studies for the adsorption of brilliant blue as a model contaminant demonstrated that a pseudo-second-order model best fitted the experimental data and that an intraparticle diffusion model suggests that there are three adsorption stages in the adsorption of brilliant blue on the aerogel. Following three cycles of adsorption and regeneration, the aerogels maintained nearly 97 and 96% of their adsorption capacity for methylene blue and Pb(II) as cationic contaminants and 89 and 80% for brilliant blue and Cr(VI) as anionic contaminants. Moreover, the aerogels showed remarkable selectivity for Pb(II) in the presence of calcium and magnesium as background ions, with a selectivity coefficient more than 2 orders of magnitude higher than calcium and magnesium. Overall, the energy-efficient and sustainable fabrication procedure, along with good structural stability, reusability, and selectivity, makes these aerogels very promising for water purification applications., QC 20230614

A long photoluminescence decay lifetime has been regarded as a generic indication of long charge carrier recombination lifetime in semiconductors such as metal halide perovskites (MHPs), which have shown tremendous success in solar cells. Here, we report that MHP polycrystalline films with extrinsic metal ions have a very long charge recombination lifetime, but a much shorter photoluminescence decay lifetime, and this huge difference can be explained by a model of lateral homojunction within each individual grain. The lateral homojunction is formed due to the doping along grain boundaries by metal ions, and then verified by nanoscale potential mapping and transient photo-response mapping. The built-in electric field within each grain reduces the recombination of free charge carriers within the perovskite grain and along grain boundaries, while the free electrons and holes are collected to cathode and anode through the grain boundaries and grain interiors, respectively. Then, the efficiencies of MHP polycrystalline solar cells are increased., ChemE/Opto-electronic Materials

Olive stone is an important biomaterial waste product generated in large amount. As a lignocellulose material, olive stone could be a sustainable resource for biosorbents. In this work, olive stone powder delignification using sodium chlorite (NaClO2) was performed to enhance metal ion adsorption capacity. The influence of the treatment on olive stone powder physical-chemical properties was studied, including specific surface area, surface chemistry, morphology, etc. The white, delignified olive stone powder was applied for metal ions (Fe3+, Cu2+, and Zn2+) adsorption. Olive stone delignification not only increases the accessibility of the olive stone powder but also broadens the applications to materials design with optical functions by the generation of a white powder., QC 20210326

A long photoluminescence decay lifetime has been regarded as a generic indication of long charge carrier recombination lifetime in semiconductors such as metal halide perovskites (MHPs), which have shown tremendous success in solar cells. Here, we report that MHP polycrystalline films with extrinsic metal ions have a very long charge recombination lifetime, but a much shorter photoluminescence decay lifetime, and this huge difference can be explained by a model of lateral homojunction within each individual grain. The lateral homojunction is formed due to the doping along grain boundaries by metal ions, and then verified by nanoscale potential mapping and transient photo-response mapping. The built-in electric field within each grain reduces the recombination of free charge carriers within the perovskite grain and along grain boundaries, while the free electrons and holes are collected to cathode and anode through the grain boundaries and grain interiors, respectively. Then, the efficiencies of MHP polycrystalline solar cells are increased.

A long photoluminescence decay lifetime has been regarded as a generic indication of long charge carrier recombination lifetime in semiconductors such as metal halide perovskites (MHPs), which have shown tremendous success in solar cells. Here, we report that MHP polycrystalline films with extrinsic metal ions have a very long charge recombination lifetime, but a much shorter photoluminescence decay lifetime, and this huge difference can be explained by a model of lateral homojunction within each individual grain. The lateral homojunction is formed due to the doping along grain boundaries by metal ions, and then verified by nanoscale potential mapping and transient photo-response mapping. The built-in electric field within each grain reduces the recombination of free charge carriers within the perovskite grain and along grain boundaries, while the free electrons and holes are collected to cathode and anode through the grain boundaries and grain interiors, respectively. Then, the efficiencies of MHP polycrystalline solar cells are increased., ChemE/Opto-electronic Materials

