To enhance flow stability and reduce hydrodynamic noise caused by fluctuating pressure,a quasiperiodic elastic support skin composed of flexible walls and elastic support elements is proposed for fluid noise reduction...To enhance flow stability and reduce hydrodynamic noise caused by fluctuating pressure,a quasiperiodic elastic support skin composed of flexible walls and elastic support elements is proposed for fluid noise reduction.The arrangement of the elastic support element is determined by the equivalent periodic distance and quasi-periodic coefficient.In this paper,a dynamic model of skin in a fluid environment is established.The influence of equivalent periodic distance and quasi-periodic coefficient on flow stability is investigated.The results suggest that arranging the elastic support elements in accordance with the quasi-periodic law can effectively enhance flow stability.Meanwhile,the hydrodynamic noise calculation results demonstrate that the skin exhibits excellent noise reduction performance,with reductions of 10 dB in the streamwise direction,11 dB in the spanwise direction,and 10 dB in the normal direction.The results also demonstrate that the stability analysis method can serve as a diagnostic tool for flow fields and guide the design of noise reduction structures.展开更多
BACKGROUND Fulminant type 1 diabetes mellitus(FT1DM)that occurs during pregnancy or the perinatal period is known as pregnancy-related FT1DM(PF),always without history of abnormal glucose metabolism.Here,we present fo...BACKGROUND Fulminant type 1 diabetes mellitus(FT1DM)that occurs during pregnancy or the perinatal period is known as pregnancy-related FT1DM(PF),always without history of abnormal glucose metabolism.Here,we present four patients who developed FT1DM during treatment but were first diagnosed with gestational diabetes mellitus(GDM).CASE SUMMARY The clinical data of four patients with GDM combined with FT1DM admitted to our hospital between July 2018 and April 2021 were collected,and the patients and their infants were followed up.All patients were diagnosed with GDM during the second trimester and were treated.The blood glucose level elevated suddenly during the third trimester and then were diagnosed with FT1DM.Two patients had an insulin allergy,and two had symptoms of upper respiratory tract infection before onset.One patient developed ketoacidosis,and three developed ketosis.Two patients had cesarean section deliveries,and two had vaginal deliveries.The growth and development of the infants were normal.C-peptide levels were lower than those at onset,suggesting progressive impairment of islet function.The frequencies of the DRB109:01,DQB103:03,DQA103:02,DPA101:03,DPA102:02,DPB105:01,DRB401:03,G 01:01,and G 01:04 human leukocyte antigen(HLA)-G alleles were high in the present study.CONCLUSION In comparison with pregnancy-associated FT1DM(PF),patients with GDM combined with FT1DM had an older age of onset,higher body mass index,slower onset,fewer prodromal symptoms,and less acidosis.The pathogenesis may be due to various factors affecting the already fragileβ-cells of GDM patients with genetically susceptible class II HLA genotypes.We speculate that GDM combined with FT1DM during pregnancy,referred to as“double diabetes,”is a subtype of PF with its own unique characteristics that should be investigated further.展开更多
目的研究骨髓间充质干细胞来源外泌体(exosomes derived from bone mesenchymal stem cells,BMSCs-Exo)对脓毒症相关急性肾损伤体外模型的作用。方法利用超速离心法提取骨髓间充质干细胞分泌的外泌体,通过透射电镜、纳米颗粒跟踪分析及W...目的研究骨髓间充质干细胞来源外泌体(exosomes derived from bone mesenchymal stem cells,BMSCs-Exo)对脓毒症相关急性肾损伤体外模型的作用。方法利用超速离心法提取骨髓间充质干细胞分泌的外泌体,通过透射电镜、纳米颗粒跟踪分析及Western印迹法鉴定外泌体。用脂多糖(lipopolysaccharide,LPS)处理人肾小管上皮细胞(HK-2)建立脓毒症相关急性肾损伤(sepsis-induced acute kidney injury,SAKI)细胞模型,将细胞分为对照组(CON组)、脂多糖组(LPS组)和脂多糖+外泌体组(LPS+EXO组)。CCK-8法检测各组细胞活性、流式细胞仪检测细胞凋亡率,应用Western印迹法检测细胞凋亡相关蛋白cleaved-Caspase3、Bax和bcl2水平,采用qRT-PCR检测炎性因子TNF-α、IL-6和IL-1βmRNA水平。结果应用LPS处理HK-2细胞成功构建了SAKI细胞模型。LPS组中,HK-2细胞经LPS(100μg/mL)处理后细胞活性和抗凋亡蛋白bcl2表达明显下降(P<0.05),而细胞凋亡率和凋亡蛋白cleaved-Caspase3、Bax表达水平显著上升(P<0.01),同时炎性指标TNF-α、IL-6和IL-1βmRNA表达上调(P<0.01)。LPS+EXO组中,BMSCs-Exo逆转了LPS对HK-2细胞的作用,细胞活性升高、凋亡蛋白cleaved-Caspase3以及Bax下降和抗凋亡蛋白bcl2升高(P<0.05),同时还下调了炎性因子(TNF-α、IL-6和IL-1β)mRNA表达水平(P<0.05)。结论BMSCs-Exo在LPS诱导的SAKI体外模型中发挥抗炎和抗凋亡的保护作用,为未来临床利用BMSCs-Exo治疗SAKI提供理论基础。展开更多
