In this paper, we investigate a sink-driven three-layer flow in a radial Hele-Shaw cell. The three fluids are of different viscosities, with one fluid occupying an annulus-like domain, forming two interfaces with the other two fluids. Using a boundary integral method and a semi-implicit time stepping scheme, we alleviate the numerical stiffness in updating the interfaces and achieve spectral accuracy in space. The interaction between the two interfaces introduces novel dynamics leading to rich pattern formation phenomena, manifested by two typical events: either one of the two interfaces reaches the sink faster than the other (forming cusp-like morphology), or they come very close to each other (suggesting a possibility of interface merging). In particular, the inner interface can be wrapped by the other to have both scenarios. We find that multiple parameters contribute to the dynamics, including the width of the annular region, the location of the sink, and the mobilities of the fluids.

Gene expression studies in organisms are often conducted using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR), and the accuracy of RT-qPCR results relies on the stability of reference genes. We examined ten candidate reference genes in Sclerodermus guani, a parasitoid wasp that is a natural enemy of long-horned beetle pests in forestry, including ACT, EF1α, Hsc70, Hsp70, SRSF7, α-tubulin, RPL7A, 18S, 28S, and SOD1, regarding variable biotic and abiotic factors such as body part, life stage, hormone, diet, and temperature. Data were analysed using four dedicated algorithms (ΔCt, BestKeeper, NormFinder, and geNorm) and one comparative tool (RefFinder). Our results showed that the most stable reference genes were RPL7A and EF1α regarding the body part, SRSF7 and Hsc70 regarding the diet, RPL7A and α-tubulin regarding the hormone, SRSF7 and RPL7A regarding the life stage, and SRSF7 and α-tubulin regarding temperature. To ascertain the applicability of specific reference genes, the expression level of the target gene (ACPase) was estimated regarding the body part using the most stable reference genes, RPL7A and EF1α, and the least stable one, SOD1. The highest expression level of ACPase was observed in the abdomen, and the validity of RPL7A and EF1α was confirmed. This study provides, for the first time, an extensive list of reliable reference genes for molecular biology studies in S. guani.

An improved Monte-Carlo algorithm is proposed to address the problem of an unclear workspace boundary in a multi-robot coordinated lifting system. The spatial configuration of a multi-robot coordinated lifting system with rolling base is analyzed, and the kinematics and static workspace of the system are established. To solve the workspace boundary, first, the error introduced by the layers is reduced using an intra-layer thinning method. Second, each layer is divided simultaneously based on rows and columns, and the initial boundary points are extracted by searching for the best value. Third, random three-dimensional points are added in the neighborhood, and pseudo-boundary points are removed using three-dimensional local spherical coordinates to achieve a high-precision solution for the workspace boundary. Finally, the workspace volume is used to analyze the influence of structural parameters on the workspace boundary. The results show that the lifting system has limited carrying capacity and a data reference for selecting the structural parameters by analyzing the factors that affect the workspace. Findings provide a basis for further studies on the structural configuration and optimization of the lifting system.

With the in-depth study of thin-film structures, nonuniform thin films with rigid elements have been applied in the aerospace and flexible electronics industries. For thin-film structures with rigid elements, there is an interaction force between the rigid element and the thin film; therefore, the wrinkling mode of the thin film changes under the influence of the interaction force. In this study, a wrinkle model was developed to predict the wrinkle morphology of thin-film structures with rigid elements on the diagonal. First, the wrinkle patterns of the rigid elements were observed at different positions using tensile experiments. Then, the relationship between the tilt of the rigid element and the wrinkle wavelength was investigated using a finite-element eigenvalue buckling analysis. Finally, local wrinkling caused by the perturbed stress of the rigid element was introduced, and a wrinkling model of a square thin film with rigid elements on the diagonal under tension was established. The theoretical analysis results were compared with simulation and experimental results, demonstrating that the model can accurately describe the wrinkle patterns of thin-film structures containing rigid elements on the diagonal under tension.

