Effects of Ultrasonic and Microwave Pretreatments on Calcium Chelating Capacity, Structure and Stability of Walnut Meal Protein Peptides

In this study, a mixture of ultrasound or microwave pretreated walnut meal protein peptides and CaCl2 was used for the preparation of walnut peptide-calcium chelate. The effects of different pretreatments on the calcium chelating capacity, structural changes and stability of walnut meal protein peptides were analyzed. The results showed that compared with walnut meal protein peptide-calcium chelate (WPP-Ca), the chelation rates of ultrasound-pretreated walnut meal protein peptide-calcium chelate (UP-WPP-Ca) and microwave-pretreated walnut meal protein peptide-calcium chelate (MP-WPP-Ca) were enhanced, which indicated that ultrasound and microwave pretreatments improved the calcium-chelating capacity of the peptides effectively. Using ultraviolet-visible (UV-Vis) absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy, it was found that ultrasound and microwave pretreatments mainly affected the calcium ion binding sites such as amino groups, carbonyl groups, carboxyl groups, amide bonds and carboxylate groups of walnut meal protein peptides. The results of X-ray diffraction (XRD) showed that ultrasound and microwave treatments changed the molecular arrangement of walnut meal protein peptides, thereby making the structure of walnut peptide-calcium chelate more ordered. Fluorescence spectroscopy showed that ultrasonic and microwave treatments promoted the chelation between aromatic amino acids and calcium ions. In addition, UP-WPP-Ca and MP-WPP-Ca showed good stability toward different pH values, temperatures, and gastrointestinal digestion. In short, ultrasonic and microwave pretreatments can improve the calcium-chelating capacity and stability of walnut meal protein peptides, which is of guiding significance for the processing of walnut peptide-calcium chelate and the development of calcium supplements

Transcutaneous auricular vagus nerve stimulation on upper limb motor function with stroke: a functional near-infrared spectroscopy pilot study

BackgroundTranscutaneous auricular vagus nerve stimulation (taVNS) emerges as a promising neuromodulatory technique. However, taVNS uses left ear stimulation in stroke survivors with either left or right hemiparesis. Understanding its influence on the cortical responses is pivotal for optimizing post-stroke rehabilitation protocols.ObjectiveThe primary objective of this study was to elucidate the influence of taVNS on cortical responses in stroke patients presenting with either left or right hemiparesis and to discern its potential ramifications for upper limb rehabilitative processes.MethodsWe employed functional near-infrared spectroscopy (fNIRS) to ascertain patterns of cerebral activation in stroke patients as they engaged in a “block transfer” task. Additionally, the Lateralization Index (LI) was utilized to quantify the lateralization dynamics of cerebral functions.ResultsIn patients exhibiting left-side hemiplegia, there was a notable increase in activation within the pre-motor and supplementary motor cortex (PMC-SMC) of the unaffected hemisphere as well as in the left Broca area. Conversely, those with right-side hemiplegia displayed heightened activation in the affected primary somatosensory cortex (PSC) region following treatment.Significantly, taVNS markedly amplified cerebral activation, with a pronounced impact on the left motor cortical network across both cohorts. Intriguingly, the LI showcased consistency, suggesting a harmonized enhancement across both compromised and uncompromised cerebral regions.ConclusionTaVNS can significantly bolster the activation within compromised cerebral territories, particularly within the left motor cortical domain, without destabilizing cerebral lateralization. TaVNS could play a pivotal role in enhancing upper limb functional restoration post-stroke through precise neuromodulatory and neuroplastic interventions

Synchronization Control of a Dual-Cylinder Lifting Gantry of Segment Erector in Shield Tunneling Machine under Unbalance Loads

Segment assembling is one of the principle processes during tunnel construction using shield tunneling machines. The segment erector is a robotic manipulator powered by a hydraulic system to assemble prefabricated concrete segments onto the excavated tunnel surface. Nowadays, automation of the segment erector has become one of the definite developing trends to further improve the efficiency and safety during construction; thus, closed-loop motion control is an essential technology. Within the segment erector, the lifting gantry is driven by dual cylinders to lift heavy segments in the radial direction. Different from the dual-cylinder mechanism used in other machines such as forklifts, the lifting gantry usually works at an inclined angle, leading to unbalanced loads on the two sides. Although strong guide rails are applied to ensure synchronization, the gantry still occasionally suffers from chattering, “pull-and-drag”, or even being stuck in practice. Therefore, precise motion tracking control as well as high-level synchronization of the dual cylinders have become essential for the lifting gantry. In this study, a complete dynamics model of the dual-cylinder lifting gantry is constructed, considering the linear motion as well as the additional rotational motion of the crossbeam, which reveals the essence of poor synchronization. Then, a two-level synchronization control scheme is synthesized. The thrust allocation is designed to coordinate the dual cylinders and keep the rotational angle of the crossbeam within a small range. The motion tracking controller is designed based on the adaptive robust control theory to guarantee the linear motion tracking precision. The theoretical performance is analyzed with corresponding proof. Finally, comparative simulations are conducted and the results show that the proposed scheme achieves high-precision motion tracking performance and simultaneous high-level synchronization of dual cylinders under unbalanced loads

A Novel Robust <i>H</i>_∞ Control Approach Based on Vehicle Lateral Dynamics for Practical Path Tracking Applications

