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Gas–solid Fluidized bed technology has a pivotal role in coal separation. Bubble movement behavior is an important factor affecting the fluidization stability. Fluidized bed measurement is an essential link in the bubble behavior study. As the main evaluation parameters, the concentration distribution and density distribution can reflect the bubble movement behavior. This work uses a noninvasive method of electrical capacitance tomography (ECT) for fluidized bed measurements, combined with COMSOL simulation validation for real-time imaging of bubbles in Geldart Group B magnetite powder particles. Meanwhile, the most suitable reconstruction algorithm for gas–solid separation fluidized bed is selected from three image reconstruction algorithms. And then concentration distribution and density distribution are analyzed. The results show that under reasonable gas velocity conditions (U–Umf =2.28 and 3.17 cm/s), the central region ([0, 1/4]) concentrations of [0.43–0.45] and [0.39–0.42] and densities of [1.98–2.06 g/cm3] and [1.86–1.96 g/cm3] are obtained by ECT measurements, respectively. Finally, the bed density obtained from the ECT sensors in the experiment was validated using three different bed density models. The error can be controlled to within 20%, which indicates that the ECT measurement method has a fairly high reliability and accuracy in dry coal beneficiation field. [ABSTRACT FROM AUTHOR]

AbstractSurface radiative exchange is widely used in the fields related to industrial and environment. Accurate and rapid calculation of the surface radiant heat flux can predict and prevent accidents. In this study, a solver for surface radiative exchange based on the OpenFOAM platform is developed. The solver’s accuracy can be verified by calculating the net heat rate of the cubic cavity and the triangular-prism geometries. The solarLoad radiation model is used to study the variation of heat flux with respect to the solar incidence angle for a satellite in orbit and a human standing in a room with a window. Finally, a Graphical User Interface (GUI) based on the PyQt5 for this solver is developed to simplify the operation process and make the solver user-friendly. [ABSTRACT FROM AUTHOR]

This study aims to identify effective teaching strategies and challenges in computer science (CS) teaching and K-12 CS teachers' needs for professional development (PD). The data were collected through semi-structured interviews with five K-12 CS teachers and eight CS instructors in higher education and analyzed using thematic analysis. The findings indicated that (1) connecting the classroom to the real world, project-based assessment, and teamwork are effective teaching strategies; (2) teaching challenges include CS teachers' knowledge gaps, students' technology access and use, and elective courses; and (3) teachers' PD opportunities and needs include content and pedagogical knowledge and an ongoing learning community. The findings offer implications for K-12 CS education and teachers' PD. [ABSTRACT FROM AUTHOR]

Existing seawalls along the eastern coast of China are increasingly becoming the focus of upgrade operations. Concerns arise regarding the settling and stability of seawalls built on soft clayey seabed during upgrade operations. Pore water pressure (PWP) and horizontal displacement accumulations induced by combined tide and wave loadings are observed in in-situ measurements of the clayey seabed underneath the seawall. The measurement results show clear correlations between the oscillations of excess PWP and variations in the tidal height. To reproduce the quasi-static interaction behaviors of the gravity-type seawall and clayey seabed under combined cyclic loadings from waves and currents, a finite element model has been built after incorporating a stiffness degradation law that is evaluated from laboratory triaxial tests on the seabed soil. Demonstrably, with a suitable stiffness degradation law for the seabed soil, the accumulative behaviors can be reasonably reproduced using finite-element modeling. [ABSTRACT FROM AUTHOR]

Spaceborne photon-counting LiDAR is significantly affected by noise, and existing denoising algorithms cannot be universally adapted to different surface types and topographies under all observation conditions. Accordingly, a new denoising method is presented to extract signal photons adaptively. The method includes two steps. First, the local neighborhood radius is calculated according to photons' density, then the first-step denoising process is completed via photons' curvature feature based on KNN search and covariance matrix. Second, the local photon filtering direction and threshold are obtained based on the first-step denoising results by RANSAC and elevation frequency histogram, and the local dense noise photons that the first-step cannot be identified are further eliminated. The following results are drawn: (1) experimental results on MATLAS with different topographies indicate that the average accuracy of second-step denoising exceeds 0.94, and the accuracy is effectively improves with the number of denoising times; (2) experiments on ICESat-2 under different observation conditions demonstrate that the algorithm can accurately identify signal photons in different surface types and topographies. Overall, the proposed algorithm has good adaptability and robustness for adaptive denoising of large-scale photons, and the denoising results can provide more reasonable and reliable data for sustainable urban development. [ABSTRACT FROM AUTHOR]

Exploring the driving factors behind urban polycentricity is of paramount significance for advancing the implementation of urban polycentric strategies. In this, paper takes 41 cities in the China's Yangtze River Delta region are taken as the research objects, and the degree of urban polycentricity is measured using non-parametric and social network methods. Then, the geographic probe method is applied to reveal the driving factors of the spatial differentiation of urban polycentricity. The research results showed that (1) the distribution of hot and cold spots of the urban polycentricity index was roughly the same between 2006 and 2015, while and the distribution of hot and cold spots of the urban polycentricity index varied greatly between 2015 and 2020. (2) In 2010, the proportions of the secondary and industry tertiary industries and the topographic relief were the main driving factors of urban polycentricity. By 2020, the population size and topographic relief were the key drivers of urban polycentricity. [ABSTRACT FROM AUTHOR]

