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In this study, we present a method for generating a synthetic gauge field in origami metamaterials with continuously varying geometrical parameters. By modulating the mass term in the Dirac equation linearly, we create a synthetic gauge field in the vertical direction, which allows for the quantization of Landau levels through the generated pseudomagnetic field. Furthermore, we demonstrate the existence and robustness of the chiral zeroth Landau level. The unique elastic snake state is realized using the coupling between the zeroth and the first Landau levels. Our results, supported by theory and simulations, establish a feasible framework for generating pseudomagnetic fields in origami metamaterials with potential applications in waveguides and cloaking., 6 pages, 4 figures

Origami structures often serve as the building block of mechanical systems due to their rich static and dynamic behaviors. Experimental observation and theoretical modeling of origami dynamics have been reported extensively, whereas the data-driven modeling of origami dynamics is still challenging due to the intrinsic nonlinearity of the system. In this study, we show how the dynamic mode decomposition (DMD) method can be enhanced by integrating geometry information of the origami structure to model origami dynamics in an efficient and accurate manner. In particular, an improved version of DMD with control, that we term geometry-informed dynamic mode decomposition~(giDMD), is developed and evaluated on the origami chain and dual Kresling origami structure to reveal the efficacy and interpretability. We show that giDMD can accurately predict the dynamics of an origami chain across frequencies, where the topological boundary state can be identified by the characteristics of giDMD. Moreover, the periodic intrawell motion can be accurately predicted in the dual origami structure. The type of dynamics in the dual origami structure can also be identified. The model learned by the giDMD also reveals the influential geometrical parameters in the origami dynamics, indicating the interpretability of this method. The accurate prediction of chaotic dynamics remains a challenge for the method. Nevertheless, we expect that the proposed giDMD approach will be helpful towards the prediction and identification of dynamics in complex origami structures, while paving the way to the application to a wider variety of lightweight and deployable structures., 11 pages, 7 figures

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Objective To investigate the value of gap balance technique guided by computer-assisted navigation in total knee replacement. Methods A total of 63 patients with primary knee osteoarthritis and underwent total knee replacement from January to June 2018 were recruited in this study. They were randomly divided into experimental group (n=31, gap balance technique guided by computer-assisted navigation) and control group (n=31, osteotomy technique). The tension of medial and lateral ligaments in the flexion and extension space was recorded, and the limb alignment, incision length, operative time, blood loss volume, drainage volume, incidence of postoperative complications, and visual analogue scale (Vas) score and knee society knee score (KSS) in 1, 6 and 12 months after operation were recorded and compared between 2 groups. Results The operative time in experimental group was significantly longer than that in the control group (P < 0.05), but there were no significant differences in incision length, blood loss, drainage volume and incidence of postoperative complications between 2 groups (P>0.05). The limb alignment was better in the experimental group than the control group [(0.63±0.54)° vs (1.98±0.52)°, P < 0.05]. In 1 month after operation, the experimental group achieved significantly better Vas score (3.53±0.51 vs 4.24±0.49, P < 0.05), but similar KSS score (69.3±5.1 vs 67.5±3.7, P>0.05) when compared with the control group. But, in 6 and 12 months after surgery, no statistic differences were seen in the above 2 scores (P>0.05). For the patients from the experimental group, the tension of medial and lateral ligaments in the flexion and extension space ranged from 70 to 95 N, with an average of 84 N. Conclusion Gap balance technique guided by computer-assisted navigation can improve the accuracy of osteotomy in total knee replacement, with postoperative benefits of significantly reducing pain and rapid recovery during the early postoperative period, but having no obvious effect on outcome after 1 year's follow-up.

