By deriving the Euler equations and Rankine–Hugoniot equations in the orthogonal frame field of the shock surface, the three-dimensional curved shock theory based on orthogonal frame of shock surface (3D-CST-boos) is established. In steady flow, this theory can be applied to three-dimensional (3-D) shocks without constraints on the incoming flow conditions. The derived equations elucidate the relationship between the first-order gradients of the preshock and postshock flow parameters and the geometric properties (curvature) of the 3-D curved shock. The correctness of 3D-CST-boos is verified for two-dimensional plane shocks and axisymmetric shocks. The analysis is then extended to the flow patterns of 3-D elliptical convex/concave shocks. Variations in the flow field behind a 3-D elliptical convex shock are explained based on different incoming flow conditions. Simultaneously, the fundamental mechanics underlying the differences between the flow fields of elliptical concave shocks and axisymmetric concave shocks are revealed using 3D-CST-boos. Finally, a concise analysis of the first-order flow parameters is presented for more complex 3-D shocks, including saddle-shaped shocks and cubic surface shocks.

Diastasis of rectus abdominis (DRA) is a common pathological condition in postpartum rehabilitation, but with limited treatment strategies. This study aimed to explore the effect of using a trunk-wearable neuromuscular electrical stimulation (NMES) device on postpartum women with moderate and severe DRA. A total of 84 postpartum women with an inter-rectus distance (IRD) of ≥3 cm were randomly assigned to two equal groups. The treatment group received a trunk-wearable NMES device and exercise therapy, whereas the control group received exercise only. We measured IRD and calculated treatment response proportion, improvement of trunk muscle strength, and low-back pain in both groups. Additionally, we evaluated quality of life (QoL) using the SF-36 questionnaire and Hernia-related Quality of Life Survey (HerQLes). Statistical analysis was performed using SAS 9.4. After 8-week treatment, the IRD of the umbilical (M3) sector showed a greater reduction in the treatment group (−10.6 [−17.9 to −3.3]%, p < 0.05). Patients in the treatment group had higher treatment response proportions (p = 0.0031 and p = 0.0010, W2 and W3, respectively). Additionally, the treatment group had higher Janda assessment scores and greater reduction in low-back pain (both p < 0.0001). QoL evaluation indicated greater improvements in the SF-36 questionnaire (pain and role-emotional scales,p < 0.05) and HerQLes (p < 0.0001) in the treatment group. The application of a trunk-wearable NMES device on DRA patients, accompanied by exercise therapy, significantly reduced IRD and increased the treatment response proportion. Moreover, we observed positive improvements in trunk muscle strength, low-back pain, and QoL.

The forced breakup of liquid jets in ambient gas surroundings is studied systematically through numerical simulations and theoretical analyses, with particular emphasis on characterising the response modes of jet breakup across wide ranges of perturbation frequency and amplitude. Simulations reveal that the breakup of liquid jet can be effectively synchronised with external actuation within a frequency range encompassing the natural breakup frequency, thereby enabling the generation of highly uniform droplets. As the perturbation frequency exceeds an upper critical value, the external perturbation cannot dominate the jet breakup, while below a lower critical frequency, the jet breaks up with multiple droplets generated within one period. A high perturbation amplitude can result in liquid accumulation, leading to the formation of a pancake-shaped jet configuration. Through spectrum analyses, the development of jet interface perturbations under different response modes is elucidated, revealing the competition between the natural frequency and the external frequency. A linear instability analysis of a liquid jet is performed, which successfully predicts the synchronised frequency range by comparing the breakup time between the free liquid jet and the actuated jet, along with the variation tendencies of jet breakup length with varying perturbation frequency, amplitude and jet velocity. Quantitative numerical results demonstrate that in the case of multiple droplet generation under low perturbation frequency, the rear droplet maintains a higher velocity than its leading counterpart and the emergence of a high-pressure zone at the leading edge of a droplet train facilitates the droplet coalescence. Furthermore, the study introduces an innovative approach by superimposing periodic pulses onto the sinusoidal perturbation waveform, enabling active modulation of multiple droplet merging dynamics. This fundamental study is intended to offer valuable guidance for the on-demand generation of droplets in various industrial applications.

Excavations at Aketala reveal traces of human activity at the oases of the western Tarim Basin, north-western China, by at least 2200 BC. The recovered artefacts indicate that, by 1800 BC, the Andronovo culture had reached this region, bringing agropastoralism and developing the earliest regional evidence of bronze manufacturing techniques.

