Encapsulation of bioactive substances for extended shelf life and controlled,targeted release is critical for their applications in food and drug delivery.Here,a new method has been developed to encapsulate bioactive ...Encapsulation of bioactive substances for extended shelf life and controlled,targeted release is critical for their applications in food and drug delivery.Here,a new method has been developed to encapsulate bioactive molecules in the crystal composites,showing greatly enhanced stability and unique pHtriggered response.Chlorophyll,a model bioactive,is first loaded in shellac nanoparticles via coprecipitation with a high encapsulation efficiency,and then the chlorophyll-loaded nanoparticles are incorporated into calcite crystals grown from a gel media containing the nanoparticles.Under the protection of shellac nanoparticles and calcite crystals,chlorophyll shows excellent stability even under light.Encapsulated chlorophyll could only be released by first dissolving the calcite crystals under acidic condition and then dissolving the shellac nanoparticles under alkaline condition.The unique pHtriggered release mimics the pH change from acidic in the stomach to alkaline in the intestine and is thus well suited for controlled,targeted intestinal release.This work suggests that the crystal composites are an ideal delivery vehicle for the functional design of bioactive molecules.展开更多
Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is report...Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is reported.Microfluidic technology is utilized to emulsify the inner aqueous phase containing the shell polymer into monodisperse drops in the outer oil phase.As the cosolvent in the inner aqueous phase diffuses into the outer oil phase,the solubility of the shell polymer decreases,which eventually precipitates.Since the shell polymer,shellac,contains both hydrophilic and hydrophobic groups,it tends to wet both the inner aqueous phase and the outer oil phase,thus forming a solid shell at the periphery of the drop.We show that the diffusion rate of hydrophilic molecules encapsulated in the water core decreases as their molecular weight increases and the property of the microcapsules could further be modified by polyelectrolyte multilayer coating.These microcapsules are fabricated using FDA-approved polymer and non-toxic solvents and are of great use in drugs,cosmetics and foods.展开更多
N6-methyladenosine(m^(6)A)is the most prevalent internal RNA modification,and its regulators include writers,readers and erasers.m^(6)A is under stringent control and takes part in many biological events,but it is not...N6-methyladenosine(m^(6)A)is the most prevalent internal RNA modification,and its regulators include writers,readers and erasers.m^(6)A is under stringent control and takes part in many biological events,but it is not known whether there is an interplay between m^(6)A and glycosylation.Here we investigated an m^(6)A reader,YTHDC1,which has been shown to be recruited to the DNA-RNA hybrid at DNA damage sites and regulate homologous recombination(HR)during DNA damage repair.We found that YTHDC1 is subject to O-linked𝛽-N-acetylglucosamine(O-GlcNAc)modification at Ser396 upon DNA damage,which is pivotal for YTHDC1 chromatin binding and ionization radiation induced focus(IRIF)formation.RNA immunoprecipitation(RIP)and molecular dynamics(MD)simulations indicate that O-GlcNAcylation is vital for YTHDC1 to bind with m^(6)A RNA.Fluorescence recovery after photo bleaching(FRAP)analysis revealed that YTHDC1 O-GlcNAcylation is essential for DNA damage-induced YTHDC1-m^(6)A condensate formation.We further demonstrate that YTHDC1 O-GlcNAcylation promotes HR-mediated DNA damage repair and cell survival,probably through recruitment of Rad51 to the damage sites.We propose that YTHDC1 O-GlcNAcylation is instrumental for HR.展开更多
Under Arctic warming,near-surface energy transfers have significantly changed,but few studies have focused on energy exchange over Arctic glacier due to limitations in available observations.In this study,the atmosphe...Under Arctic warming,near-surface energy transfers have significantly changed,but few studies have focused on energy exchange over Arctic glacier due to limitations in available observations.In this study,the atmospheric energy exchange processes over the Arctic glacier surface were analyzed by using observational data obtained in summer 2019 in comparison with those over the Arctic tundra surface.The energy budget over the glacier greatly differed from that over the tundra,characterized by less net shortwave radiation and downward sensible heat flux,due to the high albedo and icy surface.Most of the incoming solar radiation was injected into the glacier in summer,leading to snow ice melting.During the observation period,strong daily variations in near-surface heat transfer occurred over the Arctic glacier,with the maximum downward and upward heat fluxes occurring on 2 and 6 July 2019,respectively.Further analyses suggested that the maximum downward heat flux is mainly caused by the strong local thermal contrast above the glacier surface,while the maximum upward heat transfer cannot be explained by the classical turbulent heat transfer theory,possibly caused by countergradient heat transfer.Our results indicated that the near-surface energy exchange processes over Arctic glacier may be strongly related to local forcings,but a more in-depth investigation will be needed in the future when more observational data become available.展开更多
