Janus layers and electronic structure of 1T-(TiSeS)2.

TiS2-TiSe2 is one of the most studied titanium based solid solution systems. However, so far, all research on it has only focused on its disordered phase. Here, we systematically investigate its ordered phases. Using a structure search method based on the particle swarm optimization (CALYPSO) algorithm, we identify TiSeS-156 and discover a new structure (1T-(TiSeS)2). Based on first principles theory, their phonon spectra, formation energy, mechanical, electronic, thermal, and optical properties, as well as chemical bond analysis and synthetic pathways, have been investigated. The primitive cell of TiSeS-156 has three atoms and has a space group of P3m1 (no. 156). 1T-(TiSeS)2 has six atoms and has P3̄m1 symmetry (no. 164). TiSeS-156 and 1T-(TiSeS)2 are constructed by stacking the S-Ti-Se Janus layer materials. TiSeS-156 and 1T-(TiSeS)2 are narrow-gap semiconductors. The localized nature of the Ti(3d) states of TiSeS-156 and 1T-(TiSeS)2 leads to their semiconductor properties. 1T-(TiSeS)2 and TiSeS-156 have very similar mechanical, electronic, thermal, and optical properties of 1T-TiS2 and 1T-TiSe2, and are members of the 2D hexagonal lattice transition metal dichalcogenide layered material family. However, compared with 1T-TiS2 and 1T-TiSe2, TiSeS-156 and 1T-(TiSeS)2 have a wider range of potential applications, such as photovoltaic devices and photocatalysis, due to their S-Ti-Se Janus layer structure. They also provide a pathway for the preparation of Janus TiSeS monolayer and multi-layer materials. Moreover, our findings provide crucial insights for understanding the rich and complex crystal structures of the TiS2-TiSe2 system, which have broad implications for further exploration of this class of promising materials.

A Novel Method for Rolling Bearing Fault Diagnosis Based on Gramian Angular Field and CNN-ViT.

Fault diagnosis is one of the important applications of edge computing in the Industrial Internet of Things (IIoT). To address the issue that traditional fault diagnosis methods often struggle to effectively extract fault features, this paper proposes a novel rolling bearing fault diagnosis method that integrates Gramian Angular Field (GAF), Convolutional Neural Network (CNN), and Vision Transformer (ViT). First, GAF is used to convert one-dimensional vibration signals from sensors into two-dimensional images, effectively retaining the fault features of the vibration signal. Then, the CNN branch is used to extract the local features of the image, which are combined with the global features extracted by the ViT branch to diagnose the bearing fault. The effectiveness of this method is validated with two datasets. Experimental results show that the proposed method achieves average accuracies of 99.79% and 99.63% on the CWRU and XJTU-SY rolling bearing fault datasets, respectively. Compared with several widely used fault diagnosis methods, the proposed method achieves higher accuracy for different fault classifications, providing reliable technical support for performing complex fault diagnosis on edge devices.

The Lightweight Anchor Dynamic Assignment Algorithm for Object Detection.

Smart security based on object detection is one of the important applications of edge computing in IoT. Anchors in object detection refer to points on the feature map, which can be used to generate anchor boxes and serve as training samples. Current object detection models do not consider the aspect ratio of the ground-truth boxes in anchor assignment and are not well-adapted to objects with very different shapes. Therefore, this paper proposes the Lightweight Anchor Dynamic Assignment algorithm (LADA) for object detection. LADA does not change the structure of the original detection model; first, it selects an equal proportional center region based on the aspect ratio of the ground-truth box, then calculates the combined loss of anchors, and finally divides the positive and negative samples more efficiently by dynamic loss threshold without additional models. The algorithm solves the problems of poor adaptability and difficulty in the selection of the best positive samples based on IoU assignment, and the sample assignment for eccentric objects and objects with different aspect ratios was more reasonable. Compared with existing sample assignment algorithms, the LADA algorithm outperforms the MS COCO dataset by 1.66% over the AP of the baseline FCOS, and 0.76% and 0.24% over the AP of the ATSS algorithm and the PAA algorithm, respectively, with the same model structure, which demonstrates the effectiveness of the LADA algorithm.

