•This paper proposed a multi-type features fusion (MTFF) neural network for blood pressure (BP) prediction based on photoplethysmography (PPG).•The model includes two convolutional neural networks ...(CNN) and one Bi-directional long short term memory (BLSTM) network. Among them, two CNN networks are used to train the morphological and frequency spectrum features of PPG signal, and the BLSTM network is used to train the temporal features of PPG signal.•Compared with the traditional manual calculation features of blood pressure prediction method, our method automatically extracts PPG features through the deep learning model and avoids the error of manually calculating. With the training of multiple features, the deep learning model can obtain more information of PPG signals. Blood pressure prediction based on the fused features further improves accuracy.•Our model only needs PPG signal to predict blood pressure. Compared to other works that require many different type of biological signals, a single PPG signal is more convenient to obtain.
Blood pressure monitoring is very important for the prevention of cardiovascular diseases. In this paper, we proposed a multi-type features fusion (MTFF) neural network model for blood pressure (BP) prediction based on photoplethysmography (PPG). The model includes two convolutional neural networks (CNN) which used to train the morphological and frequency spectrum features of PPG signal, and one Bi-directional long short term memory (BLSTM) network which used to train the temporal features of PPG signal. These multi-features were fused through a specific fusion module after training, so more information of PPG signals were obtained and the hidden relationship between the fused features and blood pressure was established. The standard deviation (STD) and mean absolute error (MAE) of the fusion model are 7.25 mmHg and 5.59 mmHg respectively for systolic blood pressure (SBP), 4.48 mmHg and 3.36 mmHg respectively for diastolic blood pressure (DBP). The results are in full compliance with the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS) international standards. We conclude that the MTFF neural network proposed in this paper can accurately predict blood pressure. The significant difference from the traditional methods of BP prediction based on manual calculation of features is that our method automatically extracts PPG features through the deep learning model which can easily handle the complicated and tedious calculation. Compared with other similar BP prediction methods based on deep learning, three different features are trained and fused, which further improves the accuracy of BP prediction.
•Construct a spatial flow model of ecosystem services.•The spatiotemporal differentiation was analyzed by GTWR model.•Spatial pattern optimization based on Bayesian belief network.•Provides a ...reference for spatial flow pattern at the scale of urban agglomeration.
Exploring the spatial flow pattern of ecosystem services and clarifying the transmission path between the supply area and the demand area will help to formulate more scientific and reasonable ecological protection policies. This paper takes the rapid urbanization area representing the Pearl River Delta urban agglomeration as an example. Using Invest model to quantitative the assessment of the supply and demand of carbon sequestration services and water ecosystem services from 2000 to 2020, a spatial flow model of ecosystem services is constructed to clarify the spatial flow of regional ecosystem services pattern. In addition, the Geo-detector model is used to explore the driving factors of the supply and demand relationship of ecosystem services, and the spatiotemporal geographic weighted regression model is further used to analyze the temporal and spatial differentiation of the impact degree. Finally, based on the Bayesian belief network, the optimal state factor configuration is selected to optimize the spatial pattern, and the corresponding optimization strategy is given. The main conclusions are as follows: (1) The supply of carbon sequestration services in the Pearl River Delta decreased gradually during 2000–2020, while the demand increased gradually. The supply of water ecosystem services increased first and then decreased, while the demand showed a downward trend. (2) In terms of spatial heterogeneity of supply and demand matching, the main driving factors of carbon sequestration services included night light brightness value, temperature and vegetation index; The main driving factors of water ecosystem services include night light brightness value, land use type and vegetation index. (3) In terms of optimal areas for supply and demand matching, carbon sequestration services were mainly distributed in Zhaoqing, Huizhou and Jiangmen; The optimal matching areas of water ecosystem service supply and demand were mainly distributed in Zhaoqing, Guangzhou, Huizhou and other cities.
Wastewater analysis is a promising approach to monitor illicit drug abuse of a community. However, drug use estimation via wastewater analysis may be biased by sources other than abuse. This is ...especially true for methamphetamine and amphetamine as their presence in wastewater may come from many sources, such as direct disposal or excretion following administration of prescription drugs. Here we traced methamphetamine and amphetamine sources via concentration and enantiomeric profiling of the two compounds from black market to receiving waters. Methamphetamine in wastewater was found to predominantly arise from abuse, proving the feasibility of using wastewater analysis for estimating its consumption in China. Amphetamine abuse was previously considered negligible in East and Southeast Asia. However, we found that amphetamine was abused considerably (up to 90.7mg/1000inh/day) in a significant number (>20%) of major cities in China. Combined concentration and enantiomeric profiling also revealed direct disposal into receiving waters of methamphetamine manufactured by different processes. These findings have important implications for monitoring of and law enforcement against methamphetamine/amphetamine abuse and related crimes in China and abroad.
