Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at ...Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at high voltage,which leads to rapid failure both in the performance and structure of the LCO cathode.Herein,a Li_(2)CO_(3)-based additive was prepared by a simple sand-milling method,enabling a low electrochemical decomposition voltage<4.6 V from commonly>4.8 V,stabilizing the interface of the LCO cathode at 4.6 V.The decomposition of Li_(2)CO_(3)provides extra Li^(+)and CO_(2)to supplement the Li consumption required in the initial irreversible interfacial reactions and rapidly form a uniform and stable cathode electrolyte interphase layer(less organic and more inorganic components)on the LCO cathode by reducing CO_(2).Thus,the phase transformation and the emergence of high-valent Co ions on the surface of LCO at 4.6 V high voltage were inhibited.Thanks to this,with 2%Li_(2)CO_(3)-based additive,the capacity retention of commercial LCO at a high voltage of 4.6 V at 0.5 C for 100 cycles was improved from 59.3%to 79.3%.This work improves the high-voltage stability of LCO and provides a new idea for realizing the high-voltage operation of batteries.展开更多
Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different ...Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different physiological periods in the diagnosis of infertility patients. Methods: From December 2019 to May 2021, a total of 93 infertility patients were admitted and selected as the observation group. Among them, 31 cases were in the follicular stage, 31 cases in the ovulation stage, and 31 cases in the luteal stage. Ninety-three healthy women for fertility evaluation due to male infertility were selected as the control group. The control group included 31 women in the follicular phase, 31 women in the ovulatory phase, and 31 women in the luteal phase. The levels of sex hormones (prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), testosterone (T), and progesterone (P)) during different physiological phases were compared between the observation and control groups. Results: The follicular phase showed no significant difference in LH levels between the observation group and the control group. The observation group showed higher levels of PRL and P compared to the control group, while the levels of FSH, E2, and T were lower in the observation group compared to the control group. The ovulation phase showed no significant difference in PRL levels between the two groups. The observation group showed lower levels of LH, FSH, E2, T, and P compared to the control group. The luteal phase showed no statistical difference in E2 levels between the two groups. The observation group showed higher levels of PRL, LH, and FSH compared to the control group, while the levels of T and P were lower in the observation group compared to the control group. Conclusion: Infertile women show variations in hormone levels compared to the normal levels during the follicular phase, ovulatory phase, and luteal phase.展开更多
Single-crystal Nickel-rich layered oxides has been recognized as one of the promising cathodes for nextgeneration lithium batteries on account of their high capacity,while its practical application was hindered by str...Single-crystal Nickel-rich layered oxides has been recognized as one of the promising cathodes for nextgeneration lithium batteries on account of their high capacity,while its practical application was hindered by structural instability and slow Li^(+) transfer kinetics.Herein,a surface-to-bulk engineered single-crystal LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(Ni90) cathode,which features W-doped bulk and Li_(2)WO_(4) surface layer,was successfully achieved by a one-step high-valence W^(6+) modification.The as-obtained W-modified Ni90 delivers excellent cycling stability(89.8% capacity retention after 300 cycles at 0.5 C)and rate capability.The enhanced electrochemical performance was ascribed to the doped-W induced stabilized lattice oxygen,reduced Li^(+)/Ni^(2+) mixing and inhibited H2-H3 phase transition in the bulk,and Li_(2)WO_(4) layer generated stabilized cathode/electrolyte interface.In addition,the thinner LiF-rich cathode electrolyte interphase(CEI) on surface and smaller grain size for W-modified Ni90 benefit to its Li^(+) diffusion dynamics.The effect of high-valence W^(6+)on single-crystal Ni-rich cathode was firstly revealed in detail,which deepens the understanding of electrochemical behavior of Ni-rich cathode with high-valence cations modification,and provides clues for design of high-performance layered cathodes.展开更多
