Flexible multilevel nonvolatile biocompatible memristor with high durability.

Current protein or glucose based biomemristors have low resistance-switching performance and require complex structural designs, significantly hindering the development of implantable memristor devices. It is imperative to discover novel candidate materials for biomemristor with high durability and excellent biosafety for implantable health monitoring. Herein, we initially demonstrate the resistance switching characteristics of a nonvolatile memristor in a configuration of Pt/AlOOH/ITO consisting of biocompatible AlOOH nanosheets sandwiched between a Indium Tin Oxides (ITO) electrode and a platinum (Pt) counter-electrode. The hydrothermally synthesized AlOOH nanosheets have excellent biocompatibility as confirmed through the Cell Counting Kit-8 (CCK-8) tests. Four discrete resistance levels are achieved in this assembled device in responsible to different compliance currents (ICC) for the set process, where the emerging multilevel states show high durability over 103 cycles, outperforming the protein-based biomemristors under similar conditions. The excellent performance of the Pt/AlOOH/ITO memristor is attributed to the significant role of hydrogen proton with pipe effect, as confirmed by both experimental results and density functional theory (DFT) analyses. The present results indicate the nonvolatile memristors with great potential as the next generation implantable multilevel resistive memories for long-term human health monitoring.

Synergistic effect and mechanisms of ultrasound and AlOOH suspension on Al hydrolysis for hydrogen production.

Ultrasound can accelerate and change the reaction process and is widely used in the field of hydrogen production and storage. In this study, ultrasound (US) and AlOOH suspension (AH) are used to promote hydrogen production from Al hydrolysis. The results indicate that both US and AH greatly shorten the induction time and enhance the hydrogen production rate and yield. The promoting effect of US and AH on Al hydrolysis originates from the acoustic cavitation effect and catalytic effect, respectively. When AH is used in combination with US, Al hydrolysis has the best hydrogen production performance and the hydrogen yield can reach 96.6 % within 1.2 h, because there is a synergistic effect on Al hydrolysis between AH and US. Mechanism analyses reveal that the micro-jets and local high temperature environment arising from acoustic cavitation improve the catalytic activity of AlOOH, while the suspended AlOOH particles enhance the cavitation effect of US. This work provides a novel and feasible method to promote hydrogen production from Al hydrolysis.

Total recycle strategy of phosphorus recovery from wastewater using granule chitosan inlaid with γ-AlOOH.

Eutrophication which caused by excessive phosphorus in aquatic environment is a worldwide problem. Phosphorus is a nonrenewable resource widely used in agriculture and industry. Therefore, the development of economical methods for phosphorus capture and reuse from wastewater is urgently needed. In this study, a novel granule chitosan inlaid with γ-AlOOH on its structure (γ-AlOOH@CS) was prepared for phosphate removal with a recycle manner. Results showed that γ-AlOOH@CS exhibited a fast phosphate removal of 0.5 h for half adsorption capacity. The material presented a high adsorption capacity of 45.82 mg/g, the adsorption capacity maintained stability at pH 4-6, and favorable selectivity was observed when compared with other common anions. Column experiment was also performed well in treatment of the simulated wastewater. Isotherms and thermodynamics studies indicated that phosphate adsorption onto γ-AlOOH@CS was heterogeneous, spontaneous and exothermic. In material recycle experiment, by using NaOH solution as solvent and phosphoric acid as precipitant under hydrothermal reaction conditions, the products of chitosan, aluminum phosphate and sodium dihydrogen phosphate were obtained, with their purity reaching the industrial standard. Meanwhile, chitosan can be reused for new γ-AlOOH@CS preparation. This study provides a total recycle strategy of phosphorus removal from wastewater.

Boehmite enhances hair follicle growth via stimulation of dermal papilla cells by upregulating ß-catenin signalling.

Hair growth, a complex process, has long been the subject of intense research. Recent developments in material technology have revealed boehmite as a new therapeutic modality for use in wound healing and scar reduction, indicating its beneficial effects. Nonetheless, the biological bases of the beneficial effects of boehmite remain unknown. We investigated the hair growth properties of boehmite in vitro and in vivo and observed dose-dependent proliferation of human dermal papilla cells (hDPCs) in vitro and hair regrowth in a mouse model. To investigate the effects of boehmite on the promotion of cell transition to the anagen phase, we evaluated hDPC viability, alkaline phosphatase (ALP) activity, protein expression and vascular endothelial growth factor (VEGF) secretion in vitro and assessed the anagen-promoting effects of boehmite via gross observation and histological analysis in a mouse model. Boehmite increased hDPC viability, ALP activity, AKT/GSK3ß/ß-catenin pathway activity, anagen-related gene expression and VEGF secretion; moreover, it accelerated hair regrowth in a catagen-anagen transition model via upregulation of ß-catenin signalling and follicular cell proliferation. Collectively, our results indicate that boehmite accelerates hair growth, partly via its effects on critical events in the active phase of the hair follicle cycle, including the promotion of the proliferation of hDPCs and their immediate progeny to the follicle base.