We performed three-dimensional simulations to study the motion and interaction of microswimmers (pulling- and pushing-type squirmers) and spheres for Reynolds numbers ranging from 0.01 to 1 under conditions in which all particles were axially aligned with each other. We show that pullers are attractive and pushers are repulsive, in terms of the pressure at the front and rear of the squirmers. Correspondingly, the pullers always come close to each other and form a string that swims slightly faster than does a single puller. A possible reason for this finding is discussed. In contrast, whether a leading puller touches a trailing pusher depends primarily on its strength. When the two have similar strengths, they come into contact and form a stable doublet with finite inertia. The speed of the doublet is substantially higher than that of a single pusher owing to the additional force stemming from the fore and aft pressure differences of the doublet. We also demonstrate how a leading pusher interacts with a trailing puller, which is quite different. In contrast, a sphere can be directly or hydrodynamically ‘pushed’ to run by a puller or a pusher. In particular, we reveal that the sphere exhibits the highest speed when ‘pulled’ by a leading puller and ‘pushed’ by a trailing pusher simultaneously. Grouping behaviours reflect the interacting nature of the microswimmers and spheres from different aspects. A bunch of pushers/pullers eventually appears in pairs or forms a string depending on the Reynolds number, similar to groups of pushers/spheres and pullers/spheres.

Transonic buffet is a complex and strongly nonlinear unstable flow sensitive to variations in the incoming flow state. This poses great challenges for establishing accurate-enough reduced-order models, limiting the application of model-based control strategies in transonic buffet control problems. To address these challenges, this paper presents a time-variant modelling approach that incorporates rolling sampling, recursive parameter updating and inner iteration strategies under dynamic incoming flow conditions. The results demonstrate that this method successfully overcomes the difficulty in designing appropriate training signals and obtaining unstable steady base flow. Additionally, it improves the global predictive capability and identification efficiency of linear models for nonlinear flow-system responses by more than one order of magnitude. Furthermore, two adaptive control strategies – minimum variance control and generalised predictive control – are validated as effective based on the time-variant reduced-order model through numerical simulations of the transonic buffet flow over the NACA 0012 aerofoil. The adaptive controllers effectively regulate the unstable eigenvalues of the flow system, achieving the desired control outcomes. They ensure that the shock wave buffet phenomenon does not recur after control is applied, and that the actuator deflection, specifically the trailing-edge flap, returns to zero. Moreover, the control results further confirm the global instability essence of transonic buffet flow from a control perspective, thereby deepening the cognition of this nonlinear unstable flow.

With increasing age, many elderly individuals will not be able to stand normally. To solve this problem, a knee exoskeleton is designed. The knee joint is designed as a variable stiffness structure. It can adjust its stiffness according to the body’s movement state, ensuring precise assistance while also enhancing human comfort. The variable stiffness mechanism consists of an elastic output actuator and a stiffness-adjusting actuator. The elastic output actuator is mainly responsible for the output of the joint torque. The stiffness-adjusting actuator is mainly responsible for adjusting the joint stiffness. These two mechanisms are analysed separately. Based on their relationship with the whole mechanism, a stiffness model of the entire knee joint is established. Experiments are subsequently conducted to evaluate the variable stiffness joint. The stiffness identification experiment indicates that the actual stiffness of the whole knee joint is essentially consistent with the theoretical value. The trajectory tracking experiment demonstrates that the joint exhibits excellent trajectory tracking capability, although stiffness has a certain effect. The exoskeleton assistive effect experiment demonstrates the ability of the exoskeleton to assist in standing. Additionally, the experiment on subjects with exoskeletons of different stiffnesses determines the impact of stiffness on human comfort.

Thermal forcing in natural environments, such as Earth’s surface, exhibits complex spatiotemporal variations due to daily and seasonal cycles. This motivates our study of Rayleigh–Bénard convection with hybrid spatiotemporal modulation at the thermal boundary, achieved by applying a travelling thermal wave to a bottom plate with modulated wavenumber $k$ and frequency $f$. At low frequencies, spatial modulation dominates, organising coherent thermal plumes. At high frequencies, the rapid propagation of the thermal wave smooths out the plumes, thereby reducing convective efficiency. We find that the emergence of the ‘smoothing’ effect is governed by the ratio between the wave speed ($c = f/k$) and the pseudo-speed of thermal diffusion, $c_{\textit{diff}} = 4\pi k/\sqrt {\textit{RaPr}}$, a scale-dependent measure of thermal damping. By comparing these speeds, we identify distinct regimes: (i) a spatially modulated-dominated regime ($c\lt c_{\textit{diff}}$), in which the slow movement of the boundary thermal wave allows coherent thermal plumes to follow the wave, maintaining coherence in both time and space; and (ii) a travelling-wave-dominated regime ($c\gt c_{\textit{diff}}$), where the fast-moving thermal wave disrupts the spatial coherence of thermal structures near the boundary layer. These findings establish a new framework for understanding the interplay of spatial and temporal modulation, advancing our knowledge of heat transfer in systems with complex boundary conditions.