Sevoflurane induces developmental neurotoxicity in mice;however,the underlying mechanisms remain unclear.Triggering receptor expressed on myeloid cells 2(TREM2)is essential for microglia-mediated synaptic refinement d...Sevoflurane induces developmental neurotoxicity in mice;however,the underlying mechanisms remain unclear.Triggering receptor expressed on myeloid cells 2(TREM2)is essential for microglia-mediated synaptic refinement during the early stages of brain development.We explored the effects of TREM2 on dendritic spine pruning during sevoflurane-induced developmental neurotoxicity in mice.Mice were anaesthetized with sevoflurane on postnatal days 6,8,and 10.Behavioral performance was assessed using the open field test and Morris water maze test.Genetic knockdown of TREM2 and overexpression of TREM2 by stereotaxic injection were used for mechanistic experiments.Western blotting,immunofluorescence,electron microscopy,three-dimensional reconstruction,Golgi staining,and whole-cell patch-clamp recordings were performed.Sevoflurane exposures upregulated the protein expression of TREM2,increased microglia-mediated pruning of dendritic spines,and reduced synaptic multiplicity and excitability of CA1 neurons.TREM2 genetic knockdown significantly decreased dendritic spine pruning,and partially aggravated neuronal morphological abnormalities and cognitive impairments in sevoflurane-treated mice.In contrast,TREM2 overexpression enhanced microglia-mediated pruning of dendritic spines and rescued neuronal morphological abnormalities and cognitive dysfunction.TREM2 exerts a protective role against neurocognitive impairments in mice after neonatal exposures to sevoflurane by enhancing microglia-mediated pruning of dendritic spines in CA1 neurons.This provides a potential therapeutic target in the prevention of sevoflurane-induced developmental neurotoxicity.展开更多
The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE)...The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE),limiting its broader application.Herein,an ether-based electrolyte(termed FGN-182)is formulated,exhibiting ultra-stable Li metal anodes through the incorporation of LiFSI and LiNO3 as dual salts.The synergistic effect of the dual salts facilitates the formation of a highly robust SEI film with fast Li+transport kinetics.Notably,Li||Cu half cells exhibit an average CE reaching up to 99.56%.In particular,pouch cells equipped with high-loading lithium cobalt oxide(LCO,3 mAh cm^(-2))cathodes,ultrathin Li chips(25μm),and lean electrolytes(5 g Ah-1)demonstrate outstanding cycling performance,retaining 80%capacity after 125 cycles.To address the gas issue in the cathode under high voltage,cathode additives 1,3,6-tricyanohexane is incorporated with FGN-182;the resulting high-voltage LCO||Li(4.4 V)pouch cells can cycle steadily over 93 cycles.This study demonstrates that,even with the use of ether-based electrolytes,it is possible to simultaneously achieve significant improvements in both high Li utilization and electrolyte tolerance to high voltage by exploring appropriate functional additives for both the cathode and anode.展开更多
BACKGROUND Extracellular vesicles derived from mesenchymal stromal cells(MSC-EVs)can be used for anti-aging therapy and treating various aging-related diseases.However,the clinical application of MSC-EVs is still limi...BACKGROUND Extracellular vesicles derived from mesenchymal stromal cells(MSC-EVs)can be used for anti-aging therapy and treating various aging-related diseases.However,the clinical application of MSC-EVs is still limited,mainly due to insufficient in-formation on the preparation process,quality,and mechanism of action of MSC-EVs.To study the biological effects of MSC-EVs in regulating cellular senescence.METHODS In this study,we developed a clinical-grade production process for MSC-EVs and defined the release criteria for products suitable for human use.To support the clinical use of our product as a therapeutic agent,we performed efficacy assays to evaluate the anti-aging capacity of MSC-EVs in vitro and in vivo.RESULTS The functional analysis results revealed that MSC-EVs significantly reduced the levels of senescence-associatedβ-galactosidase,matrix metallopeptidase 1,P21,and interleukin-1βand increased the level of collagen I in a naturally aged cell model of human dermal fibroblasts.Similarly,treatment with MSC-EVs effectively improved D-gal-induced subacute aging in mice,aging-related histopathological changes,oxidative stress,and aging-related gene expression.CONCLUSION These findings indicate that MSC-EVs can partially alleviate D-gal-induced senescence by reducing oxidative stress and regulating metabolism.Overall,these findings strongly suggest that MSC-EVs hold promise for aging therapy.展开更多
