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Compared with high-stubble ratoon rice (RR), low-stubble RR is superior in yield potential, grain quality, and economic benefit. However, the unstable ratooning ability limits the grain yield of low-stubble RR production. Light condition during the grain-filling stage of main crop (GFMC) may be important for rice ratooning. To elucidate the role of light condition during GFMC in affecting ratooning ability, the key response periods, and their underlying mechanisms, field experiments were conducted using two indica cultivars in 2021 and 2022. To create varied light conditions at the canopy base during GFMC, two planting density treatments combining three nitrogen (N) treatments were established in 2021, and three density treatments combining two N treatments and four shading treatments were established in 2022 for the main crop. Light intensity (LI), light quality as reflected by the ratio of red light/far red light (R/FR), and light transmission ratio (LTR) at the canopy base during GFMC, and ratooning ability were dramatically altered by N fertilization but not by planting density. With increased N application, LTR, root bleeding rate, and maximum ratooning rate significantly decreased in 2021. In 2022, low N rate increased LI, R/FR, and maximum ratooning rate by 155.7–241.4%, 47.4–65.3%, and 15.6–27.5%, respectively, but reduced missing hill percentage (proportion of hills without regenerated tillers to the total number of hills) by 30.0–62.1% compared with high N rate. The missing hill percentage was negatively correlated with the indices of light condition, while the maximum ratooning rate was positively correlated with them for both cultivars. Root activity and the ratios of abscisic acid (ABA) to cytokinins (CTK), indole-3-acetic acid (IAA), and IAA ​+ ​CTK could explain the effect of light condition during GFMC on ratooning ability. Shading experiment confirmed the effect of light condition on ratooning ability and further revealed that only shading during middle and late GFMC affected ratooning ability. These findings provide new insights into the regulation of ratooning ability, which are useful for developing management practices to increase the grain yield and yield stability of low-stubble RR.

Abstract Rock bursts in roadway groups of deep mining workfaces are more likely to occur due to concentrated static loads, posing significant threats to mining safety and efficiency. In this study, the coal mine roadway groups in western China are taken as an engineering case to investigate the occurrence mechanism of rock bursts in deep mining workfaces caused by concentrated static loads. A novel prevention and control method based on hydraulic fracturing is proposed, and a sensitivity analysis is conducted on key parameters, including in-situ stress, roof firmness coefficient, flow increment, and borehole spacing, to assess their influence on the hydraulic fracturing effect. The results reveal that the failure energy and peak stress of coal pillars within the roadway group gradually increase due to the continuous pressure exerted by the overlying roof, eventually reaching the conditions necessary to trigger rock bursts. The application of a super-long horizontal staged hydraulic fracturing technology transforms the thick, hard roof into a plastic cushion, which absorbs energy and weakens the stress transfer from the overlying roof. This process effectively reduces the stress concentration in the coal pillars. Furthermore, the hydraulic fracturing effect improves with increasing in-situ stress difference and decreasing borehole spacing, while the effect of flow increment is relatively limited. The study also highlights that higher roof firmness coefficients hinder the effectiveness of hydraulic fracturing, as greater water pressure is required for fracture propagation. Field application of the hydraulic fracturing technique, with parameters including an in-situ stress difference (λ), rock strata firmness coefficient, flow rate of 50 m3/day, borehole spacing of 60 m, and a borehole horizontal level of 40–50 m above the roadway, led to a significant reduction in microseismic events and ground audio frequency, demonstrating a remarkable anti-impact effect on-site. This research provides a theoretical framework and practical insights for the prevention and mitigation of concentrated static load-induced rock bursts in similar mining roadway groups.

Abstract The complex stress environment in deep roadways, often exacerbated by thick and hard strata, frequently precipitates coal bursts, posing significant safety hazards. This paper investigates the mechanisms and preventive methods for coal bursts in the gob-side roadway floor (GSRF) under thick and hard roof in the Ordos region, China. First, the stress-distributing characters of GSRF were analyzed then a stress calculation formula was derived. A mechanical model was developed to determine the critical stress for buckling failure of the roadway floor strata. Criteria for the bursting instability of GSRF were then established. The lateral static load from the adjacent gob, the advancing static load from the working face, and the disturbance load from overlying thick and hard roof fractures combine to transmit high loads and energy to the roadway floor via the “roof → rib → floor” pathway, causing increased stress concentration and energy accumulation. When the conditions satisfy the criteria for bursting instability, coal bursts can occur on the roadway floor. To mitigate dynamic load disturbances, the paper proposes roof regional fracturing and abrasive water jet axial roof cutting. Hydraulic reaming of gutters in the roadway ribs and deep hole blasting at the roadway bottom corners are offered to alleviate the static loads on the surrounding rock. The implementation of targeted prevention measures for dynamic and static loads effectively reduces coal bursts in GSRF. These findings offer an example of preventing and controlling coal bursts in other mines of the Ordos region with comparable geological conditions.

The surrounding rock of the impact hazard roadway is often disturbed by external dynamic loads, which often leads to the occurrence of impact ground pressure. In order to explore the anti impact and pressure relief effects of large-diameter pre relief boreholes in coal seams under dynamic load disturbance conditions, a comprehensive method including theoretical analysis, laboratory experiments, and numerical simulations was used to study the dynamic load response law and limit of coal seam anti impact and pressure relief boreholes. The results indicate that the coal body in the pressure relief zone of large-diameter drilling forms a weak structure, increases the ability to attenuate dynamic loads, and reduces the possibility of impact. Under low dynamic load disturbance, the expansion of pores and cracks, and the cumulative acoustic emission events show an upward trend with the increase of disturbance period; Under higher dynamic load disturbances, the degree of damage and rupture of coal samples in boreholes intensifies, and acoustic emission events are mainly high-energy. As the dynamic load level and disturbance period increase, the distance between the stress concentration zone, elastic high-energy zone and the borehole shortens, the influence range increases, the rock movement trend strengthens, and the degree of elastic energy accumulation increases. Under low dynamic load level disturbances, drilling plays a role in energy dissipation, pressure relief, and anti-collision, which can maintain the stability of the surrounding rock. However, under high-energy dynamic load disturbances, the anti-collision of large-diameter drilling fails, and the drilling wall is prone to dynamic instability and damage, causing instability of the surrounding rock. Overall, large-diameter pressure relief boreholes have weakened structures that can dissipate energy, reduce impact, and lower the degree of dynamic load disturbance. However, under high-energy and high-frequency dynamic load disturbances, the movement trend of the surrounding rock of the pressure relief borehole increases, the degree of fracture response is severe, and the anti impact effectiveness is limited.

ABSTRACT Fusarium pseudograminearum, a soil-borne fungus, is the cause of the devastating wheat disease known as wheat crown rot (WCR). The persistence of this pathogen in the soil and crop residues contributes to the increased occurrence and severity of WCR. Therefore, developing effective strategies to prevent and manage WCR is of great importance. In this study, we isolated a bacterial strain, designated as SR9, from the stem of wheat, that exhibited potent antagonistic effects against F. pseudograminearum, as well as the biocontrol efficacy of SR9 on WCR was quantified at 83.99% ± 0.11%. We identified SR9 as Pseudomonas khavaziana and demonstrated its potential as a plant probiotic. SR9 displayed broad-spectrum antagonism against other fungal pathogens, including Neurospora dictyophora, Botrytis californica, and Botryosphaeria dothidea. Whole-genome sequencing analysis revealed that SR9 harbored genes encoding various cell wall-degrading enzymes, cellulases, and lipases, along with antifungal metabolites, which are responsible for its antagonistic activity. Gene knockout and quantitative PCR analyses reveal that phenazine is the essential factor for antagonism. SR9 possessed genes related to auxin synthesis, flagellar biosynthesis, biofilm adhesion, and the chemotaxis system, which play pivotal roles in plant colonization and growth promotion; we also evaluated the effects of SR9 on plant growth in wheat and Arabidopsis. Our findings strongly suggest that SR9 holds great promise as a biocontrol agent for WCR in sustainable agriculture.IMPORTANCEThe escalating prevalence of wheat crown rot, primarily attributed to Fusarium pseudograminearum, necessitates the development of cost-effective and eco-friendly biocontrol strategies. While plant endophytes are recognized for their biocontrol potential, reports on effective strains targeting wheat crown rot are sparse. This study introduces the Pseudomonas khavaziana SR9 strain as an efficacious antagonist to the wheat crown rot pathogen Fusarium pseudograminearum. Demonstrating a significant reduction in wheat crown rot incidence and notable plant growth promotion, SR9 emerges as a key contributor to plant health and agricultural sustainability. Our study outlines a biological approach to tackle wheat crown rot, establishing a groundwork for innovative sustainable agricultural practices.

