Particle-resolved direct numerical simulations are employed to investigate the particle–particle drag force in the bidisperse gas–particle suspensions where the particles are smooth and the single-particle velocity distribution function is Maxwellian. The particle Reynolds number ranges from 6.7 to 123.8, and in this range the particle inertia is high enough that the lubrication force is not essential. It is found that the relation derived by the kinetic theory of granular flow (KTGF) highly overestimates the particle–particle drag force. This is because the pre-collision velocities of colliding particles are not completely uncorrelated with each other. From the time sequence of collision events, it is observed that the particle pair that has just collided will probably collide again after a short time due to the restriction of the particle motion in dense suspensions. Since the post-collision velocities of the first collision cannot relax entirely in such a short time, the relative velocity before the subsequent collision is statistically smaller than the domain-averaged relative velocity. Consequently, the particle–particle drag force is over-predicted when the domain-averaged relative velocity is used. For this reason, this work assumes that the particle–particle drag force is determined by the relative velocity within a local region near large particles. When the local region is set to be the spherical shells centred on the centres of large particles and with an outer radius of a mean free path of small particles, the KTGF-based relation can reasonably predict the particle–particle drag force.

Biped robots with dynamic motion control have shown strong robustness in complex environments. However, many motion planning methods rely on models, which have difficulty dynamically modifying the walking cycle, height, and other gait parameters to cope with environmental changes. In this study, a heuristic model-free gait template planning method with dynamic motion control is proposed. The gait trajectory can be generated by inputting the desired speed, walking cycle, and support height without a model. Then, the stable walking of the biped robot can be realized by foothold adjustment and whole-body dynamics model control. The gait template can be changed in real time to achieve gait flexibility of the biped robot. Finally, the effectiveness of the method is verified by simulations and experiments of the biped robot BHR-B2. The research presented here helps improve the gait transition ability of biped robots in dynamic locomotion.

Pattern-forming with externally imposed symmetry is ubiquitous in nature but little studied. We present experimental studies of pattern formation and selection by spatial periodic forcing in rapidly rotating convection. When periodic topographic structures are constructed on the heated boundary, they modulate the local temperature and velocity fields. Symmetric convection patterns in the form of regular vortex lattices are observed near the onset of convection, when the periodicity of the external forcing is set close to the intrinsic vortex spacing. We show that the new patterns arise as a dynamical process of imperfect bifurcation which is well described by a Ginzburg–Landau-like model. We explore the phase diagram of buoyancy strength and periodicity of external forcing to find the optimal experimental settings for which the vortex patterns best match that of the external forcing.

This study is performed to figure out how the presence of diabetes affects the infection, progression and prognosis of 2019 novel coronavirus disease (COVID-19), and the effective therapy that can treat the diabetes-complicated patients with COVID-19. A multicentre study was performed in four hospitals. COVID-19 patients with diabetes mellitus (DM) or hyperglycaemia were compared with those without these conditions and matched by propensity score matching for their clinical progress and outcome. Totally, 2444 confirmed COVID-19 patients were recruited, from whom 336 had DM. Compared to 1344 non-DM patients with age and sex matched, DM-COVID-19 patients had significantly higher rates of intensive care unit entrance (12.43% vs. 6.58%, P = 0.014), kidney failure (9.20% vs. 4.05%, P = 0.027) and mortality (25.00% vs. 18.15%, P < 0.001). Age and sex-stratified comparison revealed increased susceptibility to COVID-19 only from females with DM. For either non-DM or DM group, hyperglycaemia was associated with adverse outcomes, featured by higher rates of severe pneumonia and mortality, in comparison with non-hyperglycaemia. This was accompanied by significantly altered laboratory indicators including lymphocyte and neutrophil percentage, C-reactive protein and urea nitrogen level, all with correlation coefficients >0.35. Both diabetes and hyperglycaemia were independently associated with adverse prognosis of COVID-19, with hazard ratios of 10.41 and 3.58, respectively.

