Axial strain enhances osteotomy repair with a concomitant increase in connexin43 expression

The mechanical environment is known to influence fracture healing. We speculated that connexin43 （Cx43） gap junctions, which impact skeletal homeostasis, fracture healing and the osteogenic response to mechanical load, may play a role in mediating the response of the healing bone to mechanical strain. Here, we used an established rat fracture model, which uses a 2 mm osteotomy gap stabilized by an external fixator, to examine the impact of various cyclical axial loading protocols （2%, 10%, and 30% strain） on osteotomy healing. We examined the presence of Cx43 in the osteotomy-healing environment and assessed how mechanical strain modulates Cx43 expression patterns in the callus. We demonstrated that increased cyclical axial strain results in increased radiographic and histologic bone formation. In addition, we show by immunohistochemistry that Cx43 is abundantly expressed in the healing callus, with the expression most robust in samples exposed to increased cyclical axial strain. These data are consistent with the concept that an increase in Cx43 expression by mechanical load may be part of the mechanisms by which mechanical forces enhances fracture healing.

Upper limb bilateral symmetric training with robotic assistance and clinical outcomes for stroke A pilot study

Purpose–The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training(BST)for stroke survivors affected by hemiparesis.Design/methodology/approach–Other studies have investigated symmetric physiotherapy.A key difficulty in previous work is in maintaining mirror-imaged trajectories between the affected and less-affected limbs.This obstacle was overcome in this work by using a two-armed robotic exoskeleton to enforce symmetry.In total,15 subjects,W6 months post stroke were,randomly assigned to bilateral symmetric robotic training,unilateral robotic training,and standard physical therapy.Findings–After 12 training sessions(90 minutes/session),the bilateral training group had the greatest intensity of movement training.They also had the greatest improvement in range of motion at the shoulder.The unilateral training group showed the greatest reduction in spasticity.Research limitations/implications–The rationale for symmetric physiotherapy is that it might promote connections from the undamaged brain hemisphere.The robot generated copious amounts of detailed kinematic data.Even though these data provided insights into the human to machine interface using different training modalities,it proved difficult to draw neurological conclusions.It is recommended that future research along these lines should include measures of neurophysiological change and/or changes in neurological activity.Practical implications–This research suggests that the advantage of bilateral symmetric movement over other modalities is slight,and that robotic training has comparable results with standard care.If BSTis used,care is potentially needed toavoid exacerbation of spasticity.Finally,this research includes a novel quantitative approach for evaluating robotic training.Originality/value–This study is of value to therapeutic researchers interested in new physiotherapy techniques,roboticists interested in developing rehabilitation devices,or for rehabilitation game designers interested in using virtual reality.

NaF-FeF2 nanocomposite： New type of Na-ion battery cathode material

Na-ion batteries （NIBs） are considered one of the most attractive alternatives for Li-ion batteries （LIBs） because of the natural abundance of Na and the similarities between the NIB technology and the well-established LIB technology. However, the discovery of high-performance electrode materials remains a key factor in the success of NIBs. Herein, we propose a new type of cathode material for NIBs based on a nanocomposite of an alkali metal fluoride （NaF） and a transition metal fluoride （FeF2）. Although neither of these components is electrochemically active with Na, the nanoscale mixture of the two can deliver a reversible capacity of -125 mAh/g in the voltage range of 1.2--4.8 V vs. Na/Na＋ via an Fe2＋/Fe3＋ redox couple. X-ray absorption spectroscopy reveals that the reversible Na storage is aided by the F-ions due to the decomposition of NaF, which are absorbed on the surface of FeF2, promoting the redox reaction of Fe and triggering the gradual transformation of the mother structure （FeF2） into a new （FeFB-like） host structure for the Na ions. This unique Na-ion storage phenomenon, which is reported for the first time, will introduce an avenue for designing novel cathode materials for NIBs.