The large area overhanging of thick and hard roof is one of the critical reasons for inducing coal burst. Because of the shortcomings of deep borehole blasting and conventional hydraulic fracturing for the overhanging roof, the axial roof cutting technology of abrasive jet was developed. This technology achieves the best pressure relief by implementing prefabricated axial fractures and directional hydraulic fracturing in the roadway roof borehole to create an artificial fracture network in the roadway direction and tendency direction that is most conducive to roof collapse. The field application shows that the electromagnetic wave absorption ability of the stratum was enhanced, and the apparent resistivity was increased after the axial cutting roof technology of abrasive jet was implemented. During the mining operation of working face, the stress condition of the support was improved, and the release of micro-seismic energy was more stable, effectively reducing the risk of coal burst. On the basis of site observation, the mechanism of coal burst prevention by axial roof cutting of abrasive jet was revealed, that is, the plate-like structure fixed on both sides near the working face end is damaged by axial roof cutting, reducing the basic static load Ej, which is converted from the bending elastic energy of roof into the compression elastic energy of roadway surrounding rock, and reducing the strong additional dynamic load Ed, which is generated by the sudden fracture of roof, so that the roadway surrounding rock does not have the loading conditions for starting coal burst.

In response to the challenging task of accurately identifying the main hazard-causing layer of overlying strata in the coal mine surface hydraulic fracturing construction, this study focuses on the industrial test of ground hydraulic fracturing at the 401102 working face of the Mengcun Coal Mine. The research is conducted using the methods of theoretical analysis, microseismic monitoring, and on-site investigation to reveal the dynamic disaster mechanism of mine earthquakes and rock bursts induced by the movement of thick and hard overlying strata in the coal mines. The relationship between the movement characteristics of thick and hard overlying strata based on a three-zone structure loading model of overlying strata and induced dynamic disasters is analyzed, and a prediction model for mining seismic energy and an estimation model for equivalent additional stress in mining areas based on the movement state of key layers are established. A coal mine identification technology for the main hazard-causing layer of overlying strata is proposed based on the K-means clustering algorithm and the elbow rule. The construction layer for hydraulic fracturing is determined, and an industrial test is carried out on-site. The effectiveness is verified based on the microseismic monitoring data and theoretical analysis results, leading to the following conclusions. In the Mengcun Coal Mine’s 401102 working face, both the key stratum responsible for rock bursts and mine seismic activities can be traced to the R9 key stratum of the Anding Group, situated 66 meters away from the coal seam. The primary fracturing movement of this critical stratum R9 imparts an equivalent supplementary disturbance stress value of 7.23 MPa, with the seismic energy liberated by this initial rupture motion quantifying to 6.08×105 J, thereby indicating a pronounced susceptibility towards catastrophic occurrences. After fracturing the key layer which induces mining earthquakes and rock bursts, the theoretical value of the mine earthquake energy is reduced by 94%, and the theoretical value of the equivalent disturbance stress of the working face is reduced by 76%. High-energy microseismic events above the working face with an energy of 5×103 J show a noticeable upward trend, with an upward movement of approximately 15 m. The frequency ratio of microseismic events with an energy level of 103 J or higher significantly decreases from 60.39% to 17.89%, and the maximum microseismic event energy decreases from 6.65×105 J to 9.75×103 J. The proportion of microseismic events with an energy level of 102 J and below significantly increases from 39.61% to 82.11%.

With the continuous increase of coal mining depth, the occurrence and prevention of deep rockburst in China have become normalized. In order to improve the effectiveness of deep rockburst prevention and control technology, starting from the technical difficulties of deep rockburst prevention and control in on-site engineering, combined with practical data statistics of disaster prevention and control engineering, this study demonstrates that the deep rockburst in China is due to its high geological stress and large range of human mining disturbance. The stress recovery of surrounding rock is fast after rock stress unloading during the disaster prevention and control process. The low effectiveness of rockburst prevention and control can be attributed to the new requirements of “three highs and one low” prevention and control technology in deep mining compared to that in shallow mining, including high-strength large-sized drilling to relieve pressure, in order to solve the collapse prone problem of thick and hard coal seams; small spacing high-density drilling to solve the problem of disconnected pressure relief range in drilling; multiple rounds of repeated high-frequency construction to solve the problem of rapid stress recovery after unloading pressure in deep coal seams; and the mining face is advancing at a low speed to solve the problem of high mining disturbance intensity. In response to the new requirements of “three highs and one low” prevention and control mode for deep rockburst, in order to further improve the safety and reliability of rockburst prevention and control, and based on the limitations of optimizing development and mining deployment for conventional source rockburst prevention and control, this paper proposes the technology of actively regulating the structure and load of overlying rock layers in the deep rockburst prevention and control areas, and presents some further scientific problems that need to be solved. Against the background of several typical rockburst accidents in recent years with the problem of “missed targets” in the prevention and control plans, a local targeted prevention and control technology for deep rockburst mining space has been developed, and the scientific challenges that need to be solved in the future have been pointed out. Against the background of the difficulty in evaluating safety issues after the implementation of coal mine rockburst prevention and control measures, a deep rockburst prevention and control unloading standard evaluation technology is proposed, and the scientific difficulties that need to be solved in the future are pointed out. The coal industry vigorously promotes intelligent mining, but the disaster control still relies on manual labor and personnel to operate in a high-risk environment. This paper also explores the emerging research direction and scientific challenges of intelligent mining and intelligent prevention and control of deep rockburst. Finally, it is objectively pointed out that the prevention and control of rockburst is not purely a theoretical and technical issue, and the human understanding of technical issues is also one of the important reasons for rockburst accidents. Combining with the on-site engineering practice, this paper discusses the concept and mechanism of rockburst, whether rockburst can be predicted, whether rockburst can be prevented and controlled, and how to deal with rockburst mines and other industry focused technical issues. It is pointed out that the problem of rockburst engineering is a struggle between humans and nature, which requires practitioners to objectively understand, objectively accept, and conduct in-depth research. The current achievement is of significance.

Optimized nitrogen (N) management (OPT), with reduced total N input and more N applied during panicle development, has been proved to increase grain yield of rice through panicle enlargement. However, the changes in panicle architecture and source of variation are not well understood. A hybrid rice variety named Tianyou 3618 was subjected to OPT and farmer's fertilizer practice (FFP) in early cropping seasons of 2016 and 2017. With 16.7 % less N input, OPT increased panicle size by 8.6 % and 27.4 %, and grain yield by 13.8 % and 12.3 % for 2016 and 2017, respectively. OPT had greater dry matter accumulation and N uptake from panicle initiation to heading, which bolstered panicle enlargement. The number of surviving florets per branch was quite constant under different N treatments for all primary, secondary, and tertiary branches, implying that panicle size was mainly determined by the number of branches rather than the number of florets per branch. Little change was observed between OPT and FFP in differentiation, degeneration and survival of primary branches and their florets. Surviving secondary and tertiary branches and their florets were significantly more under OPT than those under FFP. The increase in surviving secondary branches under OPT resulted from both enhanced differentiation and reduced degeneration. While the increase in surviving tertiary branches under OPT was merely from enhanced differentiation though their degeneration was also dramatically increased. Among the increased differentiated florets under OPT, 32.4%–36.3 % and 61.6%–67.7 % came from secondary and tertiary branches, respectively. Among the increased surviving florets under OPT, 62.2%–65.2 % and 32.5%–37.8 % came from secondary and tertiary branches, respectively. Both secondary branches and tertiary branches were principal contributors to the increase in panicle size of OPT. To our knowledge, this is the first report on the detailed changes in panicle architecture and their involvement in panicle enlargement and yield gain under OPT.