Biomass burning(BB)emits carbonaceous aerosols that significantly influence air quality in Southwest China during spring.To further understand the characteristics of spring BB and its original contribution to organic ...Biomass burning(BB)emits carbonaceous aerosols that significantly influence air quality in Southwest China during spring.To further understand the characteristics of spring BB and its original contribution to organic carbon(OC),daily fine particulate matter(PM_(2.5))samples were collected from March to May 2022 in Pu'er,Southwest China.The concentrations of OC,elemental carbon(EC),levoglucosan(Lev),and potassium from BB(K+BB)during the study period ranged from 5.3 to 31.2μg/m^(3),0.86-13.1μg/m^(3),0.06-0.82μg/m^(3),and 0.05-2.88μg/m^(3),respectively.To eliminate the effects of Lev degradation,this study uses the Aging of Air Mass(AAM)index to correct the atmospheric concentration of Lev and combines Bayesian mixture modeling with a molecular tracer method to assess the original contribution of BB to OC.The results indicated that the AAM index was 0.18±0.05,indicating that the degradation of Lev reached 82%.When considering the degradation of levoglucosan in the atmosphere,the primary source of BB aerosols was crop-straw combustion(71.1%),followed by the combustion of certain hardwoods and softwoods(24.9%)and grasses(4.0%).The original contribution of BB to OC was 62.4%,which was much greater than the contribution when levoglucosan degradation(23.7%)was ignored.The air mass inverse trajectories and Moderate Resolution Imaging Spectroradiometer(MODIS)fire hotspots indicated that the BB plume from Southeast Asia during spring could influence PM_(2.5)long-range transport in remote locations,and the contribution could reach 82%in Southwest China.展开更多
Health monitoring of underwater concrete facility systems is important in civil engineering. Unlike conventional manual inspection techniques, digital image processing offers a more convenient and effective approach, ...Health monitoring of underwater concrete facility systems is important in civil engineering. Unlike conventional manual inspection techniques, digital image processing offers a more convenient and effective approach, becoming an indispensable tool for structural inspection. Cracks, which are pervasive defects, are a central focus of structural deterioration research. However, the complexity of the marine environment poses challenges to underwater visibility.In this study, the underwater environment under controlled laboratory conditions is replicated, where varying turbidity and illumination conditions and images of concrete cracks are captured. An approach combining a defogging algorithm with guided and fast guided filtering techniques is proposed to enhance both natural underwater images and crack images captured through experimental photography. When applied to turbid crack images captured under two different suspension conditions, the method increases the information entropy(IE) by 32.92% and 17.92% and the underwater color image quality evaluation(UCIQE) by 35.76% and 18.36%, respectively. These results demonstrate its efficiency in enhancing image definition. The findings of this study could significantly impact the practical applications of image visualization and evaluation for underwater concrete cracks.展开更多
Community-acquired pneumonia(CAP) is one of the leading causes of morbidity and mortality in children worldwide.In this study,we aimed to describe the aetiology of viral infection of pediatric CAP in Chinese mainland....Community-acquired pneumonia(CAP) is one of the leading causes of morbidity and mortality in children worldwide.In this study,we aimed to describe the aetiology of viral infection of pediatric CAP in Chinese mainland.During November2014 to June 2016,the prospective study was conducted in 13 hospitals.The hospitalized children under 18 years old who met the criteria for CAP were enrolled.The throat swabs or nasopharyngeal aspirates(NPAs) were collected which were then screened 18 respiratory viruses using multiplex PCR assay.Viral pathogens were present in 56.6%(1539/2721) of the enrolled cases,with the detection rate of single virus in 39.8% of the cases and multiple viruses in 16.8% of the cases.The most frequently detected virus was respiratory syncytial virus(RSV)(15.2%,414/2721).The highest detection rate of virus was in <6-month-age group(70.7%,292/413).RSV,human metapneumovirus(HMPV),human parainfluenza viruses(HPIVs) and influenza B virus(Flu B) showed the similar prevalence patterns both in north and south China,but HPIVs,Flu A,human bocavirus(HBoV),human adenovirus(HAdV) and human coronaviruses(HCoVs) showed the distinct circulating patterns in north and south China.Human enterovirus/human rhinovirus(HEV/HRV)(27.6%,27/98),HBoV(18.4%,18/98),RSV(16.3%,16/98) and HMPV(14.3%,14/98) were the most commonly detected viruses in severe pneumonia cases with single virus infection.In conclusion,viral pathogens are frequently detected in pediatric CAP cases and may therefore play a vital role in the aetiology of CAP.RSV was the most important virus in hospitalized children with CAP in Chinese mainland.展开更多
