Perspective and challenges of mycorrhizal symbiosis in orchid medicinal plants.

The family Orchidaceae is of the most diverse taxon in the plant kingdom, and most of its members are highly valuable herbal medicines. Orchids have a unique mycorrhizal symbiotic relationship with specific fungi for carbohydrate and nutrient supplies in their whole lifecycle. The large-scale cultivation of the medicinal plant Gastodia elata is a successful example of using mycorrhizal symbiotic technology. In this review, we adopted G. elata and Dendrobium officinale as examples to describe the characteristics of orchid mycorrhiza and mycorrhizal benefits for host plants' growth and health (e.g. biotic and abiotic stress and secondary metabolite accumulation). The challenges in applying mycorrhizal technology to the cultivation of orchid medicinal plants in the future were also discussed. This review aims to serve as a theoretical guide for the cultivation of mycorrhizal technology in medicinal orchid plants.

Comparative analysis of the value of amide proton transfer-weighted imaging and diffusion kurtosis imaging in evaluating the histological grade of cervical squamous carcinoma.

BACKGROUND: Uterine cervical cancer (UCC) was the fourth leading cause of cancer death among women worldwide. The conventional MRI hardly revealing the microstructure information. This study aimed to compare the value of amide proton transfer-weighted imaging (APTWI) and diffusion kurtosis imaging (DKI) in evaluating the histological grade of cervical squamous carcinoma (CSC) in addition to routine diffusion-weighted imaging (DWI). METHODS: Forty-six patients with CSC underwent pelvic DKI and APTWI. The magnetization transfer ratio asymmetry (MTRasym), apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) were calculated and compared based on the histological grade. Correlation coefficients between each parameter and histological grade were calculated. RESULTS: The MTRasym and MK values of grade 1 (G1) were significantly lower than those of grade 2 (G2), and those parameters of G2 were significantly lower than those of grade 3 (G3). The MD and ADC values of G1 were significantly higher than those of G2, and those of G2 were significantly higher than those of G3. MTRasym and MK were both positively correlated with histological grade (r = 0.789 and 0.743, P <  0.001), while MD and ADC were both negatively correlated with histological grade (r = - 0.732 and - 0.644, P <  0.001). For the diagnosis of G1 and G2 CSCs, AUC (APTWI+DKI + DWI) > AUC (DKI + DWI) > AUC (APTWI+DKI) > AUC (APTWI+DWI) > AUC (MTRasym) > AUC (MK) > AUC (MD) > AUC (ADC), where the differences between AUC (APTWI+DKI + DWI), AUC (DKI + DWI) and AUC (ADC) were significant. For the diagnosis of G2 and G3 CSCs, AUC (APTWI+DKI + DWI) > AUC (APTWI+DWI) > AUC (APTWI+DKI) > AUC (DKI + DWI) > AUC (MTRasym) > AUC (MK) > AUC (MD > AUC (ADC), where the differences between AUC (APTWI+DKI + DWI), AUC (APTWI+DWI) and AUC (ADC) were significant. CONCLUSION: Compared with DWI and DKI, APTWI is more effective in identifying the histological grades of CSC. APTWI is recommended as a supplementary scan to routine DWI in CSCs.

Polyaniline-intercalated manganese dioxide nanolayers as a high-performance cathode material for an aqueous zinc-ion battery.

Rechargeable zinc-manganese dioxide batteries that use mild aqueous electrolytes are attracting extensive attention due to high energy density and environmental friendliness. Unfortunately, manganese dioxide suffers from substantial phase changes (e.g., from initial α-, ß-, or γ-phase to a layered structure and subsequent structural collapse) during cycling, leading to very poor stability at high charge/discharge depth. Herein, cyclability is improved by the design of a polyaniline-intercalated layered manganese dioxide, in which the polymer-strengthened layered structure and nanoscale size of manganese dioxide serves to eliminate phase changes and facilitate charge storage. Accordingly, an unprecedented stability of 200 cycles with at a high capacity of 280 mA h g-1 (i.e., 90% utilization of the theoretical capacity of manganese dioxide) is achieved, as well as a long-term stability of 5000 cycles at a  utilization of 40%. The encouraging performance sheds light on the design of advanced cathodes for aqueous zinc-ion batteries.