With coal resource extraction areas are constantly shifting towards the west and deeper regions, and the number of rock burst mines in the western region is increasing rapidly. As a major coal province, Shaanxi Province has a stable scale of coal development and supply, ranking among the top in the country. However, rock burst disasters are particularly prominent. In order to effectively curb the frequent occurrence of rock burst in local coal mines and provide reference for rock burst prevention and control in areas with similar conditions, the occurrence law of rock burst has been basically clarified by analyzing 24 mines and 85 rock burst cases in Shaanxi coal mines over the past 10 years, and conducted classified prevention and control research based on the main control factors. The research results indicate that coal mine rock burst in Shaanxi Province has the characteristics of concentrated disaster mines, severe disaster severity, significant overlapping effects of multiple disasters, and high difficulty in prevention and control; The monitoring technology and prevention technology of rock burst are almost synchronized with the construction process of local regulations, achieving a late start, high starting point, and demonstration effect;Based on the main controlling factors of rock burst, rock burst in Shaanxi Province is divided into three categories: hard roof dominant type, wide coal pillar dominant type, and geological structure dominant type. In response to the main controlling factors, prevention and control methods for weakening hard roof, transferring high concentrated stress of coal pillar, and releasing structural stress are proposed.Through 10 years of engineering practice, continuous optimization of mine mining design, exploration of new fracturing technologies for drilling areas along the thick and hard roof of coal seams, and increased implementation of anti burst and pressure relief technologies, the occurrence of rock burst has been decreasing year by year, with significant achievements.

The stress environments of gob-side roadways (GSRs) are becoming increasingly complex during deep coal mining under thick and hard roofs. This leads to strong strata behaviors, including roadway floor heave, roof subsidence, and even coal bursts. Among them, coal bursts pose the greatest threat to production safety in coal mines. Coal bursts in a GSR strongly correlate with the load characteristics and stress-energy evolution laws of the roadway. This study analyzes the roof structures of double working faces (DWFs) during the initial weighting stage (IWS) and full mining stage (FMS) of gob-side working faces (GSWFs). This study also explores how varying roof structures affect the stability of GSRs. Three-dimensional roof structure models of DWFs and mechanical models of dynamic and static loads superposition on a GSR throughout the IWS and FMS of a GSWF were developed. An analysis identified the primary stress sources affecting the GSR throughout various mining stages of the GSWF. Subsequently, the principle of “three-load” superposition was developed. A novel method was proposed to quantify the stress state in the GSR surrounding rock across different mining stages of the GSWF. The method quantitatively characterizes the load of the GSR surrounding rock. Based on this, the criterion for judging the burst failure of the roadway was established. Numerical simulations are used to analyze the stress-energy evolution laws of the working face, coal pillar, and GSR surrounding rock during the mining process of the GSWF. These findings offer valuable references for studying and preventing coal bursts in GSRs under equivalent geological situations.

ABSTRACT Within the realm of Gram-negative bacteria, bacteriocins are secreted almost everywhere, and the most representative are colicin and pyocin, which are secreted by Escherichia coli and Pseudomonas aeruginosa, respectively. Signal peptides at the amino terminus of bacteriocins or ABC transporters can secrete bacteriocins, which then enter bacteria through cell membrane receptors and exert toxicity. In general, the bactericidal spectrum is usually narrow, killing only the kin or closely related species. Our previous research indicates that YPK_0952 is an effector of the third Type VI secretion system (T6SS-3) in Yersinia pseudotuberculosis. Next, we sought to determine its identity and characterize its toxicity. We found that YPK_0952 (a pyocin-like effector) can achieve intra-species and inter-species competitive advantages through both contact-dependent and contact-independent mechanisms mediated by the T6SS-3 while enhancing the intestinal colonization capacity of Y. pseudotuberculosis. We further identified YPK_0952 as a DNase dependent on Mg2+, Ni2+, Mn2+, and Co2+ bivalent metal ions, and the homologous immune protein YPK_0953 can inhibit its activity. In summary, YPK_0952 exerts toxicity by degrading nucleic acids from competing cells, and YPK_0953 prevents self-attack in Y. pseudotuberculosis.IMPORTANCEBacteriocins secreted by Gram-negative bacteria generally enter cells through specific interactions on the cell surface, resulting in a narrow bactericidal spectrum. First, we identified a new pyocin-like effector protein, YPK_0952, in the third Type VI secretion system (T6SS-3) of Yersinia pseudotuberculosis. YPK_0952 is secreted by T6SS-3 and can exert DNase activity through contact-dependent and contact-independent entry into nearby cells of the same and other species (e.g., Escherichia coli) to help Y. pseudotuberculosis to exert a competitive advantage and promote intestinal colonization. This discovery lays the foundation for an in-depth study of the different effector protein types within the T6SS and their complexity in competing interactions. At the same time, this study provides a new development for the toolbox of toxin/immune pairs for studying Gram-negative bacteriocin translocation.

【Objective】Based on the evaluation of growth period and grain yield performance of ratooning rice under different cutting heights, suitable varieties were selected for ratooning rice production in North Guangdong.【Method】Thirty-four rice varieties (bred or approved in Guangdong Province) were selected for tests under mid- or low-stubble cutting heights. The growth period, grain yield and yield components under different cutting heights among the tested varieties were investigated.【Result】The main crop yield was 5 210.9-8 566.8 kg/hm2, and grain yield of Huangguanghuazhan 1 was the highest. The ratoon crop yield of low-stubble ratooning rice was 3 335.0-6 357.3 kg/hm2, 16.1% higher than that of mid-stubble ratooning rice (2 084.4-5 940.5 kg/hm2). Qingxiangyou 19 Xiang was the highest in ratoon crop yield under both cutting heights. According to cluster analysis, the ratoon crop yield and total annual grain yield under mid-stubble ratooning rice mode could be categorized to four major groups, namely, high-yield, mid-high-yield, medium-yield, and low-yield levels. Each group contained 4, 7, 18, and 5 varieties for ratoon crop yield and contained 1, 14, 14, and 5 varieties for total annual grain yield under mid-stubble ratooning rice mode. Under low-stubble cutting height, the ratoon crop yield was also categorized to four major groups with 2, 17, 14 and 5 varieties, while the total annual grain yield was divided into three major groups, containing 10, 21, and 3 varieties, respectively. In ratoon season of low-stubble ratooning rice, the growth period was prolonged by an average of 9.1 days, the number of spikelets per panicle was increased, and the effective panicles and seed setting rate were reduced compared with those in ratoon season of mid-stubble ratooning rice. Under mid-stubble cutting height, the ratooning rice regenerated from the 3rd, 4th, and 5th nodes from the top (D3, D4 and D5) contributed 4.7%, 33.3%, and 62.0% of the total grain yield per plant, respectively. Under low-stubble cutting height, the ratooning rice regenerated from D3, D4, and D5 contributed 0%, 11.9%, and 88.1% of the total yield per plant.【Conclusion】If assessed with the criteria of high- or mid-high-level ratoon crop yield and high-level total annual grain yield, 9 rice varieties, including Huangguangyouzhan, Huangguanghuazhan 1, Huangguangtaizhan, Wuyouyuehesimiao, Guang 8 Youjinzhan, Hengfengyou 387, Qingxiangyou 003, Qingxiangyou 132, and Qingxiangyou 19 Xiang are recommended for production of mid-stubble ratooning rice. Ten rice varieties, including Erguangyouzhan 3, Huangguangyouzhan, Huangguanghuazhan 1, Huangguangtaizhan, Yuehesimiao, Nanjingzhan, Yuetaiyouzhan, Wuyouyuehesimiao and Guang8youjinzhan are suitable for production of low-stubble ratooning rice. For mid-stubble ratooning rice, new tillers mainly regenerate from the 4th nodes from the top and other lower nodes below. For low-stubble ratooning rice, new tillers mainly regenerate from the 5th nodes and other lower nodes below.

【Objective】It aims to study the yield performance and source-sink-flow characteristics of new strain of super-large-panicle rice DS23 in early season, and explore the source-flow-sink characteristics and super-high yield potential of DS23, with an aim to provide theoretical basis for high-yield breeding and cultivation of early rice in South China.【Method】The study was conducted under field conditions with the new super-large panicle type strain DS23 as test material and the medium to large panicle type variety YHSM as the control. The leaf area index, SPAD value, accumulation and transport characteristics of non-structural carbohydrate (NSC) in stems, anatomical characteristics of vascular bundles and yield component factors of different panicle types of rice were measured and compared.【Result】The number of grain per panicle, grain weight, sink capacity and yield of DS23 were increased by 37.3%, 4.0%, 33.7% and 15.9% respectively compared to those of YHSM seedlings. The effective number of panicles and seed setting rate were significantly decreased by 6.8% and 15.1% compared to those of YHSM seedlings. There was no significant difference in leaf area index and flag leaf SPAD value between the two varieties at heading stage. Compared with YHSM, total mass of NSC reserved in stem and apparent contribution of transferred NSC to grain yield of DS23 were significantly reduced by 15.3% and 19.8%, respectively, and the apparent transport rate of stem sheath NSC was significantly increased by 10.3%; The DS23 vascular bundle number was significantly increased by 17.3%, and there was no significant difference in the vascular bundle area between the two varieties; DS23 showed no significant change in grain/leaf ratio, with a significant decrease in NSC/spikelet ratio of 34.2% and an increase in vascular bundle load index of 20.4%-60.2%.【Conclusion】The super-large panicle type rice germplasm DS23 planted in early season has a large sink capacity, well-developed vascular bundles transport organization, strong material transformation ability in later stage and great potential for high yield and yield increase. Improvement in seed setting rate is a main direction for exploring its super-high yield potential. The study result lays a theoretical foundation for the breeding of super-large panicle early rice varieties and the research and development of high yield cultivation techniques.