SiC/graphene nanocomposites were rapidly synthesized by hexamethyldisilane and methane decomposition in atmospheric plasmas. Results indicate that the products without methane addition were SiC/C composites composed of SiC nanoparticles with dimension of 5–30 nm and carbon nanoshells with few layers. With the addition of methane, graphene nanosheets with 1–8 layers generated, and they attached with SiC nanoparticles and carbon nanoshells, forming SiC/graphene nanocomposites with point-surface structure. The formation of graphene nanosheets improved the microwave absorption ability, and the optimal reflection loss approached −65.7 dB at 11 GHz with an absorber thickness of 1.6 mm. Electromagnetic parameters indicated the improving microwave absorption was associated to the enhanced polarization/conduction loss due to the formation of point-surface structure. [ABSTRACT FROM AUTHOR]

More and more countries have become greying societies along with the burgeoning of digital devices. The older generation suffers from a sharp digital divide. Although the information infrastructure is fully developed, the elderly, not having grown up with it, tend to lack digital literacy and hold less intention to learn to use digital technologies. In the past, it was cable TV which pervaded the market and because of its long history of development became indispensable in the lives of the elderly. Recently, the maturity of Smart TV, provides us with an appropriate digital learning tool to assist seniors in Taiwan to improve their digital literacy. This is done utilising a digital remote control, designed to be a mixture of new and old technologies that offers seniors a high degree of familiarity. The study explore the effects of technology anxiety, digital feedback, and familiar technological skills on the adoption of digital devices by the elderly. In addition, a learning strategy compatible with the existing living environment of the elderly is proposed. The findings and recommendations for an effective approach to this problem are discussed as well as limitations and future research directions. [ABSTRACT FROM AUTHOR]

Maize is an important cereal crop and plays an important role in agriculture. The leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (FPAR) are important vegetation canopy structure parameters that are closely related to crop photosynthesis, transpiration and respiration and are of great significance for crop yield estimation. Hyperspectral data can obtain the spectral characteristic parameters of crops, and LiDAR data can obtain the vertical structure index. The former focuses on horizontal characteristic information, and the latter focuses on vertical characteristic information. In this paper, random forest method is used to carry out the inversion modelling of maize LAI and FPAR, and the effects of hyperspectral data resolution, LiDAR data density and scanning angle on the inversion accuracy are tested and analysed. The results show that there is good accuracy and stability of the random forest inversion model (LAI: 0.53

The portable air purifier can't uniformly remove the PM2.5 at each personnel position in a room, which causes the unevenness of PM2.5 distribution. In order to achieve priority purification of PM2.5 at the personnel position, experiments and simulations were conducted here to determine the time required for the purifier to reduce the PM2.5 concentration in a room to 15 μg/m3 (hereafter referred to as the purification time) in each area of the room at different wind speeds. SPSS was used to conduct regression analysis of the simulated data and determine the contribution rate of each impact factor, and assess the prediction model for the purification time. This prediction model can be used to calculate the purification time of any location in rooms of different sizes. The results show that, there was a nonlinear relationship between the purification time and impact factors, however, when the purifier wind speed is determined, PM2.5 purification time shows a linear relationship with the remaining impact factors. The contribution rate of the initial PM2.5 concentration to the purification time was largest. Increasing the wind speed will further increase the contribution rate of the initial PM2.5 concentration, but reduce the contribution rate of the air supply angle, personnel distance, and personnel angle. [ABSTRACT FROM AUTHOR]

Objective To investigate what social, psychological, personality, and behavioral factors affect overtime heart rate changes of college students. Participants: The daily heart rates of over 600 undergraduates at the University of Notre Dame were unobtrusively recorded via Fitbit devices from August 16, 2015, to May 13, 2017. Method: Latent Growth-Curve modeling strategy is utilized to examine how daily mean heart rate and its standard deviation change over time, and what foregoing factors predict observed changes. Results: The mean heart rate increased and its standard deviation stayed the same over the 637 days. Heart rate levels go up with that of social contacts, an indicator of peer influence. Both daily heart rate levels and changes are also affected by multiple external factors. Conclusion: Human heart rate is not only a physiological phenomenon but also a social-psychological one, as it is systematically affected by peer networks, social contexts, and human activities. [ABSTRACT FROM AUTHOR]

Objective: To investigate the prevalence of gestational diabetes mellitus (GDM) and its determinants among pregnant women in the Tongzhou district of Beijing, China.Methods: This study was performed on data collected in the routine work of the prenatal health care system from 27,119 pregnant women in the Tongzhou district of Beijing during 2013-2018. Univariate and multivariate logistic regression analyses were used to assess the factors associated with GDM.Results: The overall prevalence of GDM was 24.24%, and it showed an increasing trend over the 6 years. A univariate analysis showed that the prevalence of GDM increased with age (p < .001). In multivariate analysis, it was found that women with a non-local household registration, as well as those without a local household registration but whose husbands had one, had a lower risk for GDM than both spouses who had local registration. Women who were overweight/obese had a higher risk for GDM than women with a normal pre-pregnancy body mass index. Multipara women had a lower likelihood of developing GDM.Conclusions: We found a slightly higher prevalence of GDM in the Tongzhou district of Beijing than has been found in other studies, and the prevalence rose over the 6 years of the study. Advanced age, pre-pregnancy overweight or obesity, and local household registration were important risk factors for GDM. Multiparity may be a protective factor against developing GDM. Intensive health education on related determinants should be strengthened for the prevention and control of GDM, especially in high-risk women. [ABSTRACT FROM AUTHOR]

