Jingjing Wan

Muscle fatigue is a common complaint in clinical practice. In humans, muscle fatigue can be defined as exercise-induced decrease in the ability to produce force. Here, to provide a general understanding and describe potential therapies for muscle fatigue, we summarize studies on muscle fatigue, including topics such as the sequence of events observed during force production, in vivo fatigue-site evaluation techniques, diagnostic markers and non-specific but effective treatments. Muscle fatigue after exercise is only partially understood and more research is needed to uncover its mechanisms and develop treatments. Xia Liu, Yang Sun and colleagues at the Second Military Medical University in Shanghai, reviewed current understanding of muscle fatigue. Published studies cover the sequence of events leading to fatigue, the techniques and biomarkers used for diagnosis and evaluation, and the effectiveness of therapies and supplements. Non-invasive techniques can assess muscle fatigue using electrical or magnetic stimulation of a muscle or other areas of the body that affect the muscle. Changes in nerve cell activity, blood flow and muscle metabolism alter the levels of biochemicals that could potentially be reliable biomarkers of muscle fatigue. The authors also review the claims and evidence for benefits of a wide range of chemical treatments and nutritional supplements.

Assembly of different metal-organic framework (MOF) building blocks into hybrid MOF-on-MOF heterostructures is promising in chemistry and materials science, however the development of ternary MOF-on-MOF heterostructures with controllable architectural and compositional complexity is challenging. Here we report the synthesis of three types of ternary MOF-on-MOF heterostructures via a multiple selective assembly strategy. This strategy relies on the choice of one host MOF with more than one facet that can arrange the growth of a guest MOF, where the arrangement is site-selective without homogenous growth of guest MOF or homogenous coating of guest on host MOF. The growth of guest MOF on a selected site of host MOF in each step provides the opportunity to further vary the combinations of arrangements in multiple steps, leading to ternary MOF-on-MOF heterostructures with tunable complexity. The developed strategy paves the way towards the rational design of intricate and unprecedented MOF-based superstructures for various applications.

Abstract Amorphous metal–organic frameworks ( a MOFs) are an emerging family of attractive materials with great application potential, however a MOFs are usually prepared under harsh conditions and a MOFs with complex compositions and structures are rarely reported. In this work, an a MOF‐dominated nanocomposite ( a MOF‐NC) with both structural and compositional complexity has been synthesized using a facile approach. A ligand‐competition amorphization mechanism is proposed based on experimental and density functional theory calculation results. The a MOF‐NC possesses a core–shell nanorod@nanosheet architecture, including a Fe‐rich Fe‐Co‐ a MOF core and a Co‐rich Fe‐Co‐ a MOF shell in the core–shell structured nanorod, and amorphous Co(OH) 2 nanosheets as the outer layer. Benefiting from the structural and compositional heterogeneity, the a MOF‐NC demonstrates an excellent oxygen evolution reaction activity with a low overpotential of 249 mV at 10.0 mA cm −2 and Tafel slope of 39.5 mV dec −1 .