Revealing the relative importance among plant species, slope positions, and soil types on rhizosphere microbial communities in northern tropical karst and non-karst seasonal rainforests of China

Rhizosphere microbes have an extremely close relationship with plants and the study on the relationship between rhizosphere microorganisms and their influencing factors is conducive to the protection of vegetation and the maintenance of biodiversity. Here we investigated how plant species, slope positions and soil types affect the rhizosphere microbial community. Slope positions and soil types were collected from northern tropical karst and non-karst seasonal rainforests. The results indicated that soil types played a predominant role in the development of rhizosphere microbial communities (28.3% of separate contribution rate), more than plant species identity (10.9% of separate contribution rate) and slope position (3.5% of separate contribution rate). Notably, environmental factors closely related to soil properties were the major influence factors that controlling the rhizosphere bacterial community structure in the northern tropical seasonal rainforest, especially pH. Additionally, plant species also influenced the rhizosphere bacterial community. In low nitrogen content soil environments, rhizosphere biomarkers of dominant plant species were often nitrogen-fixing strains. It suggested that plants might have a selective adaptation mechanism to rhizosphere microorganisms to obtain the advantages of nutrient supply. Overall, soil types exerted the biggest influence on rhizosphere microbial community structure, followed by plant species and finally slope positions

Research on middle beam pin shaft node of hydraulic support test bench based on AHP-Fuzzy analysis model

In order to improve the situation of discontinuity in the range of stresses caused by pin deformation, the mathematical theoretical model of peak contact stresses after pin node deformation in the test rig was established based on the Hertzian contact theory, and the pin node model was simulated and analysed using ANSYS software and compared with the theoretical model. The results show that the simulation results are in good agreement with the theoretical data. Combined with the actual engineering field application, five main indicators for reducing the peak stress in the contact area of the pin node hole wall were determined, namely: shaft hole gap, shaft casing thickness, node plate thickness, chamfer length, chamfer angle, and the use of Minitab software to establish the main effect cloud diagram for the three evaluation indicators: stress, tangential stress and strain; establish the affiliation function of the three evaluation indicators according to the fuzzy mathematical theory, and use the hierarchical Analysis of Hierarchy (AHP) was used to determine the weight vector of the evaluation indexes, and the optimal combination of parameters for the five main indexes was obtained by combining fuzzy comprehensive evaluation and the principle of maximum subordination, and the combination of parameters was simulated. The results show that the optimized pin node column peak stress reduction ratio is 58.77%, and the peak stress reduction ratio of the trunnion node is 12%. The optimal combination of solution parameters was applied in the field in the design and development of the 50 MN hydraulic support test stand, which verified the reasonableness of the optimised parameters and effectively improved the service life of the centre beam pin during the loading test of the hydraulic support test stand. It was further demonstrated that by adding slope chamfers to the pin nodes, setting reasonable initial clearances and plate thicknesses, the peak pin node loads could be reduced to a large extent and the length of the stress range improved, providing a reference for the practical engineering application of the design of plug-in and plug-out positioning pin assemblies for heavy equipment

Investigation of glucose-modified liposomes using polyethylene glycols with different chain lengths as the linkers for brain targeting

Background: An intimidating challenge to transporting drugs into the brain parenchyma is the presence of the blood-brain barrier (BBB). Glucose is an essential nutritional substance for brain function sustenance, which cannot be synthesized by the brain. Its transport primarily depends on the glucose transporters on the brain capillary endothelial cells. In this paper, the brain-targeted properties of glucose-modified liposomes using polyethylene glycols with different chain lengths as the linkers were compared and evaluated to establish an optimized drug-delivery system. Methods: Coumarin 6-loaded liposomes (GLU200-LIP, GLU400-LIP, GLU1000-LIP, and GLU2000-LIP) composed of phospholipids and glucose-derived cholesterols were prepared by thin-film dispersion-ultrasound method. The BBB model in vitro was developed to evaluate the transendothelial ability of the different liposomes crossing the BBB. The biodistribution of liposomes in the mice brains was identified by in vivo and ex vivo nearinfrared fluorescence imaging and confocal laser scanning microscopy and further analyzed quantitatively by high-performance liquid chromatography. Results: Glucose-derived cholesterols were synthesized and identified, and coumarin 6-loaded liposomes were prepared successfully. The particle sizes of the four types of glucose-modified liposomes were around or smaller than 100 nm with a polydispersity index less than 0.300. GLU400-LIP, GLU1000-LIP, and GLU2000-LIP achieved higher cumulative cleared volumes on BBB model in vitro after 6 hours compared with GLU200-LIP (P < 0.05) and were significantly higher than that of the conventional liposome (P < 0.001). The qualitative and quantitative biodistribution results in the mice showed that the accumulation of GLU1000-LIP in the brain was the highest among all the groups (P < 0.01 versus LIP). Conclusion: The data indicated that GLU400-LIP, GLU1000-LIP, and GLU2000-LIP all possess the potential of brain targeting, among which GLU1000-LIP, as a promising drug-delivery system, exhibited the strongest brain delivery capacity.Nanoscience & NanotechnologyPharmacology & PharmacySCI(E)0ARTICLE163-175

Extensive and drastically different alpine lake changes on Asia's high plateaus during the past four decades

