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Abstract Heterogeneous longitudinal data have become prevalent in medical, biological, and social studies. This paper proposes a finite mixture of varying coefficient models for handling heterogeneous populations. Each component of the mixture is modeled by a varying coefficient mixed-effect model that characterizes the longitudinal relations among variables. The identifiability of the mixture model is studied. Regression splines with equally spaced knots are used to approximate the varying coefficient functions, and a nested expectation maximization algorithm is developed to obtain the maximum likelihood estimation. We propose a penalized likelihood method based on the smoothly clipped absolute deviation (SCAD) penalty for the component selection of finite mixture of varying coefficient model. A modified BIC-based criterion based on the SCAD penalty, the BIC SCAD , is proposed for selecting the penalty parameter and spline space simultaneously. The asymptotic properties of parameter estimation and component selection consistency are studied under mild conditions. Simulation studies are conducted to illustrate the component selection, parameter estimation, and inference of the proposed method. The model is then applied to a heterogeneous longitudinal data set from a study of the treatment effect on the use of heroin in the California Civil Addict Program. [ABSTRACT FROM AUTHOR]

This article presents a generalized linear latent variable model for analyzing multivariate longitudinal data within the hidden Markov model framework. The relationships among multiple items are captured by several common latent factors. The linear coregionalization method is adopted to model the temporal processes of latent variables. The merit of this modeling strategy lies in the fact that the processes among latent variables are nonseparate and codependent from each other. To account for possible heterogeneity and interrelationship among the longitudinal data, a hidden Markov model is introduced to model the transition probabilities across different latent states over time. The Monte Carlo expectation conditional maximization (MCECM) algorithm is developed to estimate unknown parameters in the proposed model. The Wald- and score-type statistics are proposed to test the related dependence of processes. A simulation study is conducted to investigate the performance of the proposed methodology. An example from a longitudinal study of cocaine use is taken to illustrate the proposed methodology. [ABSTRACT FROM AUTHOR]

Vegetable cultivation in soils polluted with heavy metals, antibiotics and a high abundance of antibiotic-resistance genes (ARGs) can seriously threaten human health through the food chain. Therefore, novel techniques that not only remediate soil, but also ensure food security are urgently required. In the present study, two successive washings with 20 g L −1 of sophoroliplid solution plus ultrasonication (35 kHz) were effective in extracting 71.2% Cd, 88.2% tetracycline, 96.6% sulfadiazine, and 100% roxithromycin. Simultaneously, relative abundance of ARGs ( tet M, tet X, sul I, and sul II) was decreased to 10 −7 –10 −8 (ARG copies/16S copies). Further, lettuce cultivation in the 2nd washed soil showed significant improvement in vegetable growth indices (fresh/dry weight, root surface area, chlorophyll content and soluble protein content) and a decrease in isolate counts for antibiotic-resistant bacterial endophytes and ARG abundance in lettuce tissues. This combined cleanup strategy provides an environmentally friendly technology for ensuring vegetable security in washed soils. [ABSTRACT FROM AUTHOR]

An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs) and heavy metals in a mixed contaminated site. Elevated temperature (60 °C) combined with ultrasonication (40 kHz, 20 min) at 50 mL L−1 maize oil and 45 g L−1 carboxylmethyl-β-cyclodextrin were effective in extracting pollutants from the soil. After two successive washing cycles, the removal efficiency rates for total OCPs, mirex, endosulfans, chlordanes, Cd, and Pb were approximately 94.7%, 87.2%, 98.5%, 92.3%, 91.6%, and 87.3%, respectively. Cultivation of vetiver grass and addition of nutrients for 3 months further degraded 34.7% of the residual total OCPs and partially restored the microbiological functions of the soil. This result was indicated by the significant increase in the number, biomass C, N, and functioning diversity of soil microorganisms (p < 0.05). After the treatment, the residual OCPs and heavy metals existed as very slowly desorbing fraction and residual fraction, as evaluated by Tenax extraction combined with a first-three-compartment model and sequential extraction. Moreover, the secondary environmental risk of residual pollutants in the remediated soil was at an acceptable level. The proposed combined cleanup strategy proved to be effective and environmentally friendly. [Copyright &y& Elsevier]

Asteroid 2016 HO3 is the first of the two small bodies in the Solar System targeted by the Chinese Small Body Exploration Mission scheduled to be launched in the next few years. In this paper, we perform a full numerical simulation of a possible onboard radio science experiment to obtain the GM value of this tiny asteroid with a relative accuracy of ~10%. At such an accuracy, the GM value can be used to constrain the internal structure of the asteroid. We demonstrate that such an accuracy can be achieved through a joint estimation of the GM value and the ephemeris of the asteroid by using ground-based and onboard (spacecraft-asteroid) radiometric tracking data. • An onboard radio science experiment was simulated to estimate the GM of asteroid HO3 with a relative accuracy of ~10%. • It is possible to jointly estimate the GM and ephemeris of HO3 with high accuracy. [ABSTRACT FROM AUTHOR]