Objective To evaluate the effect of mechanical stretching in promoting tendon healing and reducing tendon adhesion during the healing of extensor flexor tendon in rats and its effects on the expression of transforming growth factor-β3 (TGF-β3) and cyclic AMP response element-binding protein (CREB). Methods Eighteen male SD rats were randomized into 3 equal groups and subjected to sham operation, flexor tendon injury of the second to fifth digits of the hind limbs without interventions (model group), or flexor tendon injury with daily passive mechanical stretching of the tendon for 1 week after the operation. The tendon was exposed only without injuries in the sham-operated group. At 1, 2, 4, and 8 weeks after the operation, tendon healing of the rats was evaluated by anatomical observation and histological examination, and the expression of TGF-β1, TGF-β3 and CREB in the tendon was detected using real-time fluorescence quantitative PCR and immunohistochemistry. Results Compared with the model group, the rats in mechanical stretching group showed better tendon healing with reduced tendon adhesion, less granular tissue and more regular cell alignment in the tendon (P < 0.05). During tendon healing, the expression of TGF-β3 and CREB mRNAs in the injured tendon were significantly higher at all the time points and the expression of TGF-β1 mRNA at the first week after the operation was significantly lower in mechanical stretching group than in the model group (P < 0.05); TGF-β1 mRNA expression was comparable between the two groups at all the later time points. Immunohistochemical studies showed significantly stronger TGF-β3 and CREB expression in the injured tendons in the mechanical stretching group after the operation, and TGF-β1 expression began to decrease significantly at 1 week after the operation (P < 0.05). Conclusion Mechanical stretching can promote the healing of the flexor tendon and reduce postoperative tendon adhesion in close relation with increased expression of TGF-β3 and CREB and reduced expression of TGF-β1 in the early stage of tendon healing.

Identifying and protecting refugia is a priority for conservation management under projected anthropogenic climate change. We have two main objectives: the first is to explore the spatial (East Asia) and temporal (Last Glacial Maximum to year 2070) distribution patterns of dominant Castanopsis species of evergreen broad-leaved forests, also the relation with their niche breadths; the second is to identify long-term stable refugia for preserving these species and provide a framework of conservation strategies. We find that there is an extraordinary richness with 32 dominant Castanopsis species, and they form both a geographically and climatically almost unbroken connection from ca. 5°N to 38°N, having thus ecological significance. During the Mid-Holocene and, particularly, the Last Glacial Maximum, the predicted suitable areas of the species as a whole were larger than those in the present. By 2070, potentially suitable areas with high richness of dominant Castanopsis species will be reduced by 94.5 % on average. No correlation between species niche breadths and distribution ranges is found, which could be due to regional climate stability. Mountains of southwestern and southern Yunnan in China are identified as climatically long-term stable refugia for 7¿9 Castanopsis species. We recommend that these refugia have the highest priority of conservation to prevent their extinction. Our suggested urgent measures include improving the effectiveness of currently protected Castanopsis species and expanding the network of protected areas to cover a larger fraction of the refugia, as well as ensuring Castanopsis species natural regeneration potential in fragmented and natural secondary forest areas., This study received financial support from the Major Program for Basic Research Project of Yunnan Province, China (202101BC070002), the Science and Technology Department of Yunnan University, China (2019YNU002), the Ministry of Science and Technology of China (2015FY210200-15), the Spanish Ministry of Science and Innovation (grant PID2020-119163GB-I00 funded by MCIN/AEI/10.13039/501100011033), the Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency of Japan (JPMEERF20202002), and the Northeastern Research Institute of Petrified Wood and Mineral Resources, Nakhon Ratchasima Rajabhat University, Thailand., Keywords 1. Introduction 2. Materials and methods 2.1. Data collection and notations 2.2. Ecological niche modeling 2.3. Data analyses 3. Results 3.1. Dominant Castanopsis species in East Asia today: richness and distribution patterns 3.2. Richness of dominant Castanopsis species shaped by climate change 3.3. Niche groups and niche breadths of dominant Castanopsis species 3.4. Climatically long-term stable refugia 4. Discussion 4.1. Richness of dominant Castanopsis species shaped by climate change 4.2. Niche groups and niche breadths of dominant Castanopsis species 4.3. Long-term stable refugia and conservation strategies 5. Conclusions CRediT authorship contribution statement Declaration of competing interest Acknowledgements Appendix A. Supplementary material References