Fusarium pseudograminearum (Fpg) is a significant pathogen responsible for fusarium crown rot (FCR) in wheat (Triticum aestivum L.), a disease with devastating impacts on crop yield. The utilization of biocontrol bacteria to combat fungal diseases in plants is a cost-effective, eco-friendly, and sustainable strategy. In this trial, an endophytic bacterial species, designated as SW, was isolated from the roots of wheat. The strain exhibited potent antagonistic effects against Fpg and reduced the FCR disease severity index by 76.07 ± 0.33% in a greenhouse pot trial. Here, 106 colony-forming units (CFUs)/mL of the SW strain was determined to be the minimum dose required to exhibit the antagonism against Fpg. The strain was identified as Bacillus atrophaeus using genome sequencing and comparison with type strains in the NCBI database. Whole-genome sequencing analysis revealed that SW harbors genes for siderophores, antifungal metabolites, and antibiotics, which are key contributors to its antagonistic activity. Additionally, the strain’s ability to utilize various carbon and nitrogen sources, successfully colonize wheat root tissues as an endophyte, and form biofilms are critical attributes for promoting plant growth. In summary, these findings demonstrate the ability of Bacillus atrophaeus to control FCR disease in wheat in a sustainable agricultural setting.

ObjectivesFor a marine 690 Vac bidirectional converter based on a three-level flying capacitor, in order to make it start stably and transition to its normal working state, the flying capacitor must be pre-charged. This paper proposes a pre-charging strategy based on single-tube control which is suitable for three-level flying capacitors.MethodsThe on-off of the three-level outer tube is controlled on the basis of the flying capacitor, and efficient and fast pre-charging control is performed.ResultsWhen this strategy is applied to a 690 Vac bidirectional converter, the pre-charging of the flying capacitor is completed within 1 second in Buck mode and less than 5 seconds in Boost mode. After pre-charging, the voltage of the flying capacitor remains at the value of half of the voltage of the high voltage side, and the voltage of the input side capacitor remains at the value of the input side voltage.ConclusionsAfter experimental verification, the proposed pre-charging strategy based on controlling the outer tube of the three-level flying capacitor can be applied to a 690 Vac bidirectional converter device without the need for additional pre-charging power devices, which not only simplifies the topology but also ensures the reliable and fast pre-charging of flying capacitors.

Aiming at the problem that the traditional discrimination method of rock burst generation lacks the consideration of the whole disaster process and has some defects, taking the decomposition of the physical process of coal mine rock burst generation as the starting point, the calculation formula and application of the discrimination index of coal mine rock burst generation based on the decomposition of physical process are investigated by using the methods of theoretical analysis, numerical simulation, mechanical derivation and engineering verification. The results show that the spatial sequence in the physical process of rock burst is the limit equilibrium zone of mining surrounding rock-near-field elastic and plastic zone of mining surrounding rock-mining activity space. The corresponding time series are burst initiation stage, burst energy transmission stage and burst ground pressure manifestation stage. To complete the whole physical process of rock burst, two mechanical conditions must be met at the same time: impact start-up and overcoming impedance. The dynamic and static load type and high static load superposition type rock burst start-up mechanical models and rock burst impedance overcoming mechanical models are established respectively. The starting energy criterion formula of rock burst and the apparent energy criterion formula of rock burst are obtained. Based on the above two formulas, the calculation formula of rock burst occurrence discrimination index has been derived considering both dynamic load sources and static load sources, and taking into account that the mechanical conditions of rock burst initiation and rock burst appearance are satisfied. According to the discriminant index formula, it is obtained that the possibility of rock burst is directly proportional to the sum of static and dynamic loads of coal and rock mass, and inversely proportional to the impedance energy of support and surrounding rock. The structural mechanics model of roadway load-reduction impedance-increase coupling anti-burst engineering based on the occurrence discrimination index of rock burst is established and applied in engineering. The practice shows that the purpose of preventing rock burst is achieved.

Aquatic plants play a key role in the structuring and functioning of shallow lake ecosystems. However, eutrophication often triggers shifts in plant communities and species diversity, especially in the early stages when the water is still clear. Additionally, water depth is an important factor regulating aquatic plant communities. We conducted a 50-day mesocosm study to investigate how water depth (50 cm and 100 cm) affected the functional traits (vertical expansion versus horizontal colonisation) of 20 aquatic plants under eutrophic clear-water conditions. Among the selected species, the submerged plants Hydrocotyle vulgaris and Limnophila indica exhibited higher plant height or biomass in deeper water, while the emergent plants Myriophyllum aquaticum showed the opposite trend. Additionally, Ludwigia peploides subsp. stipulacea exhibited better vertical growth than the remaining species, and the submerged species Vallisneria denseserrulata had better horizontal colonisation. There was a positive correlation between plant height and rhizome length, indicating the absence of a trade-off between vertical growth and horizontal expansion. Our findings suggest an overall resilience of aquatic plants to varying water depths within our study range and highlight the importance of analysing functional traits when selecting appropriate species in freshwater ecosystem restoration, particularly in the face of climate change-induced water depth fluctuations.

Mechanized ratoon rice has the advantages of low labor requirement, low costs, and high profit. In 1970s scientists and technicians in Guangdong made intensive efforts on the research and extension of cultivation technique of traditional manual-harvested ratoon rice. Recently substantial progresses in the development of low-stubble mechanized rice ratooning technology have been achieved as follows: (1) Suitable cultivars, such as Meixiangzhan2 and Qingxiangyou132, with high ratooning ability for ratoon rice system have been identified; (2) Studies revealed that the ratooning ability of rice was significantly related to the crop traits at grain-filling stage of main crop such as light transmission ratio, root activity, leaf SPAD value attenuation, and culm and sheath weight stem−1; (3) Fertilizer nitrogen (N) management strategy consisting of the late and light application of bud-promoting N and the heavy application of tiller-promoting N and panicle-promoting N has been developed. Reasonable water management method including digging surrounding ditch, draining field twice in main crop, and keeping soil wet during the initiation of axillary buds has been established; and (4) Demonstrations of low-stubble mechanized rice ratooning technology were carried out from 2017 to 2022. The ratoon crop yield ranged from 4.10 to 6.92 ​t ​ha−1 and increased year by year. Further efforts should be made on screening or breeding more cultivars suitable for mechanized ratoon rice, better understanding of the mechanisms of initiation of axillary buds and growth of regenerated tillers, and developing combine harvesters with less stubble damage. We believe that as the agro-food system transformation strengthens the mechanized rice ratooning will become one of the promising cropping systems in Guangdong as well as in South China.

This paper introduces the principle of RF MEMS switch and performs modeling analysis. By analyzing the low control voltage and microwave power of the switch, phenomena such as long response time and susceptibility to mechanical failure appear. Therefore, this paper analyzes the current research on RF MEMS switches, improves the internal structure of the switch by adding support columns, fixes the double ends of the beam, and increases the spring coefficient K to slow down the falling speed of the internal cantilever of the switch. The impact force between the cantilever and the dielectric layer is reduced, which greatly reduces the loss of the switch and the problems of mechanical fatigue failure, thus improving the service life of the switch. The simulation shows that the stability of the model is relatively high when the length of the cantilever is 300 um. After adding a 0.7 um support column at a distance of 25 um from the dielectric layer, the turn-on voltage is increased from 42.5 V to 61 V, and the switching capacitance remains unchanged. Finally, by calculating the percentage error between the simulation value and the model theory of 1.6%, the validity and accuracy of the model are checked.

