Metagenomic insights into the response of soil microbial communities to pathogenic Ralstonia solanacearum

Understanding the response of soil microbial communities to pathogenic Ralstonia solanacearum is crucial for preventing bacterial wilt outbreaks. In this study, we investigated the soil physicochemical and microbial community to assess their impact on the pathogenic R.solanacearum through metagenomics. Our results revealed that certain archaeal taxa were the main contributors influencing the health of plants. Additionally, the presence of the pathogen showed a strong negative correlation with soil phosphorus levels, while soil phosphorus was significantly correlated with bacterial and archaeal communities. We found that the network of microbial interactions in healthy plant rhizosphere soils was more complex compared to diseased soils. The diseased soil network had more linkages, particularly related to the pathogen occurrence. Within the network, the family Comamonadaceae, specifically Ramlibacter_tataouinensis, was enriched in healthy samples and showed a significantly negative correlation with the pathogen. In terms of archaea, Halorubrum, Halorussus_halophilus (family: Halobacteriaceae), and Natronomonas_pharaonis (family: Haloarculaceae) were enriched in healthy plant rhizosphere soils and showed negative correlations with R.solanacearum. These findings suggested that the presence of these archaea may potentially reduce the occurrence of bacterial wilt disease. On the other hand, Halostagnicola_larseniia and Haloterrigena_sp._BND6 (family: Natrialbaceae) had higher relative abundance in diseased plants and exhibited significantly positive correlations with R.solanacearum, indicating their potential contribution to the pathogen’s occurrence. Moreover, we explored the possibility of functional gene sharing among the correlating bacterial pairs within the Molecular Ecological Network. Our analysis revealed 468 entries of horizontal gene transfer (HGT) events, emphasizing the significance of HGT in shaping the adaptive traits of plant-associated bacteria, particularly in relation to host colonization and pathogenicity. Overall, this work revealed key factors, patterns and response mechanisms underlying the rhizosphere soil microbial populations. The findings offer valuable guidance for effectively controlling soil-borne bacterial diseases and developing sustainable agriculture practices

100 essential questions for the future of agriculture

Publication history: Accepted - 8 March 2023; Published online - 11 April 2023.The world is at a crossroad when it comes to agriculture. The global population is growing, and the demand for food is increasing, putting a strain on our agricultural resources and practices. To address this challenge, innovative, sustainable, and inclusive approaches to agriculture are urgently required. In this paper, we launched a call for Essential Questions for the Future of Agriculture and identified a priority list of 100 questions. We focus on 10 primary themes: transforming agri-food systems, enhancing resilience of agriculture to climate change, mitigating climate change through agriculture, exploring resources and technologies for breeding, advancing cultivation methods, sustaining healthy agroecosystems, enabling smart and controlled-environment agriculture for food security, promoting health and nutrition-driven agriculture, exploring economic opportunities and addressing social challenges, and integrating one health and modern agriculture. We emphasise the critical importance of interdisciplinary and multidisciplinary research that integrates both basic and applied sciences and bridges the gaps among various stakeholders for achieving sustainable agriculture. Key points Growing demand and resource limitations pose a critical challenge for agriculture, necessitating innovative and sustainable approaches. The paper identifies 100 priority questions for the future of agriculture, indicating current and future research directions. Sustainable agriculture depends on interdisciplinary and multidisciplinary research that harmonises basic and applied sciences and fosters collaboration among different stakeholders

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Study on the high-efficiency sympathetic cooling of mixed ion system with a large mass-to-charge ratio difference in a dual radio-frequency field by numerical simulations

This study proposes a method to achieve stable confinement and efficient sympathetic cooling of a mixed ion system in dual radiofrequency (RF) traps by numerical simulations. The dynamic coupling behavior, sympathetic cooling mechanism, and efficiency-affecting factors of the dual RF ion trap system were quantitatively analyzed by molecular dynamics simulations, yielding the stable confinement conditions of three-dimensional (3D) cold ion system in dual RF confinement fields and the characteristics of 3D correlation coupling between intrinsic micromotion and secular motion. The transient processes of ion intrinsic micromotion were also investigated. Herein, a reasonable second trapping potential contributed to the efficient cooling of the ion system and suppression of its micromotion. The effects of the dual RF trapping field strength on the spatial configuration and the dynamic coupling process of sympathetic cooling were investigated in mixed 3D ion crystals with a large mass-to-charge ratio (M/Q) difference, which reveals that simultaneous stable trapping and matching dynamic modes are the key to achieving efficient sympathetic cooling in the two-component ion system. These results are applicable to studies such as quantum logic manipulation, antimatter synthesis, dark ion detection, regulation of ultracold chemical reaction processes, and precision spectral measurements based on sympathetic cooling

