High Dielectric Poly(vinylidene fluoride)-Based Polymer Enables Uniform Lithium-Ion Transport in Solid-State Ionogel Electrolytes.

Ionic liquids (ILs)-incorporated solid-state polymer electrolytes (iono-SPEs) have high ionic conductivities but show non-uniform Li+ transport in different phases. This work greatly promotes Li+ transport in polymer phases by employing a poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE), PTC] as the framework of ILs to prepare iono-SPEs. Unlike PVDF, PTC with suitable polarity shows weaker adsorption energy on IL cations, reducing their possibility of occupying Li+ -hopping sites. The significantly higher dielectric constant of PTC than PVDF facilitates the dissociation of Li-anions clusters. These two factors motivate Li+ transport along PTC chains, narrowing the difference in Li+ transport among varied phases. The LiFePO4 /PTC iono-SPE/Li cells cycle steadily with capacity retention of 91.5 % after 1000 cycles at 1 C and 25 °C. This work paves a new way to induce uniform Li+ flux in iono-SPEs through polarity and dielectric design of polymer matrix.

Correlation between the efficacy of stem cell therapy for osteonecrosis of the femoral head and cell viability.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is a common disease that greatly affects the quality of life of patients. Repair of the necrotic area is key to successful treatment. Currently, the combination of stem cell transplantation and decompression is used clinically to promote the repair of necrotic areas based on the characteristics of stem cells. However, a considerable number of patients do not achieve a satisfactory outcome in terms of repair of the femoral head necrotic area, and it is very important to determine the reasons for the poor curative effect. The aim of this study was to investigate the correlation between stem cell viability and the repair efficacy of stem cell therapy combined with core decompression for early-stage ONFH. METHODS: A total of 30 patients with idiopathic ONFH underwent core decompression combined with autologous stem cell transplantation. The Harris hip score (HHS) and difference in necrosis area before and after surgery were measured. The mean repair ratio was set as the threshold to divide the patients into group A (ratio above the mean) and group B (ratio below the mean). The ultrastructure, proliferative capacity, and multidirectional differentiation ability were compared between the groups. RESULTS: At 9 months after surgery, the HHS and magnetic resonance imaging (MRI) findings improved by varying degrees. Based on the mean repair ratio of (62.2 ± 27.0)%, the threshold for dividing the patients into groups A and B was set to 62.2%. Better repair (group A) was associated with more rapid proliferation and a healthier ultrastructure. The cells in group A showed stronger specific staining signifying osteogenic and chondrogenic differentiation; alkaline phosphatase (ALP) activity, an indicator of osteogenic differentiation, was higher in group A than in group B (OD, 2.39 ± 0.44 and 1.85 ± 0.52; p <  0.05). CONCLUSIONS: The quality of implanted stem cells is closely related to treatment efficacy and determines whether the defective self-repair in the necrotic area can be corrected to enhance repair and thus achieve the desired therapeutic outcome. TRIAL REGISTRATION: The trial registration number: ChiCTR-ORC-17011698 (retrospectively registered at 2017-06-19).

Amino acid sequence motifs essential for P0-mediated suppression of RNA silencing in an isolate of potato leafroll virus from Inner Mongolia.

