Benzoate ester as a new species for supramolecular chiral assembly.

In this work, a benzoate ester molecule, dodecamethylnonacosane-2,28-diyl dibenzoate (DMNDB), has been discovered as a new species that aggregates into chiral nano-assemblies. In the tetrahydrofuran (THF)/water system, the benzoate ester, DMNDB, could self-assemble into left-handed twisted nanowires, and the most suitable THF/water volume ratio to obtain uniform twisted nanowires was 3 : 7. The driving forces of assembly and the molecular packing type in assemblies for the twisted nanowires were explored, and a possible assembly mechanism was proposed to understand the generation of chiral assemblies. Interestingly, the left-handed nanowires could cross-link and immobilize the solvent in the isopropanol (iPrOH)/water (2 : 8) system to form chiral gels. When the iPrOH/water ratio was increased to 6 : 4, the left-handed nanowires as structural units were found to evolve to right-handed nanofibers. Accordingly, the intermolecular interactions and the molecular packing type also changed with the solvent ratio. What is more, the xerogel could be obtained by drying the gel and left-handed twisted nanowires could form in the THF/water system again, showing the recyclability of chiral nanoassemblies. Also, these DMNDB chiral nanostructures exhibited potential for application in enantioselective separation by co-assembling with tetra-aniline.

Controllable Supramolecular Chiral Twisted Nanoribbons from Achiral Conjugated Oligoaniline Derivatives.

The fabrication of supramolecular chiral nanostructures from achiral materials without the need of pre-existing chirality is a major challenge associated with the origin of life. Herein, supramolecular chiral twisted nanoribbons of achiral oligoaniline derivatives were prepared via simply performing the chemical oxidation of aniline in an alcohol/water mixed solvent. In particular, the supramolecular chirality of the twisted nanoribbons could be controlled by facilely tuning the alcohol content in the mixed solvent. A tetra-aniline derivative C24H20O3N4 was attested to be the major component of the obtained nanoribbons. The main driving forces for the assembly of the oligoaniline derivative into twisted nanoribbons might be the π-π stacking and hydrogen bonding interactions among the chains which could be modulated by the alcohol content in the mixed solvent. The single-handed twisted nanoribbons could be used to separate chiral phenylalanine from a racemic mixture. Thus, it is highly anticipated that the supramolecular chirality endows π-conjugated molecules with potential application in chiral recognition.

Core-Shell Structure and Interaction Mechanism of γ-MnO2 Coated Sulfur for Improved Lithium-Sulfur Batteries.

Lithium-sulfur batteries have attracted worldwide interest due to their high theoretical capacity of 1672 mAh g-1 and low cost. However, the practical applications are hampered by capacity decay, mainly attributed to the polysulfide shuttle. Here, the authors have fabricated a solid core-shell γ-MnO2 -coated sulfur nanocomposite through the redox reaction between KMnO4 and MnSO4 . The multifunctional MnO2 shell facilitates electron and Li+ transport as well as efficiently prevents polysulfide dissolution via physical confinement and chemical interaction. Moreover, the γ-MnO2 crystallographic form also provides one-dimensional (1D) tunnels for the Li+ incorporation to alleviate insoluble Li2 S2 /Li2 S deposition at high discharge rate. More importantly, the MnO2 phase transformation to Mn3 O4 occurs during the redox reaction between polysulfides and γ-MnO2 is first thoroughly investigated. The S@γ-MnO2 composite exhibits a good capacity retention of 82% after 300 cycles (0.5 C) and a fade rate of 0.07% per cycle over 600 cycles (1 C). The degradation mechanism can probably be elucidated that the decomposition of the surface Mn3 O4 phase is the cause of polysulfide dissolution. The recent work thus sheds new light on the hitherto unknown surface interaction mechanism and the degradation mechanism of Li-S cells.

Uptake of Cd(II) Onto Raw Crab Shells: Isotherm, Kinetic, Adsorption Properties And Mechanisms.