Bulk photovoltaic effect in GaNGeC quaternary compound semiconductors.

Compared to the p-n junction photovoltaic effect, the bulk photovoltaic effect is a potential way to overcome the external limitations of solar energy conversion. It is challenging to find new materials with a bulk photovoltaic effect. In this article, using first-principles calculations and the maximum local Wannier function, we investigated the bulk photovoltaic effect in GaNGeC quaternary compound semiconductors with six different crystal structures (S-1, S-2, S-3, S-4, S-5, and S-6 for short). These semiconductors showed a large effective three-dimensional shift current conductivity, where the maximum absolute value of the shift current conductivity ranges from 10 µA V-2 to 425 µA V-2, indicating that they are promising candidates for photoelectric conversion applications. Furthermore, the electron localization function, difference charge density, and atomic configurations as well as Löwdin population analysis revealed that dimerization of the GaN layer and the GeC layer in S-5 and S-6 induces delocalization of electrons. This delocalization of electrons enhances their shift current conductivities, which provides valuable insight for further design and development of new photovoltaic materials.

Indoor Positioning System with UWB Based on a Digital Twin.

Ultra-wideband (UWB) technology is used for indoor positioning, but its positioning accuracy is usually degenerated by various obstacles in the indoor environment because of non-line-of-sight (NLOS). Facing the complex and changeable indoor environment, an indoor positioning system with UWB based on a digital twin is presented in this paper. The indoor positioning accuracy is improved with a perception-prediction feedback of cyber-physics space in this indoor positioning system. In addition, an anchor layout method with virtuality-reality interaction and an error mitigation method based on neural networks is put forward in this system. Finally, a case study is presented to validate this indoor positioning system with a significant improvement in positioning accuracy.

A Data-driven Adaptive Sampling Method Based on Edge Computing.

The rise of edge computing has promoted the development of the industrial internet of things (IIoT). Supported by edge computing technology, data acquisition can also support more complex and perfect application requirements in industrial field. Most of traditional sampling methods use constant sampling frequency and ignore the impact of changes of sampling objects during the data acquisition. For the problem of sampling distortion, edge data redundancy and energy consumption caused by constant sampling frequency of sensors in the IIoT, a data-driven adaptive sampling method based on edge computing is proposed in this paper. The method uses the latest data collected by the sensors at the edge node for linear fitting and adjusts the next sampling frequency according to the linear median jitter sum and adaptive sampling strategy. An edge data acquisition platform is established to verify the validity of the method. According to the experimental results, the proposed method is more effective than other adaptive sampling methods. Compared with constant sampling frequency, the proposed method can reduce the edge data redundancy and energy consumption by more than 13.92% and 12.86%, respectively.

[Progress in the mechanisms of response to different oxygen concentrations in Caenorhabditis elegans].

Oxygen levels are unequal in different living geographical locations of human and related to normal physiology of health. The reduction of oxygen level in the body can lead to a variety of diseases, such as stroke caused by cerebral ischemia and hypoxia. In the recent years, many studies have elucidated the molecular and cellular mechanisms of organism response to different oxygen concentrations by using the nematode Caenorhabditis elegans (C. elegans) as model organism. C. elegans can escape hypoxia or hyperoxia and adapt to the ambient oxygen environments, and there are different response and regulation mechanisms in different degrees of hypoxia environment. In this paper, recent advances in the reaction of nematodes to different oxygen concentrations and the underlying mechanism were reviewed.

Origin of structural stability of ScH3 molecular nanowires and their chemical-bonding behavior: Correlation effects of the Sc 3d electrons.

