噪声的包络调制检测(Detection of Envelope Modulation on Noise,DEMON)谱分析技术已被广泛应用于特征提取领域,但经典DEMON谱提取中高频信号频段的选取会影响DEMON谱的提取效果。针对这一问题,文中首先运用经验模态分解(Empirical Mod...噪声的包络调制检测(Detection of Envelope Modulation on Noise,DEMON)谱分析技术已被广泛应用于特征提取领域,但经典DEMON谱提取中高频信号频段的选取会影响DEMON谱的提取效果。针对这一问题,文中首先运用经验模态分解(Empirical Mode Decomposition,EMD)方法获得一系列固有模态函数(Intrinsic Mode Function,IMF),依据各阶模态函数与原信号的相关程度,筛选出更具代表性的几阶固有模态函数进行解调,再对解调的结果运用11/2维谱分析方法进行谱分析以抑制高斯噪声,通过这种方法获得的DEMON谱信噪比优于传统方法。实测湖试数据分析结果表明,该改进方法可以有效地进行特征提取,结果优于经典DEMON谱分析方法;该改进方法具有一定的实用性,有利于进行后续目标分类识别。展开更多
The present work aims to determine the geological structure, to highlight and to determine the characteristics of the fault system responsible for the current structure of the study area through the interpretation of ...The present work aims to determine the geological structure, to highlight and to determine the characteristics of the fault system responsible for the current structure of the study area through the interpretation of available aeromagnetic data. Total magnetic intensity anomaly (TMI) was critically interpreted using several analysis techniques including Reduction to Equator (RTE), First Vertical Derivative, upward continuation, spectral analysis and 2D3/4 modelling. All results obtained from the interpretation process were combined together to draw an interpretative geological map of the area and allow the general view of the surface and sub-surface structures. The interpretative geological map reveals that the geological formations of the studied area appear to be intensely fractured by an E-W, ENE-WSW and NE-SW main orientation fault system. The lineaments identified in the area study could be linked to the Pan-African orogeny and seem to correspond to deep-seated basement structures, which are referred to the tectonic boundary between Congo Craton and the Pan-African orogeny belt. According to spectral analysis results, the depths of the sources of superficial and deep magnetic anomalies are 2500 m and 12,000 m respectively. The 2D3/4 modelling of one magnetic profile plotted on the reduced residual map at the equator was performed to approximate the geometry and depth of the sources of magnetic anomalies, the model suggests the intrusion of a large body of high susceptibility during the continental collision. The results of this study can be used to better understand deep-seated basement structures and to support decisions with regard to the development of industrial areas, as well as of hydrogeological and/or mining investigations to be undertaken in the study area.展开更多
Synapses are essential units for the flow of information in the brain.Over the last 70 years,synapses have been widely studied in multiple animal models including worms,fruit flies,and rodents.In comparison,the study ...Synapses are essential units for the flow of information in the brain.Over the last 70 years,synapses have been widely studied in multiple animal models including worms,fruit flies,and rodents.In comparison,the study of human synapses has evolved significantly slower,mainly because of technical limitations.However,three novel methods allowing the analysis of molecular,morphological,and functional properties of human synapses may expand our knowledge of the human brain.Here,we briefly describe these methods,and evaluate how the information provided by each unique approach may contribute to the functional and anatomical analysis of the synaptic component of human brain circuitries.In particular,using tissue from cryopreserved human brains,synaptic plasticity can be studied in isolated synaptosomes by fluorescence analysis of single-synapse long-term potentiation（FASS-LTP）,and subpopulations of synapses can be thoroughly assessed in the ribbons of brain tissue by array tomography（AT）.Currently,it is also possible to quantify synaptic density in the living human brain by positron emission tomography（PET）,using a novel synaptic radio-ligand.Overall,data provided by FASS-LTP,AT,and PET may significantly contribute to the global understanding of synaptic structure and function in both healthy and diseased human brains,thus directly impacting translational research.展开更多
