The trade-off between yield and environmental effects caused by nitrogen fertilizer application is an important issue in wheat production.A reduction in fertile florets is one of the main reasons for the lower yields ...
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The trade-off between yield and environmental effects caused by nitrogen fertilizer application is an important issue in wheat production.A reduction in fertile florets is one of the main reasons for the lower yields under low nitrogen application ***(BRs)have been found to play a role in nitrogen-induced rice spikelet ***,whether BRs play a role in wheat floret development and the mechanisms involved are not ***,a nitrogen gradient experiment and exogenous spraying experiment were conducted to investigate the role and mechanism of BRs in wheat floret development under low nitrogen *** results showed that as the nitrogen application decreased,the endogenous BRs content of the spikes decreased,photosynthesis weakened,and total carbon,soluble sugar and starch in the spikes decreased,leading to a reduction in the number of fertile *** low nitrogen stress,exogenous spraying of 24-epibrassinolide promoted photosynthesis,and stimulated stem fructan hydrolysis and the utilization and storage of sucrose in spikes,which directed more carbohydrates to the spikes and increased the number of fertile *** conclusion,BRs mediate the effects of nitrogen fertilizer on wheat floret development,and under low nitrogen stress,foliar spraying of 24-epibrassinolide promotes the flow of carbohydrates from the stem to the spikes,alleviating wheat floret degeneration.
Aerostatic conical bearings (ACBs) are subjected to both radial and axial loads, so that the radial and axial vibrations of the system will be coupled with each other. However, research on the nonlinear behavior and s...
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Aerostatic conical bearings (ACBs) are subjected to both radial and axial loads, so that the radial and axial vibrations of the system will be coupled with each other. However, research on the nonlinear behavior and stability of the three-dimensional vibration system remains elusive. To do this, the three-dimensional transient nonlinear dynamics model of the ACB-rotor system is established in this paper. The effects of semi-cone angle, axial load, unbalance and clearance on nonlinear behaviors, onset speed of instability and failure speed are then investigated by the Gauss-Seidel and Newmark-beta methods, followed by experimental validation. The results show that, first, both the onset speed of instability and the failure speed initially increase and then decrease with the increase in semi-cone angle, whereas the excessively large semi-cone angle will render the system more prone to whirl. Second, the failure speed first increases and then decreases with the increase in axial load, and the system will exhibit instability within a specific range of axial loads. Third, increasing unbalance will suppress sub-synchronous vibrations and raise the onset speed of instability, while the excessive unbalance will reduce the failure speed. Finally, with the increase in clearance, the onset speed of instability first increases and then decreases while the failure speed consistently decreases. However, the excessively small clearance will induce system instability. This study can provide a basis for evaluating the stability of high-speed ACB-rotor systems.
NAD(P)H-dependent oxidoreductases are crucial biocatalysts for synthesizing chiral compounds. Yet, the industrial implementation of enzymatic redox reactions is often hampered by an insufficient supply of expensive ni...
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NAD(P)H-dependent oxidoreductases are crucial biocatalysts for synthesizing chiral compounds. Yet, the industrial implementation of enzymatic redox reactions is often hampered by an insufficient supply of expensive nicotinamide cofactors. Here, a cofactor self-sufficient whole-cell biocatalyst was developed for the enzymatic asymmetric reduction of 2-oxo-4-[(hydroxy)(-methyl)phosphinyl] butyric acid (PPO) to L-phosphinothricin (L-PPT). The endogenous NADP+ pool was significantly enhanced by regulating Preiss-Handler pathway toward NAD(H) synthesis and, in the meantime, introducing NAD kinase to phosphorylate NAD(H) toward NADP+. The intracellular NADP(H) concentration displayed a 2.97-fold increase with the strategy compared with the wild-type strain. Furthermore, a recombinant multi-enzyme cascade biocatalytic system was constructed based on the Escherichia coli chassis. In order to balance multi-enzyme co-expression levels, the strategy of modulating rate-limiting enzyme PmGluDH by RBS strengths regulation successfully increased the catalytic efficiency of PPO conversion. Finally, the cofactor self-sufficient whole-cell biocatalyst effectively converted 300 mM PPO to L-PPT in 2 h without the need to add exogenous cofactors, resulting in a 2.3-fold increase in PPO conversion (%) from 43% to 100%, with a high space-time yield of 706.2 g L-1 d-1 and 99.9% ee. Overall, this work demonstrates a technological example for constructing a cofactor self-sufficient system for NADPH-dependent redox biocatalysis. NADPH-dependent oxidoreductases are important catalysts for production of chiral compounds, but insufficient supply of expensive nicotinamide cofactors have prevented their widespread exploitation. In this study, the authors developed a metabolic engineering strategy and a multienzyme modulation strategy for a NADPH-dependent glufosinate dehydrogenases (GluDH) whole-cell biocatalytic system to enhance intracellular NADP+ pool and catalytic efficiency. The cofactor sel
Bearing remaining useful life (RUL) prediction is a major concern in prognostics and health management for industrial system. Recently, deep learning models have significantly advanced the development of RUL predictio...
