The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),...The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),stereo microscopy and scanning electron microscopy(SEM). The characteristics of the carbonate-free fraction of the sediments were obtained, and related influential factors were discussed. The results show that the mean grain size of this fraction is in 1.96Φ–8.19Φ, with poorly sorting and unimodal, bimodal or irregular bimodal distribution patterns. Four grain size end members of the fraction are derived with the End Member Model method. The finest end member EM1 shows a significant contribution of terrigenous materials of the aeolian input and sediment carried by the bottom current. End member EM2 with medium size mainly reflects sediment of a siliceous bioclast origin. EM3 and EM4 are interpreted as representing the coarser volcanic materials related to bedrock weathering or volcanic activities. Multi-provenance is the dominant factor controlling the grain size pattern of the carbonate-free fraction of the sediments in that area. In addition, sediment transport processes such as the bottom current and wind are the minor factors that influence the grain size distribution of the carbonate-free fraction sediments.展开更多
Particle size is an important characteristic of suspended matter,and it contains crucial information about the deposition process.Suspended particle samples in the water mixing zone of the Changjiang River Estuary wer...Particle size is an important characteristic of suspended matter,and it contains crucial information about the deposition process.Suspended particle samples in the water mixing zone of the Changjiang River Estuary were collected in December 2016.Untreated original grain size and the decentralized grain size of the suspended particles were measured via a laser particle size analyzer.Morphological characteristics and the chemical composition of the suspended particles were also studied systematically using a scanning electron microscope(SEM)with an energy dispersive X-ray spectrometer(EDS).Then,the flocculation and sedimentation of suspended matter in the water mixing zone were explored by combining them with the water mixing processes in the estuary.The average particle size of suspended matter in the mixing zone of the Changjiang River Estuary ranges fromФ5.73 toФ7.98.The particle size distribution pattern is an abnormal model with a mainly unimodal pattern.In the freshwater area that was dominated by runoff,the suspended matter is mainly composed of fine particles,the settling velocity is slow,and the flocculation is weak.Floc particles were often seen in the mixing zone,with the flocs having a relatively large particle size,a low density and a loose structure appearing at the weak mixing zone;the flocs had a compacted structure in most areas of the mixing zone.The changes of suspended particle size in the estuarine mixing zone promote the settling and deposition of suspended matter,which has an important influence on the bed geomorphology and preservation of the fine suspended particles in the estuary.展开更多
Chronic diabetic wounds present significant treatment challenges due to their complex microenvironment,often leading to subopti-mal healing outcomes.Hydrogen sulfide(H_(2)S),a crucial gaseous signaling molecule,has sh...Chronic diabetic wounds present significant treatment challenges due to their complex microenvironment,often leading to subopti-mal healing outcomes.Hydrogen sulfide(H_(2)S),a crucial gaseous signaling molecule,has shown great potential in modulating in-flammation,oxidative stress and extracellular matrix remodeling,which are essential for effective wound healing.However,con-ventional H_(2)S delivery systems lack the adaptability required to meet the dynamic demands of different healing stages,thereby limiting their therapeutic efficacy.To address this,we developed an injectable,ROS-responsive H_(2)S donor system integrated within a gelatin methacryloyl(GelMA)hydrogel matrix,forming a double-network hydrogel(GelMA-ODex@RRHD).The injectability of this hydrogel allows for minimally invasive application,con-forming closely to wound contours and ensuring uniform distribution.The incorporation of oxidatively modified dextran derivatives(ODex)not only preserves biocompatibility but also enables the chemical attachment of ROS-responsive H_(2)S donors.The GelMA-ODex@RRHD hydrogel releases H_(2)S in response to oxidative stress,optimizing the environment for cell growth,modulating macro-phage polarization and supporting vascular regeneration.This innovative material effectively suppresses inflammation during the initial phase,promotes tissue regeneration in the proliferative phase and facilitates controlled matrix remodeling in later stages,ulti-mately enhancing wound closure and functional recovery.The H_(2)S released by GelMA-ODex@RRHD not only expedited the process of wound healing but also improved the biomechanical characteristics of newborn skin in diabetic mice,particularly in terms of stiff-ness and elasticity.This enhancement resulted in the skin quality being more similar to normal skin during the wound healing pro-cess.By aligning therapeutic delivery with the natural healing process,this approach offers a promising pathway toward more effec-tive and personalized treatments for chronic diabetic wounds.展开更多