•Methamphetamine and amphetamine sources were traced via concentration and enantiomeric profiling.•Methamphetamine in Chinese wastewater was found to predominantly arise from abuse.•Amphetamine was abused considerably in a significant number of major cities in China.•Combined concentration and enantiomeric profiling revealed direct methamphetamine disposal into receiving waters.
High performance bifunctional catalysts for water splitting are very promising. Transition metal phosphides as catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) ...have attracted considerable attention due to their high performance. However, the catalyst with excellent properties still remains a significant challenge. Herein, the nanoporous NiFeMoP(np-NiFeMoP) ribbon was prepared by quenching and dealloying method. It was found that np-NiFeMoP showed excellent HER and OER performance in 1 M KOH. The overpotential of OER is as low as 197 mV at a current density of 20 mA·cm−2. When the current density is 10 mA·cm−2, the overpotential of HER is 223 mV. Moreover, np-NiFeMoP only needs a cell voltage of 1.41 V when current density is 10 mA·cm−2 for water splitting. Our current work may provide some new insights on rationally constructing nanoporous structure with rich active sites to boost the catalytic performances for overall water splitting.
•Nanoporous NiFeMoP ribbons with rich active sites were synthesized by dealloying.•Nanoporous ribbons can be directly used as bifunctional electrodes.•Nanoporous ribbons exhibited superior electrocatalytic performance and stability.
TiC reinforced titanium matrix composites are promising for advanced applications. Generally, the relative density of the composites and the interfacial bonding between the matrix and reinforced ...particles may have a great influence on the mechanical properties. This study presented the fabrication of the full-densified Ti-15Mo-xTiC (x = 1.5, 3.0, 4.5 wt%) composites through in-situ reactive sintering of Ti, Mo, and MoC powders and hot swaging process. Experimental results show the formation of TiC and the absence of MoC in the fabricated composites. After hot swaging, the TiC particles showed aligned distribution along the swaging direction, and exhibited well bonding with the β-Ti matrix. Increasing the TiC content leads to increase tensile strength and Young's modulus but decrease elongation. Ti-15Mo-4.5TiC offers and outstanding combination: ultimate tensile strength = 1290 MPa, yield strength = 1075 MPa, Young's modulus = 89 GPa, and tensile elongation = 3.1%. The strengthening effect is attributed to Mo solid solution in Ti matrix, β-Ti grain refinement, and TiC particle reinforcement. The specific contribution of each mechanism is quantitatively calculated, showing good agreement with the experimental data.
•Ti-Mo-TiC composites are fabricated by in-situ reactive sintering of Ti, Mo, and MoC powders.•The as-swaged composites shows that TiC reinforcements aligned along the swaging direction.•The ultimate strength of the as-swaged Ti-15Mo-4.5TiC composite is 1290 MPa.•The strengthen mechanisms of the Ti-Mo-TiC composites are discussed in detail.
► Removal of Ag-NPs in simulated wastewater treatment processes was examined. ► During simulated primary clarification, over 90% of Ag-NPs remained in wastewater. ► Ag-NPs were effectively removed in ...simulated sequencing batch reactor process. ► Ag-NPs in the wastewater did not significantly alter COD and NH4 removal.
The increasing utilization of silver nanoparticles in industrial and consumer products has raised concern to wastewater treatment utilities due to its antimicrobial activity. In this work, the removal of citrate stabilized silver nanoparticles (Ag-NPs) during the wastewater treatment processes and its impact on treatment performance were examined. During simulated primary clarification, over 90% of the Ag-NPs remained in the wastewater, indicating that the majority of silver nanoparticles in sewage would enter the subsequent treatment units. During sequencing batch reactor processes, silver nanoparticles were effectively removed in each cycle throughout the 15-d experimental duration. Continuous input of silver nanoparticles into the wastewater did not significantly alter chemical oxygen demand (COD) removal. NH4 removal was reduced at the beginning of the SBR experiment but quickly recovered at the later stage of the experiment. This study demonstrated that in the near future it is unlikely that citrate-stabilized Ag-NPs released into sewage will cause significant adversary effects on the COD and NH4 removal of activated sludge processes in municipal wastewater treatment plants.