The problem of a spherical cavity expanded from an initial radius to another cavity in finite soil is investigated in this paper. A similarity transformation technique is used to solve the partial differential equations (PDEs) of spherical cavity expansion, which allows the stress, displacement and pore pressure induced by cavity expansion to be captured. The derived analytical solution is validated by comparing the degenerate solution with published results on cavity expansion in an infinite medium. The present analytical method can conveniently capture the effect of the finite boundary. A simple application to compaction grouting confirms its utility in geotechnical practice. [ABSTRACT FROM AUTHOR]

Illumination is an environmental factor affecting lane-change behavior. To identify the factors associated with lane-change behaviors in low illumination, the Lane-change Behavior Questionnaire in Low Illumination was developed based on the Chinese traffic environment and low-illumination environmental conditions. The appropriate dimensional structure of the questionnaire was identified. In a sample of 214 drivers in Hefei, China, the study found that male and younger drivers were more likely to change lanes while driving in a low-illumination environment. Drivers with more experience driving in low illumination were more likely to change lanes. Risky driving behaviors and lane-change frequency were significantly positively correlated. Lane-change intention was significantly higher when respondents drove on roads with street lighting than on roads without street lighting. The regression model predicted the frequency of lane-change behavior well based on gender, weekly driving time, and lane-change and risky driving behavior factors. [ABSTRACT FROM AUTHOR]

Communication tower (CT) and its accessory equipment (AE) such as radio frequency equipment (RFE) and antenna, are essential in providing highspeed and stable mobile network services. It is necessary to routinely monitor the security and stability of CT and AE for seamless communication. There is limited research on fine segmentation of communication base station objects. This paper proposes a method for accurately segmenting the point cloud of the CT and AE from Terrestrial Laser Scanning (TLS) data. At first, the CT point cloud is accurately segmented based on region growing and Random Sample Consensus (RANSAC). Then, the point cloud of pole-shaped apart is extended to a certain distance to obtain the buffer point cloud containing AE. Normal Differential (ND) clustering is employed to obtain several groups of clusters containing planes, and calculate each plane's filling rate and size. Finally, the cluster type (such as antenna, RFE, or other) is distinguished. The experimental results demonstrate that the point-based average F1-score of CTs is 98. 70%, the point-based and object-based average F1-scores of antennas are 96. 09% and 97. 93%, and the corresponding values for the RFE are 89. 89% and 90. 00%, respectively, indicating the optimal performance of the proposed method. [ABSTRACT FROM AUTHOR]

The hydrophilicity/hydrophobicity of zeolites has been received increasing attentions due to its great influence on the physical, chemical property and application of zeolites. Generally, zeolites with different hydrophilicity/hydrophobicity exhibit different interaction with molecules/contaminations of different polarity, and thus have found promising applications in various and different fields. In this review, we first discuss the two main influence factors, i.e. SiO2/Al2O3 ratio and surface hydroxyl groups affecting hydrophilicity/hydrophobicity of aluminosilicate zeolites. Then, we give an overview of the ways for regulation of hydrophilicity/hydrophobicity of zeolites, i.e. hydrothermal synthesis, post synthesis for SiO2/Al2O3 ratio regulation and heat treatment, surface modification, water intrusion-extrusion method for hydroxyl groups regulation. The third, the hydrophilicity/hydrophobicity determination methods, i.e. water vapor adsorption, hydrocarbon/water vapor adsorption and TG experiment methods are concluded and compared. Finally, the problems and challenges for the future of this subject are discussed. [ABSTRACT FROM AUTHOR]

Combining Dirichlet Mixture Models (DMM) with deep learning models for road extraction is an attractive study topic. Benefiting from DMM, the manually labeling work is alleviated. However, DMM suffers from high computational complexity due to pixel by pixel computations. Also, traditional constant parameter settings of DMM may not be suitable for different target images. To address the above problems, we propose an improved DMM which embeds superpixel strategy and sparse representation into DMM. In our road extraction framework, we first use improved DMM to filter out most backgrounds. Then, a trained deep CNN model is used for further precise road area recognition. To further promote the processing speed, we also apply the superpixel scanning strategy for CNN models. We tested our method on a Shaoshan dataset and proved that our method not only can achieve better results than other compared state-of-the-art image segmentation methods, but the processing speed and accuracy of DMM are also improved. [ABSTRACT FROM AUTHOR]

Combining acoustic and electrical stimulation has been successfully used in patients with low-frequency residual hearing. Electrode insertion trauma, such as electrode translocation could result in loss of residual hearing. The aim of the study is to evaluate the LCI-20PI electrode array insertion trauma to the intra-cochlear structures in fresh human temporal bone specimens. The LCI-20PI electrode arrays were inserted into scalae tympani through round window membrane in 10 cochleae from ten fresh human cadavers. The intracochlear trauma was evaluated histologically by a scale of 0–4: 0 – no observable trauma, 1 – elevation of basilar membrane, 2 – rupture of basilar membrane or spiral ligament, 3–dislocation into scala vestibuli and 4 – fracture of modiolus or osseous spiral lamina. The insertion depth was measured by radiography. Histological results revealed no observable trauma in seven specimens; basal membrane elevation and rupture in two specimens; the electrode array misled into scala vestibuli in one specimen. The insertion depth varied from 228° to 288°. The insertion of the LCI-20PI electrode arrays caused no trauma in the majority of the fresh temporal bone specimens. No translocation of the electrode arrays from the scala tympani to the scala vestibuli was observed [ABSTRACT FROM AUTHOR]

