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The high-thrust linear motor used for the electromagnetic launch is switched by switches composed of anti-shunt thyristors. During the switching process, different current path states will appear, which will lead to changes in motor parameters and current fluctuation. Focusing on the air-core synchronous linear motor with parallel and series power supply, this paper analyzes the change in current path caused by the change in the trigger signal of anti-parallel thyristors in the process of sectionalized stator switching. The motor circuit model of the switching process is derived. A new sectionalized stators switching method is proposed to realize the smooth switching of the sectionalized stators linear motor. Finally, the correctness of the analysis and modeling is verified by simulation, and the effectiveness of the sectionalized stators switching method is tested by using the test prototype. [ABSTRACT FROM AUTHOR]

Heparan sulfate (HS) is a complex linear polysaccharide that modulates a wide range of biological functions. Elucidating the structure-function relationship of HS has been challenging. Here we report the generation of an HS-mutant mouse lung endothelial cell library by systematic deletion of HS genes expressed in the cell. We used this library to (1) determine that the strictly defined fine structure of HS, not its overall degree of sulfation, is more important for FGF2-FGFR1 signaling; (2) define the epitope features of commonly used anti-HS phage display antibodies; and (3) delineate the fine inter-regulation networks by which HS genes modify HS and chain length in mammalian cells at a cell-type-specific level. Our mutant-cell library will allow robust and systematic interrogation of the roles and related structures of HS in a cellular context.

Heparan Sulfate (HS) is a cell signaling molecule linked to pathological processes ranging from cancer to viral entry, yet fundamental aspects of its biosynthesis remain incompletely understood. Here, the binding preferences of the uronyl 2-O-sulfotransferase (HS2ST) are examined with variably-sulfated hexasaccharides. Surprisingly, heavily sulfated oligosaccharides formed by later-acting sulfotransferases bind more tightly to HS2ST than those corresponding to its natural substrate or product. Inhibition assays also indicate that the IC50 values correlate simply with degree of oligosaccharide sulfation. Structural analysis predicts a mode of inhibition in which 6-O-sulfate groups located on glucosamine residues present in highly-sulfated oligosaccharides occupy the canonical binding site of the nucleotide cofactor. The unexpected finding that oligosaccharides associated with later stages in HS biosynthesis inhibit HS2ST indicates that the enzyme must be separated temporally and/or spatially from downstream products during biosynthesis in vivo, and highlights a challenge for the enzymatic synthesis of lengthy HS chains in vitro.

Cephalostachyum pingbianense (Hsueh & Y.M. Yang ex Yi et al.) D.Z. Li & H.Q. Yang is unique among bamboo species for its ability to produce bamboo shoots in all seasons under natural conditions. Apart from the physiological mechanism, information regarding the effects of endophytic microorganisms on this full-year shooting characteristic is limited. We hypothesize that root endophytic microorganisms will have a positive impact on the full-year bamboo shooting characteristic of C. pingbianense by increasing the availability or supply of nutrients. To identify the seasonal variations in the root endophytic bacterial and fungal communities of C. pingbianense, and to assess their correlation with bamboo shoot productivity, the roots of C. pingbianense were selected as research materials, and the 16S rRNA and ITS rDNA genes of root endophytic microorganisms were sequenced using the Illumina platform. Following this sequencing, raw sequencing reads were processed, and OTUs were annotated. Alpha and beta diversity, microbial composition, and functional predictions were analyzed, with correlations to bamboo shoot numbers assessed. The results showed that seasonal changes significantly affected the community diversity and structure of root endophytic microbes of C. pingbianense. Bacterial communities in root samples from all seasons contained more nitrogen-fixing microorganisms, with members of the Burkholderiales and Rhizobiales predominating. The relative abundances of ectomycorrhizal and arbuscular mycorrhizal fungi in the autumn sample were significantly higher than in other seasons. Correlation analysis revealed that the bamboo shoot productivity was significantly and positively correlated with bacterial functions of nitrogen fixation, arsenate detoxification, and ureolysis, as well as with symbiotrophic fungi, ectomycorrhizal fungi, and arbuscular mycorrhizal fungi. At the genus level, the bacterial genus Herbaspirillum and the fungal genera Russula, unclassified_f_Acaulosporaceae, and unclassified_f_Glomeraceae were found to have a significant positive correlation with bamboo shoot number. Our study provides an ecological perspective for understanding the highly productive attribute of C. pingbianense and offers new insights into the forest management of woody bamboos. [ABSTRACT FROM AUTHOR]

