Chronic diabetic wounds are one of the main complications of diabetes, manifested by persistent inflammation, decreased epithelialization motility, and impaired wound healing. This will not only lead to the repeated hospitalization of patients, but also bear expensive hospitalization costs. In severe cases, it can lead to amputation, sepsis or death. Electrospun nanofibers membranes have the characteristics of high porosity, high specific surface area, and easy functionalization of structure, so they can be used as a safe and effective platform in the treatment of diabetic wounds and have great application potential. This article briefly reviewed the pathogenesis of chronic diabetic wounds and the types of dressings commonly used, and then reviewed the development of electrospinning technology in recent years and the advantages of electrospun nanofibers in the treatment of diabetic wounds. Finally, the reports of different types of nanofiber dressings on diabetic wounds are summarized, and the method of using multi-drug combination therapy in diabetic wounds is emphasized, which provides new ideas for the effective treatment of diabetic wounds.

Reestablishment of the structural and functional microvasculature would be beneficial to promote healing of diabetic wounds. We explored the role of insulin application on microvascular maturation of diabetic wounds to determine whether it is associated with insulin-induced wound healing. We adopted the multiple injections of streptozotocin (STZ) to establish a diabetic animal model. The effect of insulin on microvessel formation, especially the effect of insulin on microvascular maturation was observed by transmission electron microscopy and laser scanning confocal microscopy. The pivotal protein regulated by insulin during healing processes was explored by tropical application neutralizing antibodies to these proteins; the specific protein was further confirmed using immunoblotting. On days 7 and 11, the blood vessel in insulin-treated wounds was surrounded by more α-smooth muscle actin (α-SMA) expressing cells. The blockage of angiopoietin-1 (Ang-1), but not angiopoietin-2 (Ang-2) or platelet-derived growth factor-B (PDGF-B), resulted in reduced maturation of newly formed blood vessels despite the presence of insulin in vivo. Further analysis showed that insulin induced an increased expression of Ang-1. The blood vessels in insulin-treated wounds showing advanced coverage of pericytes and reconstruction of new vascular basement membrane suggest that insulin is a potent accelerator of microvascular maturation, which may be involved in the mechanisms of insulin-induced wound healing.

With the development of technology and the decreasing of manufacturing costs, unmanned aerial vehicle (UAV) is considered to be one of the most effective relay to expand the communication coverage and improve the performance of cellular networks. However, the communication system of UAV is very susceptible to Global Positioning System (GPS) spoofing, causing it to deviate from the original trajectory and perform abnormal behavior. To address this issue, the abnormal behavior detection scheme of UAV using Recurrent Neural Networks (RNNs) is proposed in this paper. Specifically, the reliable normal behavior models for two different scenarios are established by applying RNNs to avoid the confusion of slight offset and abnormal behavior, so as to improve the accuracy of proposed detection scheme of UAV. Besides, in order to ensure the accuracy of training samples of RNNs, Direction of Arrival (DOA) estimation algorithm is used to obtain a large number of current 2D arrival angle of UAV. Moreover, an appropriate threshold is selected through amounts of experiments to measure the Normalized Root Mean Square Error (NRMSE) between the real position and the position provided by normal behavior models, thus detecting the abnormal behavior of UAV. Experimental results reveal that the proposed abnormal behavior detection scheme is of high accuracy. INDEX TERMS UAV, abnormal behavior detection scheme, RNNs, GPS spoofing. I. INTRODUCTION Facing with the rapidly growing demand for high transmission rate and high communication coverage for wireless communication services, unmanned aerial vehicle (UAV) communication has recently become an active research area [1]. Since UAV can be deployed quickly in the air because of the specific maneuverability, it can not only provide the wireless service for some hotspots, but also offer signals to regional users instead of base station (BS) when terrestrial BS fails [2]. In addition, the flexible location of UAV can supply additional performance compared with fixed infrastructure based communications. Therefore, UAV is widely used as a communication relay to extend the communication range, thereby improving the performance of cellular network and satellite communication system [3]. However, these advantages of UAV also suffer from some challenges. UAV needs a reliable navigation system during the air communication, and the most common method to The associate editor coordinating the review of this article and approving it for publication was Shui Yu.