Search Results (51)

Iron redox cycling in paddy soils drives the release and mineralisation of dissolved organic carbon (DOC), influencing the emission of CO₂ and CH₄. Light irradiation exerts an inhibitory effect on the mineralisation of soil organic carbon, but the responses to light intensity of iron redox processes coupled with organic carbon transformation and greenhouse gas emissions remain underexplored. Here, we conducted a slurry incubation experiment with paddy soil at varying light intensities. The dynamics of soil ferrous iron [Fe(II)], DOC, dissolved inorganic carbon (DIC), and chlorophyll a, as well as headspace CO₂ and CH₄, were monitored over a 40-day period. The results demonstrated that light irradiation inhibited iron reduction, leading to a 58.1–74.7% decrease in soil Fe(II) concentration compared to dark incubation. The oxidation of Fe(II) generated from iron reduction was enhanced under light incubation (3.12–3.53 mg g⁻¹), and the oxidation rate constant trended higher with increasing light intensity. Light irradiation reduced CO₂ and CH₄ emissions to 8.8–76.9% and 2.3–6.7% of those under dark incubation, respectively. With the extension of incubation time, soil DIC concentration showed an increase followed by a decrease under light incubation, and the earlier DIC decrease occurred at higher light intensities. The DOC decrease rate constant was greater under light incubation (0.024–0.042 d⁻¹) than under dark incubation (0.012 d⁻¹). Light irradiation activated phototrophic microorganisms producing chlorophyll a (4.71–6.46 mg g⁻¹), whereas this pigment was undetectable under dark incubation. Organic carbon mineralisation was positively correlated with Fe(II) concentration, and Fe(II) oxidation was positively correlated with chlorophyll a concentration and DOC decrease (p < 0.05). Agricultural practices optimizing light exposure, such as shallow flooding or reducing plant density, are promising approaches to bolster DOC sequestration and mitigate CO₂ and CH₄ emissions in paddy fields. Full article

As the area of land being reclaimed for cotton cultivation in the inland cotton region of Northwest China continues to expand, new requirements for variety selection and promotion have emerged. Therefore, research on the effects of cotton varieties and the environment is becoming increasingly essential. This study focuses on the role of variety and site factors in cotton production, specifically examining the impact of these factors on lint, seed cotton, and lint percentage. The research extends the application of the allometry allocation model by analyzing long-term experimental data from ecological network sites and national regional trials of cotton varieties. The results indicated that between 2012 and 2018, the average seed cotton yield in the regional trials in the inland northwest cotton region ranged from 44,667.8 kg/ha to 5462.7 kg/ha, while lint yield ranged from 2044.4 kg/ha to 2261.5 kg/ha. The fluctuations in seed cotton and lint yields were not consistent. Using the GGE model to evaluate the zoning of sites, it was found that cotton performance in the inland northwest cotton region showed considerable variation between subzones, with most sites exhibiting significant differentiation across years or indicators. At the site scale, lint yield and seed weight generally aligned with the allometry distribution model. For example, the allometry distribution index fluctuated year-to-year in sites like Shihezi, Tahe, and Aksu, while interannual fluctuations were smaller at sites like Kuqa and Shache. The results from the GGE model analysis of lint percentage differentiation were consistent with the allometry distribution index. These findings suggest that the allometry distribution model can effectively assess interannual variations in varietal differences across sites. These research findings provide a theoretical foundation for future crop variety selection, habitat selection, and variety structure development in the inland cotton region of Northwest China and similar regions. Full article