Soapberry (Sapindus mukorossi Gaertn.) is a tree species of the family Sapindaceae, the pericarp of which is rich in triterpenoid saponins, which are important in chemical production, biomedicine, and other fields. Cytochrome P450 monooxygenase (CYP450) is involved in the modification of the skeletons of triterpenoid saponins and is linked to their diversity. We previously identified 323 CYP450 genes in the transcriptome of soapberry and screened 40 CYP450 genes related to the synthesis of triterpenoid saponins by gene annotation and conserved structural domain analysis. The genetic structure and phylogeny of the CYP450 genes were analyzed separately. Phylogenetic analysis categorized the CYP450 genes of soapberry into five subfamilies, the members of which had similar conserved cumulative sequences and intron structures. A cis-acting element analysis implicated several genes in the responses to environmental changes and hormones. The expression of several genes during eight periods of fruit development was analyzed by real-time quantitative qRT-PCR; most showed high expression during the first four periods of fruit development, and their expression decreased as the fruits matured. A co-expression network analysis of SmCYP450s and related genes in the triterpenoid saponin synthesis pathway was performed. Correlation analysis showed that 40 SmCYP450s may be involved in saponin synthesis in soapberry. The triterpenoid saponin synthesis-related candidate genes identified in this study provide insight into the synthesis and regulation of triterpenoid saponins in soapberry. [ABSTRACT FROM AUTHOR]

Congenital diaphragmatic hernia (CDH) is a common birth malformation with a heterogeneous etiology. In this study, we report that ablation of the heparan sulfate biosynthetic enzyme NDST1 in murine endothelium (Ndst1ECKO mice) disrupted vascular development in the diaphragm, which led to hypoxia as well as subsequent diaphragm hypoplasia and CDH. Intriguingly, the phenotypes displayed in Ndst1ECKO mice resembled the developmental defects observed in slit homolog 3 (Slit3) knockout mice. Furthermore, introduction of a heterozygous mutation in roundabout homolog 4 (Robo4), the gene encoding the cognate receptor of SLIT3, aggravated the defect in vascular development in the diaphragm and CDH. NDST1 deficiency diminished SLIT3, but not ROBO4, binding to endothelial heparan sulfate and attenuated EC migration and in vivo neovascularization normally elicited by SLIT3-ROBO4 signaling. Together, these data suggest that heparan sulfate presentation of SLIT3 to ROBO4 facilitates initiation of this signaling cascade. Thus, our results demonstrate that loss of NDST1 causes defective diaphragm vascular development and CDH and that heparan sulfate facilitates angiogenic SLIT3-ROBO4 signaling during vascular development.

In order to analyze the dynamic response of medium-speed maglev train in the speed range of 0-200km/h, the suspension performance, suspended energy consumption, and riding comfort of the train stimulated by random track irregularities are discussed in this paper. Firstly, the model of medium-speed maglev train including car body, air spring vibration isolation system, and the suspension system is established. Then, a controller based on flux inner feedback loop and PID outer feedback loop is designed for the suspension system. The established model is stimulated by the actual track power spectrum in full speed range. The simulation results show that the fluctuation of suspension gap is less than ±4mm. Furthermore, thanks to the adding of permanent magnet, the power consumption is significantly reduced, which is of benefit to the electromagnet heating problem and on-board levitation power supply system. The riding comfort of the train moving on the irregular track using Sperling index is assessed. The experimental results validate the effectiveness of the proposed analytical calculation model of medium-speed maglev train. It is shown that medium-speed maglev train achieved good performance, significant power reduction, and satisfactory riding comfort., Author(s): Peichang Yu [1]; Mengxiao Song (corresponding author) [1]; Qiang Chen [1]; Lianchun Wang [1]; Guang He [1]; Peng Leng [1] 1. Introduction As a new type of rail transportation, [...]