QRS detection is very important in cardiovascular disease diagnosis and ECG (electrocardiogram) monitor, because it is the precondition of the calculation of correlative parameters and diagnosis. This paper presents a...QRS detection is very important in cardiovascular disease diagnosis and ECG (electrocardiogram) monitor, because it is the precondition of the calculation of correlative parameters and diagnosis. This paper presents a non-parametric derivative-based method for R wave detection in ECG signal. This method firstly uses a digital filter to cut out noises from ECG signals, utilizes local polynomial fitting that is a non-parametric derivative-based method to estimate the derivative values, and then selects appropriate thresholds by the difference, and the algorithm adaptively adjusts the size of thresholds periodically according to the different needs. Afterwards, the position of R wave is detected by the estimation of the first-order derivative values with nonparametric local polynomial statistical model. In addition, in order to improve the accuracy of detection, the method of redundant detection and missing detection are applied in this paper. The clinical experimental data are used to evaluate the effectiveness of the algorithm. Experimental results show that the method in the process of the detection of R wave is much smoother, compared with differential threshold algorithm and it can detect the R wave in the ECG signals accurately.展开更多
In this paper, we try to find numerical solution of y'(x)= p(x)y(x)+g(x)+λ∫ba K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b or y'(x)= p(x)y(x)+g(x)+λ∫xa K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b by using Local p...In this paper, we try to find numerical solution of y'(x)= p(x)y(x)+g(x)+λ∫ba K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b or y'(x)= p(x)y(x)+g(x)+λ∫xa K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b by using Local polynomial regression (LPR) method. The numerical solution shows that this method is powerful in solving integro-differential equations. The method will be tested on three model problems in order to demonstrate its usefulness and accuracy.展开更多
Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal convers...Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal conversion.Also,their anti-bacterial and antifouling performances are crucial for the practical application.Herein,we introduce reduced graphene oxide(RGO)with broadband absorbance across the entire solar spectrum,and polypyrrole(PPy),an antibacterial polymer with efficient solar absorption and low thermal conductivity,to develop integrated RGO/PPy aerogel as both the solar absorber and evaporator for highly efficient solar-driven steam generation.As a result,the RGO/PPy aerogel shows strong absorption and good photothermal performance,leading to an evaporation rate of 1.44 kg·m^(−2)·h^(−1)and high salt rejection(up to 99.99%)for real seawater,with photothermal conversion efficiency>90%under one sun irradiation.The result is attributed to the localized heat at the air-water interface by the RGO/PPy and its porous nature with functional groups that facilitates the water evaporation.Moreover,the RGO/PPy demonstrates excellent durability and antibacterial efficiency close to 100%for 12 h,crucial characteristics for longterm application.Our well-designed RGO/PPy aerogel with efficient water desalination performance and antibacterial property provides a straightforward approach to improve the solar-driven evaporation performance by multifunctional materials integration,and offers a viable route towards practical seawater desalination.展开更多
Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with ...Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with AGE in Shanghai from 2018 to 2021.The overall detection rate of NoV was 11.9%(181/1545),with annual detection rates of 9.4%(36/381),13.6%(29/213),5.8%(13/226)and 14.2%(103/725),respectively.Of note,the prevalence of NoV in 2020 was significantly lower than that in 2018-2019(10.9%,65/594)(P=0.023)and 2021(14.2%,103/725)(P=0.000).The 181 NoV strains identified in this study were classified into the GI group(1.1%,2/181),GII group(98.3%,178/181)and GIX group(0.6%,1/181)according to the VP1 gene.The most common NoV VP1 genotype was GII.4 Sydney_2012(63.5%,115/181),followed by GII.3(19.9%,36/181)and GII.2(9.4%,17/181).For P genotypes,174 strains were sequenced successfully according to the RdRp gene,and the predominant genotype was GII.P16(44.8%,78/174),followed by GII.P31(25.9%,45/174)and GII.P12(21.3%,37/174).Among the 174 cases,GII.4 Sydney_2012[P16](36.8%,64/174)was the dominant genotype,followed by GII.4 Sydney_2012[P31](25.3%,44/174),GII.3[P12](20.1%,35/174)and GII.2[P16](8.0%,14/174).In particular,the dominant genotypes in Shanghai changed from GII.4 Sydney_2012[P31]in 2018-2019 to GII.4 Sydney_2012[P16]in 2020-2021.This is the first report to describe the epidemiological changes in NoV infection before and during the COVID-19 pandemic in Shanghai.These data highlight the importance of continuous surveillance for NoV in children with AGE in Shanghai.展开更多
文摘QRS detection is very important in cardiovascular disease diagnosis and ECG (electrocardiogram) monitor, because it is the precondition of the calculation of correlative parameters and diagnosis. This paper presents a non-parametric derivative-based method for R wave detection in ECG signal. This method firstly uses a digital filter to cut out noises from ECG signals, utilizes local polynomial fitting that is a non-parametric derivative-based method to estimate the derivative values, and then selects appropriate thresholds by the difference, and the algorithm adaptively adjusts the size of thresholds periodically according to the different needs. Afterwards, the position of R wave is detected by the estimation of the first-order derivative values with nonparametric local polynomial statistical model. In addition, in order to improve the accuracy of detection, the method of redundant detection and missing detection are applied in this paper. The clinical experimental data are used to evaluate the effectiveness of the algorithm. Experimental results show that the method in the process of the detection of R wave is much smoother, compared with differential threshold algorithm and it can detect the R wave in the ECG signals accurately.