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Bearing remaining useful life (RUL) prediction is a major concern in prognostics and health management for industrial system. Recently, deep learning models have significantly advanced the development of RUL prediction technologies. However, the accuracy of deep learning-based RUL prediction methods is easily affected by variable working conditions and multiple fault modes. In this paper, an information guided attention network (IGAN) is developed for bearing RUL prediction adaptive to working conditions and fault modes. First, the proposed IGAN builds the multiscale convolutional layers, which are multiple dilated convolutions with different dilation rates, to fully learn multiscale representations. This ensures that no degradation information of bearings under different working conditions and different fault modes is missed. Second, a novel plug-and-play attention block called information guided attention mechanism (IGAM) is designed to adaptively highlight the informative convolutional channels informed by working conditions and fault modes. Finally, a temporal attention mechanism is integrated into the IGAN to adaptively emphasize the degradation features at different temporal locations to further enhance the feature representation. Two case studies on a bearing dataset across different working conditions and a bearing dataset under time-varying working conditions are conducted to validate the effectiveness and superiority of the proposed method.
To meet the demands of high-speed and high-accuracy applications of robotic manipulators, this paper proposes a time-optimal multi-point trajectory planning method with continuous jerk and constant average acceleratio...
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To meet the demands of high-speed and high-accuracy applications of robotic manipulators, this paper proposes a time-optimal multi-point trajectory planning method with continuous jerk and constant average acceleration. A piecewise sine jerk model is developed for jerk continuity throughout the entire motion profile. An equivalent transformation of this complex model into the simple trapezoidal velocity model is proposed, effectively reducing the computational complexity and ensuring the reliability of real-time planning. The introduction of a parameter, named the trajectory smoothness coefficient, allows fora convenient trade-off between the priorities of speed and smoothness. The adaptive computation algorithm for peak jerk results in a constant average acceleration along paths of any length, ensuring a consistent level of work efficiency regardless of the density of path control points. Through a comprehensive evaluation of the critical constraints for each potential profile type, the single joint's time-optimal and multiple joints' time-synchronized planning problems are solved with closed-form solutions. Furthermore, by designing a multi-joint multi-point velocity look-ahead strategy, time-optimal multi-point trajectory planning for robotic manipulators is realized. Simulation and experimental results on a manipulator demonstrate the effectiveness of the proposed approach in improving time efficiency.
At present,most quantum secret sharing(QSS)protocols are more or less designed with the incorporation of classical secret sharing *** the increasing maturity of quantum technology,QSS protocols based on pure quantum m...
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At present,most quantum secret sharing(QSS)protocols are more or less designed with the incorporation of classical secret sharing *** the increasing maturity of quantum technology,QSS protocols based on pure quantum mechanics are becoming more *** secret sharing schemes cannot achieve absolute security,and their involvement can compromise the security of QSS *** paper proposes a QSS scheme based on Greenberger-Horn-Zeilinger(GHZ)basis measurement and quantum entanglement *** this protocol,the secret sender stores the secret information using Pauli *** obtain their shares by measuring the product state ***,participants complete the secret reconstruction through quantum entanglement exchange and other related quantum *** addition,the particles held by participants in the protocol do not contain any secret *** participant's particles are in a state of maximum entanglement,and no participant can deduce the particle information of other participants through their own *** the same time,the protocol is based on pure quantum mechanics and does not involve classical schemes,which avoids the problem of reduced security of the *** analysis indicates that the protocol is not vulnerable to retransmission interception and collusion ***,it is capable of detecting and terminating the protocol promptly when facing with attacks from dishonest participants.
Effective photocatalysts are essential for hydrogen production through water splitting. In this study, we predict a Z-scheme heterojunction composed of GeC and Janus SGaSnP monolayers. Binding energy analysis reveals ...
