Configurational Entropy Strategy Enhanced Structure Stability Achieves Robust Cathode for Aluminum Batteries.

Rechargeable aluminum batteries (RABs) are an emerging energy storage device owing to the vast Al resources, low cost, and high safety. However, the poor cyclability and inferior reversible capacity of cathode materials have limited the enhancement of RABs performance. Herein, a high configurational entropy strategy is presented to improve the electrochemical properties of RABs for the first time. The high-entropy (Fe, Mn, Ni, Zn, Mg)3 O4 cathode exhibits an ultra-stable cycling ability (109 mAh g-1 after 3000 cycles), high specific capacity (268 mAh g-1 at 0.5 A g-1 ), and rapid ion diffusion. Ex situ characterizations indicate that the operational mechanism of (Fe, Mn, Ni, Zn, Mg)3 O4 cathode is mainly based on the redox process of Fe, Mn, and Ni. Theoretical calculations demonstrate that the oxygen vacancies make a positive contribution to adjusting the distribution of electronic states, which is crucial for enhancing the reaction kinetics at the electrolyte and cathode interface. These findings not only propose a promising cathode material for RABs, but also provide the first elucidation of the operational mechanism and intrinsic information of high-entropy electrodes in multivalent ion batteries.

Fabrication of polyethyleneimine functionalized magnetite nanoparticles for recyclable recovery of fucoidan from aqueous solution.

Fucoidan is a kind of natural water-soluble fucose-rich sulfated polysaccharide with promising applications in the food and pharmaceutical industry. However, the traditional methods for fucoidan recovery from aqueous solution are expensive, time-consuming, and environmentally unfriendly. In this work, polyethyleneimine functionalized magnetite nanoparticles (PEI-MNPs) with well-defined core-shell structures were prepared by a Layer-by-Layer (LbL) approach using sodium tripolyphosphate (STPP) as a cross-linker. The as-prepared PEI-MNPs showed improved adsorption capability towards fucoidan at pH 4-8 due to the high density of cationic groups on the surfaces and the absence of internal pores. It was found that the adsorption process of fucoidan onto PEI-MNPs can reach to equilibrium in 50 min at room temperature. The maximum qe derived from the Langmuir isotherm at room temperature was 169.1 mg per g at a pH of 7. A selective fucoidan capture over a model protein BSA can be realized by adjusting pH (6-8) and salt concentration (0.5-2.5 M). The PEI-MNPs loading with fucoidan can be isolated from the final products by a neodymium magnet and regenerated by 4 M NaCl solution as stripping reagent. Therefore, this novel kind of PEI-MNP could be a promising candidate for highly efficient and recyclable recovery of fucoidan from an aqueous solution.

Effect of Laser Welding Parameters on Joint Structure of AZ31B Magnesium Alloy and 304 Stainless Steel.

The effects of laser welding parameters on the interface microstructure of AZ31B magnesium alloy and 304 stainless steel were investigated. After welding, a scanning electron microscope and ultra-depth of field microscope were used to observe the microstructure of the welded material, to analyze the effects of power on the interface morphology. The simulation of laser welding of magnesium and steel was carried out by the COMSOL software. The results showed that when the power was 15 W-20 W, the temperature did not reach the melting point of magnesium alloy, there was MgO at the welding, and the interface had poor connection strength. When the power was 35 W-50 W, the temperature reached or even exceeded the boiling point of magnesium alloy, and the interface formed hot cracks, pores, and oxides and had poor joint strength. When the power was 25 W-30 W, the temperature was between the melting point and boiling point of magnesium, and the interface had excellent connection strength.

Control of Calcium Phosphate Nucleation and Transformation through Interactions of Enamelin and Amelogenin Exhibits the "Goldilocks Effect".

Although amelogenin comprises the vast majority of the matrix that templates calcium phosphate nucleation during enamel formation, other proteins, particularly enamelin, are also known to play an important role in the formation of enamel's intricate architecture. However, there is little understanding of the interplay between amelogenin and enamelin in controlling processes of mineral nucleation and growth. Here, we used an in vitro model to investigate the impact of enamelin interaction with amelogenin on calcium phosphate nucleation for a range of enamelin-to-amelogenin ratios. We found that amelogenin alone is a weak promoter of nucleation, but addition of enamelin enhanced nucleation rates in a highly nonlinear, nonmonotonic manner reaching a sharp maximum at a ratio of 1:50 enamelin/amelogenin. We provide a phenomenological model to explain this effect that assumes only isolated enamelin proteins can act as sites of enhanced nucleation, while enamelin oligomers cannot. Even when interaction is random, the model reproduces the observed behavior, suggesting a simple means to tightly control the timing and extent of nucleation and phase transformation by amelogenin and enamelin.

Pyridine-ring containing twisttetraazaacene: Synthesis, physical properties, crystal structure and picric acid sensing.

Novel pyridine-ring containing twisttetraazaacene 9,14-diphenylpyreno[4,5-g]isoquinoline (1) and its full-carbon derivative 9,14-diphenyldibenzo[de,qr]tetracene (2) have been synthesized and fully characterized. Studies showed that compound 1 could identify picric acid (PA) over other common nitro compounds with high selectivity and sensitivity. Upon the addition of PA, the emission peak of compound 1 in CH3CN was red shifted from 447 to 555nm with a fluorescence quenching efficiency as high as 95%, the detection limit was calculated to be 2.42µM, while its full-carbon derivative (2) could not exhibit this kind of performance. The possible mechanism with the enhanced PA detection efficiency in pyridine-ring containing twisttetraazaacene (1) than its full-carbon derivative (2) was also investigated.

A facile synthesis of superparamagnetic Fe3O4 supraparticles@MIL-100(Fe) core-shell nanostructures: Preparation, characterization and biocompatibility.

Superparamagnetic Fe3O4 supraparticles@MIL-100(Fe) core-shell nanostructure microspheres were successfully constructed by a facile step-by-step method. The polyacrylate formed in situ during the process of the preparation of Fe3O4 supraparticles not only acted as a stabilizer on the Fe3O4 nanoparticles surface, but also played a crucial role as a "bridge" in the initial stage of the framework components selectively assembly on the Fe3O4 supraparticle surfaces. The structure and composition of the obtained microspheres were characterized by SEM, TEM, DLS, XRD, FTIR, and TG analysis. The MPMS results revealed that the introduction of the MOF shells can inhibit the interplay among the neighboring Fe3O4 supraparticles while an external magnetic field applied. The well-dispersed microspheres are biocompatible, which endow the microspheres great potential in drug targeting applications with enhanced efficiency.

Insight into the formation of magnetite mesocrystals from ferrous precursors in ethylene glycol.

Uniform magnetite mesocrystals were fabricated by solvothermal treatment of ferrous chloride in ethylene glycol in the presence of sodium hydroxide. The formation mechanism of magnetite mesocrystals in ethylene glycol was deduced by a time-dependent experiment.

Synthesis of magnetite-silica core-shell nanoparticles via direct silicon oxidation.

Magnetite-silica core-shell nanoparticles (Fe3O4@SiO2 NPs) were prepared from silicon powder by direct oxidation without using any expensive precursors (such as TEOS) and organic solvents. The as-prepared Fe3O4@SiO2 NPs were characterized by TEM, DLS, XRD, FT-IR, zeta potential and NMR Analyzer. The results show that the Fe3O4@SiO2 NPs are monodispersed core-shell nanostructures with single cores that were uniformly coated by silica shells. The relaxation property indicates that Fe3O4@SiO2 NPs have desirable characteristics for T2 MRI contrast agents. This facile and green method is promising for large-scale production, which would open new opportunities for preparing core-shell nanostructures for biomedical applications.

Facile graft of poly(2-methacryloyloxyethyl phosphorylcholine) onto Fe(3) O(4) nanoparticles by ATRP: synthesis, properties, and biocompatibility.

Magnetite (Fe(3) O(4) ) nanoparticles with the surface hydroxyl groups were achieved by a polyol process. Using 2-(4-chlorosulfonylphenyl) ethyltrichlorosilane (CTCS) as initiator, 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) as monomer, poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC)-grafted Fe(3) O(4) nanoparticles (MNP) were successfully prepared via the atom transfer radical polymerization (ATRP) method. The successful grafting of PMPC on the Fe(3) O(4) nanoparticles surface was ascertained from the FTIR analysis. The modified nanoparticles (MNP-CTCS-PMPC) showed a good biocompatibility in the cytotoxicity test in vitro. Performance testing of MNP-CTCS-PMPC was performed through magnetic resonance analysis (MR), and its r(2) /r(1) value was 24.1. These results indicated that the modified Fe(3) O(4) nanoparticles would be a potential MRI contrast reagent.