文摘In this paper, we try to find numerical solution of y'(x)= p(x)y(x)+g(x)+λ∫ba K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b or y'(x)= p(x)y(x)+g(x)+λ∫xa K(x, t)y(t)dt, y(a)=α. a≤x≤b, a≤t≤b by using Local polynomial regression (LPR) method. The numerical solution shows that this method is powerful in solving integro-differential equations. The method will be tested on three model problems in order to demonstrate its usefulness and accuracy.
基金supported by the National Key R&D Program of China(Nos.2018YFA0209500 and 2018YFA0306900)the National Natural Science Foundation of China(Nos.21872114 and 21627811).
文摘Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal conversion.Also,their anti-bacterial and antifouling performances are crucial for the practical application.Herein,we introduce reduced graphene oxide(RGO)with broadband absorbance across the entire solar spectrum,and polypyrrole(PPy),an antibacterial polymer with efficient solar absorption and low thermal conductivity,to develop integrated RGO/PPy aerogel as both the solar absorber and evaporator for highly efficient solar-driven steam generation.As a result,the RGO/PPy aerogel shows strong absorption and good photothermal performance,leading to an evaporation rate of 1.44 kg·m^(−2)·h^(−1)and high salt rejection(up to 99.99%)for real seawater,with photothermal conversion efficiency>90%under one sun irradiation.The result is attributed to the localized heat at the air-water interface by the RGO/PPy and its porous nature with functional groups that facilitates the water evaporation.Moreover,the RGO/PPy demonstrates excellent durability and antibacterial efficiency close to 100%for 12 h,crucial characteristics for longterm application.Our well-designed RGO/PPy aerogel with efficient water desalination performance and antibacterial property provides a straightforward approach to improve the solar-driven evaporation performance by multifunctional materials integration,and offers a viable route towards practical seawater desalination.
基金This work was supported by grants from the Key Development Program of the Children's Hospital of Fudan University(grant no.EK2022ZX05).
文摘Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with AGE in Shanghai from 2018 to 2021.The overall detection rate of NoV was 11.9%(181/1545),with annual detection rates of 9.4%(36/381),13.6%(29/213),5.8%(13/226)and 14.2%(103/725),respectively.Of note,the prevalence of NoV in 2020 was significantly lower than that in 2018-2019(10.9%,65/594)(P=0.023)and 2021(14.2%,103/725)(P=0.000).The 181 NoV strains identified in this study were classified into the GI group(1.1%,2/181),GII group(98.3%,178/181)and GIX group(0.6%,1/181)according to the VP1 gene.The most common NoV VP1 genotype was GII.4 Sydney_2012(63.5%,115/181),followed by GII.3(19.9%,36/181)and GII.2(9.4%,17/181).For P genotypes,174 strains were sequenced successfully according to the RdRp gene,and the predominant genotype was GII.P16(44.8%,78/174),followed by GII.P31(25.9%,45/174)and GII.P12(21.3%,37/174).Among the 174 cases,GII.4 Sydney_2012[P16](36.8%,64/174)was the dominant genotype,followed by GII.4 Sydney_2012[P31](25.3%,44/174),GII.3[P12](20.1%,35/174)and GII.2[P16](8.0%,14/174).In particular,the dominant genotypes in Shanghai changed from GII.4 Sydney_2012[P31]in 2018-2019 to GII.4 Sydney_2012[P16]in 2020-2021.This is the first report to describe the epidemiological changes in NoV infection before and during the COVID-19 pandemic in Shanghai.These data highlight the importance of continuous surveillance for NoV in children with AGE in Shanghai.