Based on the fundamental of traditional Sub-aperture coherence (SAC) algorithm, Radial Sub-aperture coherence (RSAC) and Symmetrical Radial Sub-aperture coherence (SRSAC) have been designed to achieve non-mechanical beam steering with ultra-high precision and stability by utilising two-dimensional Liquid Crystal Optical Phased Array (LCOPA). Both of them inherit the original advantages, that is, to eliminate the local pointing accuracy defects and greatly improve the angular resolution of the beam steering system. Meanwhile, the steering angle error caused by the aperture variation and the alignment error can be also effectively restricted by SRSAC. In this paper, the essential mathematical framework of SRSAC and its affiliated local error elimination method was established to supplement the theoretical support of these phase generation algorithms. By dissecting the generation mechanism of each pointing error branch, the theoretical formulae with great universality are finally proposed, which provide visualised and necessary references for the specific application in other beam control situations. [ABSTRACT FROM AUTHOR]

Plasma gas phase synthesis of graphene method is one-step synthesis, without catalyst, acid, solvent and substrate materials. In this paper, plasma pyrolysis of C2H4 for the preparation of graphene was carried out to investigate the effect of doping H2, CO2, and N2 on the morphology characteristics and chemical reaction properties of the synthesized products at different reaction temperatures ranging from 1500 to 4500 K. It was found that an increase in temperature leads to flatter morphology, less agglomeration, and a decrease in defect density and oxygen content in graphene. The addition of H2, CO2, and N2 gases affected the morphology and defect density of the products. In addition, the high temperature conditions increase the hydrogen atom concentration and etch the edges of graphene, while CO2 slows down the etching process and decreases the defect density. Doping with high enthalpy N2 favors the improvement of crystallinity and defect density at low temperatures, but increases the defect density at high temperatures. These findings contribute to further understanding of the application and optimization of the method of plasma gas phase synthesis of graphene. [ABSTRACT FROM AUTHOR]

AbstractThis article proposes a soft/hard dual-material honeycomb structure. The quasi-static and dynamic crush modes and crashworthiness of six groups of honeycombs were studied by using universal testing machine and multi-purpose impact gun system. Experimental results indicate that under quasi-static conditions, dual-material honeycombs exhibit similar crush modes, while single-material honeycombs have regular and progressive folding modes. Under dynamic impact, single-material honeycombs will collapse overall along cracks, while dual-material honeycombs exhibit layer-by-layer collapse and negative Poisson’s ratio phenomena. The dual-material structures exhibit the best crashworthiness. The bionic corrugation and dual-material design show excellent synergy in enhancing the energy-absorbing performance of the structure. [ABSTRACT FROM AUTHOR]

Sociological theories suggest that urban life affects human sociability in negative ways. People in urban areas are expected to have fewer and weaker ties than those in rural areas. Rural areas should have proportionally more local ties, whereas urban areas have stronger nonlocal ties. We test these hypotheses using comprehensive large-scale data from a mobile phone company in Spain. We examine urban and rural differences in terms of the average number of ties and the composition and strength of local vs. nonlocal ties of subscribers in 6,124 postal codes. Consistent with urbanism theories, networks in more urban areas are smaller but the effect is weak. What is more pronounced are urban–rural differences in the composition and strength of local and nonlocal ties. There is a tradeoff between strength and number of ties. In urban places where local ties are weaker, there are more such ties, whereas in rural places where local ties are stronger, there are fewer local ties. We discuss the theoretical and practical implications of the results. [ABSTRACT FROM AUTHOR]

Accurate estimation of the fraction of absorbed photosynthetically active radiation (fPAR) is important for maize growth and yield estimations. Light detection and ranging (LiDAR)-derived canopy vertical structural and hyperspectral image-derived vegetation spectral information are complementary for vegetation fPAR estimation. This study explores the potential of artificial neural networks (ANNs) with two types of data to estimate maize fPAR. First, 45 metrics were derived from LiDAR data and 13 from a hyperspectral image. Then, the ANNs and stepwise multiple linear regression (SMLR) methods were used to estimate the fPAR. Finally, model validity was assessed using in-situ data. Results showed that the ANNs performed better in fPAR inversion (R2 = 0.910, adj. R2 = 0.921, RMSE = 0.046, RRMSE = 0.056, where R2 is the coefficient of determination, adj. R2 the adjusted coefficient of determination, RMSE the root mean squared error, and RRMSE the relative root mean squared error) than SMLR (R2 = 0.638, adj. R2 = 0.609, RMSE = 0.077, RRMSE = 0.092) and SMLR with the natural logarithm of data (R2 = 0.855, adj. R2 = 0.825, RMSE = 0.067, RRMSE = 0.081). This study is helpful for guiding the accurate estimation of maize fPAR using remote sensing techniques. [ABSTRACT FROM AUTHOR]

The use of non-thermal plasma at atmospheric pressure has emerged as a technique for the substrate-free, gas-phase synthesis of graphene nanoflakes (GNFs). In this paper, a non-thermal plasma based on magnetically stabilized gliding arc discharge (MSGAD) was employed to prepare GNFs. The effects of the carbon-containing precursor, plasma gas, and arc current on the GNFs synthesis were investigated. The technique produced GNFs with sizes of 50–200 nm and 1–20 layers, spherical carbon nanoparticles with 10–40 nm diameters, and graphitic particles. The results showed that the formation of GNFs depended on the selection of proper process parameters, such as precursors with a high H/C ratio, an Ar-N2 plasma gas, a low arc current, a low precursor flow rate, and a suitable plasma gas flow rate. Correlations between the process parameters and the product morphology indicated that abundant H atoms and fewer polycyclic aromatic hydrocarbons were favorable for the formation of GNFs. [ABSTRACT FROM AUTHOR]

