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Insights into metal-matrix interactions in atomically dispersed catalytic systems are necessary to exploit the true catalytic activity of isolated metal atoms. Distinct from catalytic atoms spatially separated but immobile in a solid matrix, here we demonstrate that a trace amount of platinum naturally dissolved in liquid gallium can drive a range of catalytic reactions with enhanced kinetics at low temperature (318 to 343 K). Molecular simulations provide evidence that the platinum atoms remain in a liquid state in the gallium matrix without atomic segregation and activate the surrounding gallium atoms for catalysis. When used for electrochemical methanol oxidation, the surface platinum atoms in the gallium-platinum system exhibit an activity of [Formula: see text] three orders of magnitude higher than existing solid platinum catalysts. Such a liquid catalyst system, with a dynamic interface, sets a foundation for future exploration of high-throughput catalysis.

Low melting point eutectic systems, such as the eutectic gallium-indium (EGaIn) alloy, offer great potential in the domain of nanometallurgy; however, many of their interfacial behaviors remain to be explored. Here, a compositional change of EGaIn nanoalloys triggered by polydopamine (PDA) coating is demonstrated. Incorporating PDA on the surface of EGaIn nanoalloys renders core-shell nanostructures that accompany Ga-In phase separation within the nanoalloys. The PDA shell keeps depleting the Ga3+ from the EGaIn nanoalloys when the synthesis proceeds, leading to a Ga3+-coordinated PDA coating and a smaller nanoalloy. During this process, the eutectic nanoalloys turn into non-eutectic systems that ultimately result in the solidification of In when Ga is fully depleted. The reaction of Ga3+-coordinated PDA-coated nanoalloys with nitrogen dioxide gas is presented as an example for demonstrating the functionality of such hybrid composites. The concept of phase-separating systems, with polymeric reservoirs, may lead to tailored materials and can be explored on a variety of post-transition metals.

Understanding the interfacial contacts between liquid metals and substrate materials is becoming increasingly important for the fast-rising liquid metal-enabled technologies. However, for such technologies, probing the contact behavior and interfacial charge transport has remained challenging due to the deformable nature of liquid metals and the presence of the surface oxide layer. Here, we encapsulate eutectic gallium indium (EGaIn) micro-/nanodroplets with tungsten trioxide (WO

The separation and sensing of alkali metal ions from aqueous lithium resources is of great importance for building future renewable and lithium-based energy storage technologies. As such, interest arises for the development of functional composites selective to ionic lithium (Li+) over sodium (Na+) and potassium (K+) that allows for a range of low carbon-footprint sensing and recovery processes. Here, selective separation of Li+ from aqueous mixtures of Na+ and K+ ions using polyvinyl alcohol/maleic acid composites was enhanced by the inclusion as nano-additives of post-transition metals gallium (Ga) and indium (In), together with their alloys and oxidized species, in the composite casting process. The co-addition of Ga and In resulted in the spontaneous formation of Ga oxides and hydroxides while In remained in the metallic state. This Ga–In composite was stable in aqueous solutions containing a high concentration (0.1 M) of mixed alkali metal ions over 5 days and achieved exceptionally high selectivities of Li+ over Na+ (3.8 ± 0.1) and K+ (7.1 ± 0.1). Results from an electrochemical sensing platform technique revealed that Li+ selectivity was in the same order as the diffusion rates. This work demonstrated that the low-melting-point post-transition metal alloy enables a one-step low energy fabrication of selective polymeric composites with diverse applications for energy, sensing and separation industries. The work has implications for the efficient manufacture of renewable and lithium-based energy storage technologies.