Asia's high plateaus are sensitive to climate change and have been experiencing rapid warming over the past few decades. We found 99 new lakes and extensive lake expansion on the Tibetan Plateau during the last four decades, 1970–2013, due to increased precipitation and cryospheric contributions to its water balance. This contrasts with disappearing lakes and drastic shrinkage of lake areas on the adjacent Mongolian Plateau: 208 lakes disappeared, and 75% of the remaining lakes have shrunk. We detected a statistically significant coincidental timing of lake area changes in both plateaus, associated with the climate regime shift that occurred during 1997/1998. This distinct change in 1997/1998 is thought to be driven by large-scale atmospheric circulation changes in response to climate warming. Our findings reveal that these two adjacent plateaus have been changing in opposite directions in response to climate change. These findings shed light on the complex role of the regional climate and water cycles and provide useful information for ecological and water resource planning in these fragile landscapes.Publisher PDFPeer reviewe

Direct and indirect effects of climate on richness drive the latitudinal diversity gradient in forest trees

Data accessibility statement: Full census data are available upon reasonable request from the ForestGEO data portal, http://ctfs.si.edu/datarequest/ We thank Margie Mayfield, three anonymous reviewers and Jacob Weiner for constructive comments on the manuscript. This study was financially supported by the National Key R&D Program of China (2017YFC0506100), the National Natural Science Foundation of China (31622014 and 31570426), and the Fundamental Research Funds for the Central Universities (17lgzd24) to CC. XW was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB3103). DS was supported by the Czech Science Foundation (grant no. 16-26369S). Yves Rosseel provided us valuable suggestions on using the lavaan package conducting SEM analyses. Funding and citation information for each forest plot is available in the Supplementary Information Text 1.Peer reviewedPostprin

Generalizations of colorability and connectivity of graphs

Let G = (V, E) be a graph and A a non-trivial Abelian group, and let F( G, A) denote the set of all functions f : E (G) → A. Denote by D an orientation of E( G). Then G is A-colorable if and only if for every f ∈ F(G, A) there exists an A-coloring c: V( G) → A such that for every e = (x, y) ∈ E(G) (assumed to be directed from x to y), c( x)--c(y) ≠ f(e). We define the group chromatic number of c1 (G) to be the minimum number m for which G is A-colorable for any Abelian group A of order ≥ m under the orientation D. Chapters 2 and 3 are mainly concerned with group chromatic number and some results are given.;The edge-integrity of a graph G is defined by minS⊆E GS +mG-S , where mG-S denotes the maximum order of a component of G-S . Let I\u27(G) denote the edge-integrity of a graph G. We define a graph G to be I\u27-maximal if for every edge e in G, the complement of graph G, I\u27( G + e) \u3e I\u27( G). In chapter 4, some results of I\u27 -maximal graphs are established, the girth of a connected I\u27-maximal graph is given and lower and upper bounds on the size of I\u27-maximal connected graphs with given order and edge-integrity are investigated. Also, the I\u27-maximal trees and unicyclic graphs are completely characterized.;For any given edges e1, e 2 in E(G), a spanning trail of G with e1 as the first edge and e2 as the last edge is called a spanning (e 1, e2)-trail. In chapter 5, we consider best possible degree conditions to assure the existence of these trails for every pair of edges e1, e 2 in a 3-edge-connected graph G

Visual SLAM Mapping Based on YOLOv5 in Dynamic Scenes

When building a map of a dynamic environment, simultaneous localization and mapping systems have problems such as poor robustness and inaccurate pose estimation. This paper proposes a new mapping method based on the ORB-SLAM2 algorithm combined with the YOLOv5 network. First, the YOLOv5 network of the tracing thread is used to detect dynamic objects of each frame, and to get keyframes with detection of dynamic information. Second, the dynamic objects of each image frame are detected using the YOLOv5 network, and the detected dynamic points are rejected. Finally, the global map is constructed using the keyframes after eliminating the highly dynamic objects. The test results using the TUM dataset show that when the map is constructed in a dynamic environment, compared with the ORB-SLAM2 algorithm, the absolute trajectory error of our algorithm is reduced by 97.8%, and the relative positional error is reduced by 59.7%. The average time consumed to track each image frame is improved by 94.7% compared to DynaSLAM. In terms of algorithmic real-time performance, this paper’s algorithm is significantly better than the comparable dynamic SLAM map-building algorithm DynaSLAM

An Opposition-Based Group Search Optimizer with Diversity Guidance

Group search optimizer (GSO) which is an effective evolutionary algorithm has been successfully applied in many applications. However, the purely stochastic resampling or selection mechanism in GSO leads to long computing time and premature convergence. In this paper, we propose a diversity-guided group search optimizer (DGSO) with opposition-based learning (OBL) to overcome these limitations. Opposition-based learning is utilized to accelerate the convergence rate of GSO, while the diversity guidance (DG) is used to increase the diversity of population. When compared with the standard GSO, a novel operator using OBL and DG is developed for the population initialization as well as the generation jumping. A comprehensive set of 19 complex benchmark functions is used for experiment verification and is compared to the original GSO algorithm. Numerical experiments show that the proposed DGSO leads to better performance in comparison with the standard GSO in the convergence rate and the solution accuracy