Radio interferometric imaging samples visibility data in the spatial frequency domain and then reconstructs the image.Because of the limited number of antennas,the sampling is usually sparse and noisy.Compressed sensi...Radio interferometric imaging samples visibility data in the spatial frequency domain and then reconstructs the image.Because of the limited number of antennas,the sampling is usually sparse and noisy.Compressed sensingbased on convex optimization is an effective reconstruction method for sparse sampling conditions.The hyperparameter for the l_(1)regularization term is an important parameter that directly affects the quality of the reconstructed image.If its value is too high,the image structure will be missed.If its value is too low,the image will have a low signal-to-noise ratio.The selection of hyperparameters under different levels of image noise is studied in this paper,and solar radio images are used as examples to analyze the optimization results of compressed sensing algorithms under different noise conditions.The simulation results show that when the salt-and-pepper noise density is between 10%and 30%,the compressed sensing algorithm obtains good reconstruction results.Moreover,the optimal hyperparameter value has a linear relationship with the noise density,and the mean squared error of regression is approximately 8.10×10^(-8).展开更多
基金supported by the National Key Research and Development Program of China(2022YFB2502103)the Xiamen Science and Technology Project(No.3502Z20231057)+2 种基金the National Natural Science Foundation of China(No.22288102,No.22279107,No.22309153)the Fujian Provincial Natural Science Foundation of China(No.2024J01040)the Fundamental Research Funds for the Central Universities(No.20720230039)。
文摘Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at high voltage,which leads to rapid failure both in the performance and structure of the LCO cathode.Herein,a Li_(2)CO_(3)-based additive was prepared by a simple sand-milling method,enabling a low electrochemical decomposition voltage<4.6 V from commonly>4.8 V,stabilizing the interface of the LCO cathode at 4.6 V.The decomposition of Li_(2)CO_(3)provides extra Li^(+)and CO_(2)to supplement the Li consumption required in the initial irreversible interfacial reactions and rapidly form a uniform and stable cathode electrolyte interphase layer(less organic and more inorganic components)on the LCO cathode by reducing CO_(2).Thus,the phase transformation and the emergence of high-valent Co ions on the surface of LCO at 4.6 V high voltage were inhibited.Thanks to this,with 2%Li_(2)CO_(3)-based additive,the capacity retention of commercial LCO at a high voltage of 4.6 V at 0.5 C for 100 cycles was improved from 59.3%to 79.3%.This work improves the high-voltage stability of LCO and provides a new idea for realizing the high-voltage operation of batteries.
文摘Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different physiological periods in the diagnosis of infertility patients. Methods: From December 2019 to May 2021, a total of 93 infertility patients were admitted and selected as the observation group. Among them, 31 cases were in the follicular stage, 31 cases in the ovulation stage, and 31 cases in the luteal stage. Ninety-three healthy women for fertility evaluation due to male infertility were selected as the control group. The control group included 31 women in the follicular phase, 31 women in the ovulatory phase, and 31 women in the luteal phase. The levels of sex hormones (prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), testosterone (T), and progesterone (P)) during different physiological phases were compared between the observation and control groups. Results: The follicular phase showed no significant difference in LH levels between the observation group and the control group. The observation group showed higher levels of PRL and P compared to the control group, while the levels of FSH, E2, and T were lower in the observation group compared to the control group. The ovulation phase showed no significant difference in PRL levels between the two groups. The observation group showed lower levels of LH, FSH, E2, T, and P compared to the control group. The luteal phase showed no statistical difference in E2 levels between the two groups. The observation group showed higher levels of PRL, LH, and FSH compared to the control group, while the levels of T and P were lower in the observation group compared to the control group. Conclusion: Infertile women show variations in hormone levels compared to the normal levels during the follicular phase, ovulatory phase, and luteal phase.