Aqueous zinc ion batteries show prospects for next-generation renewable energy storage devices.However,the practical applications have been limited by the issues derived from Zn anode.As one of serious problems,Zn den...Aqueous zinc ion batteries show prospects for next-generation renewable energy storage devices.However,the practical applications have been limited by the issues derived from Zn anode.As one of serious problems,Zn dendrite growth caused from the uncontrollable Zn deposition is unfavorable.Herein,with the aim to regulate Zn deposition,an artificial solid–electrolyte interface is subtly engineered with a perovskite type material,BaTiO3,which can be polarized,and its polarization could be switched under the external electric field.Resulting from the aligned dipole in BaTiO3 layer,zinc ions could move in order during cycling process.Regulated Zn migration at the anode/electrolyte interface contributes to the even Zn stripping/plating and confined Zn dendrite growth.As a result,the reversible Zn plating/stripping processes for over 2000 h have been achieved at 1 mA cm^(−2) with capacity of 1 mAh cm−2.Furthermore,this anode endowing the electric dipoles shows enhanced cycling stability for aqueous Zn-MnO2 batteries.The battery can deliver nearly 100%Coulombic efficiency at 2 Ag^(−1) after 300 cycles.展开更多
Urban parks composed mostly of vegetation and water bodies can effectively mitigate the urban heat island effect. Many studies have investigated the cooling effects of urban parks; however, little attention has been g...Urban parks composed mostly of vegetation and water bodies can effectively mitigate the urban heat island effect. Many studies have investigated the cooling effects of urban parks; however, little attention has been given to park landscape structure. Based on landscape metrics, this study has explored the influences of the park landscape structure on its inner thermal environment, taking heavily urbanized Beijing Municipality in China as the study area. Three indices, including the percentage of landscape(PLAND), landscape shape index(LSI) and aggregation index(AI), were used to measure the composition and configuration characteristics of the landscape components inside the parks. The indices were calculated for five landscape types being interpreted from Quickbird images. Urban thermal conditions were measured using the land surface temperature(LST) derived from Landsat TM images. The results showed that the park LST had a negative relationship with the park size, but no significant relationship was found with park shape. For the park's interior landscape, however, the configuration and composition characteristics of the landscape components inside the park explained 70% of the park LST variance. The area percentage of water bodies and the aggregation index of woodland were identified as the key influencing characteristics. In addition, when the composition and configuration characteristics of the park landscape components were separately considered, the configuration characteristics(LSI and AI) explained approximately 54% of the variance in park LST, which was comparable with that explained by the composition characteristics(PLAND). Thus, this study suggested that an effective and practical way for urban cooling park design is the optimization of spatial configuration of landscape components inside the park.展开更多
In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as...In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as ‘flash drought’, developed in May with a rapid intensification afterwards, and peaked in mid-July. ~76% of crop region and 60% of grassland and pasture regions have been under moderate to severe dry conditions. This study used multiple lines of evidences, i.e., in-situ AmeriFlux measurements, spatial satellite observations, and scaled ecosystem modeling, to provide independent and complementary analysis on the impact of 2012 flash drought on the US Midwest vegetation greenness and photosynthesis carbon uptake. Three datasets consistently showed that 1) phenological activities of all biomes advanced 1–2 weeks earlier in 2012 compared to the other years of 2010–2014;2) the drought had a more severe impact on agroecosystems(crop and grassland) than on forests;3) the growth of crop and grassland was suppressed from June with significant reduction of vegetation index, sun-induced fluorescence(SIF) and gross primary production(GPP), and did not recover until the end of growing season. The modeling results showed that regional total GPP in 2012 was the lowest(1.76 Pg C/yr) during 2010–2014, and decreased by 63 Tg C compared with the other-year mean. Agroecosystems, accounting for 84% of regional GPP assimilation, were the most impacted by 2012 drought with total GPP reduction of 9%, 7%, 6%, and 29% for maize, soybean, cropland, and grassland, respectively. The frequency and severity of droughts have been predicted to increase in future. The results imply the importance to investigate the influences of flash droughts on vegetation productivity and terrestrial carbon cycling.展开更多