Incorporation of magnetite nanoparticle clusters in fluorescent silica nanoparticles for high-performance brain tumor delineation.

Bifunctional nanoprobes with both magnetic and optical contrast have been developed for ultra-sensitive brain tumor imaging at the cellular level. The nanoprobes were synthesized by simultaneously incorporating a magnetite nanoparticle cluster and fluorescence dyes into silica encapsulation by a sol-gel approach under ultrasonic treatment. The nanoprobes maintain superparamagnetic behavior at room temperature and possess enhanced transverse relaxivity and good photostability. As a glioma targeting ligand, chlorotoxin was covalently bonded to the surface of the nanoprobes. In vitro cellular uptake assays demonstrated that the nanoprobes were highly specific, taken up by human U251-MG glioma cells via receptor-mediated endocytosis. The labeled glioma cells were readily detectable by both MR imager and confocal laser scanning microscopy.

Monodisperse water-soluble magnetite nanoparticles prepared by polyol process for high-performance magnetic resonance imaging.

A new class of monodisperse water-soluble magnetite nanoparticles was prepared by a simple and inexpensive method based on a polyol process, and their potential as MRI contrast agents was investigated.

Specific targeting of gliomas with multifunctional superparamagnetic iron oxide nanoparticle optical and magnetic resonance imaging contrast agents.

AIM: To determine whether glioma cells can be specifically and efficiently targeted by superparamagnetic iron oxide nanoparticle (SPIO)-fluorescein isothiocyanate (FITC)-chlorotoxin (SPIOFC) that is detectable by magnetic resonance imaging (MRI) and optical imaging. METHODS: SPIOFC was synthesized by conjugating SPIO with FITC and chlorotoxin. Glioma cells (human U251-MG and rat C6) were cultured with SPIOFC and SPIOF (SPIO-FITC), respectively. Neural cells were treated with SPIOFC as the control for SPIOFC-targeted glioma cells. The internalization of SPIOFC by glioma cells was assessed by MRI and was quantified using inductively-coupled plasma emission spectroscopy. The optical imaging ability of SPIOFC was evaluated by confocal laser scanning microscopy. RESULTS: Iron per cell of U251 (72.5+/-1.8 pg) and C6 (74.9+/-2.2 pg) cells cultured with SPIOFC were significantly more than those of U251 (6.6+/-1.0 pg) and C6 (7.1+/-0.8 pg) cells incubated with SPIOF. The T2 signal intensity of U251 and C6 cells cultured with SPIOFC (233.6+/-25.9 and 211.4+/-17.2, respectively) were substantially lower than those of U251 and C6 cells incubated with SPIOF (2275.3+/-268.6 and 2342.7+/-222.4, respectively). Moreover, there were significant differences in iron per cell and T2 signal intensity between SPIOFC-treated neural cells (1.3+/-0.3; 2533.6+/-199.2) and SPIOFC-treated glioma cells. SPIOFC internalized by glioma cells exhibited green fluorescence by confocal laser scanning microscopy. CONCLUSION: SPIOFC is suitable for the specific and efficient targeting of glioma cells. MRI and optical imaging in conjunction with SPIOFC can differentiate glioma cells from normal brain tissue cells.

Facile synthesis of superparamagnetic magnetite nanoparticles in liquid polyols.

Magnetite nanoparticles have been successfully synthesized in liquid polyols at elevated temperature. Polyol solvent plays a crucial role in determining the morphology and colloidal stability of the resulting particles. The structure and morphology of the nanoparticles were studied using XRD, TEM, SAED, TGA and FTIR. The magnetic properties of the samples were measured using physical properties measurement system (PPMS) of Quantum Design. The results show that as-prepared magnetite nanoparticles are monodisperse, highly crystalline and superparamagnetic at room temperature. The nanoparticles can be easily dispersed in aqueous media and other polar solvents due to coated by a layer of hydrophilic polyol ligands in situ. This approach provides a facile route to prepare magnetite nanoparticles.