RESUMEN
In this work, we fabricated vanadium/zinc metal-organic frameworks (V/Zn-MOFs) derived from self-assembled metal organic frameworks, to further disperse ultrasmall Zn2VO4 nanoparticles and encapsulate them in a nitrogen-doped nanocarbon network (ZVO/NC) under in situ pyrolysis. When employed as an anode for lithium-ion batteries, ZVO/NC delivers a high reversible capacity (807 mAh g-1 at 0.5 A g-1) and excellent rate performance (372 mAh g-1 at 8.0 A g-1). Meanwhile, when used in sodium-ion batteries, it exhibits long-term cycling stability (7000 cycles with 145 mAh g-1 at 2.0 A g-1). Additionally, when employed in potassium-ion batteries, it also shows outstanding electrochemical performance with reversible capacities of 264 mAh g-1 at 0.1 A g-1 and 140 mAh g-1 at 0.5 A g-1 for 1000 cycles. The mechanism by which the pseudocapacitive behaviour of ZVO/NC enhances battery performance under a suitable electrolyte was probed, which offers useful enlightenment for the potential development of anodes of alkali-ion batteries. The performance of Zn2VO4 as an anode for SIBs/PIBs was investigated for the first time. This work provides a new horizon in the design ZVO/NC as a promising anode material owing to the intrinsically synergic effects of mixed metal species and the multiple valence states of V.
RESUMEN
In the present work, we introduce a dual carbon accommodated structure in which germanium nanoparticles are encapsulated into an ordered mesoporous carbon matrix (Ge-CMK) and further coated with an amorphous carbon layer (Ge@C-CMK) through a nano-casting route followed by chemical vapor deposition (CVD) treatment. In the resultant Ge@C-CMK composite, the unique lane-like pore structure that cooperates with the amorphous carbon surface can not only mitigate the volume expansion of germanium particles, but also improve the electrical conductivity of germanium as well as facilitate Na+/K+ diffusion. When employed as the anode of sodium-ion batteries, the Ge@C-CMK electrode exhibits stable capacity as well as long-term cycling stability (a stable capacity of 176 mAh g-1 at 1 A g-1 after 5000 cycles). Furthermore, it also delivers a reversible capacity when used as the anode of potassium-ion batteries. This demonstrates that the Ge@C-CMK electrode possesses promising application potential as an alternative anode in sodium and potassium ion storage applications.
RESUMEN
BACKGROUND: Streptococcus and Staphylococcus are the major contagious organisms causing dairy cow mastitis. Our previous studies have demonstrated that solid lipid nanoparticles (SLNs) can effectively enhance the antimicrobial activity of tilmicosin against Staphylococcus. This study aimed to evaluate the antibacterial efficacy of tilmicosin-loaded SLN (Til-SLN) against Streptococcus agalactiae. METHODS: Til-SLN was prepared using a hot homogenization and ultrasonication method as described previously. Til-SLN was labeled with rhodamine B for nanoparticle tracking. In vitro antibacterial experiments were carried out by broth dilution technique. Pharmacokinetics of the drug and distribution of the nanoparticles in mammary gland were studied after subcutaneous injection in Kunming mice. The therapeutic study was conducted in a mouse mastitis model infected with S. agalactiae. RESULTS: The results showed that the diameter, polydispersity index, zeta potential, encapsulation efficiency, and loading capacity of the nanoparticles were not significantly affected by fluorescence labeling. Til-SLN showed a sustained and enhanced antibacterial activity in vitro. Til-SLN maintained a sustained drug concentration above 17 µg/g for at least 6 days in the mammary gland, as compared with only 3 days for the same amount of tilmicosin phosphate solution. The mean residence time and elimination half-life (T1/2) of Til-SLN were much longer than those of tilmicosin phosphate solution. Most of the nanoparticles remained at the injection site and a few were transferred to the mammary glands, indicating that the drug was slowly released at the injection site and then distributed to the mammary glands. SLN significantly enhanced the therapeutic efficacy of tilmicosin as determined by lower colony forming unit counts. CONCLUSION: These results demonstrate that SLN could effectively enhance the antibacterial activity of tilmicosin against Streptococcus.