ObjectiveIn order to reduce the switching frequency of an intermediate frequency inverter power supply, ensure the quality of the output waveform and realize digitalization easily, a SPWM sampling method based on a tangent-secant midpoint approximation is proposed. MethodsIt is proven by deduction that the quantitative relationship of the natural sampling method can be approximated, and a Matlab/Simulink simulation model is built. The algorithm is designed and applied to an intermediate frequency inverter device, and the correctness of the proposed method is verified in the two aspects of simulation and experiment. ResultsThe simulation results show that the total harmonic distortion (THD) of the output waveform based on the tangent-secant midpoint approximation method is 2.64%, lower than the 3.99% of the symmetrical regular sampling method. The waveform quality of the tangent-secant midpoint approximation method is obviously better than that of the symmetrical regular sampling method, as it not only reduces the switching frequency but also takes into account the requirements of THD. ConclusionsSPWM sampling based on tangent-secant midpoint approximation is applied to the intermediate frequency power supply and is able to effectively overcome the shortcomings of the low-quality output waveform and high switching frequency of the symmetrical regular sampling method. Both theoretical analysis and engineering practice verify the rationality and correctness of the proposed method, and it can be widely extended to the field of intermediate frequency power supply installation.

【Objective】The research explored the genetic mechanism for regulating chlorophyll content and its response to nitrogen (N) fertilizer in rice, and provide new molecular marker segments for breeding of high-yield and nitrogen- efficient rice varieties.【Method】The 113 family lines of ZS 97 × MH 63 recombinant inbred lines (RIL, F11) were adopted as tested materials for QTL analysis. Field experiments were performed with split-plot design, N fertilizer rate being the main plots and RIL being subplots. The low N (no N) and normal N (130, 135 N kg/hm2) fertilizer treatments were established in the fields. The chlorophyll meter was used to determine SPAD values of leaves at 30 days after transplanting (30 DAT) and at heading (HD) stage. By using a high-density genetic map containing 1 619 Bin markers, IciMappingv3.4 software and complete interval mapping, QTL for controlling leaf chlorophyll content at two growth stages was mapped.【Result】In two N treatments at two growth stages within two years, a total of 15 QTLs for controlling leaf chlorophyll content were detected and they were located on chromosomes 1, 2, 3, 6, 7, 10 and 11. Each single QTL could explain 1.21%-40.74% of genetic contributions to traits. Through comparison of their physical loci, 6 QTLs were found to have been cloned or have the same loci being known previously for chlorophyll content. Among them, a locus, named qHDCHL6-1, regulating the chlorophyll content of flag leaf at heading stage was detected at 8.45-9.12Mb of chromosome 6. It was stably detected under two N treatments in two years, which explained 1.55%-28.01% of contributions to traits. Through functional annotation, 4 candidate genes related to chlorophyll content of flag leaf were found in the qHDCHL6-1 chromosome interval. These genes were LOC_Os06g15370 (OsNPF3.1), LOC_Os06g15420 (OsAS2), LOC_Os06g15620 (GAS) and LOC_Os06g15590, and the first three of these genes have been cloned【Conclusion】15 QTLs controlling leaf chlorophyll content of rice at 30 DAT and HD stage are detected, and a QTL locus qHDCHL6-1 with stable expression was identified, which contains 4 candidate genes.

【Objective】In order to further enhance grain yield of rice and nitrogen (N) use efficiency (NUE), N fertilizer was reduced and topdressing was delayed, together with alteration in row and plant spacing and planting density.【Method】In two late seasons, comparison trials were conducted with 8 treatments, including zero applied N (T1), farmers' practice (T2, control), 3 moderately-delayed N topdressing (T3-T5) and 3 highly-delayed N topdressing (T5-T8). T3-T8 also had alteration in N application rate, planting density and row and plant spacing.【Result】In comparison to T2, the average grain yields under T3-T5 were increased by 29.7% and 15.9%, and those of T6-T8 were increased by 26.4% and 18.6% in two late seasons, respectively. In both late seasons, nitrogen uptake and plant growth under T3-T5 and T6-T8 were slower before panicle initiation and they were both increased or accelerated thereafter. Based on average results in two late seasons, leaf area indexes at heading stage were enhanced by 8.5% and 11.8% respectively under T3-T5 and T6-T8 compared with that under T2. Leaf nitrogen contents at heading stage were enhanced by 16.8% and 23.5%, respectively. The numbers of panicles per hectare were increased by 14.5% and 15.2%, panicle size remained unchanged or was increased by 12.5%, sink sizes were increased by 13.6% and 29.3%, seed setting rate was enhanced by 9.0% or remained the same, 1000-grain weight remained identical or was decreased by 9.0%, biomasses were increased by 14.8% and 15.5%, and harvest indexes were increased by 7.2% and 6.4%, respectively. The total amounts of N uptake were increased by 27.6% and 40.7%, N uptake efficiencies were increased by 85.9% and 124.2%, agronomical efficiencies were increased by 99.1% and 102.5%, and partial factor productivity was increased by 32.1% and 36.2%, respectively. Additional N input, dense planting and alteration in row and plant spacing had little effect on yield and NUE. Highly-delayed N topdressing could further expand sink size and improve NUE, but could not enhance grain yield anymore.【Conclusion】With reduced N input, both source and sink of rice were substantially enlarged, and the yield and NUE were dramatically increased under moderately-delayed and highly-delayed N topdressing.

Fish pond rice planting is an agricultural production activity that uses aquaculture ponds to grow rice. The development of fish pond rice planting technology can keep the aquaculture area, expand the rice planting area, improve food security, and reduce pollution from aquaculture tail water. In the early season of 2022, we conducted a fish pond rice planting experiment in Guangzhou and achieved initial success. The tested rice varieties were Yuetai Youzhan, Huangguang Youzhan, Meixiangzhan No. 2, Taifengyou 208, Guanghong No. 3, Yuexiang 430, Yuenong Simiao, Wushan Simiao, and Nanjing Xiangzhan. The aquaculture varieties were largemouth black bass, Australian freshwater lobster, crucian carp and yellow catfish. The results showed that there was significant difference in grain yield among tested rice varieties under fish pond cultivation and the difference was much greater than that under field cultivation. The yield of Yuexiang 430 was the highest, reaching 390.8 kg/667m2, which was 148.6% higher than that of Taifengyou 208. The four aquaculture varieties all performed well, with high survival rate and fast growth speed, among which the Australian freshwater lobster performed the best. At present, there are still some critical problems such as high cost, lack of technical standards and lagging behind in basic research in fish pond rice planting. Coordinated efforts should be made to enhance low-cost floating bed development, improve rice and fishery matching, screen out more rice varieties, optimize fertilizer management and pest control, manufacture or adapt supporting machinery and equipment, and strengthen relevant theoretical researches. Finally, the green, high-yield and high-efficiency fish pond rice planting procedures and standards should be established through technical integration. With the deepening of research and the maturing of technologies, the fish pond rice planting technology will make increasing contributions to food security, farmers' income increase, environmental protection and beautiful countryside construction in China, especially in the southern regions.

The research on the bursting liability of coal under confining pressure and unloading damage is critical in creating prevention mechanisms for coal mass rock bursts in deep underground mines. Cyclic loading and unloading tests of variable stress with a lower limit were performed under multistage confining pressure and different amplitude unloading to explore their influence on the impact tendency of the coal bodies. Meanwhile, the characteristic parameter analysis of acoustic emissions was used to evaluate the failure. The results revealed that the accumulated number and energy of acoustic emission events gradually decreased with increasing the confining pressure. The coal specimen became denser, and the failure mode gradually transitioned from brittle to ductile. With the increase in unloading amplitude, the cumulative number of acoustic emission events in the coal specimens decreases, the damage degree to the coal body increases, the peak load decreases, and the failure mode transitions from ductile to brittle. The increase in confining pressure results in an increase in the input energy and the elastic strain energy, while the increase in the unloading range of the coal body leads to a decrease in the input energy and elastic strain energy. In addition, after the confining pressures of 3 MPa, 6 MPa, and 9 MPa, the residual elastic energy index of the coal specimens increases by 21.76%, 42.92%, and 71.69%, respectively, compared with the room pressure conditions. The residual elastic energy index decreases by 21.11% and 55.38% for the unloading amplitude of 3 MPa and 6 MPa, respectively, compared with the unloaded coal specimen, indicating that the impact tendency of the coal body is enhanced by the confining pressure conditions.

