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The oceanic trace metals iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) are crucial to marine phytoplankton growth and global carbon cycle, and the analysis of their stable isotopes can provide valuable insights into their biogeochemical cycles within the ocean. However, the simultaneous isotopic analysis of multiple elements present in seawater is challenging because of their low concentrations, limited volumes of the test samples, and high salt matrix. In this study, we present the novel method developed for the simultaneous analysis of five isotope systems by 1 L seawater sample. In the developed method, the NOBIAS Chelate-PA1 resin was used to extract metals from seawater, the AG MP-1M anion-exchange resin to purify Cu, Fe, Zn, Cd, and the NOBIAS Chelate-PA1 resin to further extract Ni from the matrix elements. Finally, a multi-collector inductively coupled plasma mass spectroscope (MC-ICPMS) was employed for the isotopic measurements using a doublespike technique or sample-standard bracketing combined with internal normalization. This method exhibited low total procedural blanks (0.04 pg, 0.04 pg, 0.21 pg, 0.15 pg, and 3 pg for Ni, Cu, Fe, Zn, and Cd, respectively) and high extraction efficiencies (100.5% ± 0.3%, 100.2% ± 0.5%, 97.8% ± 1.4%, 99.9% ± 0.8%, and 100.1% ± 0.2% for Ni, Cu, Fe, Zn, and Cd, respectively). The external errors and external precisions of this method could be considered negligible. The proposed method was further tested on the seawater samples obtained from the whole vertical profile of a water column during the Chinese GEOTRACES GP09 cruise in the Northwest Pacific, and the results showed good agreement with previous related data. This innovative method will contribute to the advancement of isotope research and enhance our understanding of the marine biogeochemical cycling of Fe, Ni, Cu, Zn, and Cd. [ABSTRACT FROM AUTHOR]

With the development of society and technology, machinery and equipment have enhanced our work efficiency but have also introduced various hazards, such as electromagnetic radiation, medical, industrial, and agricultural rays. The harms these radiations inflict on human health are significant, with severe cases leading to cancer, disability, or even life-threatening situations. Therefore, effective protective measures in some fields are crucial. This paper firstly summarized the basic principles of radiation protection for different rays, then systematically introduced the widely used manufacturing methods for flexible radiation shielding materials, including weaving with metal fibers, fiber blending, silver-plated fibers, and so on. Subsequently, the paper reviewed the testing methods of radiation-protective clothing materials. Finally, it comprehensively concluded the discussions on flexible radiation shielding materials and offered a perspective on their future development trends. [ABSTRACT FROM AUTHOR]

The application of near-infrared spectroscopy (NIRS) for rapid quantitative analysis of soil total nitrogen (STN) is of great significance to recycling nitrogen in the ecosystem and crops growth. However, collecting thousands of soil samples and chemical analysis are impracticable, more importantly a deviation from NIRS advantages of rapid, inexpensive and nondestructive. To more efficiently improve the estimation performance and reduce uncertainty of the model when working with small sample sizes (less than 100), solutions from soil particle size decomposition and model fusion were investigated. Elaborately, 123 Latosols samples were collected and decomposed them according to particle sizes to extend limited data at multiple scales. Based on all soil groups decomposed, a hyperspectral data recapture and model decision fusion method were implemented. The results demonstrated that the proposed method increased the scale of spectral data, extracted more STN-related spectral information, improved estimation accuracy, and reduced uncertainty. The fused model based on data from all decomposed groups yielded the best estimated results (root mean square error (R M S E) = 0.075 g. k g - 1 , R 2 = 0.784 , and a ratio of performance to inter-quartile distance (R P I Q) = 3.787 ) on the validation set. Through a tenfold cross-validation, the weighted fusion model with six groups of particle sizes data showed an improvement of 0.307 in R c 2 v and an improved RPIQ of 1.015 compared to models constructed using conventional machine learning (ML) techniques and limited pristine data ( R c 2 v = 0.442 , R M S E = 0.119 ). Therefore, when utilizing NIRS to build rapid and accurate STN predictive models, the proposed method demonstrates great potential in improving the reliability of soil spectral models under small sample sizes. [ABSTRACT FROM AUTHOR]