This paper proposes a robust lateral control scheme for the path tracking of autonomous vehicles. Considering the discrepancies between the model parameters and the actual values of the vehicle and the fluctuation of parameters during driving, the norm-bounded uncertainty is utilized to deal with the uncertainty of model parameters. Because some state variables in the model are difficult to measure, an H∞ observer is designed to estimate state variables and provide accurate state information to improve the robustness of path tracking. An H∞ state feedback controller is proposed to suppress system nonlinearity and uncertainty and produce the desired steering wheel angle to solve the path tracking problem. A feedforward control is designed to deal with road curvature and further reduce tracking errors. In summary, a path tracking method with H∞ performance is established based on the linear matrix inequality (LMI) technique, and the gains in observer and controller can be obtained directly. The hardware-in-the-loop (HIL) test is built to validate the real-time processing performance of the proposed method to ensure excellent practical application potential, and the effectiveness of the proposed control method is validated through the utilization of urban road and highway scenes. The experimental results indicate that the suggested control approach can track the desired trajectory more precisely compared with the model predictive control (MPC) method and make tracking errors within a small range in both urban and highway scenarios

Ability of different edible fungi to degrade crop straw

Abstract Extracellular enzymes play an important role in the growth and development of edible fungi. Extracellular enzyme activities have also become an important object of measurement. In this study, Agaricus brunnescens Peck, Coprinus comatus, and Pleurotus ostreatus were compared in terms of their enzyme production in liquid-and solid-state fermentation. Differences in the ability of various types of edible fungi to utilize biomass raw materials were analyzed by monitoring the fiber degradation rate during crop straw degradation, and changes in their cellulolytic enzyme systems during growth and metabolism were discussed. This study provided insights into the changes in the lignocellulose degradation ability of edible fungi during their growth and facilitated the discovery of new approaches to accelerate their growth in culture

“I care about winning some but losing none!”—Attentional mechanism of mutable-hidden zero effect in economic choices

In risk-related economic choices, designating zero as “winning $0” or “losing$0” asymmetrical shapes subsequent decision preferences – a phenomenon known as the mutable-zero effect. However, little is known about whether mutable-zero effect pertains to risky decision-making and what cognitive mechanisms underlie it. Here, we examine this question by conducting an eye-tracking experiment where participants (N = 110) chose between certain and risky options. Critically, risky options (“p% to win $X” in the gain domain, and “p$X” in the loss domain) were companioned with either explicit zero outcomes as “(1-p)% to win $0” or “(1-p)$0”, or hidden zero outcomes. We found, in small to medium probability intervals, that participants were more risk-aversive when observing “win $0” yet more risk-seeking when observing “lose$0”. By combining attentional drift diffusion modeling (aDDM) with cumulative prospect theory (CPT), we tested whether it was attention or value computation that give rise to our mutable-zero findings. We found that the mutable-zero effect arose from attentional bias and the starting point in the aDDM rather than from CPT-related parameters. Specifically, the attentional mechanism was asymmetrically attributed to the non-zero outcomes when presented with “win $0” as well as zero outcomes when presented with “lose$0”. These findings provide insights into the attentional mechanism underlying the mutable-zero effect and shed light on the role of “null outcomes” in economic choices

Temporal variation in soil respiration and its sensitivity to temperature along a hydrological gradient in an alpine wetland of the Tibetan Plateau

Wetlands are predicted to experience lowered water tables due to permafrost degradation in the Tibetan Plateau. These changes may affect carbon cycle processes such as soil respiration (R-s). However, the magnitude, patterns and controls of R-s remain poorly understood in alpine wetlands with their distinct hydrological regimes. Here, we conducted a field study on R-s from 2012 to 2014 in three alpine ecosystems on the Tibetan Plateau-fen, wet meadow and meadow-with soil water decreases along hydrological gradients. From 2012 to 2014, the annual R-s was 128.9-193.3 g C m(-2)yr(-1), 281.5-342.9 g C m(-2)yr(-1), and 663.4-709.1 g C m(-2)yr(-1) for the fen, wet meadow, and meadow, respectively. An abrupt increase in CO2 emissions was caused by the spring thawing of the frozen soil in the fen and wet meadow, contributing 20.4-37.6% and 13.2-17.4%, respectively, to the annual R-s. The diurnal variation in the R-s was site specific among the three ecosystems, with one peak at 1300 h in the fen and meadow and two peaks at 1300 h and 1900 h in the wet meadow. The temperature-independent components of the diurnal variation in R-s were generally explained by photosynthetically active radiation in the fen and wet meadow, but not in the meadow. The temperature sensitivity of the R-s (unconfounded Q(10)) varied significantly among the three ecosystems, with the highest values occurring in the wet meadow, implying that permafrost thaw-induced wetland drying from the fen to the wet meadow could enhance the response of CO2 emissions to climate warming but that further drying from the wet meadow to the meadow probably weakens the effect of warming on the R-s. Our study emphasized the important role of the hydrological regime in regulating the temporal variation in R-s and its response to climate warming

Functional expression of Trametes versicolor thermotolerant laccase variant in Pichia pastoris

A mutational laccase gene MLcc1 was synthesized with modified codons, based on the codon bias of Pichia pastoris, in order to improve the thermal stability of Trametes versicolor laccase. The mutant gene was subcloned into the expression vector pGAPZαA and was transformed into P. pastoris strain X33. The mature protein consisted of 498 amino acids and contained a changed aspartate with proline at the 14th position of the native laccase (NLCC1). Under optimum conditions, the laccase activity reached 194.06 U/L after 54 h by high cell density fermentation in a 5 L fermenter. After incubation at pH 4.6 for 2 h, the recombinant enzyme MLCC1 retained 54.9% of its maximum activity, whereas the wild-type enzyme retained about 50% of its maximum activity. More than 20% of the residual activity was detected after up to 120 min at 90 °C for MLCC1, whereas less than 10% of the activity was retained for NLCC1