With the ever-increasing development on novel chemicals and materials, with radically different properties and environmental behavior, it is challenging to compare their environmental behavior under similar conditions. For example, pesticides may be non-ionizable organics, ionizable organics, metal ion-based, or nanomaterials. These very different chemicals behave very differently. To date, no single modeling platform can handle all adequately, in a dynamic framework that accounts for actual variability in meteorology, rates of release to the environment, and the actual characteristics of the region of interest. Here we present ChemFate, a framework to address this challenge, by incorporating four different fate and transport models, each to address these four classes of chemicals (non-ionizable organics, ionizable organics, metal ion-based, or nanomaterials). We build upon established models, but have incorporated a number of additional processes. After demonstrating that the individual models comparable favorably with observed data and the previous models, under similar conditions, we conducted a case study with four radically different fungicides, used in the Central Valley, California. We found that although the concentrations of the non-ionizable and ionizable organic fungicide spike after application and temporarily may exceed toxicity thresholds for Daphnia Magna, they do not accumulate over time, while the metal ion and metallic nanoparticle result in increasing accumulation of Cu2+, eventually exceeding the toxicity threshold during runoff events. This case study demonstrates the value of a framework that allows the comparison of different classes of chemicals under the same conditions.

With the ever-increasing development on novel chemicals and materials, with radically different properties and environmental behavior, it is challenging to compare their environmental behavior under similar conditions. For example, pesticides may be non-ionizable organics, ionizable organics, metal ion-based, or nanomaterials. These very different chemicals behave very differently. To date, no single modeling platform can handle all adequately, in a dynamic framework that accounts for actual variability in meteorology, rates of release to the environment, and the actual characteristics of the region of interest. Here we present ChemFate, a framework to address this challenge, by incorporating four different fate and transport models, each to address these four classes of chemicals (non-ionizable organics, ionizable organics, metal ion-based, or nanomaterials). We build upon established models, but have incorporated a number of additional processes. After demonstrating that the individual models comparable favorably with observed data and the previous models, under similar conditions, we conducted a case study with four radically different fungicides, used in the Central Valley, California. We found that although the concentrations of the non-ionizable and ionizable organic fungicide spike after application and temporarily may exceed toxicity thresholds for Daphnia Magna, they do not accumulate over time, while the metal ion and metallic nanoparticle result in increasing accumulation of Cu2+, eventually exceeding the toxicity threshold during runoff events. This case study demonstrates the value of a framework that allows the comparison of different classes of chemicals under the same conditions.

The present article reviews the clinical use of thiol-based metal chelators in intoxications and overexposure with mercury (Hg), cadmium (Cd), and lead (Pb). Currently, very few commercially available pharmaceuticals can successfully reduce or prevent the toxicity of these metals. The metal chelator meso-2,3-dimercaptosuccinic acid (DMSA) is considerably less toxic than the classical agent British anti-Lewisite (BAL, 2,3-dimercaptopropanol) and is the recommended agent in poisonings with Pb and organic Hg. Its toxicity is also lower than that of DMPS (dimercaptopropane sulfonate), although DMPS is the recommended agent in acute poisonings with Hg salts. It is suggested that intracellular Cd deposits and cerebral deposits of inorganic Hg, to some extent, can be mobilized by a combination of antidotes, but clinical experience with such combinations are lacking. Alpha-lipoic acid (α-LA) has been suggested for toxic metal detoxification but is not considered a drug of choice in clinical practice. The molecular mechanisms and chemical equilibria of complex formation of the chelators with the metal ions Hg2+, Cd2+, and Pb2+ are reviewed since insight into these reactions can provide a basis for further development of therapeutics.

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.