In the high-speed railway system, trains' original timetable is often disturbed by some emergencies including geological disasters and equipment failures, which brings great influence to passengers. This paper proposes a real-time high-speed train dispatching model in case of segment blockages, where a railway network is considered. The model includes the following two parts. First, if the trains are not cancelled or decelerated after a blockage occurs, the scope of the affected trains and stations is roughly estimated via the prediction of delay propagation model. Second, with the overall delay as the objective function, this paper constructs a mixed integer nonlinear programming (MINLP) model by considering the following three adjustment strategies: cancellation, delayed departure and deceleration, where the safe headway of the train operation is guaranteed by the moving blocking principle. Furthermore, to reduce the computation complexity, the solution of the model is only considered within the scope obtained in the first stage. The model is verified by using a small railway network with Nanjing as the hub station, which shows that the model is useful for reducing the effect of a disruption on original timetable, especially in comparison with the First Scheduled First Served (FSFS) rule used in practice. [ABSTRACT FROM AUTHOR]

Facile and ecofriendly loading of micro/nano function-specific substances to create functional materials is a trend being pursued by researchers. However, current micro/nano particles loading approaches are often hindered by issues such as uneven distribution, unsatisfactory stability and complicate procedure. In this work, we present an aqueous phase reshaping method that only utilizes the moisture to fabricate the "bubble particles", which could perfectly cater to the topography of the substrate. The green preparation of bubble particles adopts an absolutely zero-pollution method, realizing the firm loading of particles on the substrate. Integrating the preparation and loading of particles overcomes the traditional complicate process, while the aqueous phase reshaping ensures uniform and firm loading of the "bubble particles" onto the substrate. Our mechanism demonstrates a significant enhancement in the interface relation after aqueous phase reshaping, with a 121-fold increase in contact surface area achieved by reducing the height by 1 µm. Furthermore, we explore for the first time the influence of the nature of the receiving substrate on the interface morphology of particles during electrostatic spraying, which has important guiding significance for the interface relationship of electrostatic spraying and even electrostatic spinning materials. We also screen out the natural antibacterial essential oil linalool as the effective specialized antibacterial agent, which can specifically inhibit the odor-producing Proteus in urine, with an antibacterial rate of up to 100%. Taken together, this simple, ecofriendly method for fabricating functional materials with optimal interface stability appears highly promising for use in various products formed by electrostatic spraying/spinning. [ABSTRACT FROM AUTHOR]

To enhance the performance of the parabolic trough solar collector (PTSC) and mitigate the circumferential temperature gradient within the absorber tube, a numerical simulation investigation was conducted involving the implementation of vortex generators. The vortex generator was composed of a ring belt and four ribs, and four types of vortex generators M1, M2, M3 and M4 were proposed. The flow and heat transfer of the absorber tube were analyzed at Reynolds numbers ranging from 10000 to 35000 and inlet temperatures between 373.15 K and 473.15 K, using the shear stress transport (SST) k-ω turbulence model. The results show that the four kinds of vortex generators—M1, M2, M3 and M4—can induce longitudinal vortices in the heat transfer fluid (HTF) within the absorber tube. These longitudinal vortices diminish the thermal boundary layer's thickness, expedite the mixing of cold and hot fluids, and enhance the overall heat transfer efficiency. Vortex generators M1 and M3 arranged in the reverse direction produce two pairs of reverse rotating longitudinal vortices, while vortex generators M2 and M4 arranged in the same direction form one pair of longitudinal vortices, so the flow resistance in M1 and M3 is slightly larger than M2 and M4. However, from the perspective of heat transfer enhancement effect and comprehensive performance, the vortex generator M3 has the best effect. In M3, the Nu/Nu0 reached the highest value of 1.238, and the performance evaluation criteria (PEC) for M3 exceeded 1, reaching a maximum of 1.11. [ABSTRACT FROM AUTHOR]

