Quantitative analysis of the dominant external factors influencing elite speed Skaters' performance using BP neural network.

Introduction: Speed skating, being a popular winter sport, imposes significant demands on elite skaters, necessitating their effective assessment and adaptation to diverse environmental factors to achieve optimal race performance. Objective: The aim of this study was to conduct a thorough analysis of the predominant external factors influencing the performance of elite speed skaters. Methods: A total of 403 races, encompassing various race distances and spanning from the 2013 to the 2022 seasons, were examined for eight high-caliber speed skaters from the Chinese national team. We developed a comprehensive analytical framework utilizing an advanced back-propagation (BP) neural neural network model to assess three key factors on race performance: ice rink altitude, ice surface temperature, and race frequency. Results: Our research indicated that the performance of all skaters improves with higher rink altitudes, particularly in races of 1,000 m and beyond. The ice surface temperature can either enhance or impaire performance and varies in its influences based on skaters' technical characteristics, which had a perceptible or even important influence on races of 1,500 m and beyond, and a negligible influence in the 500 m and 1,000 m races. An increase in race frequency generally contributed to better performance. The influence was relatively minor in the 500 m race, important in the 3,000 m race, and varied among individuals in the 1,000 m and 1,500 m races. Conclusion: The study results offer crucial guidelines for speed skaters and coaches, aiding in the optimization of their training and competition strategies, ultimately leading to improved competitive performance levels.

A New Type of Quantum Fertilizer (Silicon Quantum Dots) Promotes the Growth and Enhances the Antioxidant Defense System in Rice Seedlings by Reprogramming the Nitrogen and Carbon Metabolism.

To promote the growth and yield of crops, it is necessary to develop an effective silicon fertilizer. Herein, a new type of 2 nm silicon quantum dot (SiQD) was developed, and the phenotypic, biochemical, and metabolic responses of rice seedlings treated with SiQDs were investigated. The results indicated that the foliar application of SiQDs could significantly improve the growth of rice seedlings by increasing the uptake of nutrient elements and activating the antioxidative defense system. Furthermore, metabolomics revealed that the supply of SiQDs could significantly up-regulate several antioxidative metabolites (oxalic acid, maleic acid, glycine, lysine, and proline) by reprogramming the nitrogen- and carbon-related biological pathways. The findings provide a new strategy for developing an effective and promising quantum fertilizer in agriculture.

Mining the accident causes of railway dangerous goods transportation: A Logistics-DT-TFP based approach.

Accurately and quickly mining the hidden information in railway dangerous goods transportation (RDGT) accident reports has great significance for its safety management. In this paper, a data mining method Logistics-DT-TFP is proposed for analysing the causes of RDGT accidents. Firstly, analyse the transportation process, extract the cause of the accident, and classify the severity of the accident. Then, using ordered multi-classification Logistic regression for correlation calculation, qualitatively judge and quantitatively analyse the relationship between each cause and the severity of the accident. The feature tags of the Decision Tree (DT) are screened, the C5.0 algorithm is used to obtain the accident coupling rules. Next, the FP-Growth algorithm is used to mine frequent itemsets, and TOP-K is used to improve it and output effective association rules with the degree of lift as the indicator, which avoids repeated traversal of the database, shortens the time complexity, and reduces the impact of the minimum support setting on the calculation results. The degree of lift among the causes in the coupling chain is calculated as a complement to the extraction of coupling rules. Finally, based on the analysis and mining results of case study, the management strategies for railway dangerous goods are proposed.

Water ecological security assessment and spatial autocorrelation analysis of prefectural regions involved in the Yellow River Basin.

To have a more comprehensive understanding of the water ecological security status of the Yellow River Basin, this paper constructs a water ecological security evaluation index system founded on the Pressure-State-Response (PSR) model. The indicators are selected by considering factors such as meteorological conditions, population, economy, water resources, water environment, water ecology, land ecology, ecological service functions, pollution control, and capital investment. Then, the "single index quantification-multiple indices syntheses-poly-criteria integration (SMI-P) method was used to determine the water ecological security index (WESI) of 62 cities in the Yellow River Basin, to classify the safety levels, and combined with the spatial autocorrelation analysis to study the regional characteristics. The results prove that: (a) The overall water ecological security of the Yellow River Basin is relatively poor. Half of the 62 cities have reached the second-level warning level, and most of them are concentrated in the upper and middle reaches of the basin. (b) Wetland area is a long-term key factor in the construction of water ecological safety, and the greening rate of built-up areas has an increasing impact on water ecological safety. (c) The overall water ecological security index shows a slow upward trend, with the annual average growth rate was 0.59%. (d) The water ecological security of 62 cities in the Yellow River Basin shows significant spatial autocorrelation. The findings can offer a practical basis for the water ecological management to promote the high-quality development of the Yellow River Basin.

Complete genome analysis of bacteriophage AsXd-1, a new member of the genus Hk97virus, family Siphoviridae.

AsXd-1, a bacteriophage that infects Aeromonas salmonicida, was isolated from the wastewater of a seafood market in Shenzhen, China. The 39,014-bp genome of this phage contains 52 open reading frames (ORFs), 30 of which were found to be homologous to reference sequences that putatively encode functional phage proteins. Nine out of the remaining 22 ORFs with unknown functions were unique to AsXd-1. Gene annotation suggests that AsXd-1 has both lysogenic and lytic life cycles. Furthermore, both phylogenetic analysis based on the large subunit of terminase and genome sequence comparisons show that AsXd-1 is closely related to phages belonging to the genus Hk97virus. We thus propose AsXd-1 as a new member of the genus Hk97virus within the family Siphoviridae.

