A pair of primers was designed according to the reported conserved sequence of the defective in anther dehiscencel （DAD1） gene ofArabidopsis thaliana and Brassica rapa. A 558 bp long fragment was amplified from geno...A pair of primers was designed according to the reported conserved sequence of the defective in anther dehiscencel （DAD1） gene ofArabidopsis thaliana and Brassica rapa. A 558 bp long fragment was amplified from genomic DNA of Chinese kale, showing more than 88% identity with the known DAD1 nucleotide sequence and no intron. The reverse of the amplified fragment was ligated to the downstream of the CaMV35S promoter in the plant expression vector pBIl21. Antisense expression vector pBII21-DAD1F was constructed with DAD1 fragment of Chinese kale, and was transferred into Agrobacterium tumefaciens, which will be used in the transformation to create male sterile materials of Chinese kale.展开更多
Chemical vapor deposited （CVD） graphene is nanopatterned using a spherical block copolymer etch mask. The use of spherical rather than cylindrical block copolymers allows homogeneous patterning of cm-scale areas wit...Chemical vapor deposited （CVD） graphene is nanopatterned using a spherical block copolymer etch mask. The use of spherical rather than cylindrical block copolymers allows homogeneous patterning of cm-scale areas without any substrate surface treatment. Raman spectroscopy was used to study the con- trolled generation of point defects in the graphene lattice with increasing etching time, confirming that alongside the nanomesh patterning, the nanopatterned CVD graphene presents a high defect density between the mesh holes. The nanopatterned samples showed sensitivities for NO2 of more than one order of magnitude higher than for non-patterned graphene. NO2 concentrations as low as 300 ppt were detected with an ultimate detection limit of tens of ppt. This is the smallest value reported so far for non-UV illuminated graphene chemiresistive NO2 gas sensors. The dramatic improvement in the gas sensitivity is believed to be due to the high adsorption site density, thanks to the combination of edge sites and point defect sites. This work opens the possibility of large area fabrication of nanopatterned graphene with extremely high densities of adsorption sites for sensing applications.展开更多
Nucleic acid amplification test is a reliable method for primary human immunodeficiency virus （HIV） infection diagnosis. Herein, a novel fluorescent method for sequence-specific recognition of DNA fragment of HIV-1 ...Nucleic acid amplification test is a reliable method for primary human immunodeficiency virus （HIV） infection diagnosis. Herein, a novel fluorescent method for sequence-specific recognition of DNA fragment of HIV-1 was established based upon nicking-assisted strand displacement amplification （SDA） and triplex DNA. In the presence of target dsDNA, nicking-assisted SDA process generated a lot of ssDNA, which hybridized with molecular beacon to produce signal. The fluorescence intensity was proportional to the concentration of target dsDNA within the range from 5 to 1000 pmol/L, with a detection limit of 1.4 pmol/L. Moreover, it successfully distinguished target dsDNA from the nucleic acid extractive of human blood. Thus this method has the merit of high sensitivity, and it is suitable for sequence-specific recognition of target dsDNA in complex matrices, which made it a potential application in diagnosis of acquired immunodeflciency syndrome （AIDS） in the future.展开更多
文摘A pair of primers was designed according to the reported conserved sequence of the defective in anther dehiscencel （DAD1） gene ofArabidopsis thaliana and Brassica rapa. A 558 bp long fragment was amplified from genomic DNA of Chinese kale, showing more than 88% identity with the known DAD1 nucleotide sequence and no intron. The reverse of the amplified fragment was ligated to the downstream of the CaMV35S promoter in the plant expression vector pBIl21. Antisense expression vector pBII21-DAD1F was constructed with DAD1 fragment of Chinese kale, and was transferred into Agrobacterium tumefaciens, which will be used in the transformation to create male sterile materials of Chinese kale.
文摘Chemical vapor deposited （CVD） graphene is nanopatterned using a spherical block copolymer etch mask. The use of spherical rather than cylindrical block copolymers allows homogeneous patterning of cm-scale areas without any substrate surface treatment. Raman spectroscopy was used to study the con- trolled generation of point defects in the graphene lattice with increasing etching time, confirming that alongside the nanomesh patterning, the nanopatterned CVD graphene presents a high defect density between the mesh holes. The nanopatterned samples showed sensitivities for NO2 of more than one order of magnitude higher than for non-patterned graphene. NO2 concentrations as low as 300 ppt were detected with an ultimate detection limit of tens of ppt. This is the smallest value reported so far for non-UV illuminated graphene chemiresistive NO2 gas sensors. The dramatic improvement in the gas sensitivity is believed to be due to the high adsorption site density, thanks to the combination of edge sites and point defect sites. This work opens the possibility of large area fabrication of nanopatterned graphene with extremely high densities of adsorption sites for sensing applications.
基金supported by the National Natural Science Foundation of China(21375153)
文摘Nucleic acid amplification test is a reliable method for primary human immunodeficiency virus （HIV） infection diagnosis. Herein, a novel fluorescent method for sequence-specific recognition of DNA fragment of HIV-1 was established based upon nicking-assisted strand displacement amplification （SDA） and triplex DNA. In the presence of target dsDNA, nicking-assisted SDA process generated a lot of ssDNA, which hybridized with molecular beacon to produce signal. The fluorescence intensity was proportional to the concentration of target dsDNA within the range from 5 to 1000 pmol/L, with a detection limit of 1.4 pmol/L. Moreover, it successfully distinguished target dsDNA from the nucleic acid extractive of human blood. Thus this method has the merit of high sensitivity, and it is suitable for sequence-specific recognition of target dsDNA in complex matrices, which made it a potential application in diagnosis of acquired immunodeflciency syndrome （AIDS） in the future.