Residual heavy metals in soils will destroy microbial community stability and influence its aggregation. However, exploring microbial ecology under heavy-metal stress still requires a conjoint analysis of bacterial interspecies communication and the community diversity maintenance mechanism. In this study, soil samples were collected from a heavy-metal-contaminated site in China to investigate the ecological response of indigenous microbial communities through high-throughput sequencing. Results showed that bacterial taxa and functions generated unusual decoupling phenomena. There were no significant differences in the diversity of species with the increase in concentration of heavy metals (Hg, Se, and Cr), but the functional diversity was lost. Also, the average niche breadth of bacterial species increased from 1.70 to 2.28, but community stability declined and the species assembly was always a deterministic process (NST <0.5). After the bacterial functional assembly changed from a stochastic process to a deterministic process (NST <0.5), it was transformed into a stochastic process (NST >0.5) again under the stress of high-concentration heavy metals, indicating that the collective stress resistance of bacterial communities changed from positive mutation into passive functional propagation. The research results can provide new insight into understanding the adaptive evolution of communities and ecosystem restoration under the stress of soil heavy metals. [Display omitted] • There is an unusual decoupling relation between taxa and functional diversity. • Microbial community stability decreased due to compound heavy metals exposure. • Deterministic process dominated the assemblies of bacterial taxa. • Bacterial resistance shifted from active to passive with increasing heavy metals. [ABSTRACT FROM AUTHOR]

Endothelial cells in straight sections of vessels are known to elongate and align in the direction of flow. This phenotype has been replicated in confluent monolayers of bovine aortic endothelial cells and human umbilical vein endothelial cells (HUVECs) in cell culture under physiological shear stress. Here we report on the morphological response of human brain microvascular endothelial cells (HBMECs) in confluent monolayers in response to shear stress. Using a microfluidic platform we image confluent monolayers of HBMECs and HUVECs under shear stresses up to 16 dyne cm − 2 . From live-cell imaging we quantitatively analyze the cell morphology and cell speed as a function of time. We show that HBMECs do not undergo a classical transition from cobblestone to spindle-like morphology in response to shear stress. We further show that under shear stress, actin fibers are randomly oriented in the cells indicating that there is no cytoskeletal remodeling. These results suggest that HBMECs are programmed to resist elongation and alignment under shear stress, a phenotype that may be associated with the unique properties of the blood–brain barrier. [ABSTRACT FROM AUTHOR]

Purpose. To elucidate the apoptosis induction of Epigallocatechin-3-gallate (EGCG) on nasopharyngeal carcinoma (NPC) cells via mitochondrial signal transduction pathway regulated by EB-virus-encoded latent membrane protein 1 (LMP1).Methods. The survival rates of pTet-on-LMP1 HNE2 cells after the EGCG treatment were determined by MTT assay. Induction of apoptosis in pTet-on-LMP1 HNE2 cells after the EGCG treatment was analyzed by agarose gel electrophoresis. The activity of caspase-9 was determined by ApoAlert Caspase-9 Fluorescent Assay kit after the EGCG treatment. The protein expressions of cytochrome c and Bcl-2 were analyzed by Western blotting after the EGCG treatment.Results. EGCG inhibited the survival rates of pTet-on-LMP1 HNE2 cells and induced apoptosis of pTet-on-LMP1 HNE2 cells. EGCG raised the activities of caspase-9, enhanced the releasing of cytochrome c from the mitochondria, and suppressed the protein expression of Bcl-2. These are the key targets on the mitochondrial signal transduction pathway in apoptosis.Conclusions. EGCG inhibited the survival rate of NPC cells and induced apoptosis of NPC cells via the mitochondrial signal transduction pathway. This study suggests that the interference effect of EGCG on targets of the mitochondrial signal transduction pathway plays an important role in the anticancer function. [Copyright &y& Elsevier]