Aflatoxin B1(AFB1)is one of the most common mycotoxins that threatens human health.As singlestranded oligonucleotides with high affinity and specificity,aptamers have incomparable effect on the targeted detection of A...Aflatoxin B1(AFB1)is one of the most common mycotoxins that threatens human health.As singlestranded oligonucleotides with high affinity and specificity,aptamers have incomparable effect on the targeted detection of AFB1.Herein,after 11 rounds of selection and analysis using a modified affinity chromatography-based SELEX strategy,the truncated 37 nt aptamer AF11-2 was successfully obtained.The aptamer shows good detection performance for AFB1,and can sensitively detect AFB1 in the range of 100-1000 nmol/L,with a detection limit of 42 nmol/L.In the detection of pretreated edible peanut oil samples,AF11-2 aptamer also showed a high recovery rate and good stability for AFB1,and achieved satisfactory results.In addition,AF11-2 aptamer can significantly enhance the fluorescence ability of AFB1,which is not available in traditional Afla17-2-3 aptamer.After molecular docking analysis,it was found that AF11-2 and Afla17-2-3 had different nucleotide binding sites for AFB1.Afla17-2-3 binds to the carbonyl O of AFB1,while AF11-2 binds to the pyrrolic O of AFB1,which may be the main reason that AF11-2 can enhance the fluorescence of AFB1.展开更多
Six first row transition metal complexes with 1,6-bis（2′-pyridyl）-2,5-dithiahexane（Py;S;）, namely, MnPy;S;Cl;（1）, FePy;S;Cl;（2）, Co Py;S;Cl（3）, CoPy;S;（SCN）;（4）, NiPy;S;（SCN）;（5） and NiPy;S;（N;）;...Six first row transition metal complexes with 1,6-bis（2′-pyridyl）-2,5-dithiahexane（Py;S;）, namely, MnPy;S;Cl;（1）, FePy;S;Cl;（2）, Co Py;S;Cl（3）, CoPy;S;（SCN）;（4）, NiPy;S;（SCN）;（5） and NiPy;S;（N;）;（6）, have been synthesized. A mixture of MCl;·x H;O（M = Mn, Co） in MeOH（FeCl;·4H;O in MeCN） and the stoichiometric amount of Py;S;was stirred for 4 h at room temperature, then these aiming products 1, 2 and 3 could be obtained by purification. A mixture of MPy;S;Cl;（M = Co, Ni） in MeOH and two equivalents of KSCN or NaN;was stirred for 4 h at room temperature. After that, complexes 4, 5 and 6 could be got by purifying. For 1, 2, 3, 4 and 5, the metal centers are hexa-coordinated in a similar distorted octahedral geometry and the crystal structures have the same space group Pbcn. The crystal structure of compound 6 belongs to monoclinic with space group P21/c. The coordinated atoms around M（Ⅱ） are two pyridyl N atoms(N（1） and N（2）), two thioether S atoms(S（1） and S（2）) and two chloride ions(Cl（1） and Cl（2）) in compounds 1, 2, and 3, but in 4, 5, and 6, two chloride ions(Cl（1） and Cl（2）) are replaced by another two N atoms from N;or NCS;.展开更多
文摘噪声的包络调制检测(Detection of Envelope Modulation on Noise,DEMON)谱分析技术已被广泛应用于特征提取领域,但经典DEMON谱提取中高频信号频段的选取会影响DEMON谱的提取效果。针对这一问题,文中首先运用经验模态分解(Empirical Mode Decomposition,EMD)方法获得一系列固有模态函数(Intrinsic Mode Function,IMF),依据各阶模态函数与原信号的相关程度,筛选出更具代表性的几阶固有模态函数进行解调,再对解调的结果运用11/2维谱分析方法进行谱分析以抑制高斯噪声,通过这种方法获得的DEMON谱信噪比优于传统方法。实测湖试数据分析结果表明,该改进方法可以有效地进行特征提取,结果优于经典DEMON谱分析方法;该改进方法具有一定的实用性,有利于进行后续目标分类识别。
文摘The present work aims to determine the geological structure, to highlight and to determine the characteristics of the fault system responsible for the current structure of the study area through the interpretation of available aeromagnetic data. Total magnetic intensity anomaly (TMI) was critically interpreted using several analysis techniques including Reduction to Equator (RTE), First Vertical Derivative, upward continuation, spectral analysis and 2D3/4 modelling. All results obtained from the interpretation process were combined together to draw an interpretative geological map of the area and allow the general view of the surface and sub-surface structures. The interpretative geological map reveals that the geological formations of the studied area appear to be intensely fractured by an E-W, ENE-WSW and NE-SW main orientation fault system. The lineaments identified in the area study could be linked to the Pan-African orogeny and seem to correspond to deep-seated basement structures, which are referred to the tectonic boundary between Congo Craton and the Pan-African orogeny belt. According to spectral analysis results, the depths of the sources of superficial and deep magnetic anomalies are 2500 m and 12,000 m respectively. The 2D3/4 modelling of one magnetic profile plotted on the reduced residual map at the equator was performed to approximate the geometry and depth of the sources of magnetic anomalies, the model suggests the intrusion of a large body of high susceptibility during the continental collision. The results of this study can be used to better understand deep-seated basement structures and to support decisions with regard to the development of industrial areas, as well as of hydrogeological and/or mining investigations to be undertaken in the study area.