Genes involved in melanin production directly impact insect pigmentation and can affect diverse physiology and behaviours. The role these genes have on sex behaviour, however, is unclear. In the present study, the crucial melanin pigment gene black was functionally characterised in an urban pest, the German cockroach, Blattella germanica. RNAi knockdown of B. germanica black (Bgblack) had no effect on survival, but did result in black pigmentation of the thoraxes, abdomens, heads, wings, legs, antennae, and cerci due to cuticular accumulation of melanin. Sex-specific variation in the pigmentation pattern was apparent, with females exhibiting darker coloration on the abdomen and thorax than males. Bgblack knockdown also resulted in wing deformation and negatively impacted the contact sex pheromone-based courtship behaviour of males. This study provides evidence for black function in multiple aspects of B. germanica biology and opens new avenues of exploration for novel pest control strategies.

A dense particle suspension under shear may lose its uniform state to large local density and stress fluctuations, which challenge the mean-field description of the system. Here, we explore the novel dynamics of a non-Brownian suspension under orbital oscillations, where localized density waves along the flow direction appear beyond an excitation frequency threshold and self-organize into a hexagonal pattern across the system. The spontaneous occurrence of the inhomogeneity pattern arises from a coupling between particle advection and the shear-thickening nature of the suspension. Through linear stability analysis, we show that they overcome the stabilizing effects of particle pressure at sufficient particle volume fraction and oscillation frequency. In addition, the long-standing density waves degenerate into random fluctuations when replacing the free surface with rigid confinement. It indicates that the shear-thickened state is intrinsically heterogeneous, and the boundary conditions are crucial for developing local disturbance.

Mythimna separata (Lepidoptera: Noctuidae) is an omnivorous pest that poses a great threat to food security. Insect antimicrobial peptides (AMPs) are small peptides that are important effector molecules of innate immunity. Here, we investigated the role of the AMP cecropin B in the growth, development, and immunity of M. separata. The gene encoding M. separata cecropin B (MscecropinB) was cloned. The expression of MscecropinB was determined in different developmental stages and tissues of M. separata. It was highest in the prepupal stage, followed by the pupal stage. Among larval stages, the highest expression was observed in the fourth instar. Tissue expression analysis of fourth instar larvae showed that MscecropinB was highly expressed in the fat body and haemolymph. An increase in population density led to upregulation of MscecropinB expression. MscecropinB expression was also upregulated by the infection of third and fourth instar M. separata with Beauveria bassiana or Bacillus thuringiensis (Bt). RNA interference (RNAi) targeting MscecropinB inhibited the emergence rate and fecundity of M. separata, and resulted in an increased sensitivity to B. bassiana and Bt. The mortality of M. separata larvae was significantly higher in pathogen plus RNAi-treated M. separata than in controls treated with pathogens only. Our findings indicate that MscecropinB functions in the eclosion and fecundity of M. separata and plays an important role in resistance to infection by B. bassiana and Bt.

The global transition towards diets high in calories has contributed to 2.1 billion people becoming overweight, or obese, which damages male reproduction and harms offspring. Recently, more and more studies have shown that paternal exposure to stress closely affects the health of offspring in an intergenerational and transgenerational way. SET Domain Containing 2 (SETD2), a key epigenetic gene, is highly conserved among species, is a crucial methyltransferase for converting histone 3 lysine 36 dimethylation (H3K36me2) into histone 3 lysine 36 trimethylation (H3K36me3), and plays an important regulator in the response to stress. In this study, we compared patterns of SETD2 expression and the H3K36me3 pattern in pre-implantation embryos derived from normal or obese mice induced by high diet. The results showed that SETD2 mRNA was significantly higher in the high-fat diet (HFD) group than the control diet (CD) group at the 2-cell, 4-cell, 8-cell, and 16-cell stages, and at the morula and blastocyst stages. The relative levels of H3K36me3 in the HFD group at the 2-cell, 4-cell, 8-cell, 16-cell, morula stage, and blastocyst stage were significantly higher than in the CD group. These results indicated that dietary changes in parental generation (F0) male mice fed a HFD were traceable in SETD2/H3K36me3 in embryos, and that a paternal high-fat diet brings about adverse effects for offspring that might be related to SETD2/H3K36me3, which throws new light on the effect of paternal obesity on offspring from an epigenetic perspective.