A droplet impinging on a superhydrophobic substrate in an electric field is an important process in droplet manipulation and electrostatic spraying. Here, the entire impinging dynamic of the droplet in a vertical electric field is studied by a visualization experiment and numerical simulation with OpenFOAM. We investigate the effect of an electrostatic force on droplet impact in depth, where four ejection modes and three rebound modes are found experimentally. In particular, the filamentous ejecting phenomenon occurs after a droplet impinging on a superhydrophobic substrate is first discovered. In the numerical simulation, the strong coupling between the dynamic distribution of the interface electric charge and the evolution of the droplet profile can lead to different ejection modes, and the different ejection behaviours are caused by the combined effects of electrostatic pressure, capillary pressure, dynamic pressure and static pressure on the droplet apex. A charge scaling law for the ejection droplets is proposed. Furthermore, a set of theoretical models is established, which can successfully predict the threshold electric capillary number for different droplet ejection modes. The results reveal some important characteristics for a droplet impinging on a superhydrophobic surface in an electric field, which could facilitate the design of electrically operated droplet equipment and guide the safe and stable operation of the device.

This study examined the influences of coated folic acid (CFA) and coated riboflavin (CRF) on bull performance, nutrients digestion and ruminal fermentation. Forty-eight Angus bulls based on a randomised block and 2 × 2 factorial design were assigned to four treatments. The CFA of 0 or 6 mg of folic acid/kg DM was supplemented in diets with CRF 0 or 60 mg riboflavin (RF)/kg DM. Supplementation of CRF in diets with CFA had greater increase in daily weight gain and feed efficiency than in diets without CFA. Supplementation with CFA or CRF enhanced digestibility of DM, organic matter, crude protein, neutral-detergent fibre and non-fibre carbohydrate. Ruminal pH and ammonia N content decreased and total volatile fatty acids concentration and acetate to propionate ratio elevated for CFA or CRF addition. Supplement of CFA or CRF increased the activities of fibrolytic enzymes and the numbers of total bacteria, protozoa, fungi, dominant fibrolytic bacteria and Prevotella ruminicola. The activities of α-amylase, protease and pectinase and the numbers of Butyrivibrio fibrisolvens and Ruminobacter amylophilus were increased by CFA but were unaffected by CRF. Blood concentration of folate elevated and homocysteine decreased for CFA addition. The CRF supplementation elevated blood concentrations of folate and RF. These findings suggested that CFA or CRF inclusion had facilitating effects on performance and ruminal fermentation, and combined addition of CFA and CRF had greater increase in performance than CFA or CRF addition alone in bulls.

The wheat aphid Sitobion miscanthi (CWA) is an important harmful pest in wheat fields. Insecticide application is the main method to effectively control wheat aphids. However, CWA has developed resistance to some insecticides due to its extensive application, and understanding resistance mechanisms is crucial for the management of CWA. In our study, a new P450 gene, CYP4CJ6, was identified from CWA and showed a positive response to imidacloprid and thiamethoxam. Transcription of CYP4CJ6 was significantly induced by both imidacloprid and thiamethoxam, and overexpression of CYP4CJ6 in the imidacloprid-resistant strain was also observed. The sensitivity of CWA to these two insecticides was increased after the knockdown of CYP4CJ6. These results indicated that CYP4CJ6 could be associated with CWA resistance to imidacloprid and thiamethoxam. Subsequently, the posttranscriptional regulatory mechanism was assessed, and miR-316 was confirmed to participate in the posttranscriptional regulation of CYP4CJ6. These results are crucial for clarifying the roles of P450 in the resistance of CWA to insecticides.

Although research has shown that older nursing home residents can benefit from caring relationships with nurse aides, few studies have explored their dyadic, evolving relationship dynamics. Using a dyadic perspective, this study simultaneously explores caring relationships among older residents and nurse aides in Shanghai. In a government-sponsored nursing home in Shanghai, 20 matched resident–nurse aide dyads participated in semi-structured, in-depth interviews (N = 40). We performed thematic analysis to interpret and conceptualise the evolving caring relationships within dyads. Four types emerged during the evolution of caring relationships across the 20 dyads: (a) sharing strong rapport, (b) respecting each other, (c) hesitant responding, and (d) keeping emotional distance. Upon placement, all the residents kept emotional distance from nurse aides, and their assigned nurse aides provided care-giving by following nursing home regulations. As time passed, nurse aides began to create a family environment and tried to interact with residents on an emotional level; however, residents’ attitudes varied. The caring relationships in some dyads evolved as rapport and respect emerged, while others remained hesitant and distant. This suggests that residents and nurse aides prioritised caring relationships differently in terms of autonomy preservation and safety protection, respectively. This study sheds light on nursing home practice to facilitate building caring relationships between residents and nurse aides.