With increasing service life, concrete durability gradually deteriorates, requiring urgent repair and reinforcement. Conventional cement-based repair materials exhibit disadvantages such as high brittleness, low tensile strength, poor adhesion, and insufficient durability, making them inadequate for high-quality structural repairs. Based on the molecular structure–activity relationship, this study developed a novel waterborne epoxy–cement-based composite repair material using self-synthesized waterborne epoxy resin (WEP). The mechanism by which WEP improves the performance of cement-based materials was elucidated. The results indicate that WEP significantly influenced the early formation of silicate crystals. Furthermore, the addition of WEP enhanced material flexibility and adhesion, achieving flexural strength of 12.9 MPa and direct tensile bond strength of 2.13 MPa at 28 days, representing increases of approximately 30% and 58%, respectively, compared to the control group. Stress–strain curve analysis revealed that the ultimate strain of WEP-modified cement mortar reached 0.024%. SEM analysis revealed that cured WEP formed a dense cross-linked network with cement hydration products. This microstructural modification refined the pore structure, effectively addressing the material’s brittleness, ductility, and durability limitations. Full article

A total of 34 strains of bacteria were isolated from peanut rhizosphere soil, and all showed some in vitro inhibition of the pathogen Sclerotium rolfsii in co-culture. Strain YB-1632 produced the highest level of inhibition and also produced relatively high levels of biofilm in culture. Cell-free culture extracts and volatiles from it were also inhibitory to S. rolfsii. Based on 16S rDNA, gyrA, and gyrB sequences, it was identified as Bacillus siamensis. In the greenhouse, seed treatment resulted in a level of control of peanut sclerotium blight (PSB) comparable to that of a standard fungicide seed treatment. In addition to its antifungal activity, YB-1632 could induce disease resistance in peanut seedlings based on increasing peanut defense enzyme activities and gene expression. The priming of defense gene expression against a necrotrophic pathogen is consistent with Induced Systemic Resistance (ISR). In addition, YB-1632 produced enzyme activities in culture associated with root colonization and plant growth promotion. In the greenhouse, it increased peanut seedling growth, indicating the YB-1632 is a plant growth-promoting rhizobacterium (PGPR). In summary, YB-1632 is a promising novel PSB biocontrol agent and PGPR of peanut. Full article

Background/Objectives: The germination process initiates an active process of secondary metabolism, which produces a series of secondary metabolites, including flavonoids. Methods: A metabolomics and transcriptomics analysis was conducted on maize grains germinated at three different stages. Results: A total of 374 metabolites were detected in maize grains. From the raw maize grain to various stages of germination, 3 anthocyanins, 61 flavones, 12 flavonols, 13 flavanones, and 6 isoflavones were identified, respectively. An integrated omics analysis discovered that a total of 16 flavonoid metabolites were mapped to 4 KEGG pathways, which were associated with 40 related genes. This indicates that germination has significant benefits in improving the nutritional function of corn kernels. Conclusions: In summary, the findings of this study provide valuable insights into flavonoid metabolites and related genes, demonstrating the profound impact of germination treatment on the nutritional and functional aspects of maize grains. Full article

This study conducted an in-depth analysis of the landslide problem in the loess hill and gully area in northern Shaanxi Province, selecting the loess landslide site in Quchaigou, Ganquan County, Yan’an City, as the object to assess the stability of loess slopes under the conditions of different plant root densities and soil moisture contents through field investigation, physical mechanics experiments and numerical simulation of the GeoStudio model. Periploca sepium, a dominant species in the plant community, was selected to simulate the stability of loess slope soils under different root densities and soil water contents. The analysis showed that the stability coefficient of Periploca sepium natural soil root density was 1.263, which was a stable condition, but the stability of the stabilized slopes decreased with the increase in soil root density. Under the condition of 10% soil moisture content, the stability coefficient of the slope body is 1.136, which is a basic stable state, but with the increase in soil moisture content, the stability of the stable slope body decreases clearly. The results show that rainfall and human activities are the main triggering factors for loess landslides, and the vegetation root system has a dual role in landslide stability: on the one hand, it increases the soil shear strength, and on the other hand, it may promote water infiltration and reduce the shear strength. In addition, the high water-holding capacity and permeability anisotropy of loess may lead to a rapid increase in soil deadweight under rainfall conditions, increasing the risk of landslides. The results of this study are of great significance for disaster prevention and mitigation and regional planning and construction, and they also provide a reference for landslide studies in similar geological environments. Full article

The emulsion pump’s flow loss directly affects its performance and efficiency. However, the annular plunger chamber leakage and valve core hysteresis are challenging to avoid during operation. This study systematically investigated the impact of the annular gap in the plunger cavity on emulsion pump performance. Using theoretical analysis and computational fluid dynamics methods, it explored the mechanism of the port valve hysteresis during discharge. The simulation results show that the leakage of the annular gap is proportional to the gap thickness and the inlet pressure and inversely proportional to the dynamic viscosity of the emulsion. With the increase of plunger eccentricity, the leakage increases slowly. The increase in the outlet diameter of the port valve will lead to more significant hysteresis of the valve core. The change of outlet pressure has little effect on the hysteresis and flow of the spool, and the response speed of the wing-guided bevel discharge valve is faster than that of the ordinary poppet valve. Considering the above factors, the flow distribution process of the emulsion pump can be accurately analyzed, providing a reference for pump optimization. Full article

The continuous increase in the operating speed of rail vehicles demands higher requirements for passive safety protection and lightweight design. This paper focuses on an energy-absorbing component (circular tubes) at the end of a train. Thin-walled carbon fiber-reinforced polymer (CFRP) tubes were prepared using the filament winding process. Through a combination of sled impact tests and finite element simulations, the effects of a chamfered trigger (Tube I) and embedded trigger (Tube II) on the impact response and crashworthiness of the structure were investigated. The results showed that both triggering methods led to the progressive end failure of the tubes. Tube I exhibited a mean crush force (MCF) of 891.89 kN and specific energy absorption (SEA) of 38.69 kJ/kg. In comparison, the MCF and SEA of Tube II decreased by 21.2% and 21.9%, respectively. The reason for this reduction is that the presence of the embedded trigger in Tube II restricts the expansion of the inner plies (plies 4 to 6), thereby affecting the overall energy absorption mechanism. Based on the validated finite element model, a modeling strategy study was conducted, including the failure parameters (DFAILT/DFAILC), the friction coefficient, and the interfacial strength. It was found that the prediction results are significantly influenced by modeling methods. Specifically, as the interfacial strength decreases, the tube wall is more prone to circumferential cracking or overall buckling under axial impact. Full article

To solve the problem of large sowing amount and poor sowing uniformity for millet, according to the physical characteristics of the millet seed and its sowing agronomic requirements, an electromagnetic vibration type fine and small-amount seeder was designed, and the main technical parameters of the seeder were determined, in order to realize the functions of furrow opening, electronically controlled seed metering, soil covering and pressing. Based on the principle of electromagnetic vibration, an electromagnetic vibration type seed metering device was designed to achieve uniform seeding of the millet seed with a small sowing amount; a seeding amount electronic control device was designed using an STM32 microcontroller, which realized the switching to sowing agronomic mode and the adjustment of the seeding amount with sowing operation speed; a vibration experimental bench was set up to simulate the vibration state of field operation, and studies on the seeding performance and vibration damping of the seed metering device by the isolation spring were carried out, as well as field sowing tests for verification. When the working voltage of the seed metering device is 80–160 V, the coefficients of variation for seeding uniformity per row and for total seeding uniformity are not greater than 3.57% and 2.39%, respectively, and the seed damage rate is less than 0.5%. The installation of isolation springs can increase the maximum vibration acceleration of the seed metering device by 10.61–28.20%, significantly reducing the impact of external vibrations on the seed metering device. Within the range of suitable sowing operation speeds, the electronic control device can meet the seeding amounts along with sowing operation speed in the 6, 7.5 and 9 kg/hm² sowing agronomic modes, and the coefficient of variation for seeding uniformity per row, for total seeding uniformity and for sowing uniformity are not greater than 4.63%, 2.48% and 23.38%, respectively. This study provides a reference for the development of sowing machinery for millet crop. Full article