Regenerative involution is crucial for renewing the mammary gland and maximizing milk production. However, the temporal profiles indicators of oxidative status during this phase are still unclear. In this study, Experiment 1 aimed to investigate the dynamic changes in indicators of oxidative status in plasma during regenerative involution. The dairy goats were dried off at 8 weeks (wk) before kidding (−8 wk, n = 14) or −12 wk (n = 6). The blood samples taken at −8, −7, −6, −5, −4, −3, −2, −1 wk, on the day for kidding (0 wk) and the first week after kidding (+1 wk, milk production 1.28 ± 0.31 kg per day). Experiment 2 aimed to investigate the dynamic changes in indicators of oxidative status in mammary cells. Seven selected goats were biopsied for tissue collection and cell isolation at −8, −4, −1, +1 wk (milk production 1.28 ± 0.31 kg per day), respectively. Plasma analysis in Experiment 1 showed an increase in reactive oxygen species (ROS) levels, peaking at −4 wk (P < 0.01). No significant differences were observed between the dry-off treatments (P = 0.36). The activity of superoxide dismutase (SOD) in plasma remained stable from −7 wk to the first week after kidding (+1 wk), while glutathione peroxidase (GSH-Px) activity peaked at −4 wk. An increased catalase activity was observed at +1 wk (P < 0.01), indicating its response to lactation. In Experiment 2, an increase in ROS levels in isolated mammary cells was observed at −4 wk, while SOD, GSH-Px, and malondialdehyde levels in tissue homogenates rose around kidding (P < 0.01). The dynamic change of the oxidative status suggests that targeted antioxidant strategies would be helpful for regenerative involution of mammary gland in ruminants.

This paper presents a theoretical model for the electro-osmotic flow (EOF) of semi-dilute polyelectrolyte (PE) solutions in nanochannels. We use mean-field theories to describe the properties of electric double layer and viscosity of PE solutions that are prerequisites for constructing the EOF model. The EOF model is validated via a good match to the existing experimental results. Based on the validated EOF model, we conduct a comprehensive analysis of EOF of semi-dilute PE solutions in nanochannels. First, we observe considerable EOF of PE solutions in the uncharged nanochannels, which is in stark contrast to EOF of simple electrolyte solutions. The analyses show that the EOF of PE solutions in uncharged nanochannels is triggered by the external electric field acting on the near-wall non-electroneutral regions resulting from the confinement-induced inhomogeneous distribution of PE monomers. Although the solutions are electroneutral as a whole, the presence of local non-electroneutral regions and the mismatch between non-electroneutral regions and high-viscosity regions lead to the net EOF in uncharged nanochannels. Furthermore, we reveal that the EOF mobility $\mu _{{eof}}$ in uncharged nanochannels exhibits a scaling law $\mu _{{eof}} \propto a^{-0.44}$ (wherein $a$ denotes monomer Kuhn length) and is inversely proportional to the PE chain length, while it decreases nonlinearly with the charge fraction of the PE chains. Moreover, the EOF mobility reaches its maximum at specific bulk monomer concentration, and increases with the nanochannel height before converging to that under no confinement. Second, we analyse the EOF of PE solutions in nanochannels with various wall effects, such as surface charge density, slip length and adsorption length. When the surface charge is absent, the adsorption length significantly influences the direction and magnitude of the EOF, whereas the slip length has no effect. When the wall becomes increasingly charged, the influence of adsorption length on EOF gradually diminishes, while the importance of the slip length progressively intensifies and the EOF is highly influenced by the co-action of various wall effects in a complicated manner. When the surface wall is oppositely charged to polymer monomers, the EOF mobility varies nonlinearly with the surface charge density, while a zero net flow of EOF followed by a direction reversal is discovered when the wall is likely charged to polymer monomers.

