Increased sleep need and daytime sleepiness 6 months after traumatic brain injury: a prospective controlled clinical trial

In a controlled, prospective, electrophysiological study, Imbach et al. demonstrate increased sleep need and excessive daytime sleepiness 6 months after traumatic brain injury. Sleep is more consolidated after brain trauma, and an increase in sleep need is associated with intracranial haemorrhage. Trauma patients underestimate their increased sleep need and sleepines

Prediction method of operation state of mine belt conveyor

The sensor monitoring data combined with neural network prediction model is the mainstream method of mine belt conveyor operation state prediction. However, using contact sensor to monitor the belt conveyor running state has some problems, such as inconvenient installation and large data error, resulting in low prediction precision of belt conveyor operation state. In order to solve this problem, a prediction method of mine belt conveyor operation state based on audio signal is proposed. Firstly, the high-pass filter and Boll spectral subtraction are used to filter and reduce the noise of the original audio signal during belt conveyor operation. Secondly, the first dimension component (MFCC0) of Mel-frequency cepstral coefficients (MFCC) of audio signal is extracted by pre-emphasis, framing and windowing, Fourier transform, Mel filter energy calculation, discrete cosine transform, and input to the residual block optimized convolutional neural network combined with long and short term memory network (Res-CNN-LSTM) prediction model to reduce the amount of input data of the prediction model. Finally, the MFCC0 spatial characteristics of the belt conveyor audio signal are extracted adaptively by CNN with residual blocks, and the dimension of the data is reduced. Moreover, the temporal characteristics of the dimension-reduced data are extracted based on LSTM, so as to improve the prediction precision of the belt conveyor operation state. The experimental results show that MFCC0 can effectively characterize the audio signal characteristics of belt conveyor in different operation states. Compared with CNN, LSTM, and CNN-LSTM models, the Res-CNN-LSTM model is more accurate in predicting the operation state of the belt conveyor

Multifractal Analysis of Hydrologic Data Using Wavelet Methods and Fluctuation Analysis

We study the multifractal properties of water level with a high-frequency and massive time series using wavelet methods (estimation of Hurst exponents, multiscale diagram, and wavelet leaders for multifractal analysis (WLMF)) and multifractal detrended fluctuation analysis (MF-DFA). The dataset contains more than two million records from 10 observation sites at a northern China river. The multiscale behaviour is observed in this time series, which indicates the multifractality. This multifractality is detected via multiscale diagram. Then we focus on the multifractal analysis using MF-DFA and WLMF. The two methods give the same conclusion that at most sites the records satisfy the generalized binomial multifractal model, which is robust for different times (morning, afternoon, and evening). The variation in the detailed characteristic parameters of the multifractal model indicates that both human activities and tributaries influence the multifractality. Our work is useful for building simulation models of the water level of local rivers with many observation sites

N-doped ZrO2 nanoparticles embedded in a N-doped carbon matrix as a highly active and durable electrocatalyst for oxygen reduction

Fabricating highly efficient and robust oxygen reduction reaction (ORR) electrocatalysts is challenging but desirable for practical Zn-air batteries. As an early transition-metal oxide, zirconium dioxide (ZrO2) has emerged as an interesting catalyst owing to its unique characteristics of high stability, anti-toxicity, good catalytic activity, and small oxygen adsorption enthalpies. However, its intrinsically poor electrical conductivity makes it difficult to serve as an ORR electrocatalyst. Herein, we report ultrafine N-doped ZrO2 nanoparticles embedded in an N-doped porous carbon matrix as an ORR electrocatalyst (N-ZrO2/NC). The N-ZrO2/NC catalyst displays excellent activity and long-term durability with a half-wave potential (E1/2) of 0.84 V and a selectivity for the four-electron reduction of oxygen in 0.1 M KOH. Upon employment in a Zn-air battery, N-ZrO2/NC presented an intriguing power density of 185.9 mW cm−2 and a high specific capacity of 797.9 mA h gZn−1, exceeding those of commercial Pt/C (122.1 mW cm−2 and 782.5 mA h gZn−1). This excellent performance is mainly attributed to the ultrafine ZrO2 nanoparticles, the conductive carbon substrate, and the modified electronic band structure of ZrO2 after N-doping. Density functional theory calculations demonstrated that N-doping can reduce the band-gap of ZrO2 from 3.96 eV to 3.33 eV through the hybridization of the p state of the N atom with the 2p state of the oxygen atom; this provides enhanced electrical conductivity and results in faster electron-transfer kinetics. This work provides a new approach for the design of other enhanced semiconductor and insulator materials

Chemical Modification of B4C Films and B4C/Pd Layers Stored in Different Environments

B4C/Pd multilayers with small d-spacing can easily degrade in the air, and the exact degradation process is not clear. In this work, we studied the chemical modification of B4C films and B4C/Pd double layers stored in four different environments: a dry nitrogen environment, the atmosphere, a dry oxygen-rich environment, and a wet nitrogen environment. The XANES spectra of the B4C/Pd layers placed in a dry oxygen-rich environment showed the most significant decrease in the σ* states of the B–C bonds and an increase in the π* states of the B–O bonds compared with the other samples. X-ray photoelectron spectroscopy (XPS) measurements of the samples placed in a dry oxygen-rich environment showed more intensive B-O binding signals in the B4C/Pd layers than in the single B4C film. The results of the Fourier-transform infrared spectroscopy (FTIR) showed a similar decrease in the B–C bonds and an increase in the B–O bonds in the B4C/Pd layers in contrast to the single B4C film placed in a dry oxygen-rich environment. We concluded that the combination of palladium catalysis and the high content of oxygen in the environment promoted the oxidization of boron, deteriorated the B4C composition

Objectively Measured Physical Activity Is Associated with Static Balance in Young Adults

Purpose: Regular physical activity (PA) strengthens muscles and improves balance and coordination of human body. The aim of this study was to examine whether objectively measured physical activity (PA) and sedentary behaviors were related to static balance in young men and women. Design and setting: Cross-sectional community study. Participants: 86 healthy adults (50% women) aged 21.26 ± 2.11 years. Method: PA variables, including moderate-to-vigorous PA (MVPA), light PA (LPA), sedentary time (SED), and sedentary breaks, were measured by accelerometers on wrist (ActiGraph WGT3X-BT). The static balance was tested in the bipedal stance with eyes open or closed. The movement of the center of pressure, including total sway path length (SP), sway velocity (SV), and sway area (SA), was recorded with a three-dimensional force platform (Kistler 9287CA). The associations between PA (MVPA/LPA/SED/sedentary breaks) and static balance (SP/SV/SA) were analyzed using mixed linear regression analyses, with adjustments for condition (eyes open/closed), sex, age, body mass index (BMI), total device wearing time, and PA*condition. Data were analyzed with SPSS 24.0. Results: Better performance was observed in eyes-open condition (p < 0.05). MVPA was negatively associated with SA (p = 0.030), and SED was positively associated with SA after adjustments, respectively (p = 0.0004). No significance was found in the association of light PA, SED, or sedentary breaks with other static balance variables, respectively (p > 0.05). Conclusion: Increasing MVPA and less SED are associated with lower sway area measured by force platform, indicating more PA may related to better static balance in young adults