Tumor hypoxia hampers the therapeutic efficacy of photodynamic therapy (PDT) by hardly supplying sufficient oxygen to produce cytotoxic compounds. Herein a dual enzyme-mimicking radical generator has been developed for the in situ generation of oxygen and abundant radical oxygen species to enhance PDT efficacy under photoacoustic imaging guidance. A manganese-incorporating and photosensitizer-loaded metal organic framework exhibited both catalase-like and peroxidase-like catalytic activities specifically at the tumor microenvironment, leading to simultaneous series catalysis and parallel catalysis pathways. As a result, the MOF-based radical generator nanoparticles can not only supply oxygen for PDT to produce singlet oxygen, but also generate hydroxyl radicals, thus further enhancing the anti-cancer effect of PDT. In vitro and in vivo evaluation of the radical generator nanoparticles demonstrated the relieved tumor hypoxia microenvironment, remarkably increased level of reactive oxygen species, and significantly improved anti-cancer effect with desirable PA imaging capacity. This work presents a "series-parallel catalysis" strategy enabled by a MOF nanozyme to enhance PDT efficiency and provides new insights into a highly efficient and low-toxic anti-cancer approach.

An increasing number of peptide drugs have been identified or synthesized in recent decades, and they have played an important role in disease treatments and scientific research. Peptide drugs have become emerging candidates in the pharmaceutical market, despite some inherent disadvantages that have hindered their further development (i.e., they are chemically and physically unstable). Considering that cold-storage conditions are not easily accessible, particularly in developing countries, it remains a significant challenge to find a facile way to enhance the stability of peptide drugs. In this study, we developed an efficient and facile strategy to provide peptide drugs a strong protection against harsh conditions by biomineralizing metal-organic frameworks (MOFs) around the peptide drugs. Our results showed that the peptides released from MOFs retained their structures and full biological activities after being exposed to high temperatures, repeated freeze-thaw cycles and enzyme degradation. This study provides an alternative method for the storage of biopharmaceuticals and for enhancing their stability under ambient conditions.

Nanoparticle drug delivery is largely restricted by the low drug loading capacity of nanoparticle carriers. To address this critical challenge and maximize the potential of nanoparticle drug delivery, a 2D ultra-thin layered double hydroxide (LDH) nanosheet with exceptionally high drug loading, excellent colloidal stability, and prolonged blood circulation for cancer treatment is constructed. The nanosheet is synthesized via a biocompatible polymer-assisted bottom-up method and exhibits an ultra-thin 2D sheet-like structure that enables a considerable amount of cargo anchoring sites available for drug loading, leading to an extraordinary 734% (doxorubicin/nanoparticle mass ratio) drug loading capacity. Doxorubicin delivered by the nanosheet remains stable on the nanosheet carrier under the physiological pH condition, while showing sustained release in the tumor microenvironment and the intracellular environment, thus demonstrating on-demand drug release as a result of pH-responsive biodegradation of nanosheets. Using in vitro and in vivo 4T1 breast cancer models, the nanosheet-based ultra-high drug-loading system demonstrates even enhanced therapeutic performance compared to the multilayered LDH-based high drug-loading system, in terms of increased cellular uptake efficiency, prolonged blood circulation, superior therapeutic effect, and reduced systemic toxicity.

Liquid metals (LMs) are electronic liquid with enigmatic interfacial chemistry and physics. These features make them promising materials for driving chemical reactions on their surfaces for designing nanoarchitectonic systems. Herein, we showed the interfacial interaction between eutectic gallium-indium (EGaIn) liquid metal and graphene oxide (GO) for the reduction of both substrate-based and free-standing GO. NanoIR surface mapping indicated the successful removal of carbonyl groups. Based on the gained knowledge, a composite consisting of assembled reduced GO sheets on LM microdroplets (LM-rGO) was developed. The LM enforced Ga3+ coordination within the rGO assembly found to modify the electrochemical interface for selective dopamine sensing by separating the peaks of interfering biologicals. Subsequently, paper-based electrodes were developed and modified with the LM-rGO that presented the compatibility of the assembly with low-cost commercial technologies. The observed interfacial interaction, imparted by LM's interfaces, and electrochemical performance observed for LM-rGO will lead to effective functional materials and electrode modifiers.