This study elucidated the impacts of coenzyme Q10 (COQ10) supplementation in a high-fat diet (HFD) on growth, lipid metabolism and mitochondrial function in spotted seabass (Lateolabrax maculatus). Totally five diets were formulated: a diet with normal fat content (11 % lipid, NFD), a HFD (17 % lipid) and three additional diets by supplementing 5, 20 or 80 mg/kg of COQ10 to the HFD. After an 8-week culture period, samples were collected and analysed. The results demonstrated that COQ10 inclusion prevented the HFD-induced deterioration of growth performance and feed utilisation. COQ10 alleviated the deposition of saturated fatty acids following HFD intake and promoted the assimilation of n-3 and n-6 PUFA. Moreover, COQ10 administration inhibited the surge in serum transaminase activity and reduced hepatic lipid content following HFD ingestion, which was consistent with the results of oil red O staining. In addition, HFD feeding led to reduced hepatic citrate synthase and succinate dehydrogenase activities and decreased ATP content. Notably, COQ10 administration improved these indices and up-regulated the expression of mitochondrial biogenesis-related genes (pgc-1α, pgc-1β, nrf-1, tfam) and autophagy-related genes (pink1, mul1, atg5). In summary, supplementing 20–80 mg/kg of COQ10 in the HFD promoted growth performance, alleviated hepatic fat accumulation and enhanced liver mitochondrial function in spotted seabass.

Based on a 4f system, a 0° reflector and a single laser diode side-pump amplifier, a new amplifier is designed to compensate the spherical aberration of the amplified laser generated by a single laser diode side-pump amplifier and enhance the power of the amplified laser. Furthermore, the role of the 4f system in the passive spherical aberration compensation and its effect on the amplified laser are discussed in detail. The results indicate that the amplification efficiency is enhanced by incorporating a 4f system in a double-pass amplifier and placing a 0° reflector only at the focal point of the single-pass amplified laser. This method also effectively uses the heat from the gain medium (neodymium-doped yttrium aluminium garnet) of the amplifier to compensate the spherical aberration of the amplified laser.

This study aims to investigate the effects of the vine of Lonicera japonica Thunb (VLT) and marine-derived Bacillus amyloliquefaciens-9 (BA-9) supplementation on the growth performance, antioxidant capacity, and gut microbiota of goat kids. A total of 32 4-week-old kids were randomly assigned into four groups: a control group (CON), a group supplemented with 0.3% BA-9 (BA-9), a group supplemented with 2% VLT (VLT), and a group supplemented with both 0.3% BA-9 and 2% VLT (MIX). The results indicated that VLT supplementation significantly increased both average daily (P < 0.001) and total weight gain (TWG) (P < 0.001), while BA-9 alone had no significant effect (P > 0.05) on the average daily and TWG. Biomarker analysis of oxidative stress revealed that supplementation of VLT or BA-9 alone enhanced antioxidant capacity. The MIX group showing a higher total antioxidant capacity (T-AOC) compared with the CON, VLT, and BA-9 groups (P < 0.05). Plasma albumin (ALB) levels were significantly increased in the both VLT and BA-9 groups. Microbiota analysis revealed significant differences in α-diversity and β-diversity between the MIX and CON groups, with specific genera such as Prevotellaceae_UCG.004 and Rikenellaceae_RC9_gut_group negatively correlated with average daily gain (ADG), while Alistipes was positively correlated with T-AOC. These findings suggest that the combined supplementation of VLT and BA-9 can significantly enhance growth performance and antioxidant capacity in goat kids by modulating the composition of gut microbiota and reducing oxidative stress.

This study proposes a novel super-resolution (or SR) framework for generating high-resolution turbulent boundary layer (TBL) flow from low-resolution inputs. The framework combines a super-resolution generative adversarial neural network (SRGAN) with down-sampling modules (DMs), integrating the residual of the continuity equation into the loss function. The DMs selectively filter out components with excessive energy dissipation in low-resolution fields prior to the super-resolution process. The framework iteratively applies the SRGAN and DM procedure to fully capture the energy cascade of multi-scale flow structures, collectively termed the SRGAN-based energy cascade reconstruction framework (EC-SRGAN). Despite being trained solely on turbulent channel flow data (via ‘zero-shot transfer’), EC-SRGAN exhibits remarkable generalization in predicting TBL small-scale velocity fields, accurately reproducing wavenumber spectra compared to direct numerical simulation (DNS) results. Furthermore, a super-resolution core is trained at a specific super-resolution ratio. By leveraging this pretrained super-resolution core, EC-SRGAN efficiently reconstructs TBL fields at multiple super-resolution ratios from various levels of low-resolution inputs, showcasing strong flexibility. By learning turbulent scale invariance, EC-SRGAN demonstrates robustness across different TBL datasets. These results underscore the potential of EC-SRGAN for generating and predicting wall turbulence with high flexibility, offering promising applications in addressing diverse TBL-related challenges.