A new stable transition-metal trihydride (ScH3) molecular nanowire was recently reported by Li et al. [J. Am. Chem. Soc. 139, 6290-6293 (2017)]. Of the two typical structures (T-ScH3 and O-ScH3), T-ScH3 is more stable than O-ScH3. However, the reason why O-ScH3 is less stable than T-ScH3 was not known. Using Perdew-Burke-Ernzerhof (PBE), PBE+U, SCAN, and HSE06, as well as crystal orbital Hamilton populations (COHPs), we investigate the orbital-projected band structures and chemical bonding of T-ScH3 and O-ScH3. It is found that the energies calculated by PBE, SCAN, and HSE06 indeed reveal that T-ScH3 is more stable than O-ScH3, and there is no occupied antibonding state at the Fermi level of the COHP curves of T-ScH3, supporting the stable Sc-H bonding of T-ScH3. To the contrary, the Sc-H bonding of O-ScH3 is unstable because there exist occupied antibonding states at the Fermi level of the COHP curves of O-ScH3. We found that the results of PBE+U are consistent with those of PBE, SCAN, and HSE06 in the case of U < Uc. However, when U > Uc, the results of PBE+U are opposite to those of PBE, SCAN, and HSE06.

Allelic polymorphism of GIGANTEA is responsible for naturally occurring variation in circadian period in Brassica rapa.

GIGANTEA (GI) was originally identified by a late-flowering mutant in Arabidopsis, but subsequently has been shown to act in circadian period determination, light inhibition of hypocotyl elongation, and responses to multiple abiotic stresses, including tolerance to high salt and cold (freezing) temperature. Genetic mapping and analysis of families of heterogeneous inbred lines showed that natural variation in GI is responsible for a major quantitative trait locus in circadian period in Brassica rapa. We confirmed this conclusion by transgenic rescue of an Arabidopsis gi-201 loss of function mutant. The two B. rapa GI alleles each fully rescued the delayed flowering of Arabidopsis gi-201 but showed differential rescue of perturbations in red light inhibition of hypocotyl elongation and altered cold and salt tolerance. The B. rapa R500 GI allele, which failed to rescue the hypocotyl and abiotic stress phenotypes, disrupted circadian period determination in Arabidopsis. Analysis of chimeric B. rapa GI alleles identified the causal nucleotide polymorphism, which results in an amino acid substitution (S264A) between the two GI proteins. This polymorphism underlies variation in circadian period, cold and salt tolerance, and red light inhibition of hypocotyl elongation. Loss-of-function mutations of B. rapa GI confer delayed flowering, perturbed circadian rhythms in leaf movement, and increased freezing and increased salt tolerance, consistent with effects of similar mutations in Arabidopsis. Collectively, these data suggest that allelic variation of GI-and possibly of clock genes in general-offers an attractive target for molecular breeding for enhanced stress tolerance and potentially for improved crop yield.

Research on the Multiple Factors Influencing Human Identification Based on Pyroelectric Infrared Sensors.

Analysis of the multiple factors affecting human identification ability based on pyroelectric infrared technology is a complex problem. First, we examine various sensed pyroelectric waveforms of the human body thermal infrared signal and reveal a mechanism for affecting human identification. Then, we find that the mechanism is decided by the distance, human target, pyroelectric infrared (PIR) sensor, the body type, human moving velocity, signal modulation mask, and Fresnel lens. The mapping relationship between the sensed waveform and multiple influencing factors is established, and a group of mathematical models are deduced which fuse the macro factors and micro factors. Finally, the experimental results show the macro-factors indirectly affect the recognition ability of human based on the pyroelectric technology. At the same time, the correctness and effectiveness of the mathematical models is also verified, which make it easier to obtain more pyroelectric infrared information about the human body for discriminating human targets.

Selection during crop diversification involves correlated evolution of the circadian clock and ecophysiological traits in Brassica rapa.

