We have developed a multiplexed DNA detection method based on graphene oxide （GO） and molecular beacons （MBs） by synchronous fluorescence analysis, demonstrated it by an oligonucleotide sequence of wild-type HBV ...We have developed a multiplexed DNA detection method based on graphene oxide （GO） and molecular beacons （MBs） by synchronous fluorescence analysis, demonstrated it by an oligonucleotide sequence of wild-type HBV （T1） and a re- verse-transcription oligonucleotide sequence of the RNA fragment of HIV （T2） as a model system. In the absence of targets DNA, FAM-tagged free MB probes （PHBv） and ROX-tagged free MB probes （PHIv） are adsorbed on GO via π-π interactions between DNA nucleobases and nucleosides, and the π-rich GO brings the fluorophores of MB and GO into close proximity. And then, the fluorescence of fluorophores is quenched by GO. But in the presence of targets DNA, PHBV and PHW hybridize with their targets DNA resulting in the formation of double-stranded DNA （dsDNA）, causing the separation of PHBV and PHW from the surface of GO and the recovery of the fluorescence of fluorophores （FAM and ROX） simultaneously. The simultane- ous detection of T1 and T2 can be realized by measuring fluorescence signals of FAM and ROX, respectively. Under the op- timum conditions, the fluorescence intensities of two dyes all exhibit good linear dependence on their target DNA concentra- tion in the range of 5×10-11-5×10 9 M. The detection limit of T1 is 3×10-11 M （3σ）, and that of T2 is 2×10-11 M. Compared with other methods for DNA detection based on GO, the proposed method has some advantages including higher selectivity and shorter analytical time.展开更多
Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this...Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this study, the authors use the Mean Shift Outlier Model(MSOM) to detect outliers in HIV model based on the two-step estimation of ODE. Approximate formula for shift parameter is derived. Furthermore, a score test statistic is constructed and its approximating distribution is established. The simulation results show that: 1) The boundary points have more impact on the parameter estimation relative to interior points. 2) The proposed procedure can detect the outliers effectively. The authors illustrate the proposed approach using an application example from an HIV clinical trial and find similar pattern to the simulation studies.展开更多
文摘We have developed a multiplexed DNA detection method based on graphene oxide （GO） and molecular beacons （MBs） by synchronous fluorescence analysis, demonstrated it by an oligonucleotide sequence of wild-type HBV （T1） and a re- verse-transcription oligonucleotide sequence of the RNA fragment of HIV （T2） as a model system. In the absence of targets DNA, FAM-tagged free MB probes （PHBv） and ROX-tagged free MB probes （PHIv） are adsorbed on GO via π-π interactions between DNA nucleobases and nucleosides, and the π-rