Background: Children with seasonal influenza infection cause a significant burden of disease each year in the pediatric clinic. Influenza A and B viruses are the major types responsible for illness. A better understan...Background: Children with seasonal influenza infection cause a significant burden of disease each year in the pediatric clinic. Influenza A and B viruses are the major types responsible for illness. A better understanding of the periodicity facilitates the prevention and control of influenza in children. Objective: This study aims to analyze the epidemiological patterns and subtype characterization of influenza viruses among children in Shenzhen, China. Methods: Influenza samples were collected by nasopharyngeal swabs from influenza like illness patients in Shenzhen Children’s Hospital from January 2016 to December 2018. The positive cases and influenza subtypes were determined by gold labeled antigen detection and reverse transcriptase polymerase chain reaction. The influenza periodicity and age, subtype distribution as well as the association between climate parameters and different influenza subtypes were analyzed by SPSS 22.0. Results: The influenza positive rate during 2016-2018 was 21.0%, with a highest positive rate in the year 2018. The positive rate varied by month, season, and year describing a sequence of peaks presenting primarily in all year including spring, summer and winter. The characteristics of influenza peak were different in each year, with a spring peak in 2016 and a summer plus a winter-spring peaks in 2017 and 2018. In addition, influenza B exhibited a winter-spring seasonal pattern while influenza A displayed a more variable seasonality, highlighting influenza B rather than influenza A which had a negative association with climate parameters. Influenza-positive cases were older than influenza-negative cases (P P Conclusion: Influenza activity in children from Shenzhen typically displays both winter-spring and summer peaks. Influenza A epidemic occurred separately or co-circulated with influenza B, with a winter-spring pattern for influenza B and a much more variable seasonality for influenza A. Influenza B had a negative association with climate parameters. In addition, hospitalization with influenza often occurs in younger individuals infected with influenza A.展开更多
We discussed the decrease in residual stress,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures,which were studied by the scanning electron microscope(SEM),high-resol...We discussed the decrease in residual stress,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures,which were studied by the scanning electron microscope(SEM),high-resolution transmission electron microscopy(HRTEM),and electron backscatter diffraction(EBSD).The findings reveal that annealing processing has a significant impact on diminishing residual stresses.As the annealing temperature rose from 950 to 1150℃,the majority of the residual stresses were relieved from 60.1 MPa down to 10.9 MPa.Moreover,the stress relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary migration.Meanwhile,the annealing treatment promotes the decomposition of the Laves,accompanied by the precipitation ofμ-(Mo_(6)Co_(7))starting at 950℃ and reaching a maximum value at 1050℃.The tensile strength and plasticity of the annealing alloy at 1150℃ reached the maximum(1394 MPa,56.1%)which was 131%,200%fold than those of the as-cast alloy(1060 MPa,26.6%),but the oxidation process in the alloy was accelerated at 1150℃.The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase,along with the shape and dispersal of theγ′phase.展开更多
In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical propertie...In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.展开更多
BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infect...BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infections.Rhodococcus equi(R.equi)is a rare opportunistic pathogen in humans,and there are limited reports of infection with R.equi in post-renal transplant recipients and no uniform standard of treat-ment.This article reports on the diagnosis and treatment of a renal transplant recipient infected with R.equi 21 mo postoperatively and summarizes the charac-teristics of infection with R.equi after renal transplantation,along with a detailed review of the literature.Here,we present the case of a 25-year-old man who was infected with R.equi 21 mo after renal transplantation.Although the clinical features at the time of presentation were not specific,chest computed tomography(CT)showed a large volume of pus in the right thoracic cavity and right middle lung atelectasis,and fiberoptic bronchoscopy showed an endobronchial mass in the right middle and lower lobe orifices.Bacterial culture and metagenomic next-generation sequen-cing sequencing of the pus were suggestive of R.equi infection.The immunosup-pressive drugs were immediately suspended and intravenous vancomycin and azithromycin were administered,along with adequate drainage of the abscess.The endobronchial mass was then resected.After the patient’s clinical symptoms and chest CT presentation resolved,he was switched to intravenous ciprofloxacin and azithromycin,followed by oral ciprofloxacin and azithromycin.The patient was re-hospitalized 2 wk after discharge for recurrence of R.equi infection.He recovered after another round of adequate abscess drainage and intravenous ciprofloxacin and azithromycin.CONCLUSION Infection with R.equi in renal transplant recipients is rare and complex,and the clinical presentation lacks specificity.Elaborate antibiotic therapy is required,and adequate abscess drainage and surgical excision are necessary.Given the recurrent nature of R.equi,patients need to be followed-up closely.展开更多