Rice–fish co-cultures have been practiced for over 2000 years, and they have tremendous potential in terms of increasing food security and economic benefits. However, little research has been conducted into achieving stable yields and high lodging resistance with regard to rice while simultaneously promoting the harmonious and healthy growth of fish in rice–fish co-culture paddy fields. We conducted a field study aimed at selecting suitable rice varieties for rice–fish co-culture systems (encompassing both ratoon and main crop). This selection process was grounded in an evaluation of lodging resistance and grain yield among 33 rice varieties used throughout the studied region. The results revealed a range of lodging indices of the main crop for the second internode, spanning from 62.43 to 138.75, and the annual grain yield (main crop and ratoon crop) ranged from 7.17 to 13.10 t ha−1 within rice–fish co-culture systems. We found that the use of rice–fish co-culture farming could improve the milling quality, nutrient quality, and appearance quality of rice, though the improvement gained through co-culturing varied across rice varieties. Moreover, the lodging index of the three basal internodes of rice plants was significantly and positively correlated with the plant height and the culm fresh weight, but it was negatively correlated with the bending strength of the rice basal internodes. Additionally, the 33 tested rice varieties were clustered in accordance with their lodging resistance (i.e., high resistance with lodging indices 62.43–75.42; medium resistance with lodging indices 80.57–104.62; and low resistance with lodging indices 113.02–138.75) according to the hierarchical cluster analysis. The 33 rice varieties were also clustered in accordance with the annual (main crop and ratoon crop) grain yield (i.e., high yield with 11.17–13.10 t ha−1; medium yield with 10.15–10.83 t ha−1; and low yield with 7.16–9.88 t ha−1). In all, 11 rice varieties were identified by a comprehensive evaluation as suitable varieties for grain production in the rice–fish co-culture system. These varieties displayed favorable traits, including a high annual rice yield, strong lodging resistance, and good grain quality. This is the first study to systematically evaluate rice varieties based on grain yield, lodging resistance, and grain quality in rice–fish co-culture systems.

To evaluate the coal burst proneness more precisely, a new energy criterion namely the residual elastic energy index was proposed. This study begins by performing the single-cyclic loading-unloading uniaxial compression tests with five pre-peak unloading stress levels to explore the energy storage characteristics of coal. Five types of coals from different mines were tested, and the instantaneous destruction process of the coal specimens under compression loading was recorded using a high speed camera. The results showed a linear relationship between the elastic strain energy density and input energy density, which confirms the linear energy storage law of coal. Based on this linear energy storage law, the peak elastic strain energy density of each coal specimen was obtained precisely. Subsequently, a new energy criterion of coal burst proneness was established, which was called the residual elastic energy index (defined as the difference between the peak elastic strain energy density and post peak failure energy density). Considering the destruction process and actual failure characteristics of coal specimens, the accuracy of evaluating coal burst proneness based on the residual elastic energy index was examined. The results indicated that the residual elastic energy index enables reliable and precise evaluations of the coal burst proneness.

Super-aligned multi-walled carbon nanotube arrays on Si wafer were synthesized by low press chemical vapor deposition. The super-thin multi-walled carbon nanotube films were obtained by a drawing process on the side of the vertically aligned carbon nanotubes. The as-synthesized samples were characterized by scanning electron microscopy and optical microscopy. Terahertz time-domain measurements showed that anisotropic transmission properties were observed. The multi-walled carbon nanotube films with various two-dimensional periods and thicknesses displayed remarkably enhanced transmission at the terahertz range. Comparing experimental results with theoretical calculations revealed that the excitation of surface plasmon polaritons on the carbon nanotubes/Si interface was the key mechanism responsible for the enhanced transmission. The resonance peaks were red shifted with increasing period. In the infrared region, no obvious resonance peaks were observed.

Bacteria can use type VI secretion systems (T6SSs) to inject toxic effector proteins into adjacent cells, in a contact-dependent manner. Here, the authors provide evidence of contact-independent killing by a T6SS effector that is secreted into the extracellular milieu and then taken up by other bacterial cells.

Short basal internodes are important for lodging resistance of rice (Oryza sativa L.). Several canopy indices affect the elongation of basal internodes, but uncertainty as to the key factors determining elongation of basal internodes persists. The objectives of this study were (1) to identify key factors affecting the elongation of basal internodes and (2) to establish a quantitative relationship between basal internode length and canopy indices. An inbred rice cultivar, Yinjingruanzhan, was grown in two split-plot field experiments with three N rates (0, 75, and 150 kg N ha−1 in early season and 0, 90, and 180 kg N ha−1 in late season) as main plots, three seedling densities (16.7, 75.0, and 187.5 seedlings m−2) as subplots, and three replications in the 2015 early and late seasons in Guangzhou, China. Light intensity at base of canopy (Lb), light quality as determined from red/far-red light ratio (R/FR), light transmission ratio (LTR), leaf area index (LAI), leaf N concentration (NLV) and final length of second internode (counted from soil surface upward) (FIL) were recorded. Higher N rate and seedling density resulted in significantly longer FIL. FIL was negatively correlated with Lb, LTR, and R/FR (P 0.05). Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI (R2 = 0.82). Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL. We conclude that FIL is determined mainly by Lb and LAI at jointing stage. NLV has no direct effect on the elongation of basal internodes. N application indirectly affects FIL by changing LAI and light conditions in the rice canopy. Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice. Keywords: Internode elongation, Leaf area index, Light intensity, Light quality, R/FR, Light transmission ratio, Leaf N concentration

AbstractRockburst frequently occurs in deep multipillar gob-side entry in Inner Mongolia and Shaanxi, China. A case study of the Hongqinghe coal mine was analyzed to reveal the occurrence mechanism of rockburst in deep multipillar gob-side entry through theoretical and applied research. And new control methods were put forward. The results show that there is an essential difference between the surrounding rock load characteristics of multipillar gob-side entry and single-pillar gob-side entry. Within the influence area of the lateral goaf, more coal pillars will promote stress concentration, and the high stress concentration area will migrate to the coal pillar of mining roadway. The hanging roof of the working face can cause the stress concentration in the area of leading coal pillar to reach 5 times. The multipillar gob-side entry is less affected by the dynamic load of the roof of the lateral goaf. The ‘F-shaped and L-shaped’ stress source structure model of the deep gob-side multipillar entry was established, and the occurrence mechanism of rockburst is revealed. On the one hand, the static load of rockburst start foundation is formed under the superposition of lateral goaf, rear goaf, and multicoal pillar. On the other hand, the superposition of the foundation static load and the opportune static load induces the start of rockburst. Aiming at the two types of load sources, the fracturing method of kilometer bedding drilling in the roof of coal pillar area is proposed to reduce the foundation static load. The treatment method of periodic tendency blasting fracture of leading roadway roof in a working face reduces opportune static load. The field test has been carried out, and the effect was good.

Wild peach is an important resource for improving existing peach varieties. However, the extant populations of wild peach show fragmented distribution due to human disturbance and geographic isolation. In this study, we used natural populations (or wild populations) of Prunus persica (Rosaceae) to assess the genetic effects of habitat fragmentation. A total of 368 individuals sampled from 16 natural populations were analyzed using 23 polymorphic simple sequence repeat (SSR) markers. Prunus persica maintained low within-population genetic variation and high level of genetic differentiation. Two genetic clusters were revealed based on three different methods (UPGMA, PCoA, and STRUCTURE). All populations showed a significant heterozygosity deficiency and most extant populations experienced recent reduction in population size. A significant isolation by distance (IBD) was observed with Mantel’s test. Compared to historical gene flow, contemporary gene flow was restricted among the studied populations, suggesting a decrease in gene flow due to habitat fragmentation. Habitat fragmentation has impacted population genetic variation and genetic structure of P. persica. For breeding and conservation purpose, collecting as many individuals as possible from multiple populations to maximize genetic diversity was recommended during the process of germplasm collection. In addition, populations from central China had higher genetic diversity, suggesting these populations should be given priority for conservation and germplasm collection.

In response to water deficiency in Northern China, a scheme called the Middle Route Project was devised under the South-to-North Water Transfer Division to divert water from the Han River, the biggest tributary of the Yangtze River, to supply two provinces (Henan and Hebei) and two municipalities (Beijing and Tianjin) in the north. The minimum water qualityindex (WQImin) based on four water quality parameters and Mann-Kendall test methods were applied to determine the status of overall water quality inDanjiangkou reservoir (DKR) and downstream of Han River before and after the water intake (from 2006 to 2018). Results show that pH, dissolved oxygen, chemical oxygen demand, and ammonia nitrogen of water showed similar seasonal trends at the reservoir center, intaking place and downstream of Han River. According to WQImin index, the water quality status of most water samples at reservoir and downstream remained at good. After water diversion, water quality did not significantly differ from the status before intake at reservoir center. However, water quality was improved at intaking place and downstream. Inter-basin water diversion from reservoir did not deteriorate the local and downstream water quality, or significantly reduce the downstream flow discharge before it pours into Yangtze River. This study can inform other regions with serious water crises that both water diversion and local water quality can be preserved with appropriate environmental managements.