In this work, we study a class of dissipative, nonsmooth [Formula: see text] degree-of-freedom dynamical systems. As the dissipation is assumed to be proportional to the momentum, the dynamics in such systems is conformally symplectic, allowing us to use some of the Hamiltonian structure. We initially show that there exists an integral invariant of the Poincaré–Cartan type in such systems. Then, we prove the existence of a generalized Liouville Formula for conformally symplectic systems with rigid constraints using the integral invariant. A two degree-of-freedom system is analyzed to support the relevance of our results.

Tumor hypoxia hampers the therapeutic efficacy of photodynamic therapy (PDT) by hardly supplying sufficient oxygen to produce cytotoxic compounds. Herein a dual enzyme-mimicking radical generator has been developed for the

Low melting point eutectic systems, such as the eutectic gallium-indium (EGaIn) alloy, offer great potential in the domain of nanometallurgy; however, many of their interfacial behaviors remain to be explored. Here, a compositional change of EGaIn nanoalloys triggered by polydopamine (PDA) coating is demonstrated. Incorporating PDA on the surface of EGaIn nanoalloys renders core-shell nanostructures that accompany Ga-In phase separation within the nanoalloys. The PDA shell keeps depleting the Ga

A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO

In this paper we study an impact absorber which is similar to the Fermi accelerator and can be described as a ball moves in a periodically oscillating ring with a wall and reflects elastically from the wall. First, Poincare map of the system is established. The existence of invariant curves for the map is proved based on Moser’s twist theorem. Accordingly, the velocities of the ball are always bounded for any initial motion for all time. Moreover, the symmetry of the Poincare map is discussed. Finally, some numerical simulations are given to demonstrate the theoretical results.

Self-propelled chemical motors have found vast promise for applications from nanomedicine to environmental remediation. However, strategies for controlling their directional motion on demand still represents one of the major challenges for the development of smart motor systems to be realized in real-world applications. Here, we report for the first time the design of a novel submarine-like micromotor that is capable of directional vertical motion on centimeter scale by pH-regulated buoyancy control. With the aid of a pH-responsive, hydrophilic/hydrophobic phase-shifting polymer, gas bubbles produced by the biocatalytic metal–organic framework micromotors can be reversibly retained/expelled from the micromotors, leading to the buoyancy-controlled ascending or descending vertical motion. Importantly, anti-cancer drug-loaded micromotors showed directional cytotoxicity to three-dimensional cell cultures, depending on the pH of the cellular environment. We expect this study will open up new avenues for designing directional propulsion mechanisms for chemical motors, showing potential as autonomous robotics for in vivo delivery in complex biological environments.

An economic and facile method was urgently required for the degradation of SF6 to replace the high-energy excitation treatment. Both theoretical calculations and experimental observations were conducted to reveal the synergy of Cr/Fe/Si composites on a new technique of SF6 degradation through reacting silicon dioxide. Density functional theory (DFT) calculations show that strong adsorption of SF6 on Cr2O3, and then the fast F/O exchange between CrF3 and Fe2O3 (energy barrier was 1.45 eV) as well as FeF3 and SiO2 (energy barrier was 1.69 eV) enhanced mediated efficiency from SF6 to SiF4. The fluorine (F) migration between solid interfaces in Cr2O3&Fe2O3@SBA15 was responsible for efficient SF6 removal. The F migration route was composed of SF6 to CrF3, CrF3 to FeF3, and FeF3 to SiF4 with the lowest thermodynamic driving. Enhanced specific accumulative converted amount (SACA) of SF6 on Cr2O3&Fe2O3@SBA15 was achieved and the highest SACA was 13.98 mmol/g within 7 h, significantly higher than that on Fe2O3@SBA15 (5.74 mmol/g) and Cr2O3@SBA15 (2.71 mmol/g). Moreover, X-ray diffractometry and X-ray photoelectron spectroscopy were performed to support DFT calculations, including ion intensities detected using mass spectroscopy and composition analysis of the mediator during the reaction. Therefore, our work put forward a novel approach for economic and efficient SF6 decomposition through reacting with silicon dioxide under the mediation of Cr2O3&Fe2O3. This method was also potentially used in effective degradation of refractory non-metal halides.

