The response to the catchment changes of the sedimentary environment of the western intertidal flat of Yalu River Estuary was investigated by analyzing the vertical variations of the grain size of sediment cores,along...The response to the catchment changes of the sedimentary environment of the western intertidal flat of Yalu River Estuary was investigated by analyzing the vertical variations of the grain size of sediment cores,along with the hydrologic data and human activities in the catchment.The results demonstrated a stepwise decreasing trend for the variations of both the sediment load and water discharge into the sea,which could be divided into three stages as 1958–1970,1971–1990 and 1991–2009.Reservoir construction and the changes of catchment vegetation coverage turned out to be the two predominant contributors to the changes.There are four periods for the variation of the sensitive components of the sediment cores from 1940 to 2010,i.e.,1940–1950,1951–1980,1981–1990 and 1991–2010.The vertical distribution of grain size in the cores mainly varied with the changes of vegetation coverage in the catchment and reservoir construction from 1960 to 1980,whereas it varied depending on the intensity of water and soil erosion in the catchment from 1980 to 1990.Despite the further reduction of the water and sediment input into the sea from 1990 to 2009,this period was characterized by coarsening trends for the grain size of sediment in the estuarine intertidal flat and correspondingly,the significantly increased silt contents of the sensitive component.展开更多
Intracortical microelectrodes are used for recording activity from individual neurons,providing both a valuable neuroscience tool and an enabling medical technology for individuals with motor disabilities.Standard neu...Intracortical microelectrodes are used for recording activity from individual neurons,providing both a valuable neuroscience tool and an enabling medical technology for individuals with motor disabilities.Standard neural probes carrying the microelectrodes are rigid silicon-based structures that can penetrate the brain parenchyma to interface with the targeted neurons.Unfortunately,within weeks after implantation,neural recording quality from microelectrodes degrades,owing largely to a neuroinflammatory response.Key contributors to the neuroinflammatory response include mechanical mismatch at the device-tissue interface and oxidative stress.We developed a mechanically-adaptive,resveratrol-eluting(MARE)neural probe to mitigate both mechanical mismatch and oxidative stress and thereby promote improved neural recording quality and longevity.In this work,we demonstrate that compared to rigid silicon controls,highly-flexible MARE probes exhibit improved recording performance,more stable impedance,and a healing tissue response.With further optimization,MARE probes can serve as long-term,robust neural probes for brain-machine interface applications.展开更多
To understand the complex dynamics of neural activity in the brain across various temporal and spatial scales,it is crucial to record intracortical multimodal neural activity by combining electrophysiological recordin...To understand the complex dynamics of neural activity in the brain across various temporal and spatial scales,it is crucial to record intracortical multimodal neural activity by combining electrophysiological recording and calcium imaging techniques.This poses significant constraints on the geometrical,mechanical,and optical properties of the electrodes.Here,transparent flexible graphene–ITO-based neural microelectrodes with small feature sizes are developed and validated for simultaneous electrophysiology recording and calcium imaging in the hippocampus of freely moving mice.A micro-etching technique and an oxygen plasma pre-treating method are introduced to facilitate large-area graphene transfer and establish stable low-impedance contacts between graphene and metals,leading to the batch production of high-quality microelectrodes with interconnect widths of 10μm and recording sites diameters of 20μm.These electrodes exhibit appropriate impedance and sufficient transparency in the field of view,enabling simultaneous recording of intracortical local field potentials and even action potentials along with calcium imaging in freely moving mice.Both types of electrophysiological signals are found to correlate with calcium activity.This proof-of-concept work demonstrates that transparent flexible graphene–ITO-based neural microelectrodes are promising tools for multimodal neuroscience research.展开更多
Brain activity is highly structured within local microcircuits and brain-wide networks,involving exquisite coordination across multiple brain regions in both superficial and deep structures^([1]).To understand how bra...Brain activity is highly structured within local microcircuits and brain-wide networks,involving exquisite coordination across multiple brain regions in both superficial and deep structures^([1]).To understand how brain represents,transforms and communicates in-展开更多
基金The National Natural Science Foundation of China under contract Nos 41576043 and 40976051
文摘The response to the catchment changes of the sedimentary environment of the western intertidal flat of Yalu River Estuary was investigated by analyzing the vertical variations of the grain size of sediment cores,along with the hydrologic data and human activities in the catchment.The results demonstrated a stepwise decreasing trend for the variations of both the sediment load and water discharge into the sea,which could be divided into three stages as 1958–1970,1971–1990 and 1991–2009.Reservoir construction and the changes of catchment vegetation coverage turned out to be the two predominant contributors to the changes.There are four periods for the variation of the sensitive components of the sediment cores from 1940 to 2010,i.e.,1940–1950,1951–1980,1981–1990 and 1991–2010.The vertical distribution of grain size in the cores mainly varied with the changes of vegetation coverage in the catchment and reservoir construction from 1960 to 1980,whereas it varied depending on the intensity of water and soil erosion in the catchment from 1980 to 1990.Despite the further reduction of the water and sediment input into the sea from 1990 to 2009,this period was characterized by coarsening trends for the grain size of sediment in the estuarine intertidal flat and correspondingly,the significantly increased silt contents of the sensitive component.