In recent years, the decline of microglia in the hippocampus has been shown to play a role in the development of depression, and its reversal shows marked antidepressant-like effects. β-glucan is a polysaccharide from Saccharomyces cerevisiae and has numerous beneficial effects on the nervous system, including improving axon regeneration and cognition. Considering its immuno-stimulatory activities in cultured microglia and brain tissues, we hypothesize that β-glucan may be a potential candidate to correct the functional deficiency of microglia and thereby alleviate depression-like behaviors in chronically stressed animals. An expected, our results showed that a single injection of β-glucan 5 h before behavioral tests at a dose of 10 or 20 mg/kg, but not at a dose of 5 mg/kg, reversed the depression-like behavior induced by chronic stress in mice in the tail suspension test, forced swimming test, and sucrose preference test. The effect of β-glucan (20 mg/kg) also showed time-dependent properties that were statistically significant 5 and 8, but not 3, hours after drug injection and persisted for at least 7 days. Fourteen days after β-glucan injection, no antidepressant-like effect was observed anymore. However, this effect was overcome by a second β-glucan injection (20 mg/kg) 14 days after the first β-glucan injection. Stimulation of microglia appeared to mediate the antidepressant-like effect of β-glucan, because both inhibition of microglia and their depletion prevented the antidepressant-like effect of β-glucan. Based on these effects of β-glucan, β-glucan administration could be developed as a new strategy for the treatment of depression. [ABSTRACT FROM AUTHOR]

With a worldwide expansion of urbanization, the conservation of urban biodiversity is attracting growing attention; it is important to study the relationship between wildlife and urban green spaces. In this study, we selected 31 parks in the urban area of Fuyang City in the North China Plain. A total of 8795 individual birds from 69 species were recorded. The study found that (a) at the local level, tree diversity and heights are the most important factors contributing to each level of bird diversity, followed by the coverage of shrubs and herbs, and (b) at the landscape level, the proportion of woodland has a strong positive correlation with the multidimensional diversity of birds, followed by the patch diversity and percent of grassland. Our results showed that artificial greenland can effectively increase bird diversity. While considering urban planning and human well-being, the proportion of vegetation and landscape in urban parks should be properly planned, providing more habitats to enrich bird diversity. [ABSTRACT FROM AUTHOR]

Gas hydrates have an important role in environmental and astrochemistry, as well as in energy materials research. Although it is widely accepted that gas accumulation is an important and necessary process during hydrate nucleation, how guest molecules aggregate remains largely unknown. Here, we have performed molecular dynamics simulations to clarify the nucleation path of methane hydrate. We demonstrated that methane gather with a three-body aggregate pattern corresponding to the free energy minimum of three-methane hydrophobic interaction. Methane molecules fluctuate around one methane which later becomes the central gas molecule, and when several methanes move into the region within 0.8 nm of the potential central methane, they act as directional methane molecules. Two neighbor directional methanes and the potential central methane form a three-body aggregate as a regular triangle with a distance of ~6.7 Å which is well within the range of typical methane-methane distances in hydrates or in solution. We further showed that hydrate nucleation and growth is inextricably linked to three-body aggregates. By forming one, two, and three three-body aggregates, the possibility of hydrate nucleation at the aggregate increases from 3/6, 5/6 to 6/6. The results show three-body aggregation of guest molecules is a key step in gas hydrate formation. Gas hydrates have an important role in environmental and astrochemistry, as well as energy materials, but the hydrate nucleation process is not fully understood. Here, the authors use molecular dynamics simulations to show that methane molecules gather with a three-body aggregate pattern. [ABSTRACT FROM AUTHOR]

In this paper, the bipartite consensus problem is addressed for a class of double-integrator multi-agent systems with antagonistic interactions. The cases with and without communication time delays are considered. In particular, if the communication time delays are not taken into account, the bipartite consensus of the studied multi-agent systems with directed signed graph can be achieved by the proposed distributed controller. If the nonuniform communication time delays are considered, the bipartite consensus of the considered multi-agent systems with undirected signed graph can be achieved if the time delays are less than a derived upper bound. Moreover, we propose an algorithm to solve the so-called grouping problem. Finally, some numerical examples are provided to illustrate the correctness of the results. [ABSTRACT FROM AUTHOR]

