Based on the model of a formal neuron proposed by McCulloch and Pitts,a kind ofneural circuit,which is a CMOS Variable Threshold Logic(VTL)circuit,is given in this paperconsidering the features of the binary image pro...Based on the model of a formal neuron proposed by McCulloch and Pitts,a kind ofneural circuit,which is a CMOS Variable Threshold Logic(VTL)circuit,is given in this paperconsidering the features of the binary image processing system.The theoretical analysis,andthe simulations for the building block circuits such as D/A converters,comparator and so on aregiven.The layout design of the whole circuit are also given.The binary image processing can berealized by using the VTL circuit combined with its external auxiliary circuits.展开更多
To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip...To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip was designed based on the specific structure of neurons and the requirements for detection and modulation.Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software,and the simulation results show that the liquid within the chip can flow smoothly,ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels.By employing MEMS technology in combination with nanomaterial modification techniques,the microfluidic microelectrode array chip was fabricated successfully.Primary hippocampal neurons were cultured on the chip,forming a well-defined neural network.Spontaneous electrical activity of the detected neurons was recorded,exhibiting a 23.7%increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array.This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro,potentially serving as a novel tool in neuroscience research.展开更多
1 INTRODUCTIONWood chip refining is the most critical step in mechanical pulping.Commercical experi-ences have been gained for years.Modelling and control of chip refiners,however,pose a challenge mainly because of th...1 INTRODUCTIONWood chip refining is the most critical step in mechanical pulping.Commercical experi-ences have been gained for years.Modelling and control of chip refiners,however,pose a challenge mainly because of the stochastic nature of the process.Some attemptshave been made to employ factor analysis technique[1]in the modelling andsimulating of refiner operation[2,3].Strand[2]used common factors as links betweenintrinsic fibre properties and pulp quality.He believed that a qualitative concept onthe physical nature of these common factors could be arrived at,and thus would helpto understand what refining variables need to be controlled or adjusted in order to im-prove pulp quality.However,the linear model used in factor analysis is based on theassumption that the interactions among the system variables are linear,which,ofcourse,is not true in practice.展开更多
To find a design method for 3D active multichannel silicon microelectrode, a microstructure of active neural recording system is presented, where two 2D probes, two integrated circuits and two spacers are microassembl...To find a design method for 3D active multichannel silicon microelectrode, a microstructure of active neural recording system is presented, where two 2D probes, two integrated circuits and two spacers are microassembled on a 5 mm×7 mm silicon platform, and 32 sites neural signals can be operated simultaneously. A theoretical model for measuring the neural signal by the silicon microelectrode is proposed based on the structure and fabrication process of a single-shank probe. The method of determining the dimensional parameters of the probe shank is discussed in the following three aspects, i.e. the structures of pallium and endocranium, coupled interconnecters noise, and strength characteristic of neural probe. The design criterion is to minimize the size of the neural probe as well as that the probe has enough stiffness to pierce the endocranium. The on-chip unity-gain bandpass amplifier has an overall gain of 42 dB over a bandwidth from 60 Hz to 10 kHz; and the DC-baseline stability circuit is of high input resistance above 30 MΩ to guarantee a cutoff frequency below 100 Hz. The circuit works in stimulating or recording modes. The conversion of the modes depends on the stimulating control signal.展开更多