This article focuses on the luggage trolley transportation problem, an essential part of robotic autonomous luggage trolley collection. To efficiently address the nonholonomic constraints derived from the formation of two collaborative robots and a queue of luggage trolleys, we propose a comprehensive framework consisting of a global planning method and a real-time divide-and-conquer control strategy. The popular Hybrid A* algorithm generates a feasible path as the global planner. A model predictive controller is designed to track this path stably and in real time. To maintain the formation so that the whole queue of robots and luggage trolleys does not split, a safety filter that consists of a discrete-time control Lyapunov function and a decentralized control barrier function is implemented in the transportation process. Finally, we conduct real-world experiments to verify the effectiveness of the proposed method on three representative paths, and the results show that our approach can achieve robust performance. The demonstration video can be found at https://www.youtube.com/watch?v=iPiT8BfLIpU.

Coastal eutrophication and hypoxia remain a persistent environmental crisis despite the great efforts to reduce nutrient loading and mitigate associated environmental damages. Symptoms of this crisis have appeared to spread rapidly, reaching developing countries in Asia with emergences in Southern America and Africa. The pace of changes and the underlying drivers remain not so clear. To address the gap, we review the up-to-date status and mechanisms of eutrophication and hypoxia in global coastal oceans, upon which we examine the trajectories of changes over the 40 years or longer in six model coastal systems with varying socio-economic development statuses and different levels and histories of eutrophication. Although these coastal systems share common features of eutrophication, site-specific characteristics are also substantial, depending on the regional environmental setting and level of social-economic development along with policy implementation and management. Nevertheless, ecosystem recovery generally needs greater reduction in pressures compared to that initiated degradation and becomes less feasible to achieve past norms with a longer time anthropogenic pressures on the ecosystems. While the qualitative causality between drivers and consequences is well established, quantitative attribution of these drivers to eutrophication and hypoxia remains difficult especially when we consider the social economic drivers because the changes in coastal ecosystems are subject to multiple influences and the cause–effect relationship is often non-linear. Such relationships are further complicated by climate changes that have been accelerating over the past few decades. The knowledge gaps that limit our quantitative and mechanistic understanding of the human-coastal ocean nexus are identified, which is essential for science-based policy making. Recognizing lessons from past management practices, we advocate for a better, more efficient indexing system of coastal eutrophication and an advanced regional earth system modeling framework with optimal modules of human dimensions to facilitate the development and evaluation of effective policy and restoration actions.

The gut microbiota plays an important role in animals’ survival in their local environments. The intertidal rocky shore is a key interface of oceanic, atmospheric and terrestrial environments, and the transmission modes of microbes between an intertidal host and the environment are complex and largely ignored. In the present study, we characterized the gut microbiota of the intertidal snail Nerita yoldii, which is experiencing a northward range shift under the combined impacts of climate change and anthropogenic seascape transformation, and also determined the nearby environmental microbiota on the rock and in the seawater at five locations along the snail's distribution range in China. The gut microbial communities were significantly different from the environmental microbial communities, and the dominant phyla were Tenericutes, Cyanobacteria and Bacteroidetes, and Proteobacteria in the gut, rock and seawater microbial communities, respectively. At the genus level, Mycoplasma, with a relative abundance of 48.0 ± 10.2%, was the dominant genus in the gut microbial community, however, the relative abundances of this genus on the rock and in the water were low. These results imply that the gut microbial community of the intertidal snail N. yoldii is relatively independent from the environmental microbial community, and the dominant genus Mycoplasma in the gut, that is rare in the environment, can potentially assist the snail living in the harsh intertidal environment, especially at its northernmost distribution range edge.