Ultrasmall TiO2-Coated Reduced Graphene Oxide Composite as a High-Rate and Long-Cycle-Life Anode Material for Sodium-Ion Batteries.

Because of the low cost and abundant nature of the sodium element, sodium-ion batteries (SIBs) are attracting extensive attention, and a variety of SIB cathode materials have been discovered. However, the lack of high-performance anode materials is a major challenge of SIBs. Herein, we have synthesized ultrasmall TiO2-nanoparticle-coated reduced graphene oxide (TiO2@RGO) composites by using a one-pot hydrolysis method, which are then investigated as anode materials for SIBs. The morphology of TiO2@RGO has been characterized using transmission electron microscopy, indicating that the TiO2 nanospheres uniformly grow on the surface of the RGO nanosheet. As-prepared TiO2@RGO composites exhibited a promising electrochemical performance in terms of cycling stability and rate capability, especially the initial cycle Coulombic efficiency of 60.7%, which is higher than that in previous reports. The kinetics of the electrode reaction has been investigated by cyclic voltammetry. The results indicate that the sodium-ion intercalation/extraction behavior is not controlled by the semiinfinite diffusion process, which gives rise to an outstanding rate performance. In addition, the electrochemical performance of TiO2@RGO composites in full cells, coupled with carbon-coated Na3V2(PO4)3 as the positive material, has been investigated. The discharge specific capacity was up to 117.2 mAh g-1, and it remained at 84.6 mAh g-1 after 500 cycles under a current density of 2 A g-1, which shows excellent cycling stability.

Integrating Desalination and Energy Storage using a Saltwater-based Hybrid Sodium-ion Supercapacitor.

Ever-increasing freshwater scarcity and energy crisis problems require efficient seawater desalination and energy storage technologies; however, each target is generally considered separately. Herein, a hybrid sodium-ion supercapacitor, involving a carbon-coated nano-NaTi2 (PO4 )3 -based battery anode and an activated-carbon-based capacitive cathode, is developed to combine desalination and energy storage in one device. On charge, the supercapacitor removes salt in a flowing saltwater electrolyte through Cl- electrochemical adsorption at the cathode and Na+ intercalation at the anode. Discharge delivers useful electric energy and regenerates the electrodes. This supercapacitor can be used not only for energy storage with promising electrochemical performance (i.e., high power, high efficiency, and long cycle life), but also as a desalination device with desalination capacity of 146.8 mg g-1 , much higher than most reported capacitive and battery desalination devices. Finally, we demonstrate renewables to usable electric energy and desalted water through combining commercial photovoltaics and this hybrid supercapacitor.

A clean and membrane-free chlor-alkali process with decoupled Cl2 and H2/NaOH production.

Existing chlor-alkali processes generally use asbestos, mercury or fluorine-containing ion-exchange membranes to separate the simultaneous chlorine production on the anode and hydrogen production on the cathode, and form sodium hydroxide in the electrolyte. Here, using the Na+ de-intercalation/intercalation of a Na0.44MnO2 electrode as a redox mediator, we decouple the chlor-alkali process into two independent steps: a H2 production step with the NaOH formation in the electrolyte and a Cl2 production step. The first step involves a cathodic H2 evolution reaction (H2O → H2) and an anodic Na+ de-intercalation reaction (Na0.44MnO2 → Na0.44-xMnO2), during which NaOH is produced in the electrolyte solution. The second step depends on a cathodic Na+ intercalation reaction (Na0.44-xMnO2 → Na0.44MnO2) and an anodic Cl2 production (Cl → Cl2). The cycle of the two steps provides a membrane-free process, which is potentially a promising direction for developing clean chlor-alkali technology.