The second(O2)observational campaign of gravitational waves(GWs)organized by the LIGO/Virgo Collaborations has led to several breakthroughs such as the detection of GW signals from merger systems involving black holes...The second(O2)observational campaign of gravitational waves(GWs)organized by the LIGO/Virgo Collaborations has led to several breakthroughs such as the detection of GW signals from merger systems involving black holes or neutrons stars.During O2,14 GW alerts were sent to the astronomical community with sky regions mostly covering over hundreds of square degrees.Among them,six were finally confirmed as real astrophysical events.Since 2013,a new set of ground-based robotic telescopes called Ground-based Wide Angle Camera system(GWAC)project and its pathfinder mini-GWAC has been developed to contribute to the various challenges of multi-messenger and time domain astronomy.The GWAC system is built up in the framework of the ground-segment system of the SVOM mission that will be devoted to the study of the multi-wavelength transient sky in the next decade.During O2,only the mini-GWAC telescope network was fully operational.Due to the wide field of view and fast automatic follow-up capabilities of the mini-GWAC telescopes,they were adept to efficiently cover the sky localization areas of GW event candidates.In this paper,we present the mini-GWAC pipeline we have set up to respond to GW alerts and we report our optical follow-up observations of eight GW alerts detected during the O2 run.Our observations provided the largest coverage of the GW localization areas with a short latency made by any optical facility.We found tens of optical transient candidates in our images,but none of those could be securely associated with any confirmed black hole-black hole merger event.Based on this first experience and the near future technical improvements of our network system,we will be more competitive in detecting the optical counterparts from some GW events that will be identified during the upcoming O3 run,especially those emerging from binary neutron star mergers.展开更多
The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and n...The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids;however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a;however, safety issues should thoroughly concern its mild flammable characteristics.展开更多
文摘Background: Children with seasonal influenza infection cause a significant burden of disease each year in the pediatric clinic. Influenza A and B viruses are the major types responsible for illness. A better understanding of the periodicity facilitates the prevention and control of influenza in children. Objective: This study aims to analyze the epidemiological patterns and subtype characterization of influenza viruses among children in Shenzhen, China. Methods: Influenza samples were collected by nasopharyngeal swabs from influenza like illness patients in Shenzhen Children’s Hospital from January 2016 to December 2018. The positive cases and influenza subtypes were determined by gold labeled antigen detection and reverse transcriptase polymerase chain reaction. The influenza periodicity and age, subtype distribution as well as the association between climate parameters and different influenza subtypes were analyzed by SPSS 22.0. Results: The influenza positive rate during 2016-2018 was 21.0%, with a highest positive rate in the year 2018. The positive rate varied by month, season, and year describing a sequence of peaks presenting primarily in all year including spring, summer and winter. The characteristics of influenza peak were different in each year, with a spring peak in 2016 and a summer plus a winter-spring peaks in 2017 and 2018. In addition, influenza B exhibited a winter-spring seasonal pattern while influenza A displayed a more variable seasonality, highlighting influenza B rather than influenza A which had a negative association with climate parameters. Influenza-positive cases were older than influenza-negative cases (P P Conclusion: Influenza activity in children from Shenzhen typically displays both winter-spring and summer peaks. Influenza A epidemic occurred separately or co-circulated with influenza B, with a winter-spring pattern for influenza B and a much more variable seasonality for influenza A. Influenza B had a negative association with climate parameters. In addition, hospitalization with influenza often occurs in younger individuals infected with influenza A.
基金This work was financially supported by the National Science and Technology Major Project of China(No.J2019-VI-0006-0120)the National Key R&D Program of China(No.2021YFB3700402)the National Natural Science Foundation of China(Nos.52074092 and 52274330).
文摘We discussed the decrease in residual stress,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures,which were studied by the scanning electron microscope(SEM),high-resolution transmission electron microscopy(HRTEM),and electron backscatter diffraction(EBSD).The findings reveal that annealing processing has a significant impact on diminishing residual stresses.As the annealing temperature rose from 950 to 1150℃,the majority of the residual stresses were relieved from 60.1 MPa down to 10.9 MPa.Moreover,the stress relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary migration.Meanwhile,the annealing treatment promotes the decomposition of the Laves,accompanied by the precipitation ofμ-(Mo_(6)Co_(7))starting at 950℃ and reaching a maximum value at 1050℃.The tensile strength and plasticity of the annealing alloy at 1150℃ reached the maximum(1394 MPa,56.1%)which was 131%,200%fold than those of the as-cast alloy(1060 MPa,26.6%),but the oxidation process in the alloy was accelerated at 1150℃.The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase,along with the shape and dispersal of theγ′phase.