In this work,a series of specimens was prepared by the casting method.Sharp cube-textured substrates were processed by heavy cold rolling and recrystallization annealing(i.e.,the rolling-assisted biaxially textured su...In this work,a series of specimens was prepared by the casting method.Sharp cube-textured substrates were processed by heavy cold rolling and recrystallization annealing(i.e.,the rolling-assisted biaxially textured substrates(RABi TS) method).Both the rolling and the recrystallization texture in the alloy tapes were investigated by X-ray diffraction and electron back-scatter diffraction,respectively.The results showed that a strong copper-type deformation texture was obtained in the heavy cold-rolled substrate.In addition,the recrystallization annealing process was found to be very important for the texture transition in the Cu–Ni alloy substrates.The cube texture content in the Cu60 Ni40 alloy substrates reached 99.7%(≤10°) after optimization of the cold-rolling procedure and the recrystallizing heat-treatment process,whereas the content of low-angle grain boundaries(from 2° to 10° misorientation) in the substrate reached 95.1%.展开更多
In 2020,an unexpectedly large outbreak of the coronavirus disease 2019(COVID-19)epidemic was reported in China's Mainland.As we known,the epidemic was caused by imported cases in other provinces of China except fo...In 2020,an unexpectedly large outbreak of the coronavirus disease 2019(COVID-19)epidemic was reported in China's Mainland.As we known,the epidemic was caused by imported cases in other provinces of China except for Hubei in 2020.In this paper,we developed a differential equation model with tracing isolation strategy with close contacts of newly confirmed cases and discrete time imported cases,to perform assessment and risk analysis for COVID-19 outbreaks in Tianjin and Chongqing city.Firstly,the model behavior without imported cases was given.Then,the real-time regeneration number in Tianjin and Chongqing city revealed a trend of rapidly rising,and then falling fast.Finally,sensitivity analysis demonstrates that the earlier with Wuhan lock-down,the fewer cases in these two cities.One can obtain that the tracing isolation of close contacts of newly confirmed cases could effectively control the spread of the disease.But it is not sensitive for the more contact tracing isolation days on confirmed cases,the fewer cases.Our investigation model could be potentially helpful to provide model building technology for the transmission of COVID-19.展开更多
基金National Natural Science Foundation of China(Grant Nos.52075111,51775123)Fundamental Research Funds for the Central Universities(Grant No.3072022JC0701)。
文摘To enhance flow stability and reduce hydrodynamic noise caused by fluctuating pressure,a quasiperiodic elastic support skin composed of flexible walls and elastic support elements is proposed for fluid noise reduction.The arrangement of the elastic support element is determined by the equivalent periodic distance and quasi-periodic coefficient.In this paper,a dynamic model of skin in a fluid environment is established.The influence of equivalent periodic distance and quasi-periodic coefficient on flow stability is investigated.The results suggest that arranging the elastic support elements in accordance with the quasi-periodic law can effectively enhance flow stability.Meanwhile,the hydrodynamic noise calculation results demonstrate that the skin exhibits excellent noise reduction performance,with reductions of 10 dB in the streamwise direction,11 dB in the spanwise direction,and 10 dB in the normal direction.The results also demonstrate that the stability analysis method can serve as a diagnostic tool for flow fields and guide the design of noise reduction structures.
