Distributed implantation of a flexible microelectrode array for neural recording

Flexible multichannel electrode arrays(fMEAs)with multiple flaments can be flexibly implanted in various patterns.It is necessary to develop a method for implanting the fMEA in different locations and at various depths based on the recording demands.This study proposed a strategy for reducing the microelectrode volume with integrated packaging.An implantation system was developed specifically for semiautomatic distributed implantation.The feasibility and convenience of the fMEA and implantation platform were verified in rodents.The acute and chronic recording results provied the effectiveness of the packaging and implantation methods.These methods could provide a novel strategy for developing fMEAs with more flaments and recording sites to measure functional interactions across multiple brain regions.

Recent greening of grasslands in northern China driven by increasing precipitation

Aims Recent warmer and wetter climate in northern China remains a hot topic in recent years,yet its effect on vegetation growth has not been fully understood.This study investigated the temporal change of vegetation cover and its correlations with climatic variables from 1982 to 2018 for grasslands in northern China.Our aim is to clarify whether the warmer and wetter climate in recent years drives the greening of the vegetation in this region.Methods We investigated the temporal dynamic of vegetation normalized difference vegetation index(NDVI)and its driving forces based on long time-series data.Piecewise regression was used to examine whether there was a turning point of the trend of NDVI and climatic variables.Pearson correlation analyses were conducted to quantify the relationship between NDVI and climatic factors.Stepwise multivariable regression was used to quantify the contributions of climate variables to the temporal variations in NDVI.Important Findings We found a turning point of NDVI trend in 2008,with GIMMS NDVI indicating a slight increase of 0.00022 yr?1 during 1982–2008 to an increase of 0.002 yr?1 for GIMMS NDVI during 2008–2015 and 0.0018 yr?1 for MODIS NDVI during 2008–2018.Precipitation was the predominant driver,and air temperature and vapor pressure deficit exerted a minor impact on the temporal dynamics of NDVI.Overall,our results suggest a turning point of NDVI trend,and that recent warmer and wetter climate has caused vegetation greening,which provides insights for better predicting the vegetation cover in this region under changing climate.

IOLMaster500测量2~6岁儿童眼轴长度的重复性和再现性

目的:评估不同操作者使用光学相干生物测量仪IOLMaster500测量2~6岁儿童眼轴长度的重复性和再现性。方法:横断面研究。共纳入2016年12月至2017年3月在温州医科大学附属眼视光医院杭州院区视光门诊部就诊的102名(102只右眼)2~6岁儿童,先由一名操作者连续测得3组有效眼轴长度数据,随即换另一名操作者重复测量操作再获得3组有效眼轴长度数据。采用重复测量方差分析、Bland-Altman分析和组内相关系数(ICC)计算相关数据;2位操作者的测量结果采用不同分析方法(3次测量数据的均值,第1次测量数据);其中2组单次测量数据、均值各自进行配对t检验、Bland-Altman分析,计算组内标准差(Sw)、2.77Sw和组内变异系数(CoV)。结果:同一测量者的重复测量方差分析P值均大于0.05,差异无统计学意义,并均具有很窄的95%一致性界限(LoA)(均小于-0.04至0.04mm),ICC为1.000。不同测量者的配对t检验P值均大于0.05,差异无统计学意义,并均具有很窄的95%LoA(均小于-0.04至0.03mm),且均值法的95%LoA比单次测量法窄42.86%,两者Sw、2.77Sw数据均分别小于0.01mm和0.03mm,CoV均小于0.05%。结论:同一操作者对IOLMaster500测量2~6岁儿童眼轴长度具有良好的重复性,不同操作者测量同一患者具有良好的再现性。此外,每位操作者连续测量3次的平均值比各测1次的值具有更好的再现性。