This study prepared resistant starch (RS) from waxy corn starch and normal corn starch and analyzed the effects of its molecular and microstructural characteristics on RS content. The RS content of waxy corn resistant starch (RS-WCS) was highest at 57.8%, whereas that of normal corn resistant starch (RS-NCS) was 41.46%. The short-chain amylose contents of RS-WCS and RS-NCS were 47.08% and 37.24%, respectively, proportional to their RS content. Additionally, RS content positively correlated with crystallinity, short-range order degree, and degree of polymerization (DP), exceeding 25. Electron microscopic images, before and after enzymolysis, revealed that RS-WCS was hydrolyzed from the surface to the center by pancreatic α-amylase, while RS-NCS underwent simultaneous hydrolysis at the surface and center. These results indicate that the higher RS content in RS-WCS, compared to RS-NCS, is attributable to the synergistic effects of molecular structure and microstructure. Full article

To enhance communication and collaborative work efficiency in cyber–physical systems (CPSs) within the Industry 4.0 environment, this study investigates a graph-based machine learning approach aimed at optimizing information interaction during multi-party conversations. Devices within CPSs must efficiently exchange information in real time to synchronize operations and responses. This research treats these interactions as intricate graph structures and uses graph learning techniques to accurately identify communication links and dependencies among devices. This improvement leads to more accurate decision-making and smoother operations. Our methodology involves a real-time analysis of structural patterns and node attributes within conversations, improving information flow and comprehension. The empirical findings demonstrate that this approach significantly enhances production efficiency, system adaptability, and minimizes delays attributed to communication misunderstandings. Our method can effectively identify the communication relationships between devices, significantly improving the efficiency and accuracy of information transmission. This improved communication capability leads to an enhanced production efficiency of the entire system. Full article

Background: After the adjustment of COVID-19 epidemic policy, mainland China experienced two consecutive waves of Omicron variants within a seven-month period. In Guangzhou city, as one of the most populous regions, the viral infection characteristics, molecular epidemiology, and the dynamic of population immunity are still elusive. Methods: We launched a prospective cohort study in the Guangdong Provincial CDC from December 2022 to July 2023. Fifty participants who received the same vaccination regimen and had no previous infection were recruited. Results: 90% of individuals were infected with Omicron BA.5* variants within three weeks in the first wave. Thirteen cases (28.26%) experienced infection with XBB.1* variants, occurring from 14 weeks to 21 weeks after the first wave. BA.5* infections exhibited higher viral loads in nasopharyngeal sites compared to oropharyngeal sites. Compared to BA.5* infections, the XBB.1* infections had significantly milder clinical symptoms, lower viral loads, and shorter durations of virus positivity. The infection with the BA.5* variant elicited varying levels of neutralizing antibodies against XBB.1* among different individuals, even with similar levels of BA.5* antibodies. The level of neutralizing antibodies specific to XBB.1* determined the risk of reinfection. Conclusions: The rapid large-scale infections of the Omicron variants have quickly established herd immunity among the population in mainland China. In the future of the COVID-19 epidemic, a lower infection rate but a longer duration can be expected. Given the large population size and ongoing diversified herd immunity, it remains crucial to closely monitor the molecular epidemiology of SARS-CoV-2 for the emergence of new variants of concern in this region. Additionally, the timely evaluation of the immune status across different age groups is essential for informing future vaccination strategies and intervention policies. Full article