The interference effect and lack of selectivity are the bottlenecks for dual-mode magnetic resonance imaging (MRI) contrast agent development. To address these challenges and overcome the single mode imaging contrast limitations, a novel MgMnAl-layered double hydroxide@iron oxide nanoparticle (MgMnAl-LDH@IO NP) has been successfully synthesized as a concurrently enhanced dual-mode contrast agent for MRI of tumor tissues with sensitive pH response and high efficacy. The attachment of iron oxide nanoparticles on the surface of MgMnAl-LDH NPs led to the increased local magnetic field intensity, inducing the concurrent enhancement of both T1 and T2 relaxivity. The in vitro MRI demonstrated that the MgMnAl-LDH@IO NP could act as a pH-sensitive contrast agent for both T1- and T2-weighted MR imaging (r1, 5.67 mM-1 s-1 under pH 5.0 and 1.98 mM-1 s-1 under pH 7.4; r2, 369.12 mM-1 s-1 under pH 5.0 and 225.29 mM-1 s-1 under pH 7.4). The biocompatibility of the dual-mode contrast agent was revealed by the cytotoxicity test on fibroblast cells. Further in vivo dual-mode MR imaging exhibited that the MgMnAl-LDH@IO NP showed clear T1- and T2-weighted MR imaging of tumor tissues in breast-tumor-bearing mice. The facile synthetic method, desirable biocompatibility, sensitive stimuli response, and concurrently enhanced T1/T2 MRI signals both in vitro and in vivo encourage the great potential biomedical and clinical applications of MgMnAl-LDH@IO NP in MR imaging with improved accuracy.

Many different types of inorganic materials are processed into nano/microparticles for medical utilization. The impact of selected key characteristics of these particles, including size, shape, and surface chemistries, on biological systems, is frequently studied in clinical contexts. However, one of the most important basic characteristics of these particles, their density, is yet to be investigated. When the particles are designed for drug delivery, highly mobile macrophages are the major participants in cellular levels that process them in vivo. As such, it is essential to understand the impact of particles' densities on the mobility of macrophages. Here, inorganic particles with different densities are applied, and their interactions with macrophages studied. A set of these particles are incubated with the macrophages and the outcomes are explored by optical microscopy. This microscopic view provides the understanding of the mechanistic interactions between particles of different densities and macrophages to conclude that the particles' density can affect the migratory behaviors of macrophages: the higher the density of particles engulfed inside the macrophages, the less mobile the macrophages become. This work is a strong reminder that the density of particles cannot be neglected when they are designed to be utilized in biological applications.

In this paper, a billiard type of system is studied. The system describes the motion of a particle in a bounded domain under dissipation and periodic potential. The collisions between the particle and the boundary are elastic. The approximation scheme of Benci and Giannoni (Ann Inst H Poincare Anal Non Lineaire 6(1), 73–93, 1989) for elastic bounces in conservative systems is extended to time periodic systems with dissipations, and the existence of periodic bounce solutions is proved. Moreover, it is proved that the results still hold when the domain is unbounded, if the potential is coercive. As applications of the results, the existence of periodic bounce orbits are shown in the Fermi model, bouncing ball model with dissipation, and a class of multi-degrees-of-freedom impact systems.

We consider the Fermi–Ulam model, which can be described as a particle moving freely between two vertical rigid walls; the left one being fixed, whereas the right one moves according to a regular periodic function. The particle is elastically reflected when hitting the walls. We show that the dynamics of the model can be described by an area-preserving monotone twist map. Thus, the Aubry–Mather sets exist for every rotation number in the rotation interval. Consequently, this gives a description of global dynamics behavior, particularly a large class of periodic and quasiperiodic orbits for the model.