Crop selection often leads to dramatic morphological diversification, in which allocation to the harvestable component increases. Shifts in allocation are predicted to impact (as well as rely on) physiological traits; yet, little is known about the evolution of gas exchange and related anatomical features during crop diversification. In Brassica rapa, we tested for physiological differentiation among three crop morphotypes (leaf, turnip, and oilseed) and for correlated evolution of circadian, gas exchange, and phenological traits. We also examined internal and surficial leaf anatomical features and biochemical limits to photosynthesis. Crop types differed in gas exchange; oilseed varieties had higher net carbon assimilation and stomatal conductance relative to vegetable types. Phylogenetically independent contrasts indicated correlated evolution between circadian traits and both gas exchange and biomass accumulation; shifts to shorter circadian period (closer to 24 h) between phylogenetic nodes are associated with higher stomatal conductance, lower photosynthetic rate (when CO2 supply is factored out), and lower biomass accumulation. Crop type differences in gas exchange are also associated with stomatal density, epidermal thickness, numbers of palisade layers, and biochemical limits to photosynthesis. Brassica crop diversification involves correlated evolution of circadian and physiological traits, which is potentially relevant to understanding mechanistic targets for crop improvement.

Variation in circadian rhythms is maintained among and within populations in Boechera stricta.

Circadian clocks have evolved independently in all three domains of life, and fitness benefits of a functional clock have been demonstrated in experimental genotypes in controlled conditions. Still, little is known about genetic variation in the clock and its fitness consequences in natural populations from heterogeneous environments. Using Wyoming populations of the Arabidopsis relative Boechera stricta as our study system, we demonstrate that genetic variation in the clock can occur at multiple levels: means of circadian period among populations sampled at different elevations differed by less than 1 h, but means among families sampled within populations varied by as much as 3.5 h. Growth traits also varied among and within populations. Within the population with the most circadian variation, we observed evidence for a positive correlation between period and growth and a negative correlation between period and root-to-shoot ratio. We then tested whether performance tradeoffs existed among families of this population across simulated seasonal settings. Growth rankings of families were similar across seasonal environments, but for root-to-shoot ratio, genotype × environment interactions contributed significantly to total variation. Therefore, further experiments are needed to identify evolutionary mechanisms that preserve substantial quantitative genetic diversity in the clock in this and other species.

Preferential retention of circadian clock genes during diploidization following whole genome triplication in Brassica rapa.

Much has been learned about the architecture and function of the circadian clock of Arabidopsis thaliana, a model for plant circadian rhythms. Circadian rhythms contribute to evolutionary fitness, suggesting that circadian rhythmicity may also contribute to agricultural productivity. Therefore, we extend our study of the plant circadian clock to Brassica rapa, an agricultural crop. Since its separation from Arabidopsis, B. rapa has undergone whole genome triplication and subsequent diploidization that has involved considerable gene loss. We find that circadian clock genes are preferentially retained relative to comparison groups of their neighboring genes, a set of randomly chosen genes, and a set of housekeeping genes broadly conserved in eukaryotes. The preferential retention of clock genes is consistent with the gene dosage hypothesis, which predicts preferential retention of highly networked or dose-sensitive genes. Two gene families encoding transcription factors that play important roles in the plant core oscillator--the PSEUDO-RESPONSE REGULATORS, including TIMING OF CAB EXPRESSION1, and the REVEILLE family, including CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL--exhibit preferential retention consistent with the gene dosage hypothesis, but a third gene family, including ZEITLUPE, that encodes F-Box proteins that regulate posttranslational protein stability offers an exception.

Metal-free ferromagnetic metal and intrinsic spin semiconductor: two different kinds of SWCNT functionalized BN nanoribbons.