Background:Wound healing is a sophisticated biological process characterized by the orchestrated interplay of diverse cellular components,growth factors,and signaling cascades.Recent research has highlighted the pivot...Background:Wound healing is a sophisticated biological process characterized by the orchestrated interplay of diverse cellular components,growth factors,and signaling cascades.Recent research has highlighted the pivotal role of fibroblast exosomes in mediating intercellular communication and facilitating tissue regeneration.This investigation aimed to elucidate the therapeutic efficacy of fibroblast exosomes in enhancing wound repair mechanisms,with a particular emphasis on their differential effects in normal and diabetic wound healing paradigms.Methods:A mouse full-thickness skin defect model was used to evaluate the effects of fibroblast exosomes on wound re-epithelialization,granulation tissue formation,and epidermal barrier function.Molecular and cellular experiments were conducted to analyze the roles of exosomes in epidermal stem cell proliferation,migration,differentiation,and antioxidant stress,with further validation of the associated signaling pathways.The therapeutic efficacy was additionally confirmed in a type 1 diabetic mouse model.Results:Fibroblast exosomes significantly enhanced wound re-epithelialization by promoting the proliferation,migration,and differentiation of epidermal stem cells.Additionally,exosomes increased fibroblast abundance and myofibroblast activation,facilitating granulation tissue formation as well as improving extracellular matrix(ECM)deposition and the biomechanical properties of healed skin.Furthermore,exosomes improved epidermal barrier function by upregulating tight junction proteins(e.g.Claudin-1 and ZO-1)and reducing transepidermal water loss(TEWL).In diabetic mouse models,exosomes accelerated wound closure,restored ECM deposition and biomechanical integrity,and repaired epidermal barrier function.Mechanistically,exosomes target the 3'untranslated region(UTR)of Keap1 mRNA through miR-29a-3p and activate the KEAP1/Nrf2 antioxidant pathway,mitigating oxidative stress and protecting epidermal stem cells from reactive oxygen species(ROS)-induced damage.Conclusion:Fibroblast exosomes alleviate oxidative damage by modulating the KEAP1/Nrf2 pathway through miR-29a-3p and enhancing epidermal stem cell function.These exosomes exhibit remarkable therapeutic potential in accelerating wound healing and improving healing quality under both normal and diabetic conditions,offering a robust foundation for innovative therapeutic strategies.展开更多
Suspended particle samples collected in the water column at 7 stations in the hydrothermal vent area in the Southwest Indian Ridge were studied by electronic scanning microscope(SEM)and energy dispersive X-ray spectro...Suspended particle samples collected in the water column at 7 stations in the hydrothermal vent area in the Southwest Indian Ridge were studied by electronic scanning microscope(SEM)and energy dispersive X-ray spectrometry(EDX).A method of zinc sulfide(ZnS)mineral phase identification by SEM and EDX data was proposed,and related adequacy and limitation of the method were presented.29 ZnS particles with various morphologies were found.27 sphalerite particles and two wurtzite particles were distinguished by joint consideration of their morphology and chemical element composition.Two types of sphalerite particles with different dissolving intensities were differentiated,which may be depended on the duration of the particles existence in the water column.More than half of the total sphalerite particles include 12high Fe-containing particles(Fe[10 wt%)were found at the Station 21VII-CTD7,suggesting a close link to the adjacent active hydrothermal vent.Sphalerite particles at Station 2VI-CTD3 contained only one Fe-containing particle and their amount ranked second among that at all the survey stations,suggesting a good correspondence to the adjacent inactive hydrothermal vent.Only six non-iron ZnS particles were found at the rest eastern 5 stations,suggesting a weak influence of hydrothermal activities in the eastern area.展开更多
基金China Ocean Mineral Resources Research and Development under contract No.DY125-11-R-04the National Natural Science Foundation of China under contract No.41676036
文摘The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),stereo microscopy and scanning electron microscopy(SEM). The characteristics of the carbonate-free fraction of the sediments were obtained, and related influential factors were discussed. The results show that the mean grain size of this fraction is in 1.96Φ–8.19Φ, with poorly sorting and unimodal, bimodal or irregular bimodal distribution patterns. Four grain size end members of the fraction are derived with the End Member Model method. The finest end member EM1 shows a significant contribution of terrigenous materials of the aeolian input and sediment carried by the bottom current. End member EM2 with medium size mainly reflects sediment of a siliceous bioclast origin. EM3 and EM4 are interpreted as representing the coarser volcanic materials related to bedrock weathering or volcanic activities. Multi-provenance is the dominant factor controlling the grain size pattern of the carbonate-free fraction of the sediments in that area. In addition, sediment transport processes such as the bottom current and wind are the minor factors that influence the grain size distribution of the carbonate-free fraction sediments.