Figure S1. Distance distribution for hydrogen bonds with coordinated and noncoordinated water, separately for different nucleic bases and positions; Table S1. The calculated interaction energies and distances between five nucleic bases and noncoordinated water molecules, at the B3LYP-D3/def2-TZVP (kcal/mol) and corrected for BSSE), MP2/def2-QZVP (kcal/mol) and noncorrected for BSSE) and CCSD(kcal/mol) and T)/CBS level; Table S2. The calculated interaction energies and distances at the B3LYP-D3/def2-TZVP level between five nucleic bases and water molecules coordinated to Zn2+ ion; Table S3. A number of hydrogen bonds between nucleic bases and coordinated water, and percentage of [M(H2O)n]x+ complexes, with different kinds of metals. Figure S2. Electrostatic potential maps for the nucleic bases. Figure S3. Distribution of the distance between water oxygen and nucleic base oxygen/nitrogen found in PDB structures for noncoordinated and coordinated water

This report summarizes the work on the cloning, expression, and purification of PerR, a metal sensing regulator from Saccharopolyspora erythraea and the subsequent characterization using small angle X-ray scattering and other biochemical methods. The report aims to provide an insight into prokaryotic metal homeostasis, provide a better understanding of how PerR works and provide valuable information for the continued work on the crystallization of PerR.

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.

Two-component systems (TCSs) are essential for bacteria to sense, respond, and adapt to changing environments, such as elevation of Cu(I)/Ag(I) ions in the periplasm. In Escherichia coli, the CusS-CusR TCS up-regulates the cusCFBA genes under increased periplasmic Cu(I)/Ag(I) concentrations to help maintain metal ion homeostasis. The CusS histidine kinase is a homodimeric integral membrane protein that binds to periplasmic Cu(I)/Ag(I) and transduces a signal to its cytoplasmic kinase domain. However, the mechanism of how metal binding in the periplasm activates autophosphorylation in the cytoplasm is unknown. Here, we report that only one of the two metal ion-binding sites in CusS enhances dimerization of the sensor domain. Utilizing nanodisc technology to study full-length CusS, we show that metal-induced dimerization in the sensor domain triggers kinase activity in the cytoplasmic domain. We also investigated autophosphorylation in the cytoplasmic domain of CusS and phosphotransfer between CusS and CusR. In vitro analyses show that CusS autophosphorylates its conserved H271 residue at the N1 position of the histidine imidazole. The phosphoryl group is removed by the response regulator CusR in a reaction that requires a conserved aspartate at position 51. Functional analyses in vivo of CusS and CusR variants with mutations in the autophosphorylation or phosphoacceptor residues suggest that the phosphotransfer event is essential for metal resistance in E. coli Biochemical analysis shows that the CusS dimer autophosphorylates using a cis mechanism. Our results support a signal transduction model in which rotation and bending movements in the cytoplasmic domain maintain the mode of autophosphorylation.

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.

Figure S1. Distance distribution for hydrogen bonds with coordinated and noncoordinated water, separately for different nucleic bases and positions; Table S1. The calculated interaction energies and distances between five nucleic bases and noncoordinated water molecules, at the B3LYP-D3/def2-TZVP (kcal/mol) and corrected for BSSE), MP2/def2-QZVP (kcal/mol) and noncorrected for BSSE) and CCSD(kcal/mol) and T)/CBS level; Table S2. The calculated interaction energies and distances at the B3LYP-D3/def2-TZVP level between five nucleic bases and water molecules coordinated to Zn2+ ion; Table S3. A number of hydrogen bonds between nucleic bases and coordinated water, and percentage of [M(H2O)n]x+ complexes, with different kinds of metals. Figure S2. Electrostatic potential maps for the nucleic bases. Figure S3. Distribution of the distance between water oxygen and nucleic base oxygen/nitrogen found in PDB structures for noncoordinated and coordinated water

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.

This report summarizes the work on the cloning, expression, and purification of PerR, a metal sensing regulator from Saccharopolyspora erythraea and the subsequent characterization using small angle X-ray scattering and other biochemical methods. The report aims to provide an insight into prokaryotic metal homeostasis, provide a better understanding of how PerR works and provide valuable information for the continued work on the crystallization of PerR.

