The compactness of plant chromosome and the structures of plant cell wall and cytoplasm pose a great resistance to fluorescence in situ hybridization(FISH),and consequently many new methods for improving spatial resol...The compactness of plant chromosome and the structures of plant cell wall and cytoplasm pose a great resistance to fluorescence in situ hybridization(FISH),and consequently many new methods for improving spatial resolution are being exploited to overcome these problems.However,for plants with small chromosomes like rice and Brassica,there are still many difficulties.In this article a new and effective technique for preparation of extended DNA fibers(EDFs),using a series of treatments to prophase I chromosomes of Brassica oleracea PMCs,is presented.This technique allows longitudinal extension of the chromosomes 30-107 times longer than those of their metaphase counterparts.The length of the extended DNA fibers is between 89μm and 273μm,and the space resolution is 42.8-53.0 kb.Stretching ratios were assessed in a number of FISH experiments with super-stretched chromosomes from meiotic prophase I nuclei ofB.olerecea.Through FISH to EDFs of pachytene chromosomes hybridized in situ with SRK(S-locus receptor kinase)and SPⅡ(S-locus proteinⅡ)probes,for the first time we localized the accurate positions of S-locus and quantitatively analyzed the features of S genes in B.oleracea genome to show all S genes were single-copied.In addition,the length between two linked genes was measured to be about one micron.As a result,the highest space resolution which was about 4 kb was obtained.展开更多
In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method wa...In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.60140646)the Natural Science Foundation of Chongqing(No.7914).
文摘The compactness of plant chromosome and the structures of plant cell wall and cytoplasm pose a great resistance to fluorescence in situ hybridization(FISH),and consequently many new methods for improving spatial resolution are being exploited to overcome these problems.However,for plants with small chromosomes like rice and Brassica,there are still many difficulties.In this article a new and effective technique for preparation of extended DNA fibers(EDFs),using a series of treatments to prophase I chromosomes of Brassica oleracea PMCs,is presented.This technique allows longitudinal extension of the chromosomes 30-107 times longer than those of their metaphase counterparts.The length of the extended DNA fibers is between 89μm and 273μm,and the space resolution is 42.8-53.0 kb.Stretching ratios were assessed in a number of FISH experiments with super-stretched chromosomes from meiotic prophase I nuclei ofB.olerecea.Through FISH to EDFs of pachytene chromosomes hybridized in situ with SRK(S-locus receptor kinase)and SPⅡ(S-locus proteinⅡ)probes,for the first time we localized the accurate positions of S-locus and quantitatively analyzed the features of S genes in B.oleracea genome to show all S genes were single-copied.In addition,the length between two linked genes was measured to be about one micron.As a result,the highest space resolution which was about 4 kb was obtained.
文摘In this paper,a conventional soliton(CS)mode-locked erbium-doped fiber(EDF)laser was de-veloped using MAX phase material(MAX-PM)Nb_(4)AlC_(3)as a saturable absorber(SA).First,the liquid phase exfoliation(LPE)method was utilized to prepare Nb_(4)AlC_(3)nanosheets,and then a piece of tapered fiber was adopted to fabricate Nb_(4)AlC_(3)-SA.It was found that the saturation intensity and modulation depth of the Nb_(4)AlC_(3)-SA are 2.02 MW/cm^(2)and 1.88%.Based on the Nb_(4)AlC_(3)-SA,a conventional soliton(CS)mode-locked EDF laser was achieved.The central wavelength,pulse duration,and pulse repetition rate were found to be 1565.65 nm,615.37 fs,and 24.63 MHz,respectively.The performance is competitive and particularly superior in terms of pulse duration.This study fully confirms that Nb_(4)AlC_(3)possesses marvellous nonlinear saturable absorption properties and opens new possibilities for further research on air-stable ultrafast photon-ic devices.