The interference effect and lack of selectivity are the bottlenecks for dual-mode magnetic resonance imaging (MRI) contrast agent development. To address these challenges and overcome the single mode imaging contrast limitations, a novel MgMnAl-layered double hydroxide@iron oxide nanoparticle (MgMnAl-LDH@IO NP) has been successfully synthesized as a concurrently enhanced dual-mode contrast agent for MRI of tumor tissues with sensitive pH response and high efficacy. The attachment of iron oxide nanoparticles on the surface of MgMnAl-LDH NPs led to the increased local magnetic field intensity, inducing the concurrent enhancement of both

We report a green carbon capture and conversion technology offering scalability and economic viability for mitigating CO2 emissions. The technology uses suspensions of gallium liquid metal to reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver-gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano dimensional triboelectrochemical reactions. By altering the secondary solvent and changing the reactor height, the dissolution and conversion efficiency can be tuned. The optimum reactor height is only 27 cm, when gallium/silver fluoride mix at 7:1 mass ratio is employed as the reaction material. At CO2 input of ~8 sccm, 92% efficiency was obtained at the record low input energy of 228.5 kW∙h for the capture and conversion of a tonne of CO2. The potential impact of this green technology is remarkable, likely benefiting a variety of industries and offering an economical solution for CO2 capture and conversion.

Micro/nanoscaled motor particles represent a group of intelligent materials that can precisely and rapidly respond to biological microenvironments and improve therapeutic outcomes. In order to maximize biomedical application potentials, developing a nanoscaled motor particle that is able to move autonomously toward a biological target is highly desired but still remains a critical challenge. Herein, a 2D nanosheet-based catalytic nanomotor with chemotaxis behavior is developed for enhanced drug delivery toward the tumor microenvironment. The nanomotors are constructed via a facile one-pot method and exhibit ultrathin monolayer nanosheet morphology. The 2D structure of nanomotors allows high catalytic activity, leading to responsive, sustained, and relatively long distance movement. Importantly, this nanomotor demonstrates directional motion toward the high gradient of H2 O2 fuel, exhibiting excellent chemotactic properties. After loading an anticancer drug doxorubicin, the nanomotor shows effective inhibition on cancer cell growth in simulated tumor microenvironments. The practical drug delivery application is further strengthened by the intracellular acidity-triggered biodegradability of the nanomotor after accomplishing the directional drug delivery function. This proof-of-concept work highlights the efficient catalytic activity, tumor microenvironment-guided chemotactic movement, excellent cellular performance of the 2D nanomotor, and opens an avenue for biomedical applications such as controlled and smart drug delivery.

A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO2 emissions is reported. The technology uses suspensions of gallium liquid metal to reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver-gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano-dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio is employed to create the reaction material, 92% efficiency is obtained at a remarkably low input energy of 230 kWh (excluding the energy used for dissolving CO2 ) for the capture and conversion of a tonne of CO2 . This green technology presents an economical solution for CO2 emissions.

A zinc-dominant ferrite catalyst for efficient degradation of organic dye was prepared by the calcination of electroplating sludge (ES). Characterizations indicated that zinc ferrite (ZnFe2O4) coexisted with Fe2O3 structure was the predominant phase in the calcined electroplating sludge (CES). CES displayed a high decolorization ratio (88.3%) of methylene blue (MB) in the presence of H2O2 combined with UV irradiation. The high efficiency could be ascribed to the photocatalytic process induced by ZnFe2O4 and the photo-Fenton dye degradation by ferrous content, and a small amount of Al and Mg in the sludge might also contribute to the catalysis. Moreover, the degradation capability of dye by CES was supported by the synthetic ZnFe2O4 with different Zn to Fe molar ratio (n(Zn): n(Fe)), as 84.81%-86.83% of dye was removed with n(Zn): n(Fe) ranged from 1:0.5 to 1:3. All synthetic ferrite samples in the simulation achieved adjacent equilibrium decolorization ratio, the flexible proportioning of divalent metal ions (M2+) to trivalent metal ions (M3+) applied in the synthesis indicated that the catalyst has a high availability. Therefore, an efficacious catalyst for the degradation of dye can potentially be derived from heavy metal-containing ES, it's a novel approach for the reutilization of ES.