基金Supported by National Natural Science Foundation of China,No.82270864.
文摘BACKGROUND Fulminant type 1 diabetes mellitus(FT1DM)that occurs during pregnancy or the perinatal period is known as pregnancy-related FT1DM(PF),always without history of abnormal glucose metabolism.Here,we present four patients who developed FT1DM during treatment but were first diagnosed with gestational diabetes mellitus(GDM).CASE SUMMARY The clinical data of four patients with GDM combined with FT1DM admitted to our hospital between July 2018 and April 2021 were collected,and the patients and their infants were followed up.All patients were diagnosed with GDM during the second trimester and were treated.The blood glucose level elevated suddenly during the third trimester and then were diagnosed with FT1DM.Two patients had an insulin allergy,and two had symptoms of upper respiratory tract infection before onset.One patient developed ketoacidosis,and three developed ketosis.Two patients had cesarean section deliveries,and two had vaginal deliveries.The growth and development of the infants were normal.C-peptide levels were lower than those at onset,suggesting progressive impairment of islet function.The frequencies of the DRB109:01,DQB103:03,DQA103:02,DPA101:03,DPA102:02,DPB105:01,DRB401:03,G 01:01,and G 01:04 human leukocyte antigen(HLA)-G alleles were high in the present study.CONCLUSION In comparison with pregnancy-associated FT1DM(PF),patients with GDM combined with FT1DM had an older age of onset,higher body mass index,slower onset,fewer prodromal symptoms,and less acidosis.The pathogenesis may be due to various factors affecting the already fragileβ-cells of GDM patients with genetically susceptible class II HLA genotypes.We speculate that GDM combined with FT1DM during pregnancy,referred to as“double diabetes,”is a subtype of PF with its own unique characteristics that should be investigated further.