Smartphone-based rapid quantification of viable bacteria by single-cell microdroplet turbidity imaging.

Standard plate count (SPC) has been recognized as the golden standard for the quantification of viable bacteria. However, SPC usually takes one to several days to grow individual cells into a visible colony, which greatly hampers its application in rapid bacteria enumeration. Here we present a microdroplet turbidity imaging based digital standard plate count (dSPC) method to overcome this hurdle. Instead of cultivating on agar plates, bacteria are encapsulated in monodisperse microdroplets for single-cell cultivation. Proliferation of the encapsulated bacterial cell produced a detectable change in microdroplet turbidity, which allowed, after just a few bacterial doubling cycles (i.e., a few hours), enumeration of viable bacteria by visible-light imaging. Furthermore, a dSPC platform integrating a power-free droplet generator with smartphone-based turbidity imaging was established. As proof-of-concept demonstrations, a series of Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Bacillus subtilis) samples were quantified via the smartphone dSPC accurately within 6 hours, representing a detection sensitivity of 100 CFU ml-1 and at least 3 times faster. In addition, Enterobacter sakazakii (E. sakazakii) in infant milk powder as a real sample was enumerated within 6 hours, in contrast to the 24 hours needed in traditional SPC. Results with high accuracy and reproducibility were achieved, with no difference in counts found between dSPC and SPC. By enabling label-free, rapid, portable and low-cost enumeration and cultivation of viable bacteria onsite, smartphone dSPC forms the basis for a temporally and geographically trackable network for surveying live microbes globally where every citizen with a cellphone can contribute anytime and anywhere.

[Identifying immunogenic proteins of Erysipelothrix rhusiopathiae C43065 by MALDI-TOF mass spectrometry and cloning their encoding genes].

OBJECTIVE: To identify immunogenic proteins of Erysipelothrix rhusiopathiae C43065. METHODS: Antigens were extracted from E. rhusiopathiae C43065 by the alkaline extraction method. Proteins in the NaOH-extracted antigen were separated by SDS-PAGE and transferred to nitrocellulose membranes, and then Western blotting was performed with rabbit antiserum against the NaOH-extracted antigens. The immunogenic protein bands were identified by MALDI-TOF mass spectrometry. The genes encoding 5 major immunogenic proteins was amplified by PCR from the genomic DNA of E. rhusiopathiae C43065, and inserted into the pMD18-T vector and then sequenced. RESULTS: A total of 9 immunogenic surface proteins in the NaOH-extracted antigen from E. rhusiopathiae C43065 were successfully identified by MALDI-TOF mass spectrometry. Four of the proteins were putative virulence-associated proteins: enolase, ATP-binding cassette transporter, glyceraldehyde-3 -phosphate dehydrogenase and fructose-bisphosphate aldolase class-II. The genes encoding the chaperone protein GroEL, enolase, ATP-binding cassette transporter, glyceraldehyde-3-phosphate dehydrogenase and fructose-bisphosphate aldolase class-II were 1614, 1296, 1260, 1005 and 867 bp in length, and the nucleotide sequences homologies of the genes between the C43065 strain and the previously reported E. rhusiopathiae Fujisawa strain was more than 98%. CONCLUSION: Several putative virulence-associated proteins in the NaOH-extracted antigen of E. rhusiopathiae C43065 will be useful for elucidating the roles of these proteins in the pathogenesis of the organism.

Meglumine cyclic adenylate improves neurological function following acute spinal cord injury in rats.

Elevation of intracellular cyclic adenosine monophosphate (cAMP) levels facilitates recovery following spinal injury by suppressing secondary pathology and promoting axonal regeneration. However, this treatment strategy is limited by lack of effective and tolerable clinical agents. The present study examined the effects of meglumine cyclic adenylate (MCA) on neurological recovery, cAMP concentration, adenylate cyclase 3 (AC3) activity and phosphodiesterase 4D (PDE4D) activity during early stage acute spinal cord injury (SCI) in rats. A total of 48 Sprague­Dawley rats were randomly assigned to groups A, B or C, each consisting of 16 animals. SCI was induced by Allen's method using a 7 g x 3 cm extradural weight­drop impact on spinal cord segment T11. A total of 30 min following SCI, group A received a single 30 mg/kg­bw i.p. dose of methylprednisolone, group B received 2 mg/kg­bw i.p. MCA daily for seven days and group C were administered an equal volume of normal saline. Seven days following SCI, the spinal cord samples from eight rats per group were obtained to measure the cAMP concentration, and the activities of AC3 and PDE4D. The remaining eight rats per group were used for behavioral assessments using the inclined plane stability test and Gale scale for up to six weeks post­SCI. The drug­treated groups A and B had higher cAMP concentrations and AC3 activities but lower PDE4D activities at the lesion sites, as well as superior behavioral scores post­SCI compared with the vehicle­treated group C (P<0.05). Furthermore, cAMP was higher in group B than in group A (P<0.05). It was concluded that MCA may serve as an effective SCI treatment by activating AC3 and suppressing PDE4D.