基金funded by Merit Review Award#I01RX003083(A.H.-D./J.R.C.)and a Research Career Scientist Award Grant#12635707(J.R.C.)from the United States Department of Veterans Affairs Rehabilitation Research and Development Servicesupport was provided in a pre-doctoral fellowship to N.N.M.from the Department of Defense National Defense Science and Engineering Fellowship Program。
文摘Intracortical microelectrodes are used for recording activity from individual neurons,providing both a valuable neuroscience tool and an enabling medical technology for individuals with motor disabilities.Standard neural probes carrying the microelectrodes are rigid silicon-based structures that can penetrate the brain parenchyma to interface with the targeted neurons.Unfortunately,within weeks after implantation,neural recording quality from microelectrodes degrades,owing largely to a neuroinflammatory response.Key contributors to the neuroinflammatory response include mechanical mismatch at the device-tissue interface and oxidative stress.We developed a mechanically-adaptive,resveratrol-eluting(MARE)neural probe to mitigate both mechanical mismatch and oxidative stress and thereby promote improved neural recording quality and longevity.In this work,we demonstrate that compared to rigid silicon controls,highly-flexible MARE probes exhibit improved recording performance,more stable impedance,and a healing tissue response.With further optimization,MARE probes can serve as long-term,robust neural probes for brain-machine interface applications.
基金support of the National Key R&D Program of China(2022YFF1202303 and 2023YFF1203702)NSFC-Guangdong Joint Fund(U20A6005)+2 种基金the National Natural Science Foundation of China(62071447)STI2030-Major Projects(2021ZD0200100)the Science and Technology Innovation Committee of Shenzhen Municipality(JCYJ20220818101611024).
文摘To understand the complex dynamics of neural activity in the brain across various temporal and spatial scales,it is crucial to record intracortical multimodal neural activity by combining electrophysiological recording and calcium imaging techniques.This poses significant constraints on the geometrical,mechanical,and optical properties of the electrodes.Here,transparent flexible graphene–ITO-based neural microelectrodes with small feature sizes are developed and validated for simultaneous electrophysiology recording and calcium imaging in the hippocampus of freely moving mice.A micro-etching technique and an oxygen plasma pre-treating method are introduced to facilitate large-area graphene transfer and establish stable low-impedance contacts between graphene and metals,leading to the batch production of high-quality microelectrodes with interconnect widths of 10μm and recording sites diameters of 20μm.These electrodes exhibit appropriate impedance and sufficient transparency in the field of view,enabling simultaneous recording of intracortical local field potentials and even action potentials along with calcium imaging in freely moving mice.Both types of electrophysiological signals are found to correlate with calcium activity.This proof-of-concept work demonstrates that transparent flexible graphene–ITO-based neural microelectrodes are promising tools for multimodal neuroscience research.
文摘Brain activity is highly structured within local microcircuits and brain-wide networks,involving exquisite coordination across multiple brain regions in both superficial and deep structures^([1]).To understand how brain represents,transforms and communicates in-