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Effective photocatalysts are essential for hydrogen production through water splitting. In this study, we predict a Z-scheme heterojunction composed of GeC and Janus SGaSnP monolayers. Binding energy analysis reveals that the heterojunction exhibits excellent thermodynamic stability, particularly in the B- and D-stacking configurations. The electronic structure of the heterojunction reveals strong charge separation and migration properties, driven by the built-in electric field and Janus monolayer polarization, effectively suppressing carrier recombination. Optical absorption and free energy calculations indicate strong visible light absorption, with low hydrogen evolution reaction (HER) free energy barriers of 0.23 eV for both B- and D-stacking configurations. The oxygen evolution reaction (OER) energy barriers are close to the theoretical minimum, at 1.44 eV and 1.48 eV, respectively. Nonadiabatic molecular dynamics (NAMD) simulations show extended electron and hole transfer times, highlighting the potential for efficient photocatalytic hydrogen and oxygen generation. These results suggest the GeC/SGaSnP Z-scheme heterojunction is a promising candidate for advancing photocatalytic water-splitting technologies, with strong catalytic performance and stability.
Enzymes are highly efficient natural catalysts widely used in green biocatalysis, chemical and pharmaceutical industries. However, their industrial applications are often limited by high costs, poor stability, and low...
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Enzymes are highly efficient natural catalysts widely used in green biocatalysis, chemical and pharmaceutical industries. However, their industrial applications are often limited by high costs, poor stability, and low activity. Metal-organic frameworks (MOFs), with their exceptional porosity, structural stability, and customizable properties, present a sustainable solution for enzyme immobilization, significantly enhancing stability, reusability, and catalytic efficiency in sustainable green processes. The stability of MOFs often relies on harsh synthesis conditions, while maintaining enzyme activity necessitates natural mild environments. Despite significant research efforts to improve enzymatic performance within MOFs, the trade-offs between MOF stability and enzyme activity in enzyme-MOF hybrid systems remain only partially understood. This review underscores the critical importance of achieving this balance, summarizes the key factors and interactions within enzymes@MOF systems, and provides a comprehensive review of recent advancements aimed at striking this equilibrium, thereby fostering the development of sustainable green catalytic technologies.
Acoustic thermometry is a fast, noncontact temperature measurement method that does not require heat exchange and, thus, is suitable for real-time monitoring of changes in air temperature at high altitudes where the t...
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Acoustic thermometry is a fast, noncontact temperature measurement method that does not require heat exchange and, thus, is suitable for real-time monitoring of changes in air temperature at high altitudes where the thin air is not conducive to establishing thermal equilibrium. In this work, real-time measurements of air temperature at altitudes of up to 5200 m were achieved using a passive acoustic thermometer, which is an acoustic Fabry-Perot resonator (AFPR), consisting of an electret condenser microphone and an acoustic waveguide. The resonant frequency (f(R)) of the AFPR as a linear function of the mode order number (m) is measured using ambient white noise instead of external sound source, and the air temperature is determined based on the slope of the f(R) versus m curve. The surface air temperature changes in Beijing and the Kashgar Plateau were measured in real time over more than 15 h using the AFPR. By mounting the AFPR on a tethered balloon, the continuous monitoring of air temperature during liftoff and descent of the balloon was tested. The average deviation between the results simultaneously measured with the AFPR and commercial electronic thermometer was less than 0.5 degrees C, which verified the reliability of the AFPR-based passive acoustic thermometry. (c) 2025 Acoustical Society of America.
Macrophages play a pivotal role in systemic lupus erythematosus(SLE)*** have been made to develop multifunctional drug delivery systems capable of directing macrophage ***,we present a novel hyaluronic acid methacryla...
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Macrophages play a pivotal role in systemic lupus erythematosus(SLE)*** have been made to develop multifunctional drug delivery systems capable of directing macrophage ***,we present a novel hyaluronic acid methacrylate(HAMA)hydrogel microparticle encapsulating multiple cytokines for SLE remission though enhancing macrophage *** HAMA microparticles loaded with monocyte chemotactic protein-1(MCP-1)and interleukin-4(IL-4)were fabricated by using a microfluidic *** released MCP-1 facilitates the aggregation of inflammatory macrophages,after which IL-4 induces the macrophage phenotype shift from inflammatory M1 to immune-protective M2,thus restoring immune *** have demonstrated in MRL/lpr mice that the hydrogel microparticles could improve their efficacy of intraperitoneal drug delivery,modulate immune function,and attenuate the disease *** results suggest that our proposed microparticles delivery platform has potential clinical value for treating autoimmune diseases.
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