Sewage-based epidemiology was applied for the first time to a number of mainland Chinese megacities. The application monitored influents to 9 sewage treatment plants (STPs) to estimate the use of ...illicit drugs in Beijing, Guangzhou, Shenzhen, and Shanghai. Altogether, 11.4million inhabitants were covered during September–October 2012. 24-h composite raw sewage samples were collected for 4 consecutive days at each STP. Each collected sample was analyzed for cocaine, benzoylecgonine, ecgonine methylester, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, 6-monoacetylmorphine, amphetamine, methamphetamine, ecstasy, mephedrone, methylenedioxypyrovalerone, 11-nor-9-carboxy-delta-9-tetrahydrocannabinol, ketamine, and norketamine. Through the analysis of these chemical residues, the use of amphetamine, cannabis, cocaine, ecstasy, heroin, mephedrone, methadone, methamphetamine, methylenedioxypyrovalerone and ketamine among Chinese urban inhabitants was monitored. The results obtained demonstrated in a quantitative way that the drug use patterns of Chinese are different from their European counterparts. Abuse of methamphetamine and ketamine was particularly noteworthy in China, while consumption of cocaine and ecstasy, the most popular drugs in Europe, was very low among the sampled Chinese inhabitants. Further, the use of most drugs demonstrated a geographical trend, since their use was much higher in the southern cities of Shenzhen and Guangzhou than it was in Beijing and Shanghai. Interestingly, the exclusive, but minor, metabolite of heroin, 6-monoacetylmorphine, was detected only sporadically. This would suggest that the use of heroin among Chinese urban users sampled in the study was low. Further, the patterns of drug use observed during the study are largely consistent with trends reported by the United Nations Office on Drugs and Crime. Overall, our study suggests that sewage-based epidemiology can readily be used to monitor the use of illicit drugs in those countries/regions where traditional means to monitor drug use patterns have only yielded limited or information of questionable reliability.
•First study on sewage-based epidemiology in megacities from mainland China.•Higher consumption of methamphetamine, ecstasy, ketamine and cocaine in South compared to North.•Omnipresent use of methamphetamine among cities of mainland China.•Prevalent use of ketamine in Southern China.•Influent loads of most drugs were consistent with trends reported by the UNODC.
Porous TiAl3 intermetallics were prepared by the thermal explosion (TE) and space holder method with different particle sizes of Ti and Al powders, and their reaction behaviors were investigated. The ...results showed that with the increase in the particle size of the Ti and Al powders, the interfacial contact between the particles decreased, resulting in low interfacial energy and reaction activity, making the process difficult to initiate. Meanwhile, the heat flow rose from 358.37 J/g to 730.17 J/g and 566.74 J/g due to the extension of the solid–liquid diffusion time. The TiAl3 structures obviously expanded, and the formation of connected pore channels promoted the porosity. Only when the Ti and Al particle sizes were both small did the solid–solid diffusion significantly appear. At the same time, the TE reaction weakened, so the product particles had no time to fully grow. This indicates that the particle size of the raw materials controlled the TE reaction process by changing the solid–liquid diffusion reaction time and the degree of solid-phase diffusion.
Effects of Al and La elements on mechanical properties of CoNiFe0.6Cr0.6 high-entropy alloys (HEAs) with face-centered cubic (FCC) structure were investigated by first-principles calculations. The ...variation curves of relevant physical parameters, including lattice constants, formation enthalpy, elastic constants, elastic modulus, Poisson's ratio, Pugh's ratio, Cauchy pressure, anisotropy factors, Vickers hardness, yield strength, and energy factor, as a function of Al and La concentration were discussed in detail. Results show that the resistances to bulk, elastic, and shear deformation decrease with the increase of Al and La concentration. The addition of Al and La can improve the plasticity and ductility of HEAs. Meanwhile, with the increase of Al and La concentration, the metallic characteristic of atomic bonding strengthens and the anisotropy of materials increases. Moreover, the energy factor indicates that the addition of Al and La could promote dislocation nucleation. This study provides a guideline for further research on non-equiatomic CrFeCoNi series HEAs with designed mechanical properties.
Sewage epidemiology has been proven as an effective approach to estimate the use of illicit drugs by a population. In this study, sewage analysis was applied to examine the patterns of amphetamine ...(AMP) and methamphetamine (METH) uses in the urban area of Beijing. Influent and effluent samples were collected from all the thirteen sewage treatment plants (STPs) in the urban area during two sampling campaigns. METH concentrations in influents were found to range from several tens to several hundred ng·L−1, whereas AMP concentrations ranged from several to several tens ng·L−1. The concentration ratios between AMP and METH in influents at most STPs were close to the rate of AMP excretion following METH ingestion, indicating that AMP in sewage in Beijing was predominately from the metabolism of METH. Much higher METH loads were observed in the center part of the urban area in Beijing, indicating a strong correlation between METH use and economic level and entertainment activities. Seasonal variation in METH loads was significant, with greater use in summer than in winter. Significant difference in METH loads between weekdays and weekend days were observed in winter but not in summer. No clear trend in diurnal variation of METH use was observed. Nearly complete removal of METH occurred at the STPS in Beijing. Apparent removal rates of AMP were lower than those of METH, likely due to degradation of METH into AMP during the wastewater treatment processes. In summary, this study represents the first application of sewage epidemiology to the entire urban population of a metropolitan in mainland China and provided an overview of METH and AMP uses in the city.
•First sewage-based epidemiology of methamphetamine and amphetamine used in Beijing•Amphetamine present at low concentrations and from metabolism of methamphetamine•Globally medium-level methamphetamine loads observed in Beijing•Methamphetamine loads were higher at the urban center.•Methamphetamine loads were greater in summer than in early winter.
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