基金The National Natural Science Foundation of China under contract No.42176077。
文摘Particle size is an important characteristic of suspended matter,and it contains crucial information about the deposition process.Suspended particle samples in the water mixing zone of the Changjiang River Estuary were collected in December 2016.Untreated original grain size and the decentralized grain size of the suspended particles were measured via a laser particle size analyzer.Morphological characteristics and the chemical composition of the suspended particles were also studied systematically using a scanning electron microscope(SEM)with an energy dispersive X-ray spectrometer(EDS).Then,the flocculation and sedimentation of suspended matter in the water mixing zone were explored by combining them with the water mixing processes in the estuary.The average particle size of suspended matter in the mixing zone of the Changjiang River Estuary ranges fromФ5.73 toФ7.98.The particle size distribution pattern is an abnormal model with a mainly unimodal pattern.In the freshwater area that was dominated by runoff,the suspended matter is mainly composed of fine particles,the settling velocity is slow,and the flocculation is weak.Floc particles were often seen in the mixing zone,with the flocs having a relatively large particle size,a low density and a loose structure appearing at the weak mixing zone;the flocs had a compacted structure in most areas of the mixing zone.The changes of suspended particle size in the estuarine mixing zone promote the settling and deposition of suspended matter,which has an important influence on the bed geomorphology and preservation of the fine suspended particles in the estuary.
基金supported by the National Natural Science Foundation of China(92168106,82222039)the Natural Science Foundation of Chongqing,China(2024NSCQ-JQX0156).
文摘Chronic diabetic wounds present significant treatment challenges due to their complex microenvironment,often leading to subopti-mal healing outcomes.Hydrogen sulfide(H_(2)S),a crucial gaseous signaling molecule,has shown great potential in modulating in-flammation,oxidative stress and extracellular matrix remodeling,which are essential for effective wound healing.However,con-ventional H_(2)S delivery systems lack the adaptability required to meet the dynamic demands of different healing stages,thereby limiting their therapeutic efficacy.To address this,we developed an injectable,ROS-responsive H_(2)S donor system integrated within a gelatin methacryloyl(GelMA)hydrogel matrix,forming a double-network hydrogel(GelMA-ODex@RRHD).The injectability of this hydrogel allows for minimally invasive application,con-forming closely to wound contours and ensuring uniform distribution.The incorporation of oxidatively modified dextran derivatives(ODex)not only preserves biocompatibility but also enables the chemical attachment of ROS-responsive H_(2)S donors.The GelMA-ODex@RRHD hydrogel releases H_(2)S in response to oxidative stress,optimizing the environment for cell growth,modulating macro-phage polarization and supporting vascular regeneration.This innovative material effectively suppresses inflammation during the initial phase,promotes tissue regeneration in the proliferative phase and facilitates controlled matrix remodeling in later stages,ulti-mately enhancing wound closure and functional recovery.The H_(2)S released by GelMA-ODex@RRHD not only expedited the process of wound healing but also improved the biomechanical characteristics of newborn skin in diabetic mice,particularly in terms of stiff-ness and elasticity.This enhancement resulted in the skin quality being more similar to normal skin during the wound healing pro-cess.By aligning therapeutic delivery with the natural healing process,this approach offers a promising pathway toward more effec-tive and personalized treatments for chronic diabetic wounds.
