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As an important part of cooperative control for multiple unmanned aerial vehicles (UAVs), cooperative path planning can get optimal flight path which can satisfy different constraints. Research on cooperative path planning for multiple UAVs is summarized in this paper. Firstly, problem description and constraints are given. Then, solution frameworks and path coordination approaches are summarized. After that, several control methods commonly used in formation of multiple UAVs are introduced respectively. Lastly, possible research directions in the future time are put forward.

BACKGROUND Previous studies had shown endoscopic retrograde appendicitis therapy (ERAT) is an effective treatment for acute appendicitis. However, different studies reported conflicting outcomes regarding the effectiveness of ERAT in comparison with laparoscopic appendectomy (LA). AIM To compare the effectiveness of ERAT with LA. METHODS Randomized controlled trials (RCTs) and retrospective studies of ERAT for acute uncomplicated appendicitis were searched in PubMed, Cochrane Library, Web of Science, Embase database, China National Knowledge Infrastructure (CNKI), the WanFang Database, and Chinese Scientific Journals Database (VIP) from the establishment date to March 1 2021. Heterogeneity was assessed using the I-squared statistic. Pooled odds ratios (OR), weighted mean difference (WMD), and standard mean difference (SMD), with 95% confidence intervals (CI) were calculated through either fixed-effects or random-effects model. Sensitivity analysis was also performed. Publication bias was tested by Egger's test, and Begg’s test. The quality of included RCT were evaluated by the Jadad scale, while Newcastle-Ottawa scale is adopted for assessing the methodological quality of case-control studies. All statistical analysis was performed using Stata 15.1 statistical software. All statistical analysis was performed using Stata 15.1 statistical software. This study is registered with PROSPERO, CRD42021243955. RESULTS After screening, 10 RCTs and 2 case-control studies were included in the current systematic review. Firstly, the length of hospitalizations [WMD = -1.15, 95%CI: -1.99, -0.31; P = 0.007] was shorter than LA group. Secondly, the level of post-operative CRP [WMD = -10.06, 95%CI: (-17.39, -2.73); P = 0.007], TNF-α [WMD = -7.70, 95%CI: (-8.47, -6.93); P < 0.001], and IL-6 Levels [WMD = -9.78, 95%CI: (-10.69, -8.88); P < 0.001; P < 0.001] in ERAT group was significantly lower than LA group. Thirdly, ERAT group had a lower incidence of intestinal obstruction than LA group. [OR = 0.19, 95%CI: (0.05, 0.79); P = 0.020]. Moreover, the quality of 10 RCTs were low with 0-3 Jadad scores, while the methodological quality of two case-control studies were fair with a score of 2 (each). CONCLUSION Compared with LA, ERAT reduces operation time, the level of postoperative inflammation, and results in fewer complications and shorter recovery time, with preserving the appendix and its immune and biological functions.

Anti-ferromagnetic states widely exist on graphene zigzag edges. Our previous work (Xie et al 2018 New J. Phys. 20 013035) shows there are also various spin density wave (SDW) states in the graphene nanoribbons (GNR). In this paper, we propose some excitation mechanism of these SDW by the absorbed magnetic atoms with the mean-field Hubbard model and the first-principles calculations. With the Floquet theory, we also find that by regulating the temperature or the light intensity, there are a lot of phase transitions for these SDW. The temperature or light can dramatically modify the inter-edge coupling or the spin stiffness of GNR. The artificial magnetization technique is employed to explore the establishment process of these SDW states. Some interesting intermedia phase transitions and the corresponding spin orders are discovered. This research may be helpful in the understandings and technique controls of magnetic orders in future nano magnetic devices.

Background Interdisciplinary research is an important feature of precision medicine. However, the accurate cross-disciplinary status of precision medicine is still unclear. Objective The aim of this study is to present the nature of interdisciplinary collaboration in precision medicine based on co-occurrences and social network analysis. Methods A total of 7544 studies about precision medicine, published between 2010 and 2019, were collected from the Web of Science database. We analyzed interdisciplinarity with descriptive statistics, co-occurrence analysis, and social network analysis. An evolutionary graph and strategic diagram were created to clarify the development of streams and trends in disciplinary communities. Results The results indicate that 105 disciplines are involved in precision medicine research and cover a wide range. However, the disciplinary distribution is unbalanced. Current cross-disciplinary collaboration in precision medicine mainly focuses on clinical application and technology-associated disciplines. The characteristics of the disciplinary collaboration network are as follows: (1) disciplinary cooperation in precision medicine is not mature or centralized; (2) the leading disciplines are absent; (3) the pattern of disciplinary cooperation is mostly indirect rather than direct. There are 7 interdisciplinary communities in the precision medicine collaboration network; however, their positions in the network differ. Community 4, with disciplines such as genetics and heredity in the core position, is the most central and cooperative discipline in the interdisciplinary network. This indicates that Community 4 represents a relatively mature direction in interdisciplinary cooperation in precision medicine. Finally, according to the evolution graph, we clearly present the development streams of disciplinary collaborations in precision medicine. We describe the scale and the time frame for development trends and distributions in detail. Importantly, we use evolution graphs to accurately estimate the developmental trend of precision medicine, such as biological big data processing, molecular imaging, and widespread clinical applications. Conclusions This study can help researchers, clinicians, and policymakers comprehensively understand the overall network of interdisciplinary cooperation in precision medicine. More importantly, we quantitatively and precisely present the history of interdisciplinary cooperation and accurately predict the developing trends of interdisciplinary cooperation in precision medicine.