This study focuses on the uptake of cadmium (Cd(II)) ion from water onto raw crab shells acting as a biosorbent. Experimental data were perfectly fitted to the Langmuir and Dubinin-Radushkevich models, while the uptake kinetics are well-described using the pseudo-second-order model. The effects of experimental conditions on the uptake isotherms and kinetics are discussed in detail. A study of uptake thermodynamics has indicated that the Cd(II) uptake onto the crab shell is an endothermic and spontaneous process. For further understanding of this process, possible mechanisms of Cd(II) uptake onto crab shell have been deduced from experimental results. Desorption experiment shows that 93.7% of adsorbed Cd(II) could be recovered with a 0.1 M HNO3 solution. The inhibitory effects of other metal co-ions on the Cd(II) uptake on the crab shell are also discussed.

Removal of Pb(II) and Zn(II) from Aqueous Solutions by Raw Crab Shell: A Comparative Study.

Removals of Pb(II) and Zn(II) ions from water using crab (Clistocoeloma sinensis) shell particles as biosorbent have been compared in this study. Uptake equilibriums for two ions well described by Langmuir isotherm revealed that crab shell possessed higher uptake capacity for Pb(II) (709 mg/g) than that for Zn(II) (117 mg/g). Kinetics data for the uptake of the two metals were successfully modeled using the pseudo-second-order model, where the initial uptake rate of Pb(II) was much faster than that of Zn(II). Dubinin-Radushkevick modeling and thermodynamic parameters hinted at different uptake mechanisms of Pb(II) and Zn(II) removal by crab shell, attested by FTIR, XRD, FESEM analysis. Pb(II) ion was removed mainly through the chemical reaction, while the uptake of Zn(II) ion onto crab shell was attributed to the chelation and coordination interactions. The polluted river water and laboratory wastewater both satisfied the standards for drinking and irrigation/fishery water, respectively, after being treated with crab shell particles.

Ethanol vapor-induced fabrication of colloidal crystals with controllable layers and photonic properties.

A novel fabrication method for colloidal crystals has been proposed for the first time in this research. In this method, a suspension droplet containing colloidal particles was first spread onto a glass substrate placed in an ethanol vapor environment, and then the droplet was extracted from its center. In that case, the contact angle of the droplet reduced and the contact line receded toward the center, during which the colloidal particles self-assembled and immobilized forming a 2D colloidal crystal film on the substrate upon drying the liquid film. Alternately spreading and drying of suspension films could construct fine multi-layers of colloidal crystals, while the ethanol fraction in the suspension would be used to control roughly but rapidly the layer numbers of colloidal crystals. It was also found that the photonic properties of resultant colloidal crystal films were elevated by increasing their thickness.

HP1 induces ferroptosis of renal tubular epithelial cells through NRF2 pathway in diabetic nephropathy.

The aim of this study was to investigate the role of ferroptosis in diabetic nephropathy (DN) and the mechanism of its regulatory genes. HK-2 cells were cultured with high glucose and mice were intraperitoneally injected with streptozotocin to establish DN models. GSE111154 was analyzed to identify the abnormal expression of genes associated with DN. Cell injury was evaluated through CCK-8 assay and 4',6-diamidino-2-phenylindole/phenylindole double staining. The levels of iron, glutathione, malondialdehyde, urinary albumin, and urinary creatinine were determined by ELISA. Furthermore, western blot and RT-qPCR were used to detect protein and mRNA levels, respectively. Our data showed that heterochromatin protein 1 is an abnormally elevated gene related to DN and is further elevated by ferroptosis activators. Inhibition of HP1 significantly inhibited ferroptosis but promoted cell viability. In addition, nuclear factor erythroid2-related factor2 (NRF2) was decreased in DN cell model, but increased under the action of ferroptosis activators. NRF2 silencing reversed the protective effects of HP1 inhibition on HK-2 cells. Additionally, HP1 silencing also alleviated kidney damage in DN mice. Collectively, these findings suggest that inhibiting HP1 inhibits ferroptosis via NRF2 pathway, thereby protecting renal tubular epithelial cells from damage.

Chiral Polyaniline Hollow Nanotwists toward Efficient Enantioselective Separation of Amino Acids.