Benefits of Nano-Powder Transformer Core

Transformers are important for modern society. Without transformers, using electric power is impossible; however, most mid- and small-sized transformers have poor efficiency. These range anywhere between 50-75% efficiency, depending on the total power and magnetic core materials used. The lack of output stems mainly from an energy loss called the eddy current loss. Reducing the eddy current loss, by increasing the permeability of core materials and reducing their electrical resistance, are two major goals for many researchers in this area. A common way to reduce the eddy current loss is to make a laminated core with insulator film surface of each laminated sheet. The laminated sheet reduces the eddy current loss a great deal, but there is still some considerable ohm heat loss. Another idea being explored is the use of nano particles to build the core. This method was utilized here with the awareness that, first, nano-powder core materials cannot be easily made, and, second, coating these particles with some form of insulated materials is not simple, either. In this project, two different sub-nano materials were used to make the core. One was Iron oxide (Fe3O4), and the other one was pure iron. Neither are classified as nano particles but come very close, and were therefore an appropriate substitution in lieu of other nano particles. A transformer core was successfully made from Iron oxide, and the performance of the transformer was tested. A simple test core of pure ion powder was also made and tested. The iron oxide purchased and used here did not give the results predicted, due to its permeability being too low. For the pure iron powder, insulation coating on particles was not good enough, so the eddy current loss was higher than we hoped. Essentially, the project was not successful with the materials we had at hand. We learned that the process of successfully coating nano or sub-nano powder itself is a research topic worth pursuing. Furthermore, finding a way to determine the core material’s magnetic permeability may greatly reduce limiting factors in the development of nano and sub-nano powder cores in the future

Comparative Analysis of Macro/Microstructures and Constituents of Sorghum and Reed Straw

Node-containing straws exhibit superior mechanical properties compared to node-free straw plants, particularly in terms of shear resistance and compression resistance. We explore the relationship between the structure and mechanical properties of straw materials, providing deeper insights for the field of biomechanics. In this study, we focused on two node-containing straw plants, namely sorghum and reed. The main characteristics of sorghum and reed stalks were compared using macroscopic observation, stereomicroscopy, scanning electron microscopy, infrared spectroscopy, and EDS analysis. This study revealed numerous similarities and differences in the macro- and microstructures as well as the elemental composition of sorghum and reed stalks. The functional groups in sorghum and reed stalks were largely similar, with the primary elements being C and O. Distinguishing features included a higher tapering and a slightly larger reduction in wall thickness in sorghum stalks compared to reed stalks. The cross-section of sorghum stalks was filled with pith structures, while reed stalks exhibited a hollow structure. The vascular bundles in sorghum typically showed a paired arrangement, whereas those in reeds were arranged in odd numbers. Furthermore, sorghum straws contained more Cl and no Br, while the parenchyma of reed straws contained higher Br. The C and O proportions of sorghum straws and reed straws are 50–53% (50–51%) and 45–46% (48–49%), respectively. These variations in elemental composition are believed to be correlated with the mechanical properties of the materials. By conducting a detailed study of the micro/macrostructures and material composition of sorghum and reed straw, this paper provides valuable insights for the field of biomechanics

A new optical frequency transfer method via fibre based on active phase noise compensation with single acousto-optic modulator

In this paper, we propose and experimentally demonstrate a new method for optical frequency transfer over fibre. Instead of dual acousto-optic modulators (AOMs) as adopted in the traditional fibre phase noise compensation setup, here an active fibre phase noise compensation scheme with a single acousto-optic modulator (AOM) is used. The configuration simplifies the equipment of the user end while maintaining a high-performance optical frequency transfer stability. We demonstrate an actively stabilized coherent transfer at an optical frequency of 193.55THz over 10-km spooled fibre, obtaining a relative frequency stability (Allan deviation) of 3.84 x 10-16/1 s and 4.08 x 10-18/104 s, which is improved by about 2~3 orders of magnitude in comparison with the one without any phase noise compensation that achieves a relative frequency stability of 1.81 x 10-14/1 s and 2.48 x 10-15/104 s