Two different kinds of SWCNT functionalized zigzag edge BN nanoribbons with n chains (n-ZBNNRs), namely, (a) B-edge functionalized by (m,m)SWCNT and N-edge modified with H (nZBNNR-B-(m,m)SWCNTs); and (b) the B-edge modified with H and the N-edge functionalized by (m,m)SWCNT (nZBNNR-N-(m,m)SWCNTs), have been predicted. Amazingly, we find that unlike the semiconducting and nonmagnetic H-modified n-ZBNNRs, the nZBNNR-B-(m,m)SWCNTs are intrinsic ferromagnetic metals, regardless of ribbon widths n and tube diameters (m,m). At a given (m,m), their local magnetic moments, at first, exhibit oscillation with increasing n, whereas when n is larger than 5, they are independent of n. In contrast, unlike the metallic and nonmagnetic (m,m)SWCNTs, the nZBNNR-N-(m,m)SWCNTs are ferromagnetic intrinsic spin-semiconductors with direct band gaps, regardless of n and (m,m). Their local magnetic moments and band gaps are independent of n and (m,m). The DFT calculations reveal that the process of SWCNT functionalization of the n-ZBNNRs does not need any activation energy. Moreover, the formation energies of the SWCNT functionalized n-ZBNNRs are always less than zero. Therefore, the SWCNT functionalized n-ZBNNRs are not only stable, but can also be spontaneously formed. Furthermore, compared with n-ZBNNRs, the SWCNT functionalized n-ZBNNRs show significant improvements in their thermal and mechanical stabilities. Thus, (m,m)SWCNT functionalization of n-ZBNNRs may open new routes toward practical nanoelectronic and optoelectronic as well as spintronic devices based on BNC-based materials.

Genome-wide DNA methylation changes in skeletal muscle between young and middle-aged pigs.

BACKGROUND: Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. RESULTS: We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. CONCLUSIONS: This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research.

Vehicle routing problem with time windows and carbon emissions: a case study in logistics distribution.

Logistics and transportation industry is not only a major energy consumer, but also a major carbon emitter. Developing green logistics is the only way for the sustainable development of the logistics industry. One of the main factors of environmental pollution is caused by carbon emissions in the process of vehicle transportation, and carbon emissions of vehicle transportation are closely related to routing, road conditions, vehicle speed, and speed fluctuations. The low-carbon vehicle routing problem with high granularity time-dependent speeds, speed fluctuations, road conditions, and time windows is proposed and formally described. In order to finely evaluate the effects of vehicle speed and speed fluctuations on carbon emissions, a graph convolutional network (GCN) is used to predict the high granularity time-dependent traffic speeds. To solve this complicated low-carbon vehicle routing problem, a hybrid genetic algorithm with adaptive variable neighborhood search is proposed to obtain vehicle routing with low carbon emissions. Finally, this method is validated using a case study with the logistics and traffic data in Jingzhou, China, and also the results show the effectiveness of this proposed method.

Rhythmic Leaf and Cotyledon Movement Analysis.

The first descriptions of circadian rhythms were of the rhythmic leaf movements of plants. Rhythmic leaf movements offer a sensitive, noninvasive, nondestructive, and non-transgenic assay of plant circadian rhythms that can be readily automated, greatly facilitating genetic studies. Rhythmic leaf movement is particularly useful for the assessment of standing variation in clock function and can be readily applied to a diverse array of dicotyledonous plants, including both wild species and domesticated crops.

Analysis on Damage and Mechanical Properties of Ballastless Track in a Tunnel after a Fire.

In order to explore the damage and mechanical properties of ballastless track after a fire, the uniaxial compressive strength, shear strength, peak strain, and elastic modulus changes due to temperature were obtained through uniaxial compressive and shear tests of concrete after exposure to high temperatures. The test results showed that with increases in temperature, the uniaxial compressive strength, shear strength, and elastic modulus of concrete all presented a decreasing trend, while the peak strain had an increasing trend. Then, based on the classical damage theory model and the strength probability distribution function of concrete micro-units, the high-temperature damage constitutive equation for concrete was established, and the compressive stress-strain curve of concrete after exposure to high temperature was reproduced. Finally, using the CFD numerical simulation software, the temperature field of a ballastless track structure in a tunnel during a fire was obtained, and the temperatures at different positions of ballastless track bed were acquired. Combined with the high-temperature damage constitutive equation for concrete deduced from tests and theoretical analysis, the strength and damage values of the ballastless track bed at different positions after a tunnel fire were obtained.