Controlling weed populations by manipulating their seed banks is an important weed management option. To assist such efforts, we investigated relationships between fertilization treatments and depth-related characteristics of the weed seed bank (density, species composition and diversity) under a wheat-soybean rotation after long-term (16 years) fertilization. Numbers of weed species present and the Shannon-Wiener index were significantly lower under NPK, NP, NK, and PK fertilization treatments than under the fertilization-free control treatment (CK), and the vertical distribution of dominant species differed under the treatments. Generally, the species richness and Shannon-Wiener index decreased and the Pielou index increased with increases in soil depth, but the relationship of the Simpson index with depth was complex and unclear. The results show that effects of considered fertilization treatments on weeds warrant careful attention, and that PK fertilization would be optimal for suppressing weeds in the wheat-soybean rotation system studied. Keywords: Weed, Vertical distribution, Dominant species, Density, Diversity, Seed bank

Objective: The study aimed to describe the characteristics and containment of the Omicron variants in Shanghai compared with the previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in China. Methods: We summarized the data retrieved from the Shanghai Municipal Health Commission from January to June 2022 and the National Health Commission of the People’s Republic of China from March 2020 to August 2021. Epidemiological analysis was utilized to describe the differences among SARS-CoV-2 variants and the infection situation in the outbreaks in China. Results: The Omicron variants had the characteristics of high insidiousness, rapid transmission, high infectivity, and short incubation period, which were consistent with the characteristics of outbreaks caused by Omicron in other regions in China and abroad. There were 568978 asymptomatic infections in Shanghai from Feburary 26 to June 30, 2022, accounting for 90.73% of the SARS-CoV-2 infections in this outbreak wave. It’s significantly different from a total of 23277 SARS-CoV-2 infections in China between March 31, 2020 and August 8, 2021, of which 41.97% of the cases were asymptomatic infections. Conclusions: Compared with previous outbreaks emerged in China, the Omicron outbreak in Shanghai was characterized by multiple point dissemination, wide coverage, a large number of close contacts of confirmed infections and asymptomatic carriers, and difficult source tracing. The lessons from Shanghai’s response to Omicron showed that the dynamic zero-COVID policy is still the most suitable response to the virus which can quickly find the infections and curb the transmission route.

Abstract The transition between the planktonic state and the biofilm-associated state is a key developmental decision for pathogenic bacteria. Biofilm formation by Yersinia pestis is regulated by hmsHFRS genes (β-1, 6-N-acetyl-D-glucosamine synthesis operon) in its flea vector and in vitro. However, the mechanism of biofilm formation in Yersinia pseudotuberculosis remains elusive. In this study, we demonstrate that the LysR-type regulator RovM inversely regulates biofilm formation and motility in Y. pseudotuberculosis by acting as a transcriptional regulator of these two functions. RovM is strongly induced during growth in minimal media but strongly repressed in complex media. On one hand, RovM enhances bacterial motility by activating the expression of FlhDC, the master regulator of flagellar genes, via the recognition of an operator upstream of the flhDC promoter. On the other hand, RovM represses β-GlcNAc production under nutrition-limited conditions, negatively regulating hmsHFRS expression by directly binding to the −35 element of its promoter. Compared to wild-type bacteria, the rovM mutant established denser biofilms and caused more extensive mortality in mice and silkworm larvae. These results indicate that RovM acts as a molecular switch to coordinate the expression of genes involved in biofilm formation and motility in response to the availability of nutrients.

Understanding the responses of soil organic carbon (SOC) distribution to terrain and land use variations is important for making corresponding measures to enhance the soil quality and its carbon storage. The objective of this study was to characterize the spatial distribution of SOC, and analyze the impacts of environment factors on spatial variation of SOC along the Danjiangkou Reservoir area, China. A village size watershed was selected to investigate the SOC distribution under different terrains and land uses. We found that SOC contents followed a log-normal distribution with arithmetic and geometric means of 6.83 g kg −1 and 6.09 g kg−1, respectively, which were moderately variable (Coefficient of Variation = 49.6%) and demonstrated a moderate spatial dependence according to the nugget ratio (37.8%). The experimental variogram of SOC was best-fitted by a spherical model after the spatial outliers had been detected and subsequently eliminated. From the spatial distribution map of SOC contents, the highest SOC content occurred in the center of the watershed, which were along the main water channel or tributaries and normally had lower altitude. While,the lower values of SOC contents were located at the edge of the watershed, such as in the northwest, southwest and southeast of the area where citrus were normally planted. This spatial distribution pattern of SOC was generally consistent with the spatial structure of terrain and land use on the unique terrain of the agriculture-based reservoir area. Therefore, taking terrain and land use type into account when estimating the spatial variation of SOC pool would increase the accuracy in prediction and modeling of SOC movement at the watershed scale. Keywords: Soil organic carbon, Spatial variability, Terrain, Land use, Kriging

Abstract Reactive oxygen species (ROS) generated in aerobic metabolism and oxidative stress lead to macromolecules damage, such as to proteins, lipids, and DNA, which can be eliminated by the redox buffer mycothiol (AcCys‐GlcN‐Ins, MSH). Myo‐inositol‐phosphate synthase (Ino‐1) catalyzes the first committed step in the synthesis of MSH, thus playing a critical role in the growth of the organism. Although Ino‐1s have been systematically studied in eukaryotes, their physiological and biochemical functions remain largely unknown in bacteria. In this study, we report that Ino‐1 plays an important role in oxidative stress resistance in the gram‐positive Actinobacteria Corynebacterium glutamicum. Deletion of the ino‐1 gene resulted in a decrease in cell viability, an increase in ROS production, and the aggravation of protein carbonylation levels under various stress conditions. The physiological roles of Ino‐1 in the resistance to oxidative stresses were corroborated by the absence of MSH in the Δino‐1 mutant. In addition, we found that the homologous expression of Ino‐1 in C. glutamicum yielded a functionally active protein, while when expressed in Escherichia coliBL21(DE3), it lacked measurable activity. An examination of the molecular mass (Mr) suggested that Ino‐1 expressed in E. coliBL21(DE3) was not folded in a catalytically competent conformation. Together, the results unequivocally showed that Ino‐1 was important for the mediation of oxidative resistance by C. glutamicum.

Objective:To explore the effect of manipulation combined with treadmill training on delaying skeletal muscle atrophy after peripheral nerve injury.Methods:According to the computer random numbers, 96 male SD rats were randomly divided into 3 groups: normal control group, model control group and manipulation group, with 32 rats in each group. The model of the sciatic nerve transection of the outer membrane suture was established, the manipulation group was given manipulation therapy combined with treadmill training, the normal control group and the model control group without intervention. At 2, 3, 4 and 8 weeks after the intervention, wet weight and the number of muscle satellite cells of gastrocnemius muscle was detected in a group of 8 rats.Results:Compared with the model control group, the wet weight of gastrocnemius muscle increased steadily, and at 4th week was significantly higher than that in the model control group (P

The type VI secretion system (T6SS) is a versatile secretion system widely distributed in Gram-negative bacteria that delivers multiple effector proteins into either prokaryotic or eukaryotic cells, or into the extracellular milieu. T6SS participates in various physiological processes including bacterial competition, host infection, and stress response. Three pathogenic Yersinia species, namely Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica, possess different copies of T6SSs with distinct biological functions. This review summarizes the pathogenic, antibacterial, and stress-resistant roles of T6SS in Yersinia and the ion-transporting ability in Y. pseudotuberculosis. In addition, the T6SS-related effectors and regulators identified in Yersinia are discussed.

Traditionally, rockburst is considered as a dynamic phenomenon of sudden destruction of coal/rock mass. In this study, rockburst is treated as an event process rather than a phenomenon. This paper introduces typical rockburst process, its classification, mechanism of internal and external causes, and energy criterion. Analysis indicates that rockburst is a dynamic process that includes three sequential phases: burst start-up, burst energy transfer, and rockburst pressure behavior. Excessive static stress concentration in the strata nearby the target zone appears to be the internal cause of rockburst start-up, while the external cause is the disturbance of the static stress concentration and additional load transfer by the concentrated dynamic load occurred at further distance. Potential burst start-up area is the highest stress concentration zone within the region where stress is in the critical equilibrium state. With the identified internal and external factors that contribute to rockburst start-up, it is concluded that the rockburst preventive measures should focus on the monitoring and controlling of originating source of static and dynamic stress concentrations. Field practice proves that the reunderstanding of rockburst and the derived preventive measures are feasible and successful.