基金supported by grants from the National Natural Sciences Foundation of China(No.81630055 and No.81920108022 to GXL,No.82172232,No.31872742 and No.82472568 to WFH)the Military Medical Science and Technology Youth Training Program of the Army Military Medical University(Third Military Medical University)(No.20QNPY024 to WFH)the Special Project for Enhancing Science and Technology Innovation Ability(frontier exploration)of the Army Military Medical University(Third Military Medical University)(No.2019XQY12 to WFH).
文摘Background:Wound healing is a sophisticated biological process characterized by the orchestrated interplay of diverse cellular components,growth factors,and signaling cascades.Recent research has highlighted the pivotal role of fibroblast exosomes in mediating intercellular communication and facilitating tissue regeneration.This investigation aimed to elucidate the therapeutic efficacy of fibroblast exosomes in enhancing wound repair mechanisms,with a particular emphasis on their differential effects in normal and diabetic wound healing paradigms.Methods:A mouse full-thickness skin defect model was used to evaluate the effects of fibroblast exosomes on wound re-epithelialization,granulation tissue formation,and epidermal barrier function.Molecular and cellular experiments were conducted to analyze the roles of exosomes in epidermal stem cell proliferation,migration,differentiation,and antioxidant stress,with further validation of the associated signaling pathways.The therapeutic efficacy was additionally confirmed in a type 1 diabetic mouse model.Results:Fibroblast exosomes significantly enhanced wound re-epithelialization by promoting the proliferation,migration,and differentiation of epidermal stem cells.Additionally,exosomes increased fibroblast abundance and myofibroblast activation,facilitating granulation tissue formation as well as improving extracellular matrix(ECM)deposition and the biomechanical properties of healed skin.Furthermore,exosomes improved epidermal barrier function by upregulating tight junction proteins(e.g.Claudin-1 and ZO-1)and reducing transepidermal water loss(TEWL).In diabetic mouse models,exosomes accelerated wound closure,restored ECM deposition and biomechanical integrity,and repaired epidermal barrier function.Mechanistically,exosomes target the 3'untranslated region(UTR)of Keap1 mRNA through miR-29a-3p and activate the KEAP1/Nrf2 antioxidant pathway,mitigating oxidative stress and protecting epidermal stem cells from reactive oxygen species(ROS)-induced damage.Conclusion:Fibroblast exosomes alleviate oxidative damage by modulating the KEAP1/Nrf2 pathway through miR-29a-3p and enhancing epidermal stem cell function.These exosomes exhibit remarkable therapeutic potential in accelerating wound healing and improving healing quality under both normal and diabetic conditions,offering a robust foundation for innovative therapeutic strategies.
基金supported by the Projects of China Ocean Mineral Resources Research and Development(DYXM-11502-1-13 and DY125-11-R-01-04)
文摘Suspended particle samples collected in the water column at 7 stations in the hydrothermal vent area in the Southwest Indian Ridge were studied by electronic scanning microscope(SEM)and energy dispersive X-ray spectrometry(EDX).A method of zinc sulfide(ZnS)mineral phase identification by SEM and EDX data was proposed,and related adequacy and limitation of the method were presented.29 ZnS particles with various morphologies were found.27 sphalerite particles and two wurtzite particles were distinguished by joint consideration of their morphology and chemical element composition.Two types of sphalerite particles with different dissolving intensities were differentiated,which may be depended on the duration of the particles existence in the water column.More than half of the total sphalerite particles include 12high Fe-containing particles(Fe[10 wt%)were found at the Station 21VII-CTD7,suggesting a close link to the adjacent active hydrothermal vent.Sphalerite particles at Station 2VI-CTD3 contained only one Fe-containing particle and their amount ranked second among that at all the survey stations,suggesting a good correspondence to the adjacent inactive hydrothermal vent.Only six non-iron ZnS particles were found at the rest eastern 5 stations,suggesting a weak influence of hydrothermal activities in the eastern area.