基金supported by National Institutes of Health Grants R21-AG048506,P01-AG000538 and RO1-AG34667(to CWC)UC MEXUS-CONACYT Grant CN-16-170(to GAP and CWC)
文摘Synapses are essential units for the flow of information in the brain.Over the last 70 years,synapses have been widely studied in multiple animal models including worms,fruit flies,and rodents.In comparison,the study of human synapses has evolved significantly slower,mainly because of technical limitations.However,three novel methods allowing the analysis of molecular,morphological,and functional properties of human synapses may expand our knowledge of the human brain.Here,we briefly describe these methods,and evaluate how the information provided by each unique approach may contribute to the functional and anatomical analysis of the synaptic component of human brain circuitries.In particular,using tissue from cryopreserved human brains,synaptic plasticity can be studied in isolated synaptosomes by fluorescence analysis of single-synapse long-term potentiation（FASS-LTP）,and subpopulations of synapses can be thoroughly assessed in the ribbons of brain tissue by array tomography（AT）.Currently,it is also possible to quantify synaptic density in the living human brain by positron emission tomography（PET）,using a novel synaptic radio-ligand.Overall,data provided by FASS-LTP,AT,and PET may significantly contribute to the global understanding of synaptic structure and function in both healthy and diseased human brains,thus directly impacting translational research.
基金supported by the National Natural Science Foundation of China(Nos.32071392,21775160 and 31900999)the Natural Science Foundation of Jiangsu Province(No.BE2020766)the Science Foundation of Jiangxi Province(No.20192ACB21033)。
文摘Aflatoxin B1(AFB1)is one of the most common mycotoxins that threatens human health.As singlestranded oligonucleotides with high affinity and specificity,aptamers have incomparable effect on the targeted detection of AFB1.Herein,after 11 rounds of selection and analysis using a modified affinity chromatography-based SELEX strategy,the truncated 37 nt aptamer AF11-2 was successfully obtained.The aptamer shows good detection performance for AFB1,and can sensitively detect AFB1 in the range of 100-1000 nmol/L,with a detection limit of 42 nmol/L.In the detection of pretreated edible peanut oil samples,AF11-2 aptamer also showed a high recovery rate and good stability for AFB1,and achieved satisfactory results.In addition,AF11-2 aptamer can significantly enhance the fluorescence ability of AFB1,which is not available in traditional Afla17-2-3 aptamer.After molecular docking analysis,it was found that AF11-2 and Afla17-2-3 had different nucleotide binding sites for AFB1.Afla17-2-3 binds to the carbonyl O of AFB1,while AF11-2 binds to the pyrrolic O of AFB1,which may be the main reason that AF11-2 can enhance the fluorescence of AFB1.
基金supported by the NNSFC(Nos.21231003 and 21203195)
文摘Six first row transition metal complexes with 1,6-bis（2′-pyridyl）-2,5-dithiahexane（Py;S;）, namely, MnPy;S;Cl;（1）, FePy;S;Cl;（2）, Co Py;S;Cl（3）, CoPy;S;（SCN）;（4）, NiPy;S;（SCN）;（5） and NiPy;S;（N;）;（6）, have been synthesized. A mixture of MCl;·x H;O（M = Mn, Co） in MeOH（FeCl;·4H;O in MeCN） and the stoichiometric amount of Py;S;was stirred for 4 h at room temperature, then these aiming products 1, 2 and 3 could be obtained by purification. A mixture of MPy;S;Cl;（M = Co, Ni） in MeOH and two equivalents of KSCN or NaN;was stirred for 4 h at room temperature. After that, complexes 4, 5 and 6 could be got by purifying. For 1, 2, 3, 4 and 5, the metal centers are hexa-coordinated in a similar distorted octahedral geometry and the crystal structures have the same space group Pbcn. The crystal structure of compound 6 belongs to monoclinic with space group P21/c. The coordinated atoms around M（Ⅱ） are two pyridyl N atoms(N（1） and N（2）), two thioether S atoms(S（1） and S（2）) and two chloride ions(Cl（1） and Cl（2）) in compounds 1, 2, and 3, but in 4, 5, and 6, two chloride ions(Cl（1） and Cl（2）) are replaced by another two N atoms from N;or NCS;.