Line Shape Analysis and Dynamic Response of Ballastless Track during Jacking Rectification Fixing.

In order to study the railway line deformation and dynamic response of ballastless track structure under train load during jacking rectification fixing, a three-dimensional numerical model of the CRTS II slab ballastless track on subgrade is established by using the finite element method. The line deformation rule and local damage rule of ballastless track under jacking force are analyzed. The dynamic response laws of track structure and subgrade bed are compared considering four different connection modes between the base plate and subgrade bed under different train speeds in the process of jacking rectification fixing. The results show that jacking force and dissociation length have a small influence on the deviation value and the critical jacking force should be smaller than 375 kN in single point jacking. Under the condition of multi-point jacking, when the jacking loading length equals to 5 slabs, the critical jacking force should be smaller than 275 kN and the maximum lateral deviation value is about 22.11 mm. It is necessary to restrict the speed of passing trains to no more than 150 km/h during the jacking rectification fixing for dissociation condition without temporary restraint. When temporary restraint is applied, the speed of the train can be increased appropriately according to the actual situation. The above study results could be used as a theoretical reference for the ballastless track deviation correction.

Prevalence and risk factors of carbapenem-resistant Enterobacterales positivity by active screening in intensive care units in the Henan Province of China: A multi-center cross-sectional study.

Objective: In intensive care units (ICUs), carbapenem-resistant Enterobacterales (CRE) pose a significant threat. We aimed to examine the distribution, epidemiological characteristics, and risk factors for CRE positivity in ICUs. Materials and methods: This cross-sectional study was conducted in 96 ICUs of 78 hospitals in Henan Province, China. The clinical and microbiological data were collected. A multivariable logistic regression model was used to analyze the risk factors for CRE positivity. Results: A total of 1,009 patients were enrolled. There was a significant difference in CRE positive rate between pharyngeal and anal swabs (15.16 vs. 19.13%, P < 0.001). A total of 297 carbapenem-resistant Klebsiella pneumoniae (CR-KPN), 22 carbapenem-resistant Escherichia coli (CR-ECO), 6 carbapenem-resistant Enterobacter cloacae (CR-ECL), 19 CR-KPN/CR-ECO, and 2 CR-KPN/CR-ECL were detected. Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-beta-lactamase (NDM), and a combination of KPC and NDM were detected in 150, 9, and 11 swab samples, respectively. Multivariable logistic regression analysis determined length of ICU stay, chronic neurological disease, transfer from other hospitals, previous infection, and history of antibiotics exposure as independent risk factors for CRE positivity. Age and cardiovascular diseases were independent risk factors for mixed infections of CRE. The occurrence of CRE in secondary and tertiary hospitals was 15.06 and 25.62%, respectively (P < 0.05). Patients from tertiary hospitals had different clinical features compared with those from secondary hospitals, including longer hospital stays, a higher rate of patients transferred from other hospitals, receiving renal replacement therapy, exposure to immunosuppressive drugs, use of antibiotics, and a higher rate of the previous infection. Conclusion: In ICUs in Henan Province, CRE positive rate was very high, mostly KPC-type CR-KPN. Patients with prolonged ICU stay, chronic neurological disease, transfer from other hospitals, previous infection, and history of antibiotic exposure are prone to CRE. Age and cardiovascular diseases are susceptibility factors for mixed infections of CRE. The CRE positive rate in tertiary hospitals was higher than that in secondary hospitals, which may be related to the source of patients, antibiotic exposure, disease severity, and previous infection.