文摘目的研究骨髓间充质干细胞来源外泌体(exosomes derived from bone mesenchymal stem cells,BMSCs-Exo)对脓毒症相关急性肾损伤体外模型的作用。方法利用超速离心法提取骨髓间充质干细胞分泌的外泌体,通过透射电镜、纳米颗粒跟踪分析及Western印迹法鉴定外泌体。用脂多糖(lipopolysaccharide,LPS)处理人肾小管上皮细胞(HK-2)建立脓毒症相关急性肾损伤(sepsis-induced acute kidney injury,SAKI)细胞模型,将细胞分为对照组(CON组)、脂多糖组(LPS组)和脂多糖+外泌体组(LPS+EXO组)。CCK-8法检测各组细胞活性、流式细胞仪检测细胞凋亡率,应用Western印迹法检测细胞凋亡相关蛋白cleaved-Caspase3、Bax和bcl2水平,采用qRT-PCR检测炎性因子TNF-α、IL-6和IL-1βmRNA水平。结果应用LPS处理HK-2细胞成功构建了SAKI细胞模型。LPS组中,HK-2细胞经LPS(100μg/mL)处理后细胞活性和抗凋亡蛋白bcl2表达明显下降(P<0.05),而细胞凋亡率和凋亡蛋白cleaved-Caspase3、Bax表达水平显著上升(P<0.01),同时炎性指标TNF-α、IL-6和IL-1βmRNA表达上调(P<0.01)。LPS+EXO组中,BMSCs-Exo逆转了LPS对HK-2细胞的作用,细胞活性升高、凋亡蛋白cleaved-Caspase3以及Bax下降和抗凋亡蛋白bcl2升高(P<0.05),同时还下调了炎性因子(TNF-α、IL-6和IL-1β)mRNA表达水平(P<0.05)。结论BMSCs-Exo在LPS诱导的SAKI体外模型中发挥抗炎和抗凋亡的保护作用,为未来临床利用BMSCs-Exo治疗SAKI提供理论基础。
基金the partial financial support from the National Natural Science Foundation of China(21935003 and 21805182)National Key Research and Development Plan(2016YFB0901503)+1 种基金Shanghai Pujiang Program(18PJ1403800)the support from the Hundreds of Talents program of Sun Yat-sen University。
文摘Aqueous zinc ion batteries show prospects for next-generation renewable energy storage devices.However,the practical applications have been limited by the issues derived from Zn anode.As one of serious problems,Zn dendrite growth caused from the uncontrollable Zn deposition is unfavorable.Herein,with the aim to regulate Zn deposition,an artificial solid–electrolyte interface is subtly engineered with a perovskite type material,BaTiO3,which can be polarized,and its polarization could be switched under the external electric field.Resulting from the aligned dipole in BaTiO3 layer,zinc ions could move in order during cycling process.Regulated Zn migration at the anode/electrolyte interface contributes to the even Zn stripping/plating and confined Zn dendrite growth.As a result,the reversible Zn plating/stripping processes for over 2000 h have been achieved at 1 mA cm^(−2) with capacity of 1 mAh cm−2.Furthermore,this anode endowing the electric dipoles shows enhanced cycling stability for aqueous Zn-MnO2 batteries.The battery can deliver nearly 100%Coulombic efficiency at 2 Ag^(−1) after 300 cycles.
基金Under the auspices of the important National Project of high-resolution Earth Observation System(No.00-Y30B15-9001-14/16)National Natural Science Foundation of China(No.41421001)
文摘Urban parks composed mostly of vegetation and water bodies can effectively mitigate the urban heat island effect. Many studies have investigated the cooling effects of urban parks; however, little attention has been given to park landscape structure. Based on landscape metrics, this study has explored the influences of the park landscape structure on its inner thermal environment, taking heavily urbanized Beijing Municipality in China as the study area. Three indices, including the percentage of landscape(PLAND), landscape shape index(LSI) and aggregation index(AI), were used to measure the composition and configuration characteristics of the landscape components inside the parks. The indices were calculated for five landscape types being interpreted from Quickbird images. Urban thermal conditions were measured using the land surface temperature(LST) derived from Landsat TM images. The results showed that the park LST had a negative relationship with the park size, but no significant relationship was found with park shape. For the park's interior landscape, however, the configuration and composition characteristics of the landscape components inside the park explained 70% of the park LST variance. The area percentage of water bodies and the aggregation index of woodland were identified as the key influencing characteristics. In addition, when the composition and configuration characteristics of the park landscape components were separately considered, the configuration characteristics(LSI and AI) explained approximately 54% of the variance in park LST, which was comparable with that explained by the composition characteristics(PLAND). Thus, this study suggested that an effective and practical way for urban cooling park design is the optimization of spatial configuration of landscape components inside the park.