We present a high-resolution convergence study of detonation initiated by a temperature gradient in a stoichiometric hydrogen–oxygen mixture using the PENCIL CODE and compare with a code that employs a fifth order weighted essentially non-oscillating (WENO) scheme. With Mach numbers reaching 10–30, a certain amount of shock viscosity is needed in the PENCIL CODE to remove or reduce numerical pressure oscillations on the grid scale at the position of the shock. Detonation is found to occur for intermediate values of the shock viscosity parameter. At fixed values of this parameter, the numerical error associated with those small wiggles in the pressure profile is found to decrease with decreasing mesh width δ x like δ x − 1.4 down to δ x = 0.2 μ m . With the WENO scheme, solutions are smooth at δ x = 10 μ m , but no detonation is obtained for δ x = 5 μ m . This is argued to be an artifact of a decoupling between pressure and reaction fronts. [ABSTRACT FROM AUTHOR]

We introduce and demonstrate a new structure of polarisation grating which can substantially enlarge the deflection angle. We derive the polarisation state of a beam passing through the reflective composite polarisation grating by Jones matrix and build a rigorous simulation about the deflection angle of reflective composite polarisation grating using finite-element analysis. The theoretical diffraction efficiency of the reflective composite polarisation grating can reach up to 90%. The experimental result of deflection angle of the reflective composite polarisation grating is consistent with that of simulation. The reflective composite polarisation grating could be expected to be applied in augment reality system, spectroscopy, optical telecommunications, non-mechanical beam steering and so on. [ABSTRACT FROM AUTHOR]

In this study, an approach based on precise point positioning (PPP) is proposed for the assessment of global ionospheric maps (GIMs). This assessment is performed by comparing GIMs with vertical total electron content (VTEC) values retrieved using the PPP technique. The results indicate that the CODG, ESAG, WHUG, and CASG ionospheric products underestimate the VTEC values. There is a high level of consistency between all GIMs and PPP-VTEC values during periods of low solar activity. In addition, almost all GIMs exhibit significant discrepancies with PPP-VTEC values over the equatorial ionisation anomaly (EIA) region during periods of high solar activity. [ABSTRACT FROM AUTHOR]

This study aimed to examine the mediating effects of motivational beliefs in the relations between parental involvement and science achievement. Three types of motivational beliefs, namely, self-concept, intrinsic value, and utility value were addressed based on the Expectancy-Value Theory model. A representative national sample from Taiwan of 5042 eighth-grade students with an average age of 14.2 years was examined. The results indicated that self-concept and utility value can mediate the effects of parental involvement on science achievement, whereas intrinsic value does not have such a mediating effect. These findings provide empirical evidence revealing the prominent role of parental involvement in students' science achievement through a motivational mechanism. [ABSTRACT FROM AUTHOR]

Rather than a comprehensive review, the aim here is to provide a selection of examples showcasing the applications of synchrotron radiation in polymer and soft materials research, as well as highlighting a range of unique capabilities of each facility. This special issue will feature polymer and soft material research from a small selection of synchrotron facilities across the globe. Polymers and soft materials have a wide range of applications in different fields, including industrial, pharmaceutical, energy, and electronics. [Extracted from the article]

Skin infection is a major health issue that usually is caused by the continuous proliferation of bacteria in wounds. With the abuse of antibiotics worldwide, the battle against skin infection is becoming more and more difficult. Therefore, the development of new ways with different antibacterial mechanisms to current antibiotics is urgently needed. Inspired by the powerful inhibition of ferroptosis used in cancer therapy, here in our study, ferric-loaded lipid nanoparticles (Fe-LNPs) with unform size (∼130 nm) and surface charge (∼12 mV) were constructed and found to effectively inhibit the growth of both Gram positive (Staphylococcus aureus, S. aureus) and negative (Escherichia coli, E. coli) strains, possibly due to induction of ferroptosis-like cell death mechanisms. Most importantly, Fe-LNPs can also effectively inhibit the proliferation of S. aureus in a skin infection model and promote the healing of wounds. The Fe-LNPs can be applied as a powerful antibacterial formulation for future application in clinic. [ABSTRACT FROM AUTHOR]

The volume of gear transmission system has been concerned by people. At present, the researchers mainly focus on the optimization algorithm, but there is a lack of research on the volume model of gear transmission system. In the paper, the single-stage spur-gear transmission system is considered and the volume models for different structures of spur gear are built. Firstly, the influence of bottom clearance and the modification coefficient on the spur-gear volume are analysed. The formula of clearance volume is derived. Secondly, volume models of different structure of spur gear are built. In order to illustrate the accuracy of the models, the corresponding three-dimensional models of different structure of spur gear are established. Finally, the design parameters of spur gear are as the optimisation variables, the spur-gears design and transmission requirements are as the constraint conditions, the total minimum volume of single-stage spur-gear transmission system is as the optimisation target, the genetic algorithm (GA) toolbox in Matlab software is adopted in the optimisation. A single-stage spur-gear system is as an example, and the optimisation for minimum volume of single-stage spur-gear transmission is carried out. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms of explosions is important for minimising devastating hazards. Due to the complexity of real chemistry, a single-step reaction mechanism is usually used for theoretical and numerical studies. The purpose of this study is to look more deeply into the influence of chemistry on detonation initiated by a spontaneous wave. The results of high-resolution simulations performed for one-step models are compared with simulations for detailed chemical models for highly reactive and low reactive mixtures. The calculated induction times for H2/air and for CH4/air are validated against experimental measurements for a wide range of temperatures and pressures. It is found that the requirements in terms of temperature and size of the hot spots, which can produce a spontaneous wave capable to initiate detonation, are quantitatively and qualitatively different for one-step models compared to detailed chemical models. The time and locations when the exothermic reaction affects the coupling between the pressure wave and spontaneous wave are considerably different for a one-step and detailed models. The temperature gradients capable to produce detonation and the corresponding size of hot spots are much shallower and, correspondingly, larger than those predicted using one-step models. The impact of the detailed chemical model is particularly pronounced for the methane-air mixture. In this case, not only the hot spot size is much greater than that predicted by a one-step model, but even at the elevated pressure, the initiation of detonation by a temperature gradient is possible only if the temperature outside the gradient is rather high, so that can ignite a thermal explosion. The obtained results suggest that the one-step models do not reproduce correctly the transient and ignition processes, so that interpretation of the simulations performed using a one-step model for understanding mechanisms of flame acceleration, DDT and the origin of explosions must be considered with great caution. [ABSTRACT FROM AUTHOR]

The arc discharge method in a hydrocarbon atmosphere has a promising application in the nanocarbon synthesis field due to its high yield. In this paper, products on electrodes in an argon-methane magnetically rotating arc at atmospheric pressure are investigated. Different nanocarbons are obtained on the cathode and anode surfaces, respectively. Material analysis indicates that the products on the cathode are mainly carbon tubes. Some carbon tubes are well-aligned in one direction, and the others have a coil-like structure. The products on the anode are a mixture of graphene nano-flakes and aggregate hollow carbon particles. The hollow carbon particles exhibit a chain-like structure with internal space to be connected. To the authors' knowledge, this is possibly the first time that aggregate hollow carbon particles with a chain-like structure have been observed in the absence of any catalyst. Based on the configuration of arc plasma, the formation mechanism of electrode products is briefly proposed. [ABSTRACT FROM AUTHOR]

Two series of imperatorin analogs were synthesized based on our previous research and evaluated for their vasodilatation activities on in vitro rat mesenteric artery, basilar artery, and renal artery ring models. Target compounds were characterized by infrared, 1H NMR, and mass spectra. Most derivatives possessed significant vasodilatory activity on the mesenteric artery, and compound 3a exhibited favorable and broad vasodilatation activities on three kinds of rat artery ring models. The pharmacological results indicated that introducing nitrogen-contained ring in side chain or large steric hindrance at the distal end could increase the vasodilatory activity. Further, replacement of oxygen atom (–O–) in the skeleton of furocoumarin derivatives with nitrogen (–NH–) could cause the decrease of vasodilatory activity. The molecular docking also indicated that compound 3a showed a best affinity with α-1C receptor (PDB ID: 3G43). All these results suggested compound 3a would be a potential vasodilatory agent for hypertension. [ABSTRACT FROM AUTHOR]

Metabolomics is the science of qualitatively and quantitatively analyzing low molecular weight metabolites occur in a given biological system. It provides valuable information to elucidate the functional roles and relations of different metabolites in a metabolic pathway. In recent years, a large amount of research on microbial metabolomics has been conducted. It has become a useful tool for achieving highly efficient synthesis of target metabolites. At the same time, many studies have been conducted over the years in order to integrate metabolomics data into metabolic network modeling, which has yielded many exciting results. Additionally, metabolomics also shows great advantages in analyzing the relationship of metabolites network wide. Integrating metabolomics data into metabolic network construction and applying it in network wide analysis of cell metabolism would further improve our ability to control cellular metabolism and optimize the design of cell factories for the overproduction of valuable biochemicals. This review will examine recent progress in the application of metabolomics approaches in metabolic network modeling and network wide analysis of microbial cell metabolism. [ABSTRACT FROM AUTHOR]

Energy piles are now considered as an efficient energy solution for heating and cooling buildings. However, once the energy pile has a breakdown especially of the heat exchange elements, it is difficult to be repaired. Thus, a new design of energy piles with embedded steel tubes instead of two longitudinal bars is introduced. Heat exchange pipes were placed into the embedded steel tubes, instead of being attached to reinforcing cages, for the purpose of decreasing the damage to the pipes. Model tests on a conventional energy pile and an improved energy pile with and without a mechanical load were conducted in saturated sand. The thermo-mechanical behaviour of the two piles was comparatively analysed when heating and cooling. In the tests, pile temperature, soil temperature, horizontal earth pressure, strain and pile head displacement were all measured at different stages. Based on these measurements, thermal stress and mobilised side shear stress were studied to comprehensively evaluate the performance of the improved energy pile. The results show that the temperature variation of conventional energy pile was maximum 1.11 times after heating and 1.21 times after cooling that of improved energy pile, respectively. The horizontal earth pressure and strain of conventional energy pile also had larger variations than improved energy pile due to more obvious thermal performance. For the improved energy pile, thermal stress during heating was higher with a mechanical load than without load, but the mobilised side shear stresses were distributed similarly irrespective of mechanical load. The pile heat displacement for the two piles also shows a slight difference after heating and cooling. Moreover, the mechanical load also influenced pile head displacement too much. [ABSTRACT FROM AUTHOR]