Metal ion detection is critical in a variety of areas. The past decade has witnessed great progress in the development of metal ion sensors using functional nucleic acids (FNAs) and nanomaterials. The former has good recognition selectivity toward metal ions and the latter possesses unique properties for enhancing the performance of metal ion sensors. This review offers a summary of FNA- and nanomaterial-based metal ion detection methods. FNAs mainly include DNAzymes, G-quadruplexes, and mismatched base pairs and nanomaterials cover gold nanoparticles (GNPs), quantum dots (QDs), carbon nanotubes (CNTs), and graphene oxide (GO). The roles of FNAs and nanomaterials are introduced first. Then, various methods based on the combination of different FNAs and nanomaterials are discussed. Finally, the challenges and future directions of metal ion sensors are presented.

Metal ion detection is critical in a variety of areas. The past decade has witnessed great progress in the development of metal ion sensors using functional nucleic acids (FNAs) and nanomaterials. The former has good recognition selectivity toward metal ions and the latter possesses unique properties for enhancing the performance of metal ion sensors. This review offers a summary of FNA- and nanomaterial-based metal ion detection methods. FNAs mainly include DNAzymes, G-quadruplexes, and mismatched base pairs and nanomaterials cover gold nanoparticles (GNPs), quantum dots (QDs), carbon nanotubes (CNTs), and graphene oxide (GO). The roles of FNAs and nanomaterials are introduced first. Then, various methods based on the combination of different FNAs and nanomaterials are discussed. Finally, the challenges and future directions of metal ion sensors are presented.

Pathologic calcification leads to structural deterioration of implant materials via stiffening, stress cracking, and other structural disintegration mechanisms, and the effect can be critical for implants intended for long-term or permanent implantation. This study demonstrates the potential of using specific metal ions (MI)s for inhibiting pathological calcification in polyurethane (PU) implants. The hypothesis of using MIs as anti-calcification agents was based on the natural calcium-antagonist role of Mg2+ ions in human body, and the anti-calcification effect of Fe3+ ions in bio-prosthetic heart valves has previously been confirmed. In vitro calcification results indicated that a protective covering mesh of MI-doped PU can prevent calcification by preventing hydroxyapatite crystal growth. However, microstructure and mechanical characterisation revealed oxidative degradation effects from Fe3+ ions on the mechanical properties of the PU matrix. Therefore, from both a mechanical and anti-calcification effects point of view, Mg2+ ions are more promising candidates than Fe3+ ions. The in vitro MI release experiments demonstrated that PU microphase separation and the structural design of PU-MI matrices were important determinants of release kinetics. Increased phase separation in doped PU assisted in consistent long-term release of dissolved MIs from both hard and soft segments of the PU. The use of a composite-sandwich mesh design prevented an initial burst release which improved the late (>20 days) release rate of MIs from the matrix.

Metal ion detection is critical in a variety of areas. The past decade has witnessed great progress in the development of metal ion sensors using functional nucleic acids (FNAs) and nanomaterials. The former has good recognition selectivity toward metal ions and the latter possesses unique properties for enhancing the performance of metal ion sensors. This review offers a summary of FNA- and nanomaterial-based metal ion detection methods. FNAs mainly include DNAzymes, G-quadruplexes, and mismatched base pairs and nanomaterials cover gold nanoparticles (GNPs), quantum dots (QDs), carbon nanotubes (CNTs), and graphene oxide (GO). The roles of FNAs and nanomaterials are introduced first. Then, various methods based on the combination of different FNAs and nanomaterials are discussed. Finally, the challenges and future directions of metal ion sensors are presented.

Full-text article is free to read on the publisher's website Essential metals, such as iron and copper, play a critical role in a plethora of cellular processes including cell growth and proliferation. However, concomitantly, excess of these metal ions in the body can have deleterious effects due to their ability to generate cytotoxic reactive oxygen species (ROS). Thus, the human body has evolved a very well-orchestrated metabolic system that keeps tight control on the levels of these metal ions. Considering their very high proliferation rate, cancer cells require a high abundance of these metals compared to their normal counterparts. Interestingly, new anti-cancer agents that take advantage of the sensitivity of cancer cells to metal sequestration and their susceptibility to ROS have been developed. These ligands can avidly bind metal ions to form redox active metal complexes, which lead to generation of cytotoxic ROS. Furthermore, these agents also act as potent metastasis suppressors due to their ability to up-regulate the metastasis suppressor gene, N-myc downstream regulated gene 1. This review discusses the importance of iron and copper in the metabolism and progression of cancer, how they can be exploited to target tumors and the clinical translation of novel anti-cancer chemotherapeutics.

The active phase responsible for low-temperature CO oxidation in nanoparticulate CuO/CeO2 catalysts was identified as surface-substituted CuyCe1-yO2-x. Contrary to previous studies, our measurements on a library of well-defined CuO/CeO2 catalysts have proven that the CuO phase is a spectator species, whereas the surface-substituted CuyCe1-yO2-x phase is active for CO oxidation. Using in situ X-ray absorption spectroscopy, we found that the copper ions in CuyCe1-yO2-x remain at high oxidation states (Cu3+ and Cu2+) under oxygen-rich catalytic conditions without any evidence for Cu+. Artificial neural network potential Monte Carlo simulations suggest that Cu3+ and Cu2+ preferentially segregate to the {100} surface of the CuyCe1-yO2-x nanoparticle, which is supported by aberration-corrected electron microscopy measurements. These results pave the way for understanding, at the atomic level, the mechanisms and descriptors pertinent for CO oxidation on these materials and hence the rational design of next-generation catalysts.

Nowadays, finely controlling the mechanical properties of polymeric materials is possible by incorporating supramolecular motifs into their architecture. In this context, the synthesis of a side-chain terpyridine-functionalized poly(2-(dimethylamino)ethyl methacrylate) is reported via reversible addition-fragmentation chain transfer polymerization. By addition of transition metal ions, concentrated aqueous solutions of this polymer turn into metallo-supramolecular hydrogels whose dynamic mechanical properties are investigated by rotational rheometry. Hence, the possibility for the material to relax mechanical constrains via dissociation of transient cross-links is brought into light. In addition, the complex phenomena occurring under large oscillatory shear are interpreted in the context of transient networks.

The banana peel is a residue from the agroindustry. It is a biodegradable material, with low cost and presents affinity for organic compounds and toxic metals. In this research, the potential adsorption of banana peel was evaluated for removal of ion lead in wastewater. Initially was prepared the adsorbent and adsorbate, subsequently all samples were characterized by techniques FTIR, MEV and TG/DSC. Subsequently, they were tested ion adsorption lead.Functional groups present on banana peel as lignin, cellulose and hemicellulose were observed. Adsorption best results occurred at 50 ° C with approximately 99.6%. Thus it was concluded that the banana peel besides being a natural adsorbent has good feasibility to be used as an alternative material for its low cost, ease of handling and selectivity., A casca da banana é um resíduo proveniente da agroindústria. Trata-se de um material biodegradável, com baixo custo e apresenta afinidade por compostos orgânicos e metais tóxicos. Neste trabalho avaliou o potencial adsortivo da casca da banana na remoção de chumbo em efluentes. Inicialmente foi preparado o adsorvente e adsorvato, em seguida as amostras foram caracterizadas pelas técnicas FTIR, MEVe TG/DSC. Posteriormente, foram testadas na adsorção do íon chumbo. Foram observados os grupos funcionais presentes na casca da banana como a lignina, celulose e hemicelulose. Os melhores resultados de adsorção ocorreram à 50 °C com aproximadamente 99,6%. Dessa forma foi possível concluir que a casca da banana além de ser um bom adsorvente natural tem viabilidade para ser utilizado como material alternativo pelo seu baixo custo, facilidade de manuseio e seletividade.