• 1-Butene "precoking" can effectively enhance the ethene selectivity. • The presituated "coke" was relatively evenly distributed. • The mechanistic origin of the increase in ethene selectivity is clarified. Control of product selectivity is a central yet challenging issue in catalysis chemistry, both in academia and industry. The ever-increasing market demand for ethene, together with relatively low ethene selectivity, necessitates the upgrading of the current methanol-to-olefins (MTO) industry to enhance ethene selectivity. We report here an operable strategy, 1-butene "precoking" technology, by which ethene selectivity has been unprecedentedly enhanced while the catalyst lifespan has been conserved. We also made effects to provide more insight into the long-standing controversies regarding the mechanistic origin of the increase in ethene selectivity. With the aid of a 12C-/13C-methanol switch experiment, MD calculations, and FTIR analysis, it was demonstrated that ethene increase is neither simply—or solely—caused by the configurational diffusion effect, nor due to the transition-state shape selectivity or methylnaphthalene species, but rather to the spatial siting of the presituated "coke". The relatively evenly distributed presituated coke extends the reaction zone toward the near-core of the SAPO-34 crystal, elongating the diffusion trajectories of molecules and allowing more acid sites to be utilized. The diffusion-hindered higher olefinic intermediates tend to evolve to active aromatic species, which, in turn, lead substantially to ethene. This mechanistic understanding could be also applicable to explaining ethene increase with time on stream (TOS) on parent SAPO-34. [ABSTRACT FROM AUTHOR]

Marine sediment microorganisms play an important role in the biogeochemical cycle of elements and the transformation of exogenous pollutants; therefore, it is important to study the microbial assembly process and inter taxa associations. In this study, we investigated the profiles and assembly processes of microbial communities of sediments collected from 19 points in the Yellow Sea. As revealed by 16S rRNA sequencing, Proteobacteria (43.11%–65.54%) was the dominant phylum in marine sediment. Further, the physicochemical properties of sediments were significantly influenced by depth (P < 0.05), and the effects of homogeneous selection became greater with increasing depth. The microbial species located in marine sediment at 35°N had a significantly higher co-occurrence relationship (82.76%) than those at 34°N (57.99%) and 36°N (54.07%). Additionally, the microbial community structure of the sediments changed significantly at the genus level with strong fluctuations in the physicochemical properties. By contrast, the carbon, nitrogen, and sulfur associated functional gene diversity and abundance showed no clear variation among different locations, indicating the probable functional redundancy and a potential functional gene pool of the microbes in marine sediments. This study could provide new insights into the composition of microorganisms in sediments in the Yellow Sea, the driving force of microbial diversity, the assembly process, the modes of species' co-occurrence, and their ecological functions. [Display omitted] • Physical properties explained 11.61% of the variation in microbial composition. • Microbial co-occurrence relationships in sediments at 35°N were strengthened. • Environmental selection strengthened with increasing depth. • Functional redundancy existed in the marine sediments. [ABSTRACT FROM AUTHOR]

Stress is well known to contribute to the development of both neurological and psychiatric diseases. In the central nervous system, a role for STING (stimulator of interferon genes) in modulating immunological responses has been widely suggested, and this protein possesses both neurotoxic and neuroprotective properties. However, the potential role of the STING signalling pathway and the underlying regulatory mechanism in chronic stress have not been well established. In this study, C57BL/6 mice were subjected to intermittent restraint stress for 14 days (6 h/day), and sucrose preference, elevated plus maze, and tail suspension tests were performed by mice subjected to chronic restraint stress (RST). Here, we showed that RST mice displayed depression-like behaviours, accompanied by increased levels of proinflammatory cytokines in the brain. We also observed remarkably decreased levels of the pathway components STING, p-TBK1 (phospho-TANK-binding kinase-1), and p-IRF3 (phospho-interferon regulatory factor-3) in the hippocampus and the prefrontal cortex of RST mice. Significant reductions in STING fluorescence intensity were also observed in the hippocampus and the prefrontal cortex of RST mice. Next, fluorescently labelled latex beads, flow cytometry, and CD68-positive cell counts were utilized to evaluate the phagocytic abilities of microglia in vivo and in vitro. Importantly, our results first indicated that activation of the STING pathway by administration of the STING agonist 2′3-cGAMP enhanced microglial phagocytosis and suppressed the release of the proinflammatory cytokines TNF-α, IL-6, and IL-1β in the brains of RST mice, which further led to antidepressant effects. Based on the results of our study, the amelioration of stress-driven depression-like behaviours by activation of the STING pathway is associated with the suppression of neuroinflammation and enhanced phagocytosis. [Display omitted] • Chronic restraint stress induces depression-like behaviours and neuroinflammation. • The number of microglia is increased and cells are activated towards a proinflammatory phenotype during chronic stress. • STING activation enhances microglial phagocytosis through STING-dependent IFN-β signalling and inhibits the production of proinflammatory cytokines in the brain. • Activation of the STING signalling pathway ameliorates depression-like behaviours during chronic stress. [ABSTRACT FROM AUTHOR]