基金National Key Research and Development Program of China (2022YFB2502103)National Natural Science Foundation of China (22279107, 22309153)Fundamental Research Funds for the Central Universities (20720230039)。
文摘Single-crystal Nickel-rich layered oxides has been recognized as one of the promising cathodes for nextgeneration lithium batteries on account of their high capacity,while its practical application was hindered by structural instability and slow Li^(+) transfer kinetics.Herein,a surface-to-bulk engineered single-crystal LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(Ni90) cathode,which features W-doped bulk and Li_(2)WO_(4) surface layer,was successfully achieved by a one-step high-valence W^(6+) modification.The as-obtained W-modified Ni90 delivers excellent cycling stability(89.8% capacity retention after 300 cycles at 0.5 C)and rate capability.The enhanced electrochemical performance was ascribed to the doped-W induced stabilized lattice oxygen,reduced Li^(+)/Ni^(2+) mixing and inhibited H2-H3 phase transition in the bulk,and Li_(2)WO_(4) layer generated stabilized cathode/electrolyte interface.In addition,the thinner LiF-rich cathode electrolyte interphase(CEI) on surface and smaller grain size for W-modified Ni90 benefit to its Li^(+) diffusion dynamics.The effect of high-valence W^(6+)on single-crystal Ni-rich cathode was firstly revealed in detail,which deepens the understanding of electrochemical behavior of Ni-rich cathode with high-valence cations modification,and provides clues for design of high-performance layered cathodes.
基金National Natural Science Foundation of China(82072130 and 82001126)Key Medical Research Projects in Jiangsu Province(ZD2022021)+6 种基金Six Talent Peaks Project in Jiangsu Province(WSN-022)Suzhou Clinical Medical Center for Anaesthesiology(Szlcyxzxj202102)Jiangsu Medical Association Anaesthesia Research Project(SYH-32021-0036(2021031))Suzhou Medical Health Science and Technology Innovation Project(SKY2022136)Jiangsu Provincial Colleges of Natural Science General Program(22KJD320002)Health Talent Plan Project in Suzhou(GSWS2022007)Gusu Health Talent Project of Soochow(GSWS2021062).
文摘Sevoflurane induces developmental neurotoxicity in mice;however,the underlying mechanisms remain unclear.Triggering receptor expressed on myeloid cells 2(TREM2)is essential for microglia-mediated synaptic refinement during the early stages of brain development.We explored the effects of TREM2 on dendritic spine pruning during sevoflurane-induced developmental neurotoxicity in mice.Mice were anaesthetized with sevoflurane on postnatal days 6,8,and 10.Behavioral performance was assessed using the open field test and Morris water maze test.Genetic knockdown of TREM2 and overexpression of TREM2 by stereotaxic injection were used for mechanistic experiments.Western blotting,immunofluorescence,electron microscopy,three-dimensional reconstruction,Golgi staining,and whole-cell patch-clamp recordings were performed.Sevoflurane exposures upregulated the protein expression of TREM2,increased microglia-mediated pruning of dendritic spines,and reduced synaptic multiplicity and excitability of CA1 neurons.TREM2 genetic knockdown significantly decreased dendritic spine pruning,and partially aggravated neuronal morphological abnormalities and cognitive impairments in sevoflurane-treated mice.In contrast,TREM2 overexpression enhanced microglia-mediated pruning of dendritic spines and rescued neuronal morphological abnormalities and cognitive dysfunction.TREM2 exerts a protective role against neurocognitive impairments in mice after neonatal exposures to sevoflurane by enhancing microglia-mediated pruning of dendritic spines in CA1 neurons.This provides a potential therapeutic target in the prevention of sevoflurane-induced developmental neurotoxicity.
基金supported by the National Key Research and Development Program of China(2022YFB2502103)the Xiamen Science and Technology Project(3502Z20231057)+1 种基金the National Natural Science Foundation of China(Nos.22279107 and 22288102)J.You,R.Wei,and L.Niu acknowledge the China Scholarship Council(CSC)for a doctoral scholarship(Grant Nos.202006310030,202108530138,and 202108530139).