Prenatal malnutrition may increase the risk of depressive symptoms in adulthood. This study investigated the association between prenatal exposure to malnutrition with risk of depressive symptoms in middle-aged and older adults using the Chinese Great Famine of 1959–1961 as a natural experiment. Data were obtained from the China Health and Retirement Longitudinal Study baseline survey (2011). A total of 5391 individuals born from 1956 to 1965 were included in the study. Depressive symptoms were ascertained via the Center for Epidemiological Studies Depression Scale short form. Famine severity was measured using the cohort size shrinkage index. Difference-in-differences models were used to explore the association between prenatal famine exposure and later-life depressive symptoms. Compared with the post-famine cohort (1963–1965), famine cohorts (1959–1962) were 4.74 times (95% CI = 1.28–8.20) as likely to develop depressive symptoms. The stratified analysis found that prenatal exposure to famine was associated with depressive symptoms in rural residents but not those living in urban areas. In rural females, prenatal malnutrition was associated with a higher risk of depressive symptoms. However, there was no significant association between prenatal malnutrition and depressive symptoms in rural males. Our results indicated that prenatal malnutrition may contribute to a higher risk for depressive symptoms in later life among female rural residents. Full article

High-strength alloyed steel has been widely used in engineering equipment because of its exceptional strength and toughness, particularly at low temperatures. However, the performance of high-strength alloy steel has not been fully developed, and it is necessary to further optimize the microstructure and mechanical properties. Therefore, the focus of this study is on the phase transition and corresponding mechanical properties of high-strength low-carbon alloyed steels. Three experimental steels were austenitized at 900 °C for 1 h, followed by water quenching, and were then tempered at 570, 600, and 630 °C. They were denoted as QT570, QIT600, and QIT630, respectively. The results show that appropriate intercritical tempering of QIT600 steel significantly increases the proportion of retained austenite and promotes VC precipitation within tempered martensite in comparison to QT570 and QIT630 steels. The enrichment of multiple alloys improved the thermal stability of retained austenite, which was further demonstrated with low-temperature insulation tests. Meanwhile, QIT600 steel with 18 vol.% of retained austenite achieved a superior yield strength of 1025 MPa, an elongation of 21%, and a cryogenic impact energy of 1.25 MJ/m². The plasticity induced by the transformation of the retained austenite significantly enhanced the strain-hardening rate and postponed necking, thereby increasing elongation. The retained austenite enhanced cryogenic toughness by significantly arresting crack growth and increasing the ability of plastic deformation. Full article

Mechanisms by which BK_Ca (large-conductance calcium-sensitive potassium) channels are involved in vascular remodeling in hypertension are not fully understood. Vascular smooth muscle cell (VSMC) proliferation and vascular morphology were compared between hypertensive and normotensive rats. BK_Ca channel activity, protein expression, and interaction with IP3R (inositol 1,4,5-trisphosphate receptor) were examined using patch clamp, Western blot analysis, and coimmunoprecipitation. On inside-out patches of VSMCs, the Ca²⁺-sensitivity and voltage-dependence of BK_Ca channels were similar between hypertensive and normotensive rats. In whole-cell patch clamp configuration, treatment of cells with the IP3R agonist, Adenophostin A (AdA), significantly increased BK_Ca channel currents in VSMCs of both strains of rats, suggesting IP3R-BK_Ca coupling; however, the AdA-induced increases in BK_Ca currents were attenuated in VSMCs of hypertensive rats, indicating possible IP3R-BK_Ca decoupling, causing BK_Ca dysfunction. Co-immunoprecipitation and Western blot analysis demonstrated that BK_Ca and IP3R proteins were associated together in VSMCs; however, the association of BK_Ca and IP3R proteins was dramatically reduced in VSMCs of hypertensive rats. Genetic disruption of IP3R-BK_Ca coupling using junctophilin-2 shRNA dramatically augmented Ang II-induced proliferation in VSMCs of normotensive rats. Subcutaneous infusion of NS1619, a BK_Ca opener, to reverse BK_Ca dysfunction caused by IP3R-BK_Ca decoupling significantly attenuated vascular hypertrophy in hypertensive rats. In summary, the data from this study demonstrate that loss of IP3R-BK_Ca coupling in VSMCs induces BK_Ca channel dysfunction, enhances VSMC proliferation, and thus, may contribute to vascular hypertrophy in hypertension. Full article