Polerovirus P0 suppressors of host gene silencing contain a consensus F-box-like motif with Leu/Pro (L/P) requirements for suppressor activity. The Inner Mongolian Potato leafroll virus (PLRV) P0 protein (P0(PL-IM)) has an unusual F-box-like motif that contains a Trp/Gly (W/G) sequence and an additional GW/WG-like motif (G139/W140/G141) that is lacking in other P0 proteins. We used Agrobacterium infiltration-mediated RNA silencing assays to establish that P0(PL-IM) has a strong suppressor activity. Mutagenesis experiments demonstrated that the P0(PL-IM) F-box-like motif encompasses amino acids 76-LPRHLHYECLEWGLLCG THP-95, and that the suppressor activity is abolished by L76A, W87A, or G88A substitution. The suppressor activity is also weakened substantially by mutations within the G139/W140/G141 region and is eliminated by a mutation (F220R) in a C-terminal conserved sequence of P0(PL-IM). As has been observed with other P0 proteins, P0(PL-IM) suppression is correlated with reduced accumulation of the host AGO1-silencing complex protein. However, P0(PL-IM) fails to bind SKP1, which functions in a proteasome pathway that may be involved in AGO1 degradation. These results suggest that P0(PL-IM) may suppress RNA silencing by using an alternative pathway to target AGO1 for degradation. Our results help improve our understanding of the molecular mechanisms involved in PLRV infection.

Influence of Carbonate Solvents on Solid Electrolyte Interphase Composition over Si Electrodes Monitored by In Situ and Ex Situ Spectroscopies.

A solid electrolyte interphase (SEI) layer on Si-based anodes should have high mechanical properties to adapt the volume changes of Si with low thickness and good ionic conductivity. To better understand the influence of carbonate solvents on the SEI composition and mechanism of formation, systematic studies were performed using dimethyl carbonate (DMC) or propylene carbonate (PC) solvent and LiPF6 as a salt. A 1 M LiPF6/EC-DMC was used for comparison. The surface chemical composition of the Si electrode was analyzed at different potentials of lithiation/delithiation and after a few cycles. Ex situ X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results demonstrate that a thinner and more stable SEI layer is formed in LiPF6/DMC. The in situ Fourier transform infrared spectroscopy proves that the coordination between Li+ and DMC is weaker, and fewer DMC molecules take part in the formation of the SEI layer. The higher capacity retention during 60 cycles and less significant morphological modifications of the Si electrode in 1 M LiPF6/DMC compared to other electrolytes were demonstrated, confirming a good and stable interfacial layer. The possible surface reactions are discussed, and the difference in the mechanisms of formation of SEI in these three various electrolytes is proposed.

Multivalent Amide-Hydrogen-Bond Supramolecular Binder Enhances the Cyclic Stability of Silicon-Based Anodes for Lithium-Ion Batteries.

A supramolecular polymer, poly(N-acryloyl glycinamide) (PNAGA), with a bisamide group on each side of the chain forming multiple amide-hydrogen bonds was synthesized in this work as a binder for silicon (Si)-based anodes. This supramolecular polymer binder with improved mechanical properties presents good interfacial adhesion with Si particles forming hydrogen bonds and enhances the adhesive strength between the electrode material film and the copper current collector. Benefiting from the highly stable inter- and intramolecular multiple amide-hydrogen bonds of the PNAGA binder, the electrode structure maintains integrity and a stable solid electrolyte interphase (SEI) layer is formed on the surface of Si particles. The effect of different binders on the composition of the SEI film was also investigated by X-photoelectron spectroscopy (XPS) characterization. In comparison with polyacrylamide (PAM), which has a similar structure to PNAGA, and the traditional sodium alginate (SA) binder, the Si electrode containing the PNAGA binder shows improved electrochemical performance. The capacity retention is 84% after 100 cycles at 420 mA g-1, and the capacity remains at 1942.6 mAh g-1 after 400 cycles at 1260 mA g-1. Even with a mass loading of 1.2 mg cm-2 Si, the electrode with the PNAGA binder exhibits high initial areal capacity (2.64 mAh cm-2) and good cycling performance (81% capacity retention after 50 cycles). Moreover, the application of the PNAGA binder also brings a stable cycle performance to the commercial Si-graphite (SiC) anode material.

A high-performance alginate hydrogel binder for the Si/C anode of a Li-ion battery.

An alginate hydrogel binder is prepared through the cross linking effect of Na alginate with Ca(2+) ions, which leads to a remarkable improvement in the electrochemical performance of the Si/C anode of a Li-ion battery.