文摘The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE),limiting its broader application.Herein,an ether-based electrolyte(termed FGN-182)is formulated,exhibiting ultra-stable Li metal anodes through the incorporation of LiFSI and LiNO3 as dual salts.The synergistic effect of the dual salts facilitates the formation of a highly robust SEI film with fast Li+transport kinetics.Notably,Li||Cu half cells exhibit an average CE reaching up to 99.56%.In particular,pouch cells equipped with high-loading lithium cobalt oxide(LCO,3 mAh cm^(-2))cathodes,ultrathin Li chips(25μm),and lean electrolytes(5 g Ah-1)demonstrate outstanding cycling performance,retaining 80%capacity after 125 cycles.To address the gas issue in the cathode under high voltage,cathode additives 1,3,6-tricyanohexane is incorporated with FGN-182;the resulting high-voltage LCO||Li(4.4 V)pouch cells can cycle steadily over 93 cycles.This study demonstrates that,even with the use of ether-based electrolytes,it is possible to simultaneously achieve significant improvements in both high Li utilization and electrolyte tolerance to high voltage by exploring appropriate functional additives for both the cathode and anode.
基金Supported by the Ministry of Science and Technology of China,No.2021YFA1101502。
文摘BACKGROUND Extracellular vesicles derived from mesenchymal stromal cells(MSC-EVs)can be used for anti-aging therapy and treating various aging-related diseases.However,the clinical application of MSC-EVs is still limited,mainly due to insufficient in-formation on the preparation process,quality,and mechanism of action of MSC-EVs.To study the biological effects of MSC-EVs in regulating cellular senescence.METHODS In this study,we developed a clinical-grade production process for MSC-EVs and defined the release criteria for products suitable for human use.To support the clinical use of our product as a therapeutic agent,we performed efficacy assays to evaluate the anti-aging capacity of MSC-EVs in vitro and in vivo.RESULTS The functional analysis results revealed that MSC-EVs significantly reduced the levels of senescence-associatedβ-galactosidase,matrix metallopeptidase 1,P21,and interleukin-1βand increased the level of collagen I in a naturally aged cell model of human dermal fibroblasts.Similarly,treatment with MSC-EVs effectively improved D-gal-induced subacute aging in mice,aging-related histopathological changes,oxidative stress,and aging-related gene expression.CONCLUSION These findings indicate that MSC-EVs can partially alleviate D-gal-induced senescence by reducing oxidative stress and regulating metabolism.Overall,these findings strongly suggest that MSC-EVs hold promise for aging therapy.
基金supported by the Basic Research Key Project of Science and Technology Department of Yunnan Province(No.202401AS070116)the National Natural Science Foundation of China(No.21966016)。
文摘Biomass burning(BB)emits carbonaceous aerosols that significantly influence air quality in Southwest China during spring.To further understand the characteristics of spring BB and its original contribution to organic carbon(OC),daily fine particulate matter(PM_(2.5))samples were collected from March to May 2022 in Pu'er,Southwest China.The concentrations of OC,elemental carbon(EC),levoglucosan(Lev),and potassium from BB(K+BB)during the study period ranged from 5.3 to 31.2μg/m^(3),0.86-13.1μg/m^(3),0.06-0.82μg/m^(3),and 0.05-2.88μg/m^(3),respectively.To eliminate the effects of Lev degradation,this study uses the Aging of Air Mass(AAM)index to correct the atmospheric concentration of Lev and combines Bayesian mixture modeling with a molecular tracer method to assess the original contribution of BB to OC.The results indicated that the AAM index was 0.18±0.05,indicating that the degradation of Lev reached 82%.When considering the degradation of levoglucosan in the atmosphere,the primary source of BB aerosols was crop-straw combustion(71.1%),followed by the combustion of certain hardwoods and softwoods(24.9%)and grasses(4.0%).The original contribution of BB to OC was 62.4%,which was much greater than the contribution when levoglucosan degradation(23.7%)was ignored.The air mass inverse trajectories and Moderate Resolution Imaging Spectroradiometer(MODIS)fire hotspots indicated that the BB plume from Southeast Asia during spring could influence PM_(2.5)long-range transport in remote locations,and the contribution could reach 82%in Southwest China.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52175245)the Natural Science Foundation of Hubei Province (Grant No. 2021CFB462)。