The banana peel is a residue from the agroindustry. It is a biodegradable material, with low cost and presents affinity for organic compounds and toxic metals. In this research, the potential adsorption of banana peel was evaluated for removal of ion lead in wastewater. Initially was prepared the adsorbent and adsorbate, subsequently all samples were characterized by techniques FTIR, MEV and TG/DSC. Subsequently, they were tested ion adsorption lead.Functional groups present on banana peel as lignin, cellulose and hemicellulose were observed. Adsorption best results occurred at 50 ° C with approximately 99.6%. Thus it was concluded that the banana peel besides being a natural adsorbent has good feasibility to be used as an alternative material for its low cost, ease of handling and selectivity., A casca da banana é um resíduo proveniente da agroindústria. Trata-se de um material biodegradável, com baixo custo e apresenta afinidade por compostos orgânicos e metais tóxicos. Neste trabalho avaliou o potencial adsortivo da casca da banana na remoção de chumbo em efluentes. Inicialmente foi preparado o adsorvente e adsorvato, em seguida as amostras foram caracterizadas pelas técnicas FTIR, MEVe TG/DSC. Posteriormente, foram testadas na adsorção do íon chumbo. Foram observados os grupos funcionais presentes na casca da banana como a lignina, celulose e hemicelulose. Os melhores resultados de adsorção ocorreram à 50 °C com aproximadamente 99,6%. Dessa forma foi possível concluir que a casca da banana além de ser um bom adsorvente natural tem viabilidade para ser utilizado como material alternativo pelo seu baixo custo, facilidade de manuseio e seletividade.

A novel protein with anti-tumor activities named malanin was isolated and purified from an endemic plant in Yunnan and Guangxi provinces. Effects of copper ion, silver ion and calcium ion on malanin and apo-malanin fluorescence spectra were studied. The results showed that copper ion leads to obvious statistic quenching of malanin and apo-malanin fluorescence. The dissociation constant of them from malanin and apo-malanin were about 2.37×10-4 and 2.66×10-4 mol·L-1, respectively. The silver ion did not have quenching action on malanin fluorescence, but it had statistic quenching effect on apo-malanin fluorescence, and its dissociation constant was 2.37×10-4 mol·L-1. Calcium ion did not have quenching action on malanin and apo-malanin fluorescence. It plays an important role in keeping malanin natural conformation.

We have obtained a 1.55-Å crystal structure of a hammerhead ribozyme derived from Schistosoma mansoni under conditions that permit detailed observations of Na(+) ion binding in the ribozyme's active site. At least two such Na(+) ions are observed. The first Na(+) ion binds to the N7 of G10.1 and the adjacent A9 phosphate in a manner identical with that previously observed for divalent cations. A second Na(+) ion binds to the Hoogsteen face of G12, the general base in the hammerhead cleavage reaction, thereby potentially dissipating the negative charge of the catalytically active enolate form of the nucleotide base. A potential but more ambiguous third site bridges the A9 and scissile phosphates in a manner consistent with that of previous predictions. Hammerhead ribozymes have been observed to be active in the presence of high concentrations of monovalent cations, including Na(+), but the mechanism by which monovalent cations substitute for divalent cations in hammerhead catalysis remains unclear. Our results enable us to suggest that Na(+) directly and specifically substitutes for divalent cations in the hammerhead active site. The detailed geometry of the pre-catalytic active-site complex is also revealed with a new level of precision, thanks to the quality of the electron density maps obtained from what is currently the highest-resolution ribozyme structure in the Protein Data Bank.

We have obtained a 1.55-Å crystal structure of a hammerhead ribozyme derived from Schistosoma mansoni under conditions that permit detailed observations of Na(+) ion binding in the ribozyme's active site. At least two such Na(+) ions are observed. The first Na(+) ion binds to the N7 of G10.1 and the adjacent A9 phosphate in a manner identical with that previously observed for divalent cations. A second Na(+) ion binds to the Hoogsteen face of G12, the general base in the hammerhead cleavage reaction, thereby potentially dissipating the negative charge of the catalytically active enolate form of the nucleotide base. A potential but more ambiguous third site bridges the A9 and scissile phosphates in a manner consistent with that of previous predictions. Hammerhead ribozymes have been observed to be active in the presence of high concentrations of monovalent cations, including Na(+), but the mechanism by which monovalent cations substitute for divalent cations in hammerhead catalysis remains unclear. Our results enable us to suggest that Na(+) directly and specifically substitutes for divalent cations in the hammerhead active site. The detailed geometry of the pre-catalytic active-site complex is also revealed with a new level of precision, thanks to the quality of the electron density maps obtained from what is currently the highest-resolution ribozyme structure in the Protein Data Bank.