An economic and facile method was urgently required for the degradation of SF

A ternary CaMgFe-LDH was developed for the immobilization of aqueous arsenic from capillary water in paddy soils, with an outstanding removal performance for aqueous arsenite (As(III)). In an As(III) solution, the ternary LDH achieved a removal capacity for arsenite of approximately 16 mg g−1 after 5 h, with a low equilibrium concentration of As(III) (0.048 mg L−1). The As(III) removal capacity of LDH was studied with the different Ca/Mg molar ratios in LDH, which demonstrated that ternary LDHs with a higher Ca content can remove As(III) more effectively and rapidly. Accordingly, the ternary LDH material was used in the immobilization of total arsenic from a paddy soil system, achieving a removal efficiency for As(III) of 47% and a total As concentration of 346 μg L−1 in capillary water after 40 days. Compared to that of the binary Mg–Fe LDH, the As removal performance of the ternary LDH was higher, which was attributed to the As precipitation with Ca in the first 20 days during the experiment. This, along with the efficient adsorption of As on the residual Mg–Fe-LDH framework, was responsible for the low concentration of As. Therefore, our study proposes a promising approach to the remediation of arsenic-contaminated paddy soils.

In this study, the exfoliation of waste printed circuit boards (WPCBs) layers was conducted in an ionic liquid, 1-ethyl-3-methylimizadolium tetrafluoroborate . The transformation of brominated epoxy resins (BER), the major ingredient in WPCBs, was characterised, and the result indicated that the concentration of BER in the achieved approximately 28 g·L−1 while WPCBs layers were separated completely. Moreover, the dissolution of WPCBs metals during the exfoliation was determined. This demonstrated that concentration of copper became the highest in solution among the metals being tested as the concentration of metals decreased in the order as Cu≫Al>Sn>Pb>Fe>Mg≈Zn>Cd>Cr>Ni≈Mn. The dissolution of the metals in N2 and air atmospheres was similar. Accordingly, the WPCBs exfoliation was carried out under various conditions, which revealed that smaller size (1 × 1 cm2) of WPCB pieces, a higher reaction temperature (240°C) and a longer separation time could improve the extent of the exfoliation. Therefore, the cur...

Therapeutic nanocatalysis has emerged as an intriguing strategy for efficient cancer‐specific therapy, but the traditional inorganic nanocatalysts suffer from low catalytic efficiency and difficulty in biodegradation, hindering their further clinical translation. Herein, a tumor microenvironment‐triggered, biodegradable and biocompatible nanocatalyst employing 2D hydroxide nanosheet is presented, and is shown to have high catalytic capacity to efficiently produce abundant hydroxyl radicals under the tumor microenvironment and consequently kill tumor cells selectively. A polyethylene glycol (PEG)‐conjugated Fe2+‐containing hydroxide nanosheet is successfully constructed via a facile but efficient bottom‐up approach that concurrently realizes nanosheet synthesis and PEGylation. Importantly, the nanosheets are featured with high catalytic activity to disproportionate H2O2 in tumors, and consequently generate abundant hydroxyl radicals at a high reaction rate under tumorous acidic condition; the highly toxic hydroxyl radicals, as a result, cause the death of tumor cells in vitro and suppress the tumor growth in vivo without the use of any supplementary toxic agent, only with the biocompatible nanocatalysts. Meanwhile, the desirable biodegradation and biocompatibility of the hydroxide nanosheet render a high degree of safety to the organism. Therefore, this work provides the first paradigm of biodegradable 2D nanocatalytic platform with concurrently high catalytic‐therapeutic performance and biosafety for efficient tumor‐specific treatment.

