Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable...Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.展开更多
Background:Congenital heart disease(CHD)is the most common congenital anomaly,but whether the COVID-19 pandemic affects its prevalence is unknown.We aimed to compare the incidence of CHD during the COVID-19 pandemic w...Background:Congenital heart disease(CHD)is the most common congenital anomaly,but whether the COVID-19 pandemic affects its prevalence is unknown.We aimed to compare the incidence of CHD during the COVID-19 pandemic with that before the pandemic in China.Methods:This multicenter retrospective observational study involved all newborns in seven representative cities of China between 01 September 2019,and 31 December 2021.All the newborns underwent pulse oximetry monitoring combined with cardiac murmur auscultation in the first 6 h to 72 h after birth for CHD screening.We defined fetuses born in and beyond September 2020 as the exposed group,and before as the non-exposed group.The incidence of CHD and specific heart abnormalities,including atrial septal defect(ASD)and ventricular septal defect(VSD),before and during the COVID-19 pandemic were compared.Results:The study included 492,662 newborns;217,003 newborns born before September 2020 and 275,659 newborns born in and beyond September 2020.There were 3115 patients with CHD in total during the whole study period.Of those,1055(September 2019 to August 2020)and 2060(September 2020 to December 2021)were less and more affected by the pandemic,respectively.There was a significant increase in the incidence of CHD in the early stage of the COVID-19 pandemic(7.78 per 1000 births)compared to that before the pandemic(4.86 per 1000 births)(p<0.001).The birth prevalence of ASD and VSD significantly increased during the pandemic from 3.991 per 1000 births to 4.717 per 1000 births(p=0.008)and from 1.650 per 1000 births to 3.508 per 1000 births(p<0.001),respectively.Conclusions:The incidence of CHD increased during the COVID-19 pandemic,which was possibly related to the reallocation of medical resources,increased psychological pressure,and increased socioeconomic deprivation,though underlying mechanisms remain unclear.展开更多
The conversion of solar energy to facilitate the photocatalytic transformation of CO_(2)into CH4 addresses the energy shortage caused by reducing humans’excessive dependence on fossil fuels and contributes substantia...The conversion of solar energy to facilitate the photocatalytic transformation of CO_(2)into CH4 addresses the energy shortage caused by reducing humans’excessive dependence on fossil fuels and contributes substantially to the goal of carbon neu-trality.However,there are still many limitations on the conversion of CO_(2)to CH_(4).In this work,a series of ZrO_(2)/Bi_(19)S_(27)Br_(3)composite photocatalysts was prepared by the solvothermal method and applied to the methanation reaction of CO_(2).Combin-ing Bi_(19)S_(27)Br_(3)with ZrO_(2)forms a heterojunction with a strong coupling interface.This greatly enhanced the CO_(2)adsorption performance of the 50-ZrO_(2)/Bi_(19)S_(27)Br_(3)composite and promoted the effective separation of photogenerated electron–hole pairs.Without the addition of photosensitizers,the CH_(4)selectivity of the 50-ZrO_(2)/Bi_(19)S_(27)Br_(3)composite is approximately 63%,and the CH_(4)generation rate is 18.04μmol/(gcat·h),which is noticeably higher than that of ZrO_(2)or Bi_(19)S_(27)Br_(3).This research demonstrated enhanced photocatalytic CO_(2)reduction efficiency using Bi_(19)S_(27)Br_(3)-based materials,providing a novel approach for the use of CO_(2)resources.展开更多
脱水应答元件结合蛋白(Dehydration-responsive element binding proteins,DREBs)是一类重要的植物耐逆相关转录因子。蒙古沙冬青Ammopiptanthus mongolicus是中国西北荒漠区特有的强耐逆常绿阔叶灌木。为探明其AmDREB1F基因在耐受非生...脱水应答元件结合蛋白(Dehydration-responsive element binding proteins,DREBs)是一类重要的植物耐逆相关转录因子。蒙古沙冬青Ammopiptanthus mongolicus是中国西北荒漠区特有的强耐逆常绿阔叶灌木。为探明其AmDREB1F基因在耐受非生物逆境中的功能和作用机理,文中对该基因编码蛋白的亚细胞定位、表达模式和转基因拟南芥的耐逆性进行了分析。结果表明:AmDREB1F编码的蛋白质定位于细胞核内;在室内培养幼苗中,该基因在正常条件下不表达,在低温和干旱胁迫下有较明显表达,在高盐和高温胁迫下仅有微弱表达,而在脱落酸(Abscisicacid,ABA)处理下不表达;在野外生长植株的叶片中,其表达量在秋末、冬季和早春远高于其他季节,而不同器官相比,其在根和未成熟果荚中的表达量远高于其他器官;将AmDREB1F在拟南芥中组成型表达可提高多个受DREBs调控的胁迫响应基因的转录水平,增强转基因株系对干旱、高盐和低温以及氧化胁迫的耐性,同时导致其生长发育延滞,外施赤霉素3可消除生长延滞现象;将该基因进行胁迫诱导表达也可提高转基因拟南芥对上述非生物胁迫的耐受性,而不影响其生长发育。这些结果说明AmDREB1F可能通过ABA非依赖的信号途径在响应和耐受逆境胁迫中起正调节作用。展开更多
基金supported by the National Natural Science Foundation of China(Nos.21971223 and 21772178)。
文摘Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.
基金funded by Central Guiding Fund for Local Science and Technology Development Projects(No.2023ZY1058)the National Nature Science Foundation of China(No.82270309)both awarded to Weize Xu.
文摘Background:Congenital heart disease(CHD)is the most common congenital anomaly,but whether the COVID-19 pandemic affects its prevalence is unknown.We aimed to compare the incidence of CHD during the COVID-19 pandemic with that before the pandemic in China.Methods:This multicenter retrospective observational study involved all newborns in seven representative cities of China between 01 September 2019,and 31 December 2021.All the newborns underwent pulse oximetry monitoring combined with cardiac murmur auscultation in the first 6 h to 72 h after birth for CHD screening.We defined fetuses born in and beyond September 2020 as the exposed group,and before as the non-exposed group.The incidence of CHD and specific heart abnormalities,including atrial septal defect(ASD)and ventricular septal defect(VSD),before and during the COVID-19 pandemic were compared.Results:The study included 492,662 newborns;217,003 newborns born before September 2020 and 275,659 newborns born in and beyond September 2020.There were 3115 patients with CHD in total during the whole study period.Of those,1055(September 2019 to August 2020)and 2060(September 2020 to December 2021)were less and more affected by the pandemic,respectively.There was a significant increase in the incidence of CHD in the early stage of the COVID-19 pandemic(7.78 per 1000 births)compared to that before the pandemic(4.86 per 1000 births)(p<0.001).The birth prevalence of ASD and VSD significantly increased during the pandemic from 3.991 per 1000 births to 4.717 per 1000 births(p=0.008)and from 1.650 per 1000 births to 3.508 per 1000 births(p<0.001),respectively.Conclusions:The incidence of CHD increased during the COVID-19 pandemic,which was possibly related to the reallocation of medical resources,increased psychological pressure,and increased socioeconomic deprivation,though underlying mechanisms remain unclear.
基金supported by the National Natural Science Foundation of China(Nos.22378172,22138011,22378206).
文摘The conversion of solar energy to facilitate the photocatalytic transformation of CO_(2)into CH4 addresses the energy shortage caused by reducing humans’excessive dependence on fossil fuels and contributes substantially to the goal of carbon neu-trality.However,there are still many limitations on the conversion of CO_(2)to CH_(4).In this work,a series of ZrO_(2)/Bi_(19)S_(27)Br_(3)composite photocatalysts was prepared by the solvothermal method and applied to the methanation reaction of CO_(2).Combin-ing Bi_(19)S_(27)Br_(3)with ZrO_(2)forms a heterojunction with a strong coupling interface.This greatly enhanced the CO_(2)adsorption performance of the 50-ZrO_(2)/Bi_(19)S_(27)Br_(3)composite and promoted the effective separation of photogenerated electron–hole pairs.Without the addition of photosensitizers,the CH_(4)selectivity of the 50-ZrO_(2)/Bi_(19)S_(27)Br_(3)composite is approximately 63%,and the CH_(4)generation rate is 18.04μmol/(gcat·h),which is noticeably higher than that of ZrO_(2)or Bi_(19)S_(27)Br_(3).This research demonstrated enhanced photocatalytic CO_(2)reduction efficiency using Bi_(19)S_(27)Br_(3)-based materials,providing a novel approach for the use of CO_(2)resources.
文摘脱水应答元件结合蛋白(Dehydration-responsive element binding proteins,DREBs)是一类重要的植物耐逆相关转录因子。蒙古沙冬青Ammopiptanthus mongolicus是中国西北荒漠区特有的强耐逆常绿阔叶灌木。为探明其AmDREB1F基因在耐受非生物逆境中的功能和作用机理,文中对该基因编码蛋白的亚细胞定位、表达模式和转基因拟南芥的耐逆性进行了分析。结果表明:AmDREB1F编码的蛋白质定位于细胞核内;在室内培养幼苗中,该基因在正常条件下不表达,在低温和干旱胁迫下有较明显表达,在高盐和高温胁迫下仅有微弱表达,而在脱落酸(Abscisicacid,ABA)处理下不表达;在野外生长植株的叶片中,其表达量在秋末、冬季和早春远高于其他季节,而不同器官相比,其在根和未成熟果荚中的表达量远高于其他器官;将AmDREB1F在拟南芥中组成型表达可提高多个受DREBs调控的胁迫响应基因的转录水平,增强转基因株系对干旱、高盐和低温以及氧化胁迫的耐性,同时导致其生长发育延滞,外施赤霉素3可消除生长延滞现象;将该基因进行胁迫诱导表达也可提高转基因拟南芥对上述非生物胁迫的耐受性,而不影响其生长发育。这些结果说明AmDREB1F可能通过ABA非依赖的信号途径在响应和耐受逆境胁迫中起正调节作用。