Chitosan-boehmite desiccant composite as a promising adsorbent towards heavy metal removal.

Owing to the widespread occurrence and potential health effects, many treatment strategies have been developed across the world to remove the heavy metal contaminants in water. Developing affordable and sustainable nanoscale materials are the prime factors for the success of such treatment systems in the field. The present study explores the use of desiccant waste, exhausted after several cycles of dehumidification processes. The granulated composite desiccant is composed of boehmite nanoparticles reinforced with chitosan fibrils. The composite was synthesized via a simple and scalable one-pot sol-gel route at atmospheric pressure and room temperature. The desiccant was employed for dehumidification/regeneration cycles. The reuse potential of exhausted desiccant towards enhanced removal of metal ions was analyzed and demonstrated. After adsorption the nanocomposite was characterized to establish its chemical composition and structure. Batch and fixed-bed column adsorption experiments were performed to evaluate the removal efficiency of the nanocomposite and to assess the parameters that influence the adsorption process. The experimental evidences confirm the fast kinetics of adsorption/desorption and effective regeneration of the composite. The enhanced removal capacity, excellent reuse potential, high stable granules, eco-friendly synthesis approach makes the adsorbent an excellent candidate for the removal of wide range of heavy metals in water.

Therapeutic potential of topically administered γ-AlOOH on 2,4-dinitrochlorobenzene-induced atopic dermatitis-like lesions in Balb/c mice.

Boehmite (γ-AlOOH) has a wide range of applications in a variety of industrial and biological fields. However, little is known about its potential roles in skin diseases. The current study investigated its effect on atopic dermatitis (AD). Following characterization, cytotoxicity, pro-inflammatory response and oxidative stress associated with boehmite were assessed, using TNF-α-induced keratinocytes and mast cells. In addition, therapeutic effects of boehmite, topically administered to Balb/c mice induced by 2,4-dinitrochlorobenzene (DNCB), were evaluated. Expression of cytokines (TLSP, IL-25 and IL-33) and the generation of ROS from keratinocytes induced by TNF-α were significantly inhibited by boehmite without affecting cell viability. MAPKs (ERK, JNK and p38) required for cytokine expression were suppressed by boehmite treatment. Up-regulation of cytokines (TSLP, IL-4, IL-5, IL-13, RANTES) in human mast cells treated with phorbol 12-myristate 13-acetate and calcium ionophore was also suppressed by boehmite. Boehmite improved the AD severity score, epidermal hyperplasia and transepidermal water loss in DNCB-induced AD-like lesions. Moreover, Th2-mediated cytokine expression, mast cell hyperplasia and destruction of the skin barrier were improved by boehmite treatment. Overall, we demonstrated that boehmite may potentially protect against AD.

Formation of CoAl layered double hydroxide on the boehmite surface and its role in tungstate sorption.

Sorption of tungstate on boehmite (γ-AlOOH) is increased by co-sorption with Co2+ over the near-neutral pH range. Batch uptake experiments show up to a 3-fold increase in tungstate uptake over the range WO42-=50-1000µmol/L compared to boehmite not treated with Co2+. Desorption experiments reveal a corresponding decrease in sorption reversibility for tungstate co-sorbed with Co2+. Reaction of boehmite with Co2+ results in the formation of CoAl layered double hydroxide (LDH), as confirmed by X-ray diffraction and X-ray absorption spectroscopy. Tungsten L3-edge X-ray absorption near edge structure (XANES) reveals that W(VI) is octahedrally coordinated in all sorption samples, with polymeric tungstate species forming at higher tungstate concentrations. X-ray diffraction and X-ray absorption spectroscopy indicate that the mechanism for enhancement of tungstate uptake is the formation of surface complexes on boehmite at low tungstate concentrations, while exchange into the CoAl LDH becomes important at higher tungstate concentrations. The results provide a basis for developing strategies to enhance tungstate sorption and to limit its environmental mobility at near-neutral pH conditions.