We consider the dynamics of the IS–LM economic model, which is a fundamental macroeconomic model describing the relationship between interest rates and assets market. There is generally a long time lag between changes in the interest rate and the consequential effects on the economy. Therefore, most central banks change the interest rates slowly, which yields a slow–fast IS–LM model. Using geometric singular perturbation theory, we establish the sufficient and necessary conditions on the existence of relaxation oscillations for the slow–fast IS–LM model. We also apply our abstract genericity results to study some concrete particular slow–fast IS–LM models. Numerical simulations are presented to validate the theoretical results. [ABSTRACT FROM AUTHOR]

The aim of the paper is to use the moving least square meshless method to study the coupled problem between radiation and natural convection in semitransparent medium of 2D and 3D geometries. The flow is incompressible, laminar, and governed in the vorticity-stream function formulation (2D) and vorticity-vector potential formulation (3D) of Navier–Stokes equations. We use the discrete ordinate method to solve the radiative transfer equation. We study the influence of optical thickness, albedo, heat source, and geometry shape to the flow patterns and temperature distributions. The examples (square, cylindrical ring, and cubic) are taken to compare to the references to check the performance of the proposed method. The results show that the moving least square meshless method is capable to deal with the coupled radiation and natural convection with stability and accuracy. [ABSTRACT FROM PUBLISHER]

Taiwanese students are featured as having high academic achievement but low motivational beliefs according to the serial results of the Trends in Mathematics and Science Study (TIMSS). Moreover, given that the role of context has become more important in the development of academic motivation theory, this study aimed to examine the relationship between motivational beliefs and science achievement at both the student and school levels. Based on the Expectancy-Value Theory, the three motivational beliefs, namely self-concept, intrinsic value, and utility value, were the focuses of this study. The two-level hierarchical linear model was used to analyse the Taiwanese TIMSS 2011 eighth-grade student data. The results indicated that each motivational belief had a positive predictive effect on science achievement. Additionally, a positive school contextual effect of self-concept on science achievement was identified. Furthermore, school-mean utility value had a negative moderating effect on the relationship between utility value and science achievement. In conclusion, this study sheds light on the functioning of motivational beliefs in science learning among Taiwanese adolescents with consideration of the school motivational contexts. [ABSTRACT FROM AUTHOR]

Objectives: Long-termd-galactose injection induces accelerated aging in experimental rodent models. The aim of this study was to determine the effects of dietary fructo-oligosaccharide (FO) on the brain β-amyloid (Aβ), amyloid-associated enzymes, cognitive function, and plasma antioxidant levels ind-galactose-treated Balb/c mice. Methods: The subcutaneous (s.c.) injection and the dietary treatment were conducted simultaneously for 49 days. Mice (12 weeks of age) were divided into five groups (n = 14/group): control (s.c. saline, control diet) serving as a young control, DG (s.c. 1.2 gd-galactose/kg body weight, control diet), DG + LFO (2.5% w/w FO, low-dose FO diet), DG + HFO (5% w/w FO, high-dose FO diet), and DG + E (α-tocopherol 0.2% w/w, vitamin E diet) as an antioxidant reference group. Another group of older mice (64 weeks of age) without any injection served as a natural aging (NA) group. Results: The DG and NA groups had greater Aβ levels in the cortex, hippocampus, and the whole brain. High-dose FO, similar to α-tocopherol, attenuated thed-galactose-induced Aβ density in the cortex and hippocampus. In addition, FO attenuated thed-galactose-induced protein expression of Aβ and beta-site amyloid precursor cleaving enzyme of the whole brain in a dose–response manner. Either dose of FO supplementation, similar to α-tocopherol, attenuated thed-galactose-induced cognitive dysfunction. In addition, FO improved the plasma ascorbic acid level in a dose–response manner. Conclusion: Dietary FO (2.5–5% w/w diet) could attenuate the development of Alzheimer's disease, which was likely to be associated with its systematic antioxidant effects. [ABSTRACT FROM AUTHOR]

This article reports an empirical study that revisits the unique selling proposition (USP) concept by delineating the content domains based on an operational definition. A revised USP (RUSP) scale was developed and purified, resulting in five dimensions that were consistent with our theoretical conceptualization. An application study further demonstrated that a high or low level of RUSP characteristics in an ad is associated with ad effectiveness measures. Theoretical contributions, managerial applications, and future research directions are discussed. [ABSTRACT FROM AUTHOR]

This study contributes to the extant literature on destination management organization (DMO)-led postings used in the online tourist community as a means to facilitate word-of-mouth (WOM) communications. Our proposed framework summarizes key antecedent variables of the usage rate and activity level of online community, number and types of information, and consumer responses. It examines the active role of DMO-led postings as a WOM communication tool to influence tourist attitudes and facilitate potential travelers' decision making. The results demonstrate that message sender and message format have both a main effect and an interactive effect on the number of information cues and consumer responses. Research contributions, managerial implications, and future research directions are considered. [ABSTRACT FROM PUBLISHER]