In the field of developmental neurobiology, accurate and ordered regulation of the cell cycle and apoptosis are crucial factors contributing to the normal formation of the neural tube. Preliminary studies identified s...In the field of developmental neurobiology, accurate and ordered regulation of the cell cycle and apoptosis are crucial factors contributing to the normal formation of the neural tube. Preliminary studies identified several genes involved in the development of neural tube defects. In this study, we established a model of developmental neural tube defects by administration of retinoic acid to pregnant rats. Gene chip hybridization analysis showed that genes related to the cell cycle and apoptosis, signal transduction, transcription and translation regulation, energy and metabolism, heat shock, and matrix and cytoskeletal proteins were all involved in the formation of developmental neural tube defects. Among these, cell cycle-related genes were predominant. Retinoic acid treat-ment caused differential expression of three cell cycle-related genes p57kip2, Cdk5 and Spin, the expression levels of which were downregulated by retinoic acid and upregulated during normal neural tube formation. The results of this study indicate that cell cycle-related genes play an im-portant role in the formation of neural tube defects. P57kip2, Cdk5 and Spin may be critical genes in the pathogenesis of neural tube defects.展开更多
The theoretical basis of the grinding chips thermal flow being regarded as the characteristic signal of on line identification is summarized. And on line identification of grinding burn and wheel wear based on the g...The theoretical basis of the grinding chips thermal flow being regarded as the characteristic signal of on line identification is summarized. And on line identification of grinding burn and wheel wear based on the grinding chips thermal flow is introduc展开更多
In this study, an Alzheimer＇s disease model was established in rats through stereotactic injection of condensed amyloid beta 1-40 into the bilateral hippocampus, and the changes of gene expression profile in the hipp...In this study, an Alzheimer＇s disease model was established in rats through stereotactic injection of condensed amyloid beta 1-40 into the bilateral hippocampus, and the changes of gene expression profile in the hippocampus of rat models and sham-operated rats were compared by genome expression profiling analysis. Results showed that the expression of 50 genes was significantly up-regulated （fold change 〉 2）, while 21 genes were significantly down-regulated in the hippocampus of Alzheimer＇s disease model rats （fold change 〈 0.5） compared with the sham-operation group. The differentially expressed genes are involved in many functions, such as brain nerve system development, neuronal differentiation and functional regulation, cellular growth, differentiation and apoptosis, synaptogenesis and plasticity, inflammatory and immune responses, ion channels/transporters, signal transduction, cell material/energy metabolism. Our findings indicate that several genes were abnormally expressed in the metabolic and signal transduction pathways in the hippocampus of amyloid beta 1 40-induced rat model of Alzheimer＇s disease, thereby affecting the hippocampal and brain functions.展开更多
文摘Based on the model of a formal neuron proposed by McCulloch and Pitts,a kind ofneural circuit,which is a CMOS Variable Threshold Logic(VTL)circuit,is given in this paperconsidering the features of the binary image processing system.The theoretical analysis,andthe simulations for the building block circuits such as D/A converters,comparator and so on aregiven.The layout design of the whole circuit are also given.The binary image processing can berealized by using the VTL circuit combined with its external auxiliary circuits.
基金sponsored by the National Natural Science Foundation of China (Grant Nos.61960206012,62121003,T2293731,62171434,61975206,61971400,and 61973292)the National Key Research and Development Program of China (Grant Nos.2022YFB3205602 and 2022YFC2402501)+1 种基金Major Program of Scientific and Technical Innovation 2030 (Grant No.2021ZD02016030)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No.GJJSTD20210004).
文摘To enable the detection and modulation of modularized neural networks in vitro,this study proposes a microfluidic microelectrode array chip for the cultivation,compartmentalization,and control of neural cells.The chip was designed based on the specific structure of neurons and the requirements for detection and modulation.Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software,and the simulation results show that the liquid within the chip can flow smoothly,ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels.By employing MEMS technology in combination with nanomaterial modification techniques,the microfluidic microelectrode array chip was fabricated successfully.Primary hippocampal neurons were cultured on the chip,forming a well-defined neural network.Spontaneous electrical activity of the detected neurons was recorded,exhibiting a 23.7%increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array.This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro,potentially serving as a novel tool in neuroscience research.
