In-situ monitoring of pesticide residues during crop growth or/and in related products is of great significance in avoiding the abuse of pesticides but remains challenging thus far.In this report,we proposed a backgro...In-situ monitoring of pesticide residues during crop growth or/and in related products is of great significance in avoiding the abuse of pesticides but remains challenging thus far.In this report,we proposed a background-free surface-enhanced Raman spectroscopy(bf-SERS)platform to non-destructively track the nitrile-bearing pesticide residues in soybean leaves with high sensitivity and selectivity.The outstanding feature of the assay stems from the dramatic Raman enhancement effect of the 50 nm-sized gold nanoparticles(AuNPs)towards the pesticides and simultaneously the background-free Raman signal of the nitrile group in the so-called Raman-silent region(1800-2800 cm^(-1)).This bf-SERS assay was applied to evaluate the penetration effects of nitrile-bearing pesticides and monitor their residues in soybean leaves after rinsing with various solutions,providing a reliable tool for guiding the safe use of nitrile-bearing pesticides in agriculture.展开更多
We review the recent progress of photonic generation of millimeter wave （MMW）-ultra-wideband （UWB） signals. To fully satisfy the standard defined by the Federal Communications Commission （FCC）, the baseband sign...We review the recent progress of photonic generation of millimeter wave （MMW）-ultra-wideband （UWB） signals. To fully satisfy the standard defined by the Federal Communications Commission （FCC）, the baseband signal （background signal） and the residual local oscillator （LO） signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.展开更多
The introduction of a double-chopping scheme eliminates the background level in the optical sampling system, where a Si avalanche photodiode acts as a two-photon absorber. We successfully demonstrate background-free o...The introduction of a double-chopping scheme eliminates the background level in the optical sampling system, where a Si avalanche photodiode acts as a two-photon absorber. We successfully demonstrate background-free optical sampling of 40-GHz and 160-GHz pulse trains.展开更多
Although immobilization-free and label-free electrochemical DNA(E-DNA)biosensors have engaged tremendous interest due to their superior properties,such as easy operation,time-saving and cost-saving,most of them are fa...Although immobilization-free and label-free electrochemical DNA(E-DNA)biosensors have engaged tremendous interest due to their superior properties,such as easy operation,time-saving and cost-saving,most of them are fabricated in homogeneous modes and usually produce high background current.In the present work,we proposed a new immobilization-free and label-free heterogeneous E-DNA assay based on a dual-blocker-aided multibranched hybridization chain reaction(HCR)for one-pot nucleic acid detection with zero background.The target nucleic acid triggers the HCR involving cascaded hybridization between two metastable hairpins,resulting in the generation of HCR products with multibranched arms,which can be captured onto the electrode viaπ-πstacking interactions between multibranched arms and reduced graphene oxide(rGO).Prior to the incubation process with an electrode,two blockers are designed to prohibit the nonspecific absorption of unreacted hairpin probes.Thus,an immobilization-free and label-free heterogeneous electrochemical assay for one-pot nucleic acid detection with zero background is readily realized.This strategy also presents additional merits of simplicity and cheap cost,since probe immobilization,signal tag labeling,and multiple incubation processes are avoided.Therefore,the as-proposed effective and versatile biosensor has great potential to be applied in nucleic acid-related practical biosensing.展开更多
基金the support from the Shanxi Province Key R&D Plans(Nos.201903D211006-1 and 201803D221020-2)the Natural Science Foundation of Shanxi Province(No.201901D111225)+1 种基金the National Natural Science Foundation of China(Nos.21775075 and 21977053)the Fundamental Research Funds for the Central Universities,Nankai University(No.2122018165)。
文摘In-situ monitoring of pesticide residues during crop growth or/and in related products is of great significance in avoiding the abuse of pesticides but remains challenging thus far.In this report,we proposed a background-free surface-enhanced Raman spectroscopy(bf-SERS)platform to non-destructively track the nitrile-bearing pesticide residues in soybean leaves with high sensitivity and selectivity.The outstanding feature of the assay stems from the dramatic Raman enhancement effect of the 50 nm-sized gold nanoparticles(AuNPs)towards the pesticides and simultaneously the background-free Raman signal of the nitrile group in the so-called Raman-silent region(1800-2800 cm^(-1)).This bf-SERS assay was applied to evaluate the penetration effects of nitrile-bearing pesticides and monitor their residues in soybean leaves after rinsing with various solutions,providing a reliable tool for guiding the safe use of nitrile-bearing pesticides in agriculture.
基金supported in part by the National Natural Science Foundation of China(Nos.61377069,61431003,and 61335005)the National 863 Program of China(No.2015AA017002)the Beijing Nova Program
文摘We review the recent progress of photonic generation of millimeter wave （MMW）-ultra-wideband （UWB） signals. To fully satisfy the standard defined by the Federal Communications Commission （FCC）, the baseband signal （background signal） and the residual local oscillator （LO） signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.
文摘The introduction of a double-chopping scheme eliminates the background level in the optical sampling system, where a Si avalanche photodiode acts as a two-photon absorber. We successfully demonstrate background-free optical sampling of 40-GHz and 160-GHz pulse trains.
基金supported by the National Natural Science Foundation of China(22304062)the Zhejiang Provincial Natural Science Foundation of China(LTGY24B050002)+1 种基金the Program for Science and Technology of Jiaxing(2023AY40028)the Baiqing Foundation of Jiaxing University(CD70621010).
文摘Although immobilization-free and label-free electrochemical DNA(E-DNA)biosensors have engaged tremendous interest due to their superior properties,such as easy operation,time-saving and cost-saving,most of them are fabricated in homogeneous modes and usually produce high background current.In the present work,we proposed a new immobilization-free and label-free heterogeneous E-DNA assay based on a dual-blocker-aided multibranched hybridization chain reaction(HCR)for one-pot nucleic acid detection with zero background.The target nucleic acid triggers the HCR involving cascaded hybridization between two metastable hairpins,resulting in the generation of HCR products with multibranched arms,which can be captured onto the electrode viaπ-πstacking interactions between multibranched arms and reduced graphene oxide(rGO).Prior to the incubation process with an electrode,two blockers are designed to prohibit the nonspecific absorption of unreacted hairpin probes.Thus,an immobilization-free and label-free heterogeneous electrochemical assay for one-pot nucleic acid detection with zero background is readily realized.This strategy also presents additional merits of simplicity and cheap cost,since probe immobilization,signal tag labeling,and multiple incubation processes are avoided.Therefore,the as-proposed effective and versatile biosensor has great potential to be applied in nucleic acid-related practical biosensing.