基金Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20210527National Natural Science Foundation of China,Grant/Award Number:42107158Training Program for Innovation and Entrepreneurship,China University of Mining and Technology。
文摘In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.
基金Supported by Science and Technology Project of Guizhou Province,No.ZK[2023]380.
文摘BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infections.Rhodococcus equi(R.equi)is a rare opportunistic pathogen in humans,and there are limited reports of infection with R.equi in post-renal transplant recipients and no uniform standard of treat-ment.This article reports on the diagnosis and treatment of a renal transplant recipient infected with R.equi 21 mo postoperatively and summarizes the charac-teristics of infection with R.equi after renal transplantation,along with a detailed review of the literature.Here,we present the case of a 25-year-old man who was infected with R.equi 21 mo after renal transplantation.Although the clinical features at the time of presentation were not specific,chest computed tomography(CT)showed a large volume of pus in the right thoracic cavity and right middle lung atelectasis,and fiberoptic bronchoscopy showed an endobronchial mass in the right middle and lower lobe orifices.Bacterial culture and metagenomic next-generation sequen-cing sequencing of the pus were suggestive of R.equi infection.The immunosup-pressive drugs were immediately suspended and intravenous vancomycin and azithromycin were administered,along with adequate drainage of the abscess.The endobronchial mass was then resected.After the patient’s clinical symptoms and chest CT presentation resolved,he was switched to intravenous ciprofloxacin and azithromycin,followed by oral ciprofloxacin and azithromycin.The patient was re-hospitalized 2 wk after discharge for recurrence of R.equi infection.He recovered after another round of adequate abscess drainage and intravenous ciprofloxacin and azithromycin.CONCLUSION Infection with R.equi in renal transplant recipients is rare and complex,and the clinical presentation lacks specificity.Elaborate antibiotic therapy is required,and adequate abscess drainage and surgical excision are necessary.Given the recurrent nature of R.equi,patients need to be followed-up closely.
基金supported by the National Natural Science Foundation of China(Grant Nos.11533003,11673006,U1331202,U1931133 and U1938201)the Guangxi Science Foundation(2016GXNSFFA380006,AD17129006and 2018GXNSFGA281007)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB23040000)the Strategic Pioneer Program on Space Science,Chinese Academy of Sciences(XDA15052600)financial support from the Chinese Academy of Sciences PIFI post-doctoral fellowship program(program C)financial support of the Univ Earth S Labex program at Sorbonne Paris Cité(ANR-10-LABX-0023 and ANR-11-IDEX-0005-02)
文摘The second(O2)observational campaign of gravitational waves(GWs)organized by the LIGO/Virgo Collaborations has led to several breakthroughs such as the detection of GW signals from merger systems involving black holes or neutrons stars.During O2,14 GW alerts were sent to the astronomical community with sky regions mostly covering over hundreds of square degrees.Among them,six were finally confirmed as real astrophysical events.Since 2013,a new set of ground-based robotic telescopes called Ground-based Wide Angle Camera system(GWAC)project and its pathfinder mini-GWAC has been developed to contribute to the various challenges of multi-messenger and time domain astronomy.The GWAC system is built up in the framework of the ground-segment system of the SVOM mission that will be devoted to the study of the multi-wavelength transient sky in the next decade.During O2,only the mini-GWAC telescope network was fully operational.Due to the wide field of view and fast automatic follow-up capabilities of the mini-GWAC telescopes,they were adept to efficiently cover the sky localization areas of GW event candidates.In this paper,we present the mini-GWAC pipeline we have set up to respond to GW alerts and we report our optical follow-up observations of eight GW alerts detected during the O2 run.Our observations provided the largest coverage of the GW localization areas with a short latency made by any optical facility.We found tens of optical transient candidates in our images,but none of those could be securely associated with any confirmed black hole-black hole merger event.Based on this first experience and the near future technical improvements of our network system,we will be more competitive in detecting the optical counterparts from some GW events that will be identified during the upcoming O3 run,especially those emerging from binary neutron star mergers.
文摘The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids;however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a;however, safety issues should thoroughly concern its mild flammable characteristics.