High-precision Mars orientation and rotation parameters (MOP) can constrain the internal structure of the planet and the modeling of processes such as polar dry ice waning and waxing. Currently, these orientation parameters are obtained by using traditional range and Doppler measurements between Earth stations and a Mars lander, but these estimations are limited by the propagation delays caused by interplanetary plasma and neutral atmospheres. Unlike the existing approaches, the inverse Very Long Baseline Interferometry (VLBI) involves more than one lander on the planet allowing to cancel these effects by differentiation, providing measurements with a higher-precision. In this study, we perform numerical simulations to assess the precision with which one could determine the MOP using inverse VLBI. Our results are compared with classical two-way range and Doppler. We show that the precession rate can be estimated with inverse VLBI with only 0.05 mas/year uncertainty, which is one order of magnitude better than with two-way range and Doppler. The accuracy of the nutation parameters reaches 1–5 mas, and the accuracy of the Chandler wobble component is down to 0.01 mas, which meets the requirements for investigations on the internal structure of Mars. The accuracy of the Length-of-Day (LOD) variations however, do not show significant improvement with the inverse VLBI technique. We also considered the impact of the lander baseline orientation on the results. Two landers at the same longitude has no additional benefits for the estimation of MOP. But the estimated LOD amplitudes are better than 1 mas when the two landers were at the same latitude. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides (OCPs) contaminated sites pose great threats to both human health and environmental safety. Targeted bioremediation in these regions largely depends on microbial diversity and activity. This study applied metagenomics to characterize the microbial communities and functional groups composition features during independent or simultaneous rapeseed oil and tartaric acid applications, as well as the degradation kinetics of OCPs. Results showed that: the degradation rates of α-chlordane, β-chlordane and mirex were better when (0.50% w/w) rapeseed oil and (0.05 mol L−1) tartaric acid were applied simultaneously than singular use, yielding removal rates of 56.4%, 53.9%, and 49.4%, respectively. Meanwhile, bio-stimulation facilitated microbial enzyme (catalase/superoxide dismutase/peroxidase) activity in soils significantly, promoting the growth of dominant bacterial communities. Classification at phylum level showed that the relative abundance of Proteobacteria was significantly increased (p < 0.05). Network analysis showed that bio-stimulation substantially increased the dominant bacterial community's proportion, especially Proteobacteria. The functional gene results illustrated that bio-stimulation facilitated total relative abundance of degradation genes, phosphorus, carbon, nitrogen, sulfur metabolic genes, and iron transporting genes (p < 0.05). In metabolic pathways, functional genes related to methanogenesis and ammonia generation were markedly upregulated, indicating that bio-stimulation promoted the transformation of metabolic genes, such as carbon and nitrogen. This research is conducive to exploring the microbiological response mechanisms of bio-stimulation in indigenous flora, which may provide technical support for assessing the microbial ecological remediation outcomes of bio-stimulation in OCP contaminated sites. [Display omitted] • Simultaneous addition of rapeseed oil and tartaric acid accelerated OCP degradation. • Bio-stimulation promoted dominant phylum Proteobacteria and genus Anaeromyxobacter. • Bio-stimulation facilitated environmental functional genes significantly. • Bio-stimulation plays an important role in methane and ammonia metabolic cycling. [ABSTRACT FROM AUTHOR]

• First, the mathematical modelling of a manned two-wheeled vehicle is derived by using state space equation and the included perturbations are described in detail. Perturbation estimation technique is further adopted to provide with online estimations for perturbations. • Second, a hierarchical sliding mode control (HSMC) is used to handle the coupling effects and uncertainties of the underactuated two-wheeled vehicle, thus both balancing and velocity control purposes are achieved. Also, since most of the underactuated control systems only discuss the regulation not tracking problems, it is the first time that the HSMC is developed for the vehicle to achieve velocity tracking while balancing the chassis with driver around the upright position. The stability proof of the proposed scheme with PE is presented in detail. • Third, a group of experimental results for different driving situation (regulation task with slight and vigorous push, velocity tracking and balancing control on flat and inclined surfaces) are given to show the robust control performance of the proposed scheme, with convincing comparisons with the HSMC, adaptive HSMC and conventional linear feedback control. The readers can clearly see the significant improvements on balancing and velocity tracking performances by the proposed control. This paper presents the design and implementation of hierarchical sliding mode control (HSMC) with perturbation estimation (PE) technique on a two-wheeled self-balancing vehicle (TWSBV), to simultaneously realize real-time balancing and velocity tracking control purposes. Considering the fact that the TWSBV system is a typical second-order underactuated system with one controlled actuator and two required control objectives, two sliding surfaces constructed by the velocity and tilt angle information are first designed and an HSMC is proposed to simultaneously achieve both balancing control and velocity control. In order to further enhance the ability of disturbance rejection of the HSMC control, the PE is used to assist with the proposed control for estimating the perturbations online such that the uncertainty bound information is not required in the control design. The excellent balancing and velocity tracking performance can be well achieved even under external disturbances. The effectiveness of the proposed control is verified by a group of comparative experimental investigations on a real TWSBV. [ABSTRACT FROM AUTHOR]