Integrons are important genetic elements that allow easy acquisition and dissemination of antimicrobial resistance genes. Studies reporting occurrence of integrons in Staphylococcus aureus (S. aureus) isolated from bovine mastitis in large dairy farms across China are scarce. The aim of this study was to investigate the occurrence of class 1 integrons (intI1), antimicrobial resistance (AMR) and associated genes in S. aureus isolated from bovine mastitis and their associations. Minimum inhibitory concentrations (MICs) were determined to evaluate the AMR phenotypes, whereas PCR was carried out to assess the occurrence of AMR genes and intI1. In addition, index cluster analysis was used to estimate associations between AMR phenotype, genotype and intI1 in 103 isolates. Overall, 83% of S. aureus were intI1-positive and 5 types of gene cassettes were detected. Susceptibility against single antimicrobial agents ranged from 0% (erythromycin), 12% (ampicillin) and 16% (penicillin G) to 96% (gentamicin). Most isolates (64%) were intermediate-resistant against erythromycin, whereas resistance against ceftriaxone (22%), clindamycin (4%), cefotaxime (2%), tetracycline (1%) and ciprofloxacin (1%) were relatively uncommon. The predominant resistant gene was blaZ gene (n = 88, 85%) followed by tetD gene (n = 85, 83%). With an estimated prevalence of 12% of the mecA gene, methicillin-resistant S. aureus isolates had higher MIC50 and MIC90 for majority of antimicrobials than methicillin-susceptible S. aureus isolates. Presence of the ermC gene was associated with erythromycin resistance. Ampicillin, erythromycin and penicillin G resistance were associated with intI1. The data presented in our study indicated that class 1 integron-mediated resistance possibly plays an important role in dissemination of AMR in S. aureus isolated from bovine mastitis.

The formation and structure of hematite aggregates were examined by dynamic and static light scattering techniques. A large range in coagulation kinetics was studied by varying either indifferent electrolyte (KCl) concentration or surface complexing anion (H2PO4-) concentration, PT, at pH 6.0 ± 0.1. Diffusion limited aggregation (DLA) was induced by counterion screening at [KCl] > 80 mM or by surface charge neutralization at P T = 31 μM (and ionic strength =1.0 mM). In DLA, the fractal dimension, df, of aggregates formed by either surface charge neutralization or counterion screening was 1.7 ± 0.1. A reduction in the rate of coagulation in KCl for [KCl] > critical coagulation concentration (CCC) produced an increase in df to 2.1 ± 0.1. For aggregation induced by phosphate adsorption at constant ionic strength, there was no apparent trend in df with coagulation rate. The value of df was consistently less than 1.8 when reaction limited aggregation (RLA) resulted from surface charge neutralization rather than counterion screening. TEM observations of aggregates formed in the presence or absence of phosphate confirm that, when RLA is induced by phosphate adsorption, resulting aggregates are much looser in structure than those formed by counterion screening. The results suggest that the high-affinity binding of phosphate to hematite may result in a nonrandom distribution of surface charge that facilitates the coalescence of positive and negative charge crystal faces.

The surface modification of Zeolite 4A using cetyl trimethyl ammonium bromide (CTAB) as a modifier via an ultrasonic method was carried out and the surface physicochemical properties measured. Response surface methodology (RSM) was developed with CTAB concentration, handling time, and handling temperature as variables, to help predict the performance of the modified zeolite under particular conditions. The influence of organic-modified surface treatment and of the amount of modified zeolite on the water-absorption capability of starch-g-poly (acrylic acid) hydrogel composites was also assessed. The results showed that the channels and skeleton structure of zeolite 4A were unchanged after organic modification by CTAB and the surface modification was effective. The results suggest that organic-modified zeolite 4A has improved the water-absorption capability.

Aiming to identify the complexing mechanisms of heavy metal cations on edge surfaces of 2:1-type clay minerals, systemic first-principles molecular dynamics (FPMD) simulations were conducted and the microscopic structures and complex free energies were obtained. Taking Cd(II) as a model cation, the structures on both (010) and (110) edges of the complexes were derived for the three possible binding sites (≡SiO, ≡Al(OH)2/≡AlOH≡AlSiO, and vacant sites). The stable complexes adsorbed on the three binding sites on both terminations had similar structures. The free energies of the complexes on (010) edges were calculated by using the constrained FPMD method. The free energies of complexes on the ≡SiO and ≡Al(OH)2 sites were similar and they were both significantly lower than the free energy of the complex on the octahedral vacant site. In association with the concept of high energy site (HES) and low energy site (LES) in the 2 Site Protolysis Non Electrostatic Surface Complexation and Cation Exchange (2SPNE SC/CE) sorption model, the vacant site was assigned to HES and the other two sites to LES, respectively.