Remobilisation of non-structural carbohydrates (NSC) from leaves and stems and unloading into developing grains are essential for yield formation of rice. In present study, three recombinant inbred lines of rice, R91, R156 and R201 have been tested for source-flow-sink related attributes determining the nature of NSC accumulation and translocation at two nitrogen levels in the field. Compared to R91 and R156, R201 had lower grain filling percentage, harvest index, and grain yield. Meanwhile, R201 had significantly lower stem NSC translocation during grain filling stage. Grain filling percentage, harvest index, and grain yield showed the consistent trend with stem NSC translocation among the three lines. In comparison with R91 and R156, R201 had similarity in leaf area index, specific leaf weight, stem NSC concentration at heading, biomass, panicles m-2, spikelets per panicle, remobilization capability of assimilation in stems, sink capacity, sink activity, number and cross sectional area of small vascular bundles, greater number and cross sectional area of large vascular bundles, and higher SPAD, suggesting that source, flow, and sink were not the limiting factors for low stem NSC translocation and grain filling percentage of R201. However, R201 had significant higher stem and rachis NSC concentrations at maturity, which implied that unloading in the developing grains might result in low NSC translocation in R201. The results indicate that stem NSC translocation could be beneficial for enhancement of grain yield potential, and poor unloading into caryopsis may be the possible cause of low stem NSC translocation, poor grain filling and yield formation in R201.

Lignocellulosic biomass is an abundant and renewable resource for biofuels and bio-based chemicals. Vanillin is one of the major phenolic inhibitors in biomass production using lignocellulose. To assess the response of Corynebacterium glutamicum to vanillin stress, we performed a global transcriptional response analysis. The transcriptional data showed that the vanillin stress not only affected the genes involved in degradation of vanillin, but also differentially regulated several genes related to the stress response, ribosome/translation, protein secretion, and the cell envelope. Moreover, deletion of the sigH or msrA gene in C. glutamicum resulted in a decrease in cell viability under vanillin stress. These insights will promote further engineering of model industrial strains, with enhanced tolerance or degradation ability to vanillin to enable suitable production of biofuels and bio-based chemicals from lignocellulosic biomass.

Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds.

Extreme weather conditions with negative impacts can strongly affect agricultural production. In the Danjiangkou reservoir area, citrus yields were greatly influenced by cold weather conditions and drought stress in 2011. Soil straw mulching (SM) practices have a major effect on soil water and thermal regimes. A two-year field experiment was conducted to evaluate whether the SM practices can help achieve favorable citrus fruit yields. Results showed that the annual total runoff was significantly (P

Purpose This study aims to systematically review the efficacy and safety of total ankle replacement (TAR) and ankle fusion (AF) as treatment options for end-stage ankle arthritis. Methods A comprehensive literature search was conducted on data from multiple databases, including PubMed, The Cochrane Library, Construction and Building Materials, Embase, Web of Science, and Scopus for RCTs and prospective cohort studies comparing TAR and AF in patients with end-stage ankle arthritis from inception up to June, 2023. Our primary outcomes of interest included patients’ clinical function scores and complications. We employed Review Manager 5.4 and Stata/MP 14.0 software for the meta-analysis. Results Our analysis incorporated 13 comparative studies, including 11 prospective studies, one pilot RCT, and one RCT. The pooled results revealed no significant difference in postoperative Short Form-36 scores between the TAR and AF groups (MD = −1.19, 95% CI: −3.89 to 1.50, p = .39). However, the postoperative Foot and Ankle Ability Measure scores in the AF group were significantly higher than in the TAR group (MD = 8.30, 95% CI: 1.01–15.60, p = .03). There was no significant difference in postoperative complication rates between the TAR and AF groups (RR = 0.95, 95% CI: 0.59 to 1.54, p = .85). Conclusion Currently available evidence suggests no significant disparity in postoperative outcomes between TAR and AF. In the short term, TAR demonstrates better clinical scores than AF and lower complication rates. Conversely, in the long term, AF exhibits superior clinical scores and lower complication rates, although this difference is not statistically significant.

Tumor angiogenesis is a hallmark of cancer. Therapeutic drug inhibitors targeting angiogenesis are clinically effective. We have previously identified GT198 (gene symbol PSMC3IP, also known as Hop2) as an oncoprotein that induces tumor angiogenesis in human cancers, including oral cancer. In this study, we show that the GT198 protein is a direct drug target of more than a dozen oncology drugs and several clinically successful anticancer herbs. GT198 is a DNA repair protein that binds to DNA. Using an in vitro DNA-binding assay, we tested the approved oncology drug set VII from the National Cancer Institute containing 129 oncology drugs. Identified GT198 inhibitors include but are not limited to mitoxantrone, doxorubicin, paclitaxel, etoposide, dactinomycin, and imatinib. Paclitaxel and etoposide have higher binding affinities, whereas doxorubicin has higher binding efficacy due to competitive inhibition. GT198 shares protein sequence homology with DNA topoisomerases, which are known drug targets, so that GT198 is likely a new drug target previously unrecognized. To seek more powerful GT198 inhibitors, we further tested several anticancer herbal extracts. The positive anticancer herbs with high affinity and high efficacy are all clinically successful ones, including allspice from Jamaica, Gleditsia sinensis or honey locust from China, and BIRM from Ecuador. Partial purification of allspice using an organic chemical approach demonstrated great feasibility of natural product purification, when the activity is monitored by the in vitro DNA-binding assay using GT198 as a target. Together, our study reveals GT198 as a new targeting mechanism for existing oncology drugs. The study also delivers an excellent drug target suitable for compound identification and natural product purification. In particular, this study opens an opportunity to rapidly identify drugs with high efficacy and low toxicity from nature.

Background Soil phosphorus (P) deficiency is one of the major limiting factors to crop production. The development of crop varieties with improved P use efficiency (PUE) is an important strategy for sustainable agriculture. The objectives of this research were to identify quantitative trait loci (QTLs) linked to PUE traits using a high-density single nucleotide polymorphism (SNP) map and to estimate the epistatic interactions and environmental effects in rice (Oryza sativa L.). Results We conducted a two-year field experiment under low and normal P conditions using a recombinant inbred population of rice derived from Zhenshan 97 and Minghui 63 (indica). We investigated three yield traits, biomass (BIOM), harvest index (HI), and grain yield (Yield), and eight PUE traits: total P uptake (PUP), P harvest index (PHI), grain P use efficiency (gPUE) based on P accumulation in grains, straw P use efficiency (strPUE) based on P accumulation in straw, P use efficiency for biomass (PUEb) and for grain yield (PUEg) based on P accumulation in the whole plant, P translocation (PT), and P translocation efficiency (PTE). Of the 36 QTLs and 24 epistatic interactions identified, 26 QTLs and 12 interactions were detected for PUE traits. The environment affected seven QTLs and three epistatic interactions. Four QTLs (qPHI1 and qPHI2 for PHI, qPUEg2 for PUEg, and qPTE8 for PTE) with strong effects were environmentally independent. By comparing our results with similar QTLs in previous studies, three QTLs for PUE traits (qPUP1 and qPUP10 for PUP, and qPHI6 for PHI) were found across various genetic backgrounds. Seven regions were shared by QTLs for yield and PUE traits. Conclusion Most QTLs linked to PUE traits were different from those linked to yield traits, suggesting different genetic controls underlying these two traits. Those chromosomal regions with large effects that are not affected by different environments are promising for improving P use efficiency. The seven regions shared by QTLs linked to yield and PUE traits imply the possibility of the simultaneous improvement of yield and PUE traits. [ABSTRACT FROM AUTHOR]

Sophisticated biomimetic microstructures/nanostructures have attracted attention worldwide, but their fabrication technique significantly restricts their application. This study uses natural sharkskin to investigate amplification (i.e., the bioscaling forming process) and thus acquire a complex microstructure that cannot be fabricated by traditional micromachining techniques. The bioscaling forming process adjusts the optimal function region of natural surfaces by utilizing the solvent-swelling effect of polydimethylsiloxane. To accurately replicate amplified sharkskin, the swelling ratio and rate in gaseous and liquid n-hexane were investigated. Epoxy resin was used to produce a positive sharkskin mold. A comparison between the microstructure of the original and amplified sharkskin shows that the swelling ratio can reach a maximum of 34% with gaseous n-hexane and 39% with liquid n-hexane. The accuracy of bioscaling forming was higher than 95%. The drag-reducing effect was also tested. When the sharkskin was amplified 1.34 times, the optimal velocity range of the drag reduction moved from 5.0 to 3.5 m s-1. [ABSTRACT FROM AUTHOR]