Studies on the atmospheric structure over the Antarctic Plateau are important for better understanding the weather and climate systems of polar regions.In the summer of 2017,an observational experiment was conducted a...Studies on the atmospheric structure over the Antarctic Plateau are important for better understanding the weather and climate systems of polar regions.In the summer of 2017,an observational experiment was conducted at Dome-A,the highest station in Antarctica,with a total of 32 profiles obtained from global positioning system(GPS)radiosondes.Based on observational data,the atmospheric temperature,humidity,and wind structures and their variations are investigated,and compared with those from four other stations inside the Antarctic circle.Distinguished thermal and dynamic structures were revealed over Dome-A,characterized by the lowest temperature,the highest tropopause,the largest lapse rate,and the most frequent temperature and humidity inversion.During the experiment,a prominent blocking event was identified,with great influence on the atmospheric structure over Dome-A.The blocking high produced a strong anticyclone that brought warm and moist air to the hinterland of the Antarctic Plateau,causing a much warmer,wetter,and windier troposphere over the Dome-A station.Meanwhile,a polar air mass was forced out of the Antarctic,formed a cold surge extending as far as southern New Zealand and affected the weather there.Our results proved that there would be a direct interaction between the atmosphere over the hinterland of the Antarctic Plateau and mid latitudes with the action of a blocking high.Further studies are needed to explore the interaction between the atmospheric systems over the Antarctic and mid latitudes under intense synoptic disturbance,with longterm data and numerical modeling.展开更多
基金supported by the National Natural Science Foundation of China (Nos.21878258,11704331 and 51625304)“the Fundamental Research Funds for the Central Universities” (No. 2018QNA4046)
文摘Encapsulation of bioactive substances for extended shelf life and controlled,targeted release is critical for their applications in food and drug delivery.Here,a new method has been developed to encapsulate bioactive molecules in the crystal composites,showing greatly enhanced stability and unique pHtriggered response.Chlorophyll,a model bioactive,is first loaded in shellac nanoparticles via coprecipitation with a high encapsulation efficiency,and then the chlorophyll-loaded nanoparticles are incorporated into calcite crystals grown from a gel media containing the nanoparticles.Under the protection of shellac nanoparticles and calcite crystals,chlorophyll shows excellent stability even under light.Encapsulated chlorophyll could only be released by first dissolving the calcite crystals under acidic condition and then dissolving the shellac nanoparticles under alkaline condition.The unique pHtriggered release mimics the pH change from acidic in the stomach to alkaline in the intestine and is thus well suited for controlled,targeted intestinal release.This work suggests that the crystal composites are an ideal delivery vehicle for the functional design of bioactive molecules.
基金the Youth Founds of the State Key Laboratory of Fluid Power and Mechatronic Systems(Zhejiang University)“Thousand Talents Program” for Distinguished Young Scholars+2 种基金C.-X.Zhao acknowledges financial support from Australian Research Council through the award of a 2014 ARC Future Fellowship(No.FT140100726)supported by the National Science Foundation of U.S.A.(No.DMR-1310266)the Harvard Materials Research Science and Engineering Center(No.DMR-1420570)
文摘Biocompatible microcapsules with a water core are widely used to encapsulate hydrophilic actives.Here,a facile method to fabricate monodisperse biocompatible microcapsules with a water core in large quantity is reported.Microfluidic technology is utilized to emulsify the inner aqueous phase containing the shell polymer into monodisperse drops in the outer oil phase.As the cosolvent in the inner aqueous phase diffuses into the outer oil phase,the solubility of the shell polymer decreases,which eventually precipitates.Since the shell polymer,shellac,contains both hydrophilic and hydrophobic groups,it tends to wet both the inner aqueous phase and the outer oil phase,thus forming a solid shell at the periphery of the drop.We show that the diffusion rate of hydrophilic molecules encapsulated in the water core decreases as their molecular weight increases and the property of the microcapsules could further be modified by polyelectrolyte multilayer coating.These microcapsules are fabricated using FDA-approved polymer and non-toxic solvents and are of great use in drugs,cosmetics and foods.