The heavy metal (HM) evaporation in the thermal treatment of fly ash (FA) from municipal solid waste incineration (MSWI) has attracted considerable attention because the inhalation of or skin exposure to heavy metal raises human health risks. In this study, the washing and chemical treatments of FA were performed to inhibit the evaporation of HM (Zn, Pb and Cd) followed by a volatilization test of the pretreated FA at a temperature of up to 1000 °C. The results indicate that the evaporation behavior of HMs in fly ash was significantly affected by chemical speciation. The evaporation ratios of HMs with different speciations decreased in the order of acid soluble (F1) > reducible (F2) > oxidizable (F3) > residual (F4). The washing pretreatment process on fly ash would largely inhibit the evaporation of HMs by removing most of the metal chlorides, which are the dominant component of the F1 fraction. Meanwhile, the fly ash after phosphate chemical pretreatment has the least evaporation via converting the F1 fraction into the chemically stable F4 fraction. Therefore, the controllable formation of chemical speciation could effectively inhibit HM evaporation in fly ash.

During the pretreatment and recycling processes, the re-suspended dust from municipal solid waste incinerator (MSWI) fly ash might pose a significant health risk to onsite workers due to its toxic heavy metal content. In this work, the morphological and mineralogical characteristics of fly ash in different particle sizes are presented. The concentrations of seven trace elements (Zn, Pb, Cu, Cd, Cr, Fe and Mn) in these samples were determined. The results show that volatile metals, such as Zn, Pb, Cu and Cd, were easily concentrated in the fine particles, especially in Dp2.5-1 and Dp1, with soluble and exchangeable substances as the main chemical species. The health risk assessment illustrated that the cumulative hazard indexes for non-carcinogenic metals in Dp10-5, Dp5-2.5, Dp2.5-1, and Dp1 were 1.69, 1.41, 1.78 and 2.64, respectively, which were higher than the acceptable threshold values (1.0). The cumulative carcinogenic risk was also higher than the threshold value (10−6). For the onsite workers, the relatively apparent non-carcinogenic and carcinogenic effects were from Pb and Cr, respectively. The above findings suggest that fine-grained fly ash contained a considerable amount of heavy metals and exhibited a great health risk.

Conjugating nanoparticles with polyethylene glycol (PEG) is a useful strategy to improve the colloidal and biological stability of nanoparticles. However, studies on PEGylation of two-dimensional layered double hydroxide (LDH) nanoparticles are very limited. The present work reported two functionalization approaches to synthesize PEG-conjugated LDH nanoparticles by introducing phosphonic acid terminated PEG before and after LDH aging. The successful PEGylation was confirmed and suggested to be via electrostatic interaction and a ligand exchange process. Different functionalization approaches resulted in different binding types of PEG on/in LDH nanoparticles. The PEG coating maintained the dispersity of LDH nanoparticles in water and saline with the feeding mass ratio of 1:1. Further colloidal stability tests of PEGylated LDHs revealed that the PEGylated LDH dispersity was affected by the feeding mass ratio of PEG/LDH, the molar weight of PEG and anions intercalated in the LDHs. In a test to determine the extent of non-specific protein adsorption, the PEGylation was effective at resisting non-specific bovine serum albumin adsorption on LDH nanoparticles with both functionalization methods investigated. Moreover, PEGylated LDH nanoparticles had no effect on cell viability up to 500 µg/mL, and demonstrated enhanced cellular uptake in a SK-MEL-28 cell culture. The results in this work indicate that conjugating phosphonic acid-terminated PEG on LDH nanoparticles is a promising strategy to improve the colloidal and biological stability of LDHs for biomedical applications.