Controllable fabrication of complex chiral nanostructures of functional materials from achiral systems remains a great challenge. Herein, polyaniline (PANI) hollow nanotwists as complex chiral nanostructures have been prepared by chemical oxidation of aniline in an achiral HCl/isopropyl alcohol/water mixed solvent. The chiral oligoaniline twisted nanoribbons generated at the early reaction stage have been established to act as reactive sacrificial templates for inducing the growth of PANI hollow nanotwists. Single-handed PANI hollow nanotwists achieved by tuning the alcohol content in the solvent have been applied to separate several chiral amino acids from their racemic mixtures with high performance, indicating their high potential for enantioselective separation applications.

Dilute anionic surfactant solution route to polyaniline rectangular sub-microtubes as a novel nanostructure.

A facile and low-cost approach has been developed for tailoring polyaniline rectangular sub-microtubes as a novel nanostructure of a conducting polymer in dilute sodium dodecyl sulfate (SDS) solution by the oxidation polymerization of aniline at room temperature. It was found that the size and uniformity of polyaniline rectangular sub-microtubes could be appropriately adjusted by tuning the concentration of aniline and the molar ratio of oxidant to aniline, respectively. The morphological evolution of rectangular sub-microtubes under different reaction times has been followed, and a possible formation mechanism has also been discussed in this report. The directing role of other anionic surfactants with -SO3(-) as the hydrophilic group for constructing polyaniline rectangular sub-microtubes has been investigated in detail.

Mesoporous Hybrid Shells of Carbonized Polyaniline/Mn2O3 as Non-Precious Efficient Oxygen Reduction Reaction Catalyst.

Mesoporous hybrid shells of carbonized polyaniline (CPANI)/Mn2O3 with well-controlled diameter and high surface area have been synthesized through surface protected calcination processes. Originating from polystyrene template, PANI, MnO2, and SiO2 were sequentially loaded, followed by template removal and calcination, resulting in the desired CPANI/Mn2O3 hybrid shells. The introduction of SiO2 shell was established to play the determining role in maintaining the configuration during calcination process under high temperature. The CPANI/Mn2O3 hybrid shells showed outstanding electrocatalytic activity toward oxygen reduction reaction (ORR), with the onset potential at +0.974 V (versus RHE), the specific current at 60.8 mA/mg, and an overall quasi 4-electron transfer, which are comparable to those of the benchmark Pt/C. The remarkable ORR performance was attributed to the high specific surface area, the surface oxidation state of Mn, and composition-codependent behavior.

A facile strategy to colloidal crystals by drying condensed suspension droplets.

Drying condensed colloid suspension droplet on a horizontal glass substrate has been developed as a simple strategy to fabricate highly-ordered colloidal crystals. A uniform film obtained at above room temperature possessed a face-center-cubic (fcc) crystalline structure and excellent photonic properties. It was found that raising the drying temperature has resulted in a reduction in the lattice spacing of fcc colloidal crystals. The formation reason of uniform fcc colloidal crystals was directly related to the high drying temperature and the large colloid concentration. A ring-shaped stain generated by drying at room temperature has exhibited other highly-ordered microstructures with colloidal crystals, such as body center cubic (bcc) structure.

Controlled nanoscale diffusion-limited chemical etching for releasing polystyrene nanocones from recyclable alumina templates.

We report a controllable nanoscale diffusion-limited chemical etching for detaching aligned polystyrene nanocones from 3D taper-nanopore alumina templates, which can be recycled.

Polyaniline fan-like architectures of rectangular sub-microtubes synthesized in dilute inorganic Acid solution.

Rectangular-tube-based fan-like polyaniline has been readily fabricated by the oxidation polymerization of low-concentration aniline in dilute HCl aqueous solution for the first time. Different from the conventional polymerization that proceeds in concentrated acidic solution (to produce nanofibers), this synthesis was conducted in dilute inorganic acid solution at room temperature and created polyaniline hierarchical fan-like architectures. The morphological evolution of the product has been followed with respect to the reaction time, based on which conceivable interpretations of the formation of rectangular tubes and their assembly into fan-like architectures are given. Other inorganic acids (HNO(3) , H(2) SO(4) , and H(3) PO(4) ) with low concentrations have been used to replace HCl in the reaction system to validate the adaptability of this approach in this report.