The ICESat-2 (Ice, Cloud, and Land Elevation Satellite-2) can collect earth surface elevation data with high precision on a global scale. However, the collected photon data contains a large amount of background noise due to the influence of sunlight, cloud reflection, and other factors. For photon data of different scenes, how to effectively denoise and achieve accurate classification of photon point clouds is crucial for subsequent applications. This study proposes a random forest based method for denoising and classifying ICESat-2 photon data in urban areas by fusing spectral features from Sentinel-2 images and spatial distribution features from photon data. The experimental results show that the method can effectively identify various types of photons. Compared with the reference data, the overall accuracy of photon denoising and classification is 95.97% on average, and the average kappa coefficient is 94.18%. Further analysis demonstrates that the addition of sentinel-2 spectral information can effectively improve the classification accuracy of photon point clouds in urban areas, and the photon classification method of combining photon lidar data and optical images can be a promising solution to improve classification accuracy. [ABSTRACT FROM AUTHOR]

Bone defects are very common, and there has been a great deal of research in the field of orthopedics to find ideal materials to repair such defects. Nanohydroxyapatite is a good bone substitute material; it has a number of structural similarities to natural bone, can promote new bone formation, is noncytotoxic, and has good biodegradability and biocompatibility. The use of composite and polymeric biomaterials can overcome the problems associated with the brittleness and weak mechanical properties of nanohydroxyapatite. Nanohydroxyapatite and its composite biomaterials were confirmed to play important roles in bone defect repair. This review presents a comparison of research regarding use of nanohydroxyapatite and its composite biomaterials in repairing bone defects. The goal is to identify the artificial bone substitute materials with the best biocompatibility and clinical repairing effects for various individuals and clinical situations. [ABSTRACT FROM AUTHOR]

Effective production of arachidonic acid (ARA) usingMortierella alpinawas conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6–1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13–28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L. [ABSTRACT FROM PUBLISHER]

Context:Sensitive, non-invasive biomarkers that facilitate Parkinson’s disease (PD) detection and stage assignment are currently unavailable. Objective:The objective of this study is to investigate the potential of circulating microRNAs (miRNAs) as novel biomarkers for PD. Materials and methods:Solexa sequencing technology and quantitative real-time PCR were applied to screen and verify altered serum miRNAs in PD patients. Results:Serum miR-141, miR-214, miR-146b-5p, and miR-193a-3p were decreased significantly in PD patients compared with controls. Furthermore, the 4-miRNA panel enabled the differentiation of HY stage 1 and 2 PD patients from controls. Discussion and conclusion:The four serum miRNAs may represent novel biomarkers for the early detection of PD. [ABSTRACT FROM PUBLISHER]

Under the serious circumstances ofCamellia oleiferaadulteration, the accurate examination for quality trait ofC. oleiferaoil is extremely urgent. The use of near infrared transmittance spectroscopy as a rapid and cost-efficient classification technique for the authentication ofCamelliaoil was investigated. At the same time, the feasibility of near infrared transmittance spectroscopy for the rapid determination of soybean oil and maize oil adulterated in binary and ternary systemCamelliaoils was explored. The results showed that identifications was made based on the slight difference in raw near infrared transmittance spectra inCamelliaoils, soybean oils, maize oils, and those adulterated with soybean and maize oil with discriminant equations techniques. Furthermore, the performance of near infrared transmittance spectroscopy models for binary and ternary system adulteratedCamelliaoils was satisfactory. Moreover, the near infrared transmittance spectroscopy calibration model of soybean oil (0–50%) in binary system adulteratedCamelliaoils was the best, and correlation coefficients of the cross-validation (Rcv) was 0.99999. For the near infrared transmittance spectroscopy calibration model of maize oil in binary system (0–50%) and ternary system (0–40%) adulteratedCamelliaoils, theRcvwere 0.99996 and 0.99961, respectively. In addition, the coefficients of external validation for three models were obtained (0.9998, 0.9999, and 0.9967, respectively). In all, near infrared transmittance spectroscopy could be conducted to identifyCamelliaoils and detect soybean oil and maize oil adulterated in binary and ternay systemCamelliaoils from the methodology. [ABSTRACT FROM AUTHOR]

The leaf area index (LAI) is a key input parameter in ecosystem models and plays a vital role in gas–vegetation exchange processes. Several studies have recently been conducted to estimate the LAI of low-stature vegetation using airborne discrete-return light detection and ranging (lidar) data. However, few studies have been carried out to estimate the LAI of low-stature vegetation using airborne full-waveform lidar data. The objective of this research is to explore the potential of airborne full-waveform lidar for LAI estimation of maize. First, waveform processing was conducted for better extraction of waveform-derived metrics for LAI estimation. A method of faint returns retrieval was also proposed to obtain ground returns. Second, the LAIs of maize were estimated based on the Beer–Lambert law. Finally, the LAI estimates were validated using field-measured LAIs in Huailai, Hebei Province of China. Results indicated that maize LAI could be successfully retrieved with high accuracy (R2 = 0.724, RMSE = 0.449) using full-waveform lidar data by the method proposed in this study. [ABSTRACT FROM PUBLISHER]

In this paper, the robust stochastic stability is investigated for a class of uncertain discrete-time impulsive Markovian jump delay systems with multiplicative noises. Using the method of stochastic Lyapunov functionals construction, it is shown that impulses can stabilise the original impulse-free unstable systems. Moreover, the stability property of the impulse-free systems can be retained in the cases of appropriately large impulsive time interval. Some numerical examples are exploited to demonstrate the effectiveness and the superiority of the proposed results. [ABSTRACT FROM PUBLISHER]