文摘1 INTRODUCTIONWood chip refining is the most critical step in mechanical pulping.Commercical experi-ences have been gained for years.Modelling and control of chip refiners,however,pose a challenge mainly because of the stochastic nature of the process.Some attemptshave been made to employ factor analysis technique[1]in the modelling andsimulating of refiner operation[2,3].Strand[2]used common factors as links betweenintrinsic fibre properties and pulp quality.He believed that a qualitative concept onthe physical nature of these common factors could be arrived at,and thus would helpto understand what refining variables need to be controlled or adjusted in order to im-prove pulp quality.However,the linear model used in factor analysis is based on theassumption that the interactions among the system variables are linear,which,ofcourse,is not true in practice.
基金Supported by Tianjin Municipal Science and Technology Commission(No. 05YFSYSF01700).
文摘To find a design method for 3D active multichannel silicon microelectrode, a microstructure of active neural recording system is presented, where two 2D probes, two integrated circuits and two spacers are microassembled on a 5 mm×7 mm silicon platform, and 32 sites neural signals can be operated simultaneously. A theoretical model for measuring the neural signal by the silicon microelectrode is proposed based on the structure and fabrication process of a single-shank probe. The method of determining the dimensional parameters of the probe shank is discussed in the following three aspects, i.e. the structures of pallium and endocranium, coupled interconnecters noise, and strength characteristic of neural probe. The design criterion is to minimize the size of the neural probe as well as that the probe has enough stiffness to pierce the endocranium. The on-chip unity-gain bandpass amplifier has an overall gain of 42 dB over a bandwidth from 60 Hz to 10 kHz; and the DC-baseline stability circuit is of high input resistance above 30 MΩ to guarantee a cutoff frequency below 100 Hz. The circuit works in stimulating or recording modes. The conversion of the modes depends on the stimulating control signal.
基金supported by the Science and Technology Key Program of Sichuan Provincial Health Ministry,No.080128
文摘In the field of developmental neurobiology, accurate and ordered regulation of the cell cycle and apoptosis are crucial factors contributing to the normal formation of the neural tube. Preliminary studies identified several genes involved in the development of neural tube defects. In this study, we established a model of developmental neural tube defects by administration of retinoic acid to pregnant rats. Gene chip hybridization analysis showed that genes related to the cell cycle and apoptosis, signal transduction, transcription and translation regulation, energy and metabolism, heat shock, and matrix and cytoskeletal proteins were all involved in the formation of developmental neural tube defects. Among these, cell cycle-related genes were predominant. Retinoic acid treat-ment caused differential expression of three cell cycle-related genes p57kip2, Cdk5 and Spin, the expression levels of which were downregulated by retinoic acid and upregulated during normal neural tube formation. The results of this study indicate that cell cycle-related genes play an im-portant role in the formation of neural tube defects. P57kip2, Cdk5 and Spin may be critical genes in the pathogenesis of neural tube defects.
文摘The theoretical basis of the grinding chips thermal flow being regarded as the characteristic signal of on line identification is summarized. And on line identification of grinding burn and wheel wear based on the grinding chips thermal flow is introduc
基金sponsored by the National Natural Science Foundation of China,No. 30973779
文摘In this study, an Alzheimer＇s disease model was established in rats through stereotactic injection of condensed amyloid beta 1-40 into the bilateral hippocampus, and the changes of gene expression profile in the hippocampus of rat models and sham-operated rats were compared by genome expression profiling analysis. Results showed that the expression of 50 genes was significantly up-regulated （fold change 〉 2）, while 21 genes were significantly down-regulated in the hippocampus of Alzheimer＇s disease model rats （fold change 〈 0.5） compared with the sham-operation group. The differentially expressed genes are involved in many functions, such as brain nerve system development, neuronal differentiation and functional regulation, cellular growth, differentiation and apoptosis, synaptogenesis and plasticity, inflammatory and immune responses, ion channels/transporters, signal transduction, cell material/energy metabolism. Our findings indicate that several genes were abnormally expressed in the metabolic and signal transduction pathways in the hippocampus of amyloid beta 1 40-induced rat model of Alzheimer＇s disease, thereby affecting the hippocampal and brain functions.