The mounting interest in layered double hydroxide (LDH) nanoparticles as drug carriers and bio-imaging contrast agents makes biosafety evaluation of LDH essential. Considering the important role of blood circulation in bio-distribution of nanoparticles, the present work evaluated the impact of MgAl-LDHs on key components of the circulatory system, including vascular cells (vascular smooth muscle cells (SMCs) and endothelial cells (HUVECs)), red blood cells (RBCs), and complement activation. The results showed that LDH had no effects on SMCs and HUVECs at concentrations up to 500 and 10 µg/mL respectively, in terms of cell proliferation and viability. LDH (10 µg/mL) did not change either the migration distance or the number of migrating SMCs in culture. Moreover, LDH (400 µg/mL) had a negligible effect on RBCs’ lysis, and there was no significant increase in levels of complement activation product, C5a, in the presence of LDH (20 or 200 µg/mL). The low toxicity for vascular cells and blood cells combined with low immunogenicity sheds a light on the biosafety of LDH nanoparticles, and encourages further studies into their biomedical applications.

2D nanomaterials represent one of the next-generation biomaterials with versatile physicochemical advantages that allow for diverse biomedical applications in disease diagnosis, prevention, and treatment. In particular, layered double hydroxide (LDH) nanoparticles, as a typical 2D nanomaterial, have recently shown unprecedented advances in controllable and simplified chemical construction, versatile surface engineering, and comprehensive biological investigation. To realize in vivo biomedical applications, recent efforts have been substantially devoted to a few critical aspects of LDH nanomedicine including nanoparticle stability in physiological environments, accumulation at the disease-targeted site, selective biological response to the nanoparticle, systematic biosafety examination, integration with multiple diagnostic and therapeutic modalities, and the adjuvant activity and suitability for gene-based and protein-based vaccines, which are herein comprehensively reviewed. The challenges and future development strategies of LDH nanomedicine are also discussed toward practical biomedical applications to benefit patients.

The purpose of this study was to develop a process to recover value product from serpentine wastes using countercurrent leaching and solvent extraction. Countercurrent leaching of serpentine waste was carried out in 31% hydrochloric acid solution at 90°C using refluxing process. After countercurrent leaching of three times, acid concentration of leaching solution decreased from 5–6 to 0·5 mol L−1 and metal ion concentrations increased double. Solid residues were separated from countercurrent leaching solution by filtering process. The filtered leaching solution was extracted by mono-(2-ethylhexyl) 2-ethylhexyl phosphonate (P507) extractant saponified by sodium bicarbonate. The impure elements of iron, aluminum, and calcium were removed from countercurrent leaching solution. Subsequently, naphthenic acid extractant saponified with sodium carbonate was used to extract nickel from above raffinate solution, and remaining element was only magnesium in raffinate solution. Filtered solid residues were le...

The Chinese integrated circuit industry has been transformed from a small state-owned sector into a global competitor, but chip manufacturing produces large amounts of calcium fluoride sludge (CFS). The current treating method is landfill in China. In order to solve the problem of unavailable landfill sites and the dissolved CFS polluting water sources, CFS was tested as a component for a ceramic product made with sodium borate, sodium phosphate, and waste alumina using a low temperature sintering technology. The ceramic was characterized by X-ray diffraction (XRD), microstructure, compressive strength. XRD and microstructure analyses verified that CFS was transformed into Na2Ca(PO4)F as an inert crystalline phase in ceramic, which is enclosed by the borophosphate glass liquid phase. Toxicity characteristic leaching procedure and corrosion resistance tests verified that fluorine from CFS was solidified in the inert crystalline phase, which did not release to cause secondary pollution. This novel technology produces high-performance ceramic as a construction material, in accordance with the concept of sustainable development.

We have studied a Filippov system [Formula: see text] with small [Formula: see text], [Formula: see text] and [Formula: see text] being periodic. Since [Formula: see text] is an abstract function, the subharmonic Melnikov function cannot be computed. In other words, for this system the Melnikov method loses effectiveness. First, we proved that the equation has a unique harmonic solution, a unique [Formula: see text]-subharmonic solution for any [Formula: see text] and they are Lyapunov asymptotically stable. Moreover, this equation has no other type of periodic solutions. Further, the attractor of this system is not chaotic. Finally, some numerical examples are given.