文摘Health monitoring of underwater concrete facility systems is important in civil engineering. Unlike conventional manual inspection techniques, digital image processing offers a more convenient and effective approach, becoming an indispensable tool for structural inspection. Cracks, which are pervasive defects, are a central focus of structural deterioration research. However, the complexity of the marine environment poses challenges to underwater visibility.In this study, the underwater environment under controlled laboratory conditions is replicated, where varying turbidity and illumination conditions and images of concrete cracks are captured. An approach combining a defogging algorithm with guided and fast guided filtering techniques is proposed to enhance both natural underwater images and crack images captured through experimental photography. When applied to turbid crack images captured under two different suspension conditions, the method increases the information entropy(IE) by 32.92% and 17.92% and the underwater color image quality evaluation(UCIQE) by 35.76% and 18.36%, respectively. These results demonstrate its efficiency in enhancing image definition. The findings of this study could significantly impact the practical applications of image visualization and evaluation for underwater concrete cracks.
基金This study was supported by National Science and Technology Supported Projects(grant number:2013BAI09B11)the National Major Science&Technology Project for Control and Prevention of Major Infectious Diseases in China(grant number:2018ZX10201002-008-008,2017ZX10103004-004)。
文摘Community-acquired pneumonia(CAP) is one of the leading causes of morbidity and mortality in children worldwide.In this study,we aimed to describe the aetiology of viral infection of pediatric CAP in Chinese mainland.During November2014 to June 2016,the prospective study was conducted in 13 hospitals.The hospitalized children under 18 years old who met the criteria for CAP were enrolled.The throat swabs or nasopharyngeal aspirates(NPAs) were collected which were then screened 18 respiratory viruses using multiplex PCR assay.Viral pathogens were present in 56.6%(1539/2721) of the enrolled cases,with the detection rate of single virus in 39.8% of the cases and multiple viruses in 16.8% of the cases.The most frequently detected virus was respiratory syncytial virus(RSV)(15.2%,414/2721).The highest detection rate of virus was in <6-month-age group(70.7%,292/413).RSV,human metapneumovirus(HMPV),human parainfluenza viruses(HPIVs) and influenza B virus(Flu B) showed the similar prevalence patterns both in north and south China,but HPIVs,Flu A,human bocavirus(HBoV),human adenovirus(HAdV) and human coronaviruses(HCoVs) showed the distinct circulating patterns in north and south China.Human enterovirus/human rhinovirus(HEV/HRV)(27.6%,27/98),HBoV(18.4%,18/98),RSV(16.3%,16/98) and HMPV(14.3%,14/98) were the most commonly detected viruses in severe pneumonia cases with single virus infection.In conclusion,viral pathogens are frequently detected in pediatric CAP cases and may therefore play a vital role in the aetiology of CAP.RSV was the most important virus in hospitalized children with CAP in Chinese mainland.
文摘Radio interferometric imaging samples visibility data in the spatial frequency domain and then reconstructs the image.Because of the limited number of antennas,the sampling is usually sparse and noisy.Compressed sensingbased on convex optimization is an effective reconstruction method for sparse sampling conditions.The hyperparameter for the l_(1)regularization term is an important parameter that directly affects the quality of the reconstructed image.If its value is too high,the image structure will be missed.If its value is too low,the image will have a low signal-to-noise ratio.The selection of hyperparameters under different levels of image noise is studied in this paper,and solar radio images are used as examples to analyze the optimization results of compressed sensing algorithms under different noise conditions.The simulation results show that when the salt-and-pepper noise density is between 10%and 30%,the compressed sensing algorithm obtains good reconstruction results.Moreover,the optimal hyperparameter value has a linear relationship with the noise density,and the mean squared error of regression is approximately 8.10×10^(-8).