Research on Active Rear-Wheel Steering Control Method With Sliding Mode Control Optimized by Model Predictive

At present, the rapid development of electric vehicles and the innovation of related technologies have made the active steering control technology of electric vehicles a hot research topic. In this paper, a rear-wheel active steering control strategy based on sliding mode predictive control algorithm was proposed to improve the handling stability and active safety of electric vehicles. Among them, for the jitter problem of the sliding mode control algorithm this paper corrects and optimizes the control rate of the sliding mode control algorithm by adopting the ideas of feedback correction and rolling optimization in the model predictive control algorithm to suppress the jitter problem of the sliding mode control algorithm. At the same time, joint Carsim/Simulink simulation experiments and hardware-in-the-loop experiments were completed under different working conditions, and the simulation results were compared and analyzed with those of front-wheel steering vehicles with the same parameters and active rear-wheel steering vehicles with the sliding mode control algorithm. According to the experimental results, the sliding mode control algorithm optimized based on the model prediction algorithm proposed in this paper reduces the steady-state error of the vehicle yaw rate and the overshoot of the yaw rate by 30.012% and 18.103%, respectively, compared with the sliding mode control algorithm, and the output of the controller eliminates its jitter. The results showed that the proposed sliding mode predictive control algorithm had better control accuracy, better transient response characteristics, and smoother control output. Compared with the front-wheel steering vehicle, the ideal value yaw rate and target trajectory were accurately tracked, and the deviations of yaw rate and sideslip angle were reduced by 28.324% and 68.517%, respectively. The results showed that the proposed active rear-wheel steering control strategy provided better high-speed handling stability and active safety for the vehicle

Molecular simulation study of the influence of different surfactants on the wetting characteristics of anthracite

The reduction of dust pollution in coal mines is of great importance both for protection of the environment and for the occupational safety and health of coal mine workers. The reduction of dust from anthracite has been a challenge due to its inherent hydrophobicity and high metamorphism. As a result, surfactants are commonly added to water to improve the wettability of coal, thereby improving the dust reduction efficiency of a water spray system. To clarify from a microscopic perspective the effect of different surfactants on the wettability of anthracite, models for the anthracite-surfactant-water system were established, and adsorption configuration, relative concentration distribution, and the diffusion coefficients of water molecules in the systems were thoroughly investigated with molecular simulations. The results showed the directional arrangement of surfactants in the simulation systems after 150 ps of equilibration, resulting in the reduced surface tension of the water-surfactant solution and enhanced wettability of anthracite. Along the (001) normal direction, the relative concentration of sodium dodecylbenzenesulfonate (SDBS) (15.32), the anthracite-water overlapping area, the diffusion rate of water molecules, and the activity (DSDBS = 0.97 × 10-8 m2·s−1) were maximized, indicating the excellent wettability effect of SDBS. The results of the study are of practical significance for improving the wetting effect of anthracite, improving the dust reduction efficiency, and safeguarding the occupational safety and health of personnel

A New Mapping Function for Spaceborne TEC Conversion Based on the Plasmaspheric Scale Height

The mapping function is crucial for the conversion of slant total electron content (TEC) to vertical TEC for low Earth orbit (LEO) satellite-based observations. Instead of collapsing the ionosphere into one single shell in commonly used mapping models, we defined a new mapping function assuming the vertical ionospheric distribution as an exponential profiler with one simple parameter: the plasmaspheric scale height in the zenith direction of LEO satellites. The scale height obtained by an empirical model introduces spatial and temporal variances into the mapping function. The performance of the new method is compared with the mapping function F&K by simulating experiments based on the global core plasma model (GCPM), and it is discussed along with the latitude, seasons, local time, as well as solar activity conditions and varying LEO orbit altitudes. The assessment indicates that the new mapping function has a comparable or better performance than the F&K mapping model, especially on the TEC conversion of low elevation angles