To accurately predict propagation dynamics for single or multiple change propagations across different product development stages in a sequential or concurrent way is critical for decision-making of implementing change requests. In this paper, a change propagation dynamic model is built based on the compartmentalization of engineering entities into susceptible engineering entities and affected engineering entities (SA), the ordinary differential equations for describing the rate of affected entities with respect to the total ones and the duration for resolving all the changes for every moment are presented by combining the calculations of change impacts with different split and joint junctions. Considering the difficulty of finding analytical solutions to the differential equations, algorithms for sequential and concurrent simulations of change propagations across different development stages, and random and GA (Genetic Algorithm)-based optimal selections of feasible propagation paths are developed to obtain numerical solutions for single and multiple change requests. Simulation results show that change ripples and blossoms can be observed in both sequential and concurrent change propagations, and these propagation patterns are not sensitive to the initial change effect and the threshold value for propagations, while critical change propagation paths and the number of initiated changes have important effects on both concurrent and sequential change propagation process. It is also demonstrated that concurrent propagation strategy is advantageous for processing single or few of initiated changes since it can shorten product redevelopment time, sequential propagation strategy has an advantage of robustness for handling multiple initiated change requests.

Metabolically healthy obesity (MHO) might be an alternative valuable target in obesity treatment. We aimed to assess whether alternative Mediterranean (aMED) diet and Dietary Approaches to Stop Hypertension (DASH) diet were favourably associated with obesity and MHO phenotype in a Chinese multi-ethnic population. We conducted this cross-sectional analysis using the baseline data of the China Multi-Ethnic Cohort study that enrolled 99 556 participants from seven diverse ethnic groups. Participants with self-reported cardiometabolic diseases were excluded to eliminate possible reverse causality. Marginal structural logistic models were used to estimate the associations, with confounders determined by directed acyclic graph (DAG). Among 65 699 included participants, 11·2 % were with obesity. MHO phenotype was present in 5·7 % of total population and 52·7 % of population with obesity. Compared with the lowest quintile, the highest quintile of DASH diet score had 23 % decreased odds of obesity (OR = 0·77, 95 % CI 0·71, 0·83, P trend < 0·001) and 27 % increased odds of MHO (OR = 1·27, 95 % CI 1·10, 1·48, P trend = 0·001) in population with obesity. However, aMED diet showed no obvious favourable associations. Further adjusting for BMI did not change the associations between diet scores and MHO. Results were robust to various sensitivity analyses. In conclusion, DASH diet rather than aMED diet is associated with reduced risk of obesity and presents BMI-independent metabolic benefits in this large population-based study. Recommendation for adhering to DASH diet may benefit the prevention of obesity and related metabolic disorders in Chinese population.

The article aims to estimate and forecast the transmissibility of shigellosis and explore the association of meteorological factors with shigellosis. The mathematical model named Susceptible–Exposed–Symptomatic/Asymptomatic–Recovered–Water/Food (SEIARW) was used to explore the feature of shigellosis transmission based on the data of Wuhan City, China, from 2005 to 2017. The study applied effective reproduction number (Reff) to estimate the transmissibility. Daily meteorological data from 2008 to 2017 were used to determine Spearman's correlation with reported new cases and Reff. The SEIARW model fit the data well (χ2 = 0.00046, p > 0.999). The simulation results showed that the reservoir-to-person transmission of the shigellosis route has been interrupted. The Reff would be reduced to a transmission threshold of 1.00 (95% confidence interval (CI) 0.82–1.19) in 2035. Reducing the infectious period to 11.25 days would also decrease the value of Reff to 0.99. There was a significant correlation between new cases of shigellosis and atmospheric pressure, temperature, wind speed and sun hours per day. The correlation coefficients, although statistically significant, were very low (<0.3). In Wuhan, China, the main transmission pattern of shigellosis is person-to-person. Meteorological factors, especially daily atmospheric pressure and temperature, may influence the epidemic of shigellosis.