In this paper we study a normalized anisotropic Gauss curvature flow of strictly convex, closed hypersurfaces in the Euclidean space. We prove that the flow exists for all time and converges smoothly to the unique, strictly convex solution of a Monge-Ampère type equation and we obtain a new existence result of solutions to the Dual Orlicz-Minkowski problem for smooth measures, especially for even smooth measures.

The Rhynchonellida is a major group of brachiopods that survived the “big five” mass extinctions and flourished after the Permian/Triassic (P/Tr) crisis. However, phylogenetic and character evolution in the Rhynchonellida across the P/Tr transition is poorly understood. In view of the widespread homoplasy across this order, we employ a tip-dated Bayesian analysis to reconstruct phylogenetic relationships for late Permian–Triassic rhynchonellides. The same data were also analyzed using three other methods: undated Bayesian, equal-weighting, and implied-weighting parsimony. Compared with trees generated by other methods, those constructed by tip-dating best account for the homoplasy in this group and are closer to previous assumptions on the evolution of this order. Based on the analyses of multiple trees, the major increase in lineage richness occurred in the Early and early Middle Triassic. Also, richness in the Anisian almost reached the highest level seen in the Triassic. According to fossil records, a pronounced reduction in shell size and in the development of ornamentation occurred after the P/Tr extinction, which is largely due to the loss of large and highly sculptured genera and the diversification of small-sized and weakly ornamented genera. Ancestral-state estimation of shell size and development of ornamentation, coupled with comparisons of other characters, indicate that the Early–Middle Triassic mature “small-sized taxa” may have characters displayed by juveniles of their ancestors. This suggests that for these genera, paedomorphosis was possibly a strategy to survive and diversify in the harsh environment after the P/Tr extinction.

This paper reports a new phenomenon in the near-free-surface region of open channel flows (OCFs): namely that higher relative population densities of spanwise vortices are observed than are seen at equivalent positions in turbulent boundary layers. The presence of additional retrograde spanwise vortices in OCFs throughout the region $y/h>0.2$ (where $y$ is the distance to the wall and $h$ is the water depth) prompts us to re-examine the wall-normal extent that the free-surface effect can reach, which is classically expected to be limited within the surface and blockage layers. Finally, possible mechanisms for the phenomenon of additional spanwise vortices in OCFs are provided.

In recent years, the controlling nutritional status (CONUT) score has increasingly became an effective indicator associated with tumor prognosis. This study was conducted to synthesise data on the prognostic value of CONUT score on patients with upper tract urothelial carcinoma (UTUC) or renal cell carcinoma (RCC) undergoing nephrectomy. We designed and performed a systematic analysis of studies that verified the correlation between preoperative CONUT score and prognosis for UTUC and RCC using PubMed, Web of Science and Embase. The conclusion was clarified by pooled hazard ratios (HR) and 95% confidence intervals (95% CI). Subgroup analysis were further conducted in accordance with different primary tumor. Six studies involving 3529 patients were included in this evidence synthesis, which revealed that the CONUT score had a potential role to predict the survival of UTUC and RCC patients accepting surgery. Pooled analysis showed that the overall survival (OS, HR 2·32, p < 0·0001), cancer-specific survival (CSS, HR 2·68, p < 0·0001) and disease-free survival (DFS, HR 1·62, p < 0·00001) were inferior in the high CONUT score group when compared with low score group. Subgroup analysis revealed that this result was in line with UTUC (OS: HR 1·86, p = 0·02; CSS: HR 2·24, p = 0·01; DFS: HR 1·54, p < 0·00001) and RCC (OS: HR 3·05, p < 0·00001; CSS: HR 3·47, p < 0·00001; DFS: HR 2·21, p = 0·0005) patients respectively. Consequently, the CONUT score is a valuable preoperative index to predict the survival of patients with UTUC or RCC undergoing nephrectomy.