As an acidic glycoprotein,carcinoembryonic antigen(CEA)is of great value as a broad-spectrum tumor marker in the differential diagnosis and surveillance of malignant tumors.In this work,we report an electrochemical ap...As an acidic glycoprotein,carcinoembryonic antigen(CEA)is of great value as a broad-spectrum tumor marker in the differential diagnosis and surveillance of malignant tumors.In this work,we report an electrochemical aptasensor for the ultrasensitive and highly selective detection of CEA,taking advantage of the dual amplification by the boronate affinity-assisted electrochemically controlled atom transfer radical polymerization(BA-eATRP).Specifically,the BAeATRP-based electrochemical aptasensing of CEA involves the capture of target antigens by nucleic acid aptamers,the covalent crosslinking of ATRP initiators to CEA antigens via the selective interactions between the phenylboronic acid(PBA)group and the cis-diol group of the monosaccharide residues,and the collection of the ferrocene(Fc)reporters via the eATRP of ferrocenylmethyl methacrylate(FcMMA).As CEA is decorated with hundreds of cis-diol groups,the BA-based crosslinking can result in the labeling of each CEA with hundreds of ATRP initiators;furthermore,the eATRP of FcMMA results in the surface-initiated growth of long-chain ferrocenyl polymers,leading to the tethering of each ATRP initiator-conjugated site with hundreds to thousands of Fc reporters.Such that,the BAeATRP can result in the efficient labeling of each CEA with a plenty of Fc reporters.Under the optimized conditions,the BA-eATRP-based strategy enables the highly selective aptasensing of CEA at a concentration as low as 0.34 pg·mL^(-1),with a linear range of 1.01000 pg·mL^(-1).Besides,this aptasensor has been successfully applied to the quantitative analysis of CEA in human serum.The BA-eATRP-based electrochemical aptasensor is cost-effective and simple in operation,holding broad application prospect in the ultrasensitive and highly selective detection of CEA.展开更多
The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affec...The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affected by several parameters which includes the type of technology used,components used for the selected technology,aging,usage,operating and environmental conditions.The effect of gain resistors and their manufacturing tolerances on differential amplifier-based buck converter current measurement is investigated in this work.The analysis mainly focused on the output voltage variation and its accuracy with respect to the change in gain resistance tolerances.The gain resistors with 5%,1%,0.5%and 0.1%manufacturing tolerances taken for the worst-case analysis and the calculated performance results are compared and verified with the simula-tion results.The Operational amplifiers(Op-Amp)for high frequency power con-verter applications must operate in a high frequency noise environment and the intended current measuring system must manage common mode noise distur-bances paired with the signal to be measured.Based on the Common Mode Rejec-tion Ratio(CMRR)the common mode voltages and noise signals will effectively getfiltered out.Lesser CMRR results in lower common mode signal rejection,resulting in poor precision and noise rejection.In differential amplifiers,the CMRR predominantly depends on gain resistors.So,the variations in Common Mode Rejection Ratio due to gain resistor tolerances also analyzed and compared with the output voltage variations.Besides the effects of resistor tolerances,this paper also examines the effect of Op-Amp offset voltage on output accuracy spe-cifically for low magnitude input currents.The obtained results from this analysis clearly shows that the gain resistors with 0.1%tolerance gives maximum accuracy with improved CMRR and accuracy at low magnitude input currents will get well improved by using Op-Amps with Low Offset voltage specifications.展开更多
The mammalian neocortex gives rise to perception and initiates voluntary motor responses.The cortical laminae are comprised of six distinct cellular layers of local circuit neurons and projection neurons.To explore mo...The mammalian neocortex gives rise to perception and initiates voluntary motor responses.The cortical laminae are comprised of six distinct cellular layers of local circuit neurons and projection neurons.To explore molecular identities of the distinct cortical projection neurons,discovery-orientated genomic approaches have been adopted.Microarray analysis of dissected cortical tissues has been applied to identify cortical layer markers.Early neuronal cells were sorted by FACS from GFP-labeled embryonic brains for gene expression profiling.Laser capture microdissection of retrograde-labeled pro-jection neurons,when coupled with optimal RNA amplification technology,has become a valuable strategy for neuronal isolation and gene expression analysis in differentiated neurons.RNA sequencing technology is promising not only for the determination of gene expression,but also for discovery of posttranscriptional modifications of the complex neural system.There is no doubt that advances in genomic studies are opening up novel research avenues for our understanding of the cortical neuronal functions.展开更多
基金This work was co-supported by the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010618)the Young Talent Support Project of Guangzhou Association for Science and Technology(No.QT-2023-009)+2 种基金the National Natural Science Foundation of China(No.21904026,21974031)the Guangzhou Science and Technology Project(No.202201010600,202201020170,202201000002)the Innovation Training Program for College Students of Guangzhou University(No.202211078113,S202111078031).
