Ti and Mg codoped Li 3 V 2À2x Ti x Mg x (PO 4 ) 3 (x = 0, 0.05, 0.10, 0.20, and 0.25) samples were prepared by a solÀgel method. The effects of Ti and Mg codoping on the physical and electrochemical characteristics of Li 3 V 2 (PO 4 ) 3 were investigated. Compared with the XRD pattern of the undoped sample, those of the Ti and Mg codoped samples have no extra reflections, which indicates that Ti and Mg enter the structure of Li 3 V 2 (PO 4 ) 3 . According to the results of chargeÀdischarge measurements, the initial capacity of Li 3 V 2À2x Ti x Mg x (PO 4 ) 3 at a low current density (0.2 C) decreases with increasing x. However, the discharge capacities at higher current densities (1 and 2 C) and the cycling stability are improved by a low amount of Ti and Mg codoping (x = 0.05), and moreover, EIS measurements indicate the lower charge transfer resistance of Li 3 V 1.9 Ti 0.05 Mg 0.05 (PO 4 ) 3 . The improved electrochemical performance of Li 3 V 1.9 Ti 0.05 Mg 0.05 (PO 4 ) 3 can be attributed to its higher structural stability and smaller particle size. When x is higher than 0.05, the charge transfer resistance increases with increasing x, which leads to their poor electrochemical performance.

No abstract

No abstract

Near‐infrared (NIR) activatable upconversion nanoparticles (UCNPs) enable wireless‐based phototherapies by converting deep‐tissue‐penetrating NIR to visible light. UCNPs are therefore ideal as wireless transducers for photodynamic therapy (PDT) of deep‐sited tumors. However, the retention of unsequestered UCNPs in tissue with minimal options for removal limits their clinical translation. To address this shortcoming, biocompatible UCNPs implants are developed to deliver upconversion photonic properties in a flexible, optical guide design. To enhance its translatability, the UCNPs implant is constructed with an FDA‐approved poly(ethylene glycol) diacrylate (PEGDA) core clad with fluorinated ethylene propylene (FEP). The emission spectrum of the UCNPs implant can be tuned to overlap with the absorption spectra of the clinically relevant photosensitizer, 5‐aminolevulinic acid (5‐ALA). The UCNPs implant can wirelessly transmit upconverted visible light till 8 cm in length and in a bendable manner even when implanted underneath the skin or scalp. With this system, it is demonstrated that NIR‐based chronic PDT is achievable in an untethered and noninvasive manner in a mouse xenograft glioblastoma multiforme (GBM) model. It is postulated that such encapsulated UCNPs implants represent a translational shift for wireless deep‐tissue phototherapy by enabling sequestration of UCNPs without compromising wireless deep‐tissue light delivery.

Various asymmetric microporous poly(vinylidene fluoride) (PVDF) hollow fiber membranes with different pore sizes and effective porosities were prepared by the phase inversion method using dimethylacetamide (DMAc) as solvent and LiCl and water as additives. The membranes were characterized using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) for its microstructure and surface pore size. A gas permeation method was also applied for determining and comparing the effective surface porosity and mean pore size of the different membranes. Moreover, the contact angle with water, critical entry pressure (CEP) of water and collapsing pressure of the PVDF hollow fibers were also determined. Five membrane modules were prepared using the spun hollow fibers and applied in removing 1,1,1-trichloroethane (TCA) from its aqueous solution by vacuum membrane distillation (VMD) process. The effects of dope composition and spinning conditions on hollow fiber morphology and TCA separation by VMD process are examined. Post-treating of the spun fibers by solvent exchange using ethanol produced membranes exhibiting higher porosity and higher permeability. A highly porous hollow fiber membrane with a smaller mean pore size can achieve both high TCA permeation flux and high separation factor.

Two water-soluble chitosan derivatives, O-carboxymethyl chitosan (O-CM-chitosan) and N-[(2-hydroxy-3-N,N-dimethylhexadecyl ammonium)propyl] chitosan chloride (N-CQ-chitosan), were prepared, and the therapeutic effects of chitosan, O-CM-chitosan, and N-CQ-chitosan on insulin resistance were simultaneously evaluated by rats fed on a high-fat diet. The parameters of high-fat diet-induced rats indicated that chitosan and its two derivatives not only have low cytotoxicity but can control overnutrition by fat and achieve insulin resistance therapy. However, the results in experiment in vivo showed that the therapeutic degree varied by the molecular weight and surface charge of chitosan, O-CM-chitosan, and N-CQ-chitosan. N-CQ-chitosan with a MW of 5 × 10(4) decreased body weight, the ratio of fat to body weight, triglyceride, fasting plasma glucose, fasting plasma insulin, free fatty acid, and leptin by 11, 17, 44, 46, 44, 87, and 64% and increased fecal lipid by 95%, respectively.

With the rapid development of portable and wearable electronic devices, self-supporting flexible supercapacitors have attracted much attention, and higher requirements have been put forward for the electrode of the device, that is, it is necessary to have good mechanical properties while satisfying excellent electrochemical performance. In this work, a facile method was invented to obtain excellent self-supported flexible electrode materials with high mechanical properties and outstanding electrochemical performance by combining cellulose nanofibrils (CNFs) and reduced graphene oxide (RGO). We focused on the effect of the ratio of the addition of CNFs and the formation process of the film on the electrochemical and mechanical properties. The results show that the CNFs/RGO12 (where the ratio of CNFs to GO is 1:2) film displayed outstanding comprehensive properties; its tensile strength and conductivity were up to 83 MPa and 202.94 S/m, respectively, and its CA value was as high as 146 mF cm−2 under the current density of 5 mA cm−2. Furthermore, the initial retention rate of the specific capacitance was about 83.7% when recycled 2000 times; moreover, its capacitance did not change much after perpendicular bending 200 times. Therefore, the films prepared by this study have great potential in the field of flexible supercapacitors.

No abstract