摘 要 通过分析不同择伐强度下思茅松(Pinus kesiya)天然林乔木种群的生态位、种间联结、种内与种间竞争和群落稳定性, 探讨干扰强度对思茅松天然林乔木种群种间与种内关系的影响。结果表明: (1)择伐干扰改变了大多数乔木树种在群落中的优 势地位, 思茅松优势地位未受影响, 随着择伐干扰强度的增加, 思茅松在群落中的生态位宽度逐渐变大, 在重度干扰的群落 中与红木荷(Schima wallichii)一起成为生态幅度最大的树种。(2)通过种间联结与生态位重叠分析发现, 随着干扰强度的加剧, 乔木种群的种间关系发生变化, 中度干扰群落中物种之间的生态位重叠明显高于未干扰和重度干扰群落, 而在三类群落中, 思茅松与其他种群之间的重叠值较小。随着干扰强度增加, 种群间正联结与负联结的种对所占的比例逐渐增加。(3) Hegyi竞 争指数表明, 三类群落中思茅松种群的竞争压力主要来自种间, 而干扰强度进一步增加了思茅松种群的种间竞争强度, 其种 内平均竞争指数随着对象木胸径的增加而减少。(4)林窗是思茅松种群种间和种内关系变化的主要原因, 三类群落都处于较不 稳定的阶段, 但中度干扰群落的物种丰富度与稳定性都高于未干扰和重度干扰的群落。择伐原则依据森林管理的目的而确定

Seedling,made up of small individuals of woody plant species in the understorey,is an important component of many forests and considered as an important source for natural restoration in forest ecosystems.Simultaneously seedling plays an important role in the regeneration of numerous tree species.Based on space-for-time substitution method,we treated coniferous and broad-leaved mixed forest,secondary monsoon evergreen broad-leaved forest(MEBF),primary MEBF in the same area as three different stages of secondary succession of MEBF.Eight sampling plots representing the three different stages distribute in Caiyanghe nature reserve,surrounding the areas of Meizihu and Xinfang reservoir of Puer,in Yunnan Province,the southwest of China.We investigated seedling regeneration characteristics of woody plants of MEBF during secondary succession by looking at species composition,density,height level and the relationship with environmental factors.Overall,we found 2014 individuals of woody seedlings belonging to 101 species(dominated by understory tree species) in the eight plots covering 144-m2 area.The species richness of tree seedling,shrub seedling and liana seedling were 50,29 and 22 respectively,and their corresponding individuals were 1499,299 and 216.Tree seedling was the main component of woody plant seedling,such as Castanopsis echidnocarpa.Pinus kesiya var.langbianensis are dominant species in coniferous and broad-leaved mixed forest,however,their seedlings rarely appeared in the understory.The pine seedling stages need more light than shade-tolerant species which can conserve seedling bank in understory and waited for appropriate chance to regeneration.The woody plant seedling density of coniferous and broad-leaved mixed forest,secondary and mature MEBF was 183±5.69,240±20.31 and 372.5±4.5 individuals per 18m2.As succession progresses,the density of total woody seedlings,tree seedlings and liana seedlings all increased,while the density of shrub seedlings did not change significantly.Celastrus virens as a liana was particularly conspicuous in mature MEBF.Species richness of liana seedlings tended to increase,while species richness of tree seedlings and shrub seedlings remained relatively stable along the succession gradient.The Shannon-Wiener index of woody seedlings was significantly lower in primary MEBF than those in mixed forest and secondary MEBF.The abundance of woody seedlings in secondary and primary MEBF decreased with the increase of height level,while in mixed forest,the abundance of woody seedlings form a unimodal pattern with peak at 20 cm.Species richness,however,showed consistent(increasing or decreasing) pattern with the increase of height level in all these forest types.Distribution of woody seedlings abundance concentrated in 0—20 cm in the three community types.Woody seedlings species richness of mature MEBF was significantly lower than coniferous and broad-leaved mixed forest when height level was at Ⅰand Ⅱ.Srensen index indicated a close link between tree and liana seedlings and the species composition of the community.Moreover,tree seedling density distribution was significantly negatively correlated with the slope of the plot,while shrub seedling density was significantly positively related to soil pH.