文摘As an acidic glycoprotein,carcinoembryonic antigen(CEA)is of great value as a broad-spectrum tumor marker in the differential diagnosis and surveillance of malignant tumors.In this work,we report an electrochemical aptasensor for the ultrasensitive and highly selective detection of CEA,taking advantage of the dual amplification by the boronate affinity-assisted electrochemically controlled atom transfer radical polymerization(BA-eATRP).Specifically,the BAeATRP-based electrochemical aptasensing of CEA involves the capture of target antigens by nucleic acid aptamers,the covalent crosslinking of ATRP initiators to CEA antigens via the selective interactions between the phenylboronic acid(PBA)group and the cis-diol group of the monosaccharide residues,and the collection of the ferrocene(Fc)reporters via the eATRP of ferrocenylmethyl methacrylate(FcMMA).As CEA is decorated with hundreds of cis-diol groups,the BA-based crosslinking can result in the labeling of each CEA with hundreds of ATRP initiators;furthermore,the eATRP of FcMMA results in the surface-initiated growth of long-chain ferrocenyl polymers,leading to the tethering of each ATRP initiator-conjugated site with hundreds to thousands of Fc reporters.Such that,the BAeATRP can result in the efficient labeling of each CEA with a plenty of Fc reporters.Under the optimized conditions,the BA-eATRP-based strategy enables the highly selective aptasensing of CEA at a concentration as low as 0.34 pg·mL^(-1),with a linear range of 1.01000 pg·mL^(-1).Besides,this aptasensor has been successfully applied to the quantitative analysis of CEA in human serum.The BA-eATRP-based electrochemical aptasensor is cost-effective and simple in operation,holding broad application prospect in the ultrasensitive and highly selective detection of CEA.
文摘The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affected by several parameters which includes the type of technology used,components used for the selected technology,aging,usage,operating and environmental conditions.The effect of gain resistors and their manufacturing tolerances on differential amplifier-based buck converter current measurement is investigated in this work.The analysis mainly focused on the output voltage variation and its accuracy with respect to the change in gain resistance tolerances.The gain resistors with 5%,1%,0.5%and 0.1%manufacturing tolerances taken for the worst-case analysis and the calculated performance results are compared and verified with the simula-tion results.The Operational amplifiers(Op-Amp)for high frequency power con-verter applications must operate in a high frequency noise environment and the intended current measuring system must manage common mode noise distur-bances paired with the signal to be measured.Based on the Common Mode Rejec-tion Ratio(CMRR)the common mode voltages and noise signals will effectively getfiltered out.Lesser CMRR results in lower common mode signal rejection,resulting in poor precision and noise rejection.In differential amplifiers,the CMRR predominantly depends on gain resistors.So,the variations in Common Mode Rejection Ratio due to gain resistor tolerances also analyzed and compared with the output voltage variations.Besides the effects of resistor tolerances,this paper also examines the effect of Op-Amp offset voltage on output accuracy spe-cifically for low magnitude input currents.The obtained results from this analysis clearly shows that the gain resistors with 0.1%tolerance gives maximum accuracy with improved CMRR and accuracy at low magnitude input currents will get well improved by using Op-Amps with Low Offset voltage specifications.
基金supported by grants 30840034 and 30970924 from the National Natural Science Foundation of China.
文摘The mammalian neocortex gives rise to perception and initiates voluntary motor responses.The cortical laminae are comprised of six distinct cellular layers of local circuit neurons and projection neurons.To explore molecular identities of the distinct cortical projection neurons,discovery-orientated genomic approaches have been adopted.Microarray analysis of dissected cortical tissues has been applied to identify cortical layer markers.Early neuronal cells were sorted by FACS from GFP-labeled embryonic brains for gene expression profiling.Laser capture microdissection of retrograde-labeled pro-jection neurons,when coupled with optimal RNA amplification technology,has become a valuable strategy for neuronal isolation and gene expression analysis in differentiated neurons.RNA sequencing technology is promising not only for the determination of gene expression,but also for discovery of posttranscriptional modifications of the complex neural system.There is no doubt that advances in genomic studies are opening up novel research avenues for our understanding of the cortical neuronal functions.