Four different M2þeMgeAl hydrotalcite (HT) materials were investigated for their effect on biohydrogen enhancement, where M2þ is Fe and/or Zn. HTs were synthesized by the coprecipitation method and characterized by infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The effect of FeeZneMgeAl HTs dose (0e833 mg/L) on hydrogen production was investigated in batch tests using sucrose-fed anaerobic mixed culture at 37 C. The best catalytic activity was observed on MgeAl HT at 167 mg/L with the maximum hydrogen yield of 2.30 0.37 mol H2/mol sucrose, which was 44% higher than the control. The major metabolites detected in the test were acetic acid (3.6 g/L), butyric acid (4.1 g/L), and lactic acid (0.5 g/L). The basic properties of the different catalysts played an important role in stimulating or inhibiting the activity of hydrogen producing bacteria. Calcined MgeAl HT did not promote biohydrogen production, suggesting that the catalytic enhancement was related to immobilization of bacteria in the electrostatically charged HT interlayers., Postprint (published version)

The transport of trivalent metals (Cr(III) and Fe(III)) through cation-exchange membranes is studied and compared with the transport of mono- and divalent ions by means of chronopotentiometry and current-voltage characteristics. The species present in solutions of sulfate salts of multivalent metals give rise to different transport properties depending on the applied current. The detection of various transition times in the chronopotentiograms and two limiting current densities in the current-voltage curves reveals a change in the species being transported in the diffusion boundary layers and inside the membrane phase. At overlimiting current regimes, two different mass transfer mechanisms can predominate depending on the electrolyte composition. For the most concentrated solutions, gravitational convection promotes a decrease in the diffusion boundary layer thickness and the resistance of the membrane system decreases, whereas electroconvection takes place for both concentrated and weak electrolytes when a certain threshold in the membrane voltage drop is surpassed. The initial salt concentration has a significant effect on the emergence of the overlimiting conductance, since the length of the plateau of the current-voltage curves diminishes as a consequence of the size of the cations involved and the equilibrium conditions in which they take part.

The transport of trivalent metals (Cr(III) and Fe(III)) through cation-exchange membranes is studied and compared with the transport of mono- and divalent ions by means of chronopotentiometry and current-voltage characteristics. The species present in solutions of sulfate salts of multivalent metals give rise to different transport properties depending on the applied current. The detection of various transition times in the chronopotentiograms and two limiting current densities in the current-voltage curves reveals a change in the species being transported in the diffusion boundary layers and inside the membrane phase. At overlimiting current regimes, two different mass transfer mechanisms can predominate depending on the electrolyte composition. For the most concentrated solutions, gravitational convection promotes a decrease in the diffusion boundary layer thickness and the resistance of the membrane system decreases, whereas electroconvection takes place for both concentrated and weak electrolytes when a certain threshold in the membrane voltage drop is surpassed. The initial salt concentration has a significant effect on the emergence of the overlimiting conductance, since the length of the plateau of the current-voltage curves diminishes as a consequence of the size of the cations involved and the equilibrium conditions in which they take part.

We have reported a hexaphenylsilole/polymethyl methacrylate (HPS/PMMA) composite film with a lotus-leaf-like structure shows highly stability and excellent sensitivities for metal ions (Fe3+ and Hg2+) a few years ago. In the above paper, it was considered that the special surface morphology is the important aspects which enhance the stability of the sensor. But it is still a lack of research on the sensing mechanism. In this paper, the sensing mechanism of fiber membrane is continuing to study in detail. The experimental results show that the electron-transfer mechanism is a crucial factor for the fluorescent quenching.

We have reported a hexaphenylsilole/polymethyl methacrylate (HPS/PMMA) composite film with a lotus-leaf-like structure shows highly stability and excellent sensitivities for metal ions (Fe3+ and Hg2+) a few years ago. In the above paper, it was considered that the special surface morphology is the important aspects which enhance the stability of the sensor. But it is still a lack of research on the sensing mechanism. In this paper, the sensing mechanism of fiber membrane is continuing to study in detail. The experimental results show that the electron-transfer mechanism is a crucial factor for the fluorescent quenching.