In this paper, we study the stabilization problem for a class of linear systems with a time-varying state delay. An event-triggered static output feedback controller is proposed, such that the sampling frequency and the update time of the controller are both lowered. First, we present a novel event-triggering mechanism depending not only on the output but also on an exponential term, with which less sampling is required and Zeno behavior can be excluded at the same time. Some sufficient conditions are then obtained, under which an exponential convergence can be achieved by means of the comparison principle approach. It is further shown that the parameters design can be easily given if the case reduces to the state feedback control. Moreover, two examples are presented to show the effectiveness of the results. [ABSTRACT FROM AUTHOR]

This paper solves the rotating consensus problem for a group of double-integrator agents with event-based communication only. We propose a distributed event-based rotating consensus protocol, which guarantees that a consensus regarding both position and velocity is achieved when all agents exhibit circular motion around the same center. It is observed that overall less communication is required as the communication between agents is only needed at event times. Moreover, with the proposed event-based protocol, it is proved that Zeno behavior can be strictly avoided for each agent. Numerical simulations show that this event-based control law can efficiently solve the rotating consensus problem. [ABSTRACT FROM AUTHOR]

Recently, the loss and dystrophy of hippocampal microglia induced by chronic unpredictable stress (CUS) has been reported to mediate the development of major depression in mice whose microglial cells were labeled with enhanced green fluorescent protein-conjuncted-CX3C receptor type 1. However, whether this happens in endogenous microglia with no genetic intervention remains unclear. Here, we addressed this issue in mice treated with different types of chronic stresses, including the CUS, chronic restraint stress (CRS) and chronic social defeat stress (CSDS). Results showed that the cellular numbers, process lengths, soma areas and activation markers of endogenous hippocampal but not cortical microglia, were markedly reduced by CUS, CRS and CSDS treatment. Administration of mice with two classical stimulators of microglia, lipopolysaccharide (LPS) or macrophage colony-stimulating factor (M-CSF), reversed the CUS-, CRS- and CSDS-induced reductions in endogenous hippocampal microglial numbers, and also improved the CUS-, CRS- or CSDS-induced behavioral abnormalities, including the increases in the immobile time in the forced swimming test and tail suspension test, the inhibition of sucrose preference, and the decrease in the time spent in the center of open field. Furthermore, inhibition of the initial activation of hippocampal microglia by minocycline pretreatment also reversed the reduction in hippocampal microglial numbers as well as the behavioral abnormalities induced by CUS, CRS and CSDS treatment. These results provide compelling evidences to show that different types of chronic stresses can trigger the loss of endogenous hippocampal microglia and restoration of microglial numbers may have therapeutic values in major depression. [ABSTRACT FROM AUTHOR]

This paper studies the stochastic robust stability for impulsive interval neural networks with distributed time-varying delays of neutral type. The present model is a more general description of the real world in nature, where both discrete delays and distributed delays are taken into consideration. The parameter uncertainties are assumed to be bounded and laid in a certain interval. By constructing a novel Lyapunov-Krasovskii functional, together with some inequality techniques and stochastic stability theory, some sufficient criteria are driven in terms of linear matrix inequalities (LMI), which are easily to verify and can be solved by MATLAB. Furthermore, the results obtained in this paper are less conservative and cover more situations compared with the ones published in the literature. [ABSTRACT FROM AUTHOR]

This paper derives some sufficient conditions for exponential stability in the mean square of stochastic discrete-time delayed Hopfield neural networks (DHNN) with impulse effects. The Lyapunov-Krasovskii stability theory, Halanay inequality, and linear matrix inequality (LMI) are employed to investigate the problem. It is shown that the impulses in certain regions might preserve the stability property of the DHNN when the impulses-free part converges to its equilibrium point. Moreover, the feasible interval of the jump operator is also derived. [ABSTRACT FROM AUTHOR]