基金supported by the National Natural Science Foundation of China(NSFC)(32271285 and 31872720)R&D Program of Beijing Municipal Education Commission(KZ202210028043)+5 种基金supported by NSFC(32071277)Natural Science Foundation of Hebei province(C2021201012)S&T Program of Hebei(216Z2602G)Interdisciplinary Research Program of Natural Science of Hebei University(DXK202006)supported by Beijing National Laboratory for Molecular Sciences(BNLMS202108)the Chinese Academy of Sciences Pioneer Hundred Talents Program.W.Q.is supported by NSFC(32088101).
文摘N6-methyladenosine(m^(6)A)is the most prevalent internal RNA modification,and its regulators include writers,readers and erasers.m^(6)A is under stringent control and takes part in many biological events,but it is not known whether there is an interplay between m^(6)A and glycosylation.Here we investigated an m^(6)A reader,YTHDC1,which has been shown to be recruited to the DNA-RNA hybrid at DNA damage sites and regulate homologous recombination(HR)during DNA damage repair.We found that YTHDC1 is subject to O-linked𝛽-N-acetylglucosamine(O-GlcNAc)modification at Ser396 upon DNA damage,which is pivotal for YTHDC1 chromatin binding and ionization radiation induced focus(IRIF)formation.RNA immunoprecipitation(RIP)and molecular dynamics(MD)simulations indicate that O-GlcNAcylation is vital for YTHDC1 to bind with m^(6)A RNA.Fluorescence recovery after photo bleaching(FRAP)analysis revealed that YTHDC1 O-GlcNAcylation is essential for DNA damage-induced YTHDC1-m^(6)A condensate formation.We further demonstrate that YTHDC1 O-GlcNAcylation promotes HR-mediated DNA damage repair and cell survival,probably through recruitment of Rad51 to the damage sites.We propose that YTHDC1 O-GlcNAcylation is instrumental for HR.
基金Supported by the National Key Research and Development Program of China(2022YFC2807203 and 2022YFC3702001-03)Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0105)+1 种基金National Natural Science Foundation of China(41830968)Planning Project of Institute of Atmospheric Physics,Chinese Academy of Sciences(E268091801).
文摘Under Arctic warming,near-surface energy transfers have significantly changed,but few studies have focused on energy exchange over Arctic glacier due to limitations in available observations.In this study,the atmospheric energy exchange processes over the Arctic glacier surface were analyzed by using observational data obtained in summer 2019 in comparison with those over the Arctic tundra surface.The energy budget over the glacier greatly differed from that over the tundra,characterized by less net shortwave radiation and downward sensible heat flux,due to the high albedo and icy surface.Most of the incoming solar radiation was injected into the glacier in summer,leading to snow ice melting.During the observation period,strong daily variations in near-surface heat transfer occurred over the Arctic glacier,with the maximum downward and upward heat fluxes occurring on 2 and 6 July 2019,respectively.Further analyses suggested that the maximum downward heat flux is mainly caused by the strong local thermal contrast above the glacier surface,while the maximum upward heat transfer cannot be explained by the classical turbulent heat transfer theory,possibly caused by countergradient heat transfer.Our results indicated that the near-surface energy exchange processes over Arctic glacier may be strongly related to local forcings,but a more in-depth investigation will be needed in the future when more observational data become available.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19070401)Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0105)+1 种基金National Natural Science Foundation of China(41830968)CAS Key Subordinate Projects(KGFZD-135-16-023 and KFZD-SW-426)。
文摘Studies on the atmospheric structure over the Antarctic Plateau are important for better understanding the weather and climate systems of polar regions.In the summer of 2017,an observational experiment was conducted at Dome-A,the highest station in Antarctica,with a total of 32 profiles obtained from global positioning system(GPS)radiosondes.Based on observational data,the atmospheric temperature,humidity,and wind structures and their variations are investigated,and compared with those from four other stations inside the Antarctic circle.Distinguished thermal and dynamic structures were revealed over Dome-A,characterized by the lowest temperature,the highest tropopause,the largest lapse rate,and the most frequent temperature and humidity inversion.During the experiment,a prominent blocking event was identified,with great influence on the atmospheric structure over Dome-A.The blocking high produced a strong anticyclone that brought warm and moist air to the hinterland of the Antarctic Plateau,causing a much warmer,wetter,and windier troposphere over the Dome-A station.Meanwhile,a polar air mass was forced out of the Antarctic,formed a cold surge extending as far as southern New Zealand and affected the weather there.Our results proved that there would be a direct interaction between the atmosphere over the hinterland of the Antarctic Plateau and mid latitudes with the action of a blocking high.Further studies are needed to explore the interaction between the atmospheric systems over the Antarctic and mid latitudes under intense synoptic disturbance,with longterm data and numerical modeling.