基金Under the auspices of the National Natural Science Foundation of China(No.41801340)Natural Science Foundation of Liaoning,China(No.20180550238)the Key Research Program of Frontier Sciences by Chinese Academy of Sciences(No.QYZDB-SSW-DQC005)
文摘In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as ‘flash drought’, developed in May with a rapid intensification afterwards, and peaked in mid-July. ~76% of crop region and 60% of grassland and pasture regions have been under moderate to severe dry conditions. This study used multiple lines of evidences, i.e., in-situ AmeriFlux measurements, spatial satellite observations, and scaled ecosystem modeling, to provide independent and complementary analysis on the impact of 2012 flash drought on the US Midwest vegetation greenness and photosynthesis carbon uptake. Three datasets consistently showed that 1) phenological activities of all biomes advanced 1–2 weeks earlier in 2012 compared to the other years of 2010–2014;2) the drought had a more severe impact on agroecosystems(crop and grassland) than on forests;3) the growth of crop and grassland was suppressed from June with significant reduction of vegetation index, sun-induced fluorescence(SIF) and gross primary production(GPP), and did not recover until the end of growing season. The modeling results showed that regional total GPP in 2012 was the lowest(1.76 Pg C/yr) during 2010–2014, and decreased by 63 Tg C compared with the other-year mean. Agroecosystems, accounting for 84% of regional GPP assimilation, were the most impacted by 2012 drought with total GPP reduction of 9%, 7%, 6%, and 29% for maize, soybean, cropland, and grassland, respectively. The frequency and severity of droughts have been predicted to increase in future. The results imply the importance to investigate the influences of flash droughts on vegetation productivity and terrestrial carbon cycling.
基金financially supported by the National Natural Science Foundation of China (No.51571002)the Beijing Natural Science Foundation (No.2172008)+4 种基金the Doctoral Program of Higher Education of Special Research Fund of China (No.20121103110012)the Beijing Municipal Natural Science Foundation B Type (No.KZ201310005003)the China Scholarship Councilthe Technology Program of Beijing CityBeijing University of Technology
文摘In this work,a series of specimens was prepared by the casting method.Sharp cube-textured substrates were processed by heavy cold rolling and recrystallization annealing(i.e.,the rolling-assisted biaxially textured substrates(RABi TS) method).Both the rolling and the recrystallization texture in the alloy tapes were investigated by X-ray diffraction and electron back-scatter diffraction,respectively.The results showed that a strong copper-type deformation texture was obtained in the heavy cold-rolled substrate.In addition,the recrystallization annealing process was found to be very important for the texture transition in the Cu–Ni alloy substrates.The cube texture content in the Cu60 Ni40 alloy substrates reached 99.7%(≤10°) after optimization of the cold-rolling procedure and the recrystallizing heat-treatment process,whereas the content of low-angle grain boundaries(from 2° to 10° misorientation) in the substrate reached 95.1%.
基金The project is funded by the National Natural Science Foundation of China under Grants(11801398,12022113,11671241,61873154,11601292)Natural Science Foundation of Shanxi Province Grant No.201801D221024.
文摘In 2020,an unexpectedly large outbreak of the coronavirus disease 2019(COVID-19)epidemic was reported in China's Mainland.As we known,the epidemic was caused by imported cases in other provinces of China except for Hubei in 2020.In this paper,we developed a differential equation model with tracing isolation strategy with close contacts of newly confirmed cases and discrete time imported cases,to perform assessment and risk analysis for COVID-19 outbreaks in Tianjin and Chongqing city.Firstly,the model behavior without imported cases was given.Then,the real-time regeneration number in Tianjin and Chongqing city revealed a trend of rapidly rising,and then falling fast.Finally,sensitivity analysis demonstrates that the earlier with Wuhan lock-down,the fewer cases in these two cities.One can obtain that the tracing isolation of close contacts of newly confirmed cases could effectively control the spread of the disease.But it is not sensitive for the more contact tracing isolation days on confirmed cases,the fewer cases.Our investigation model could be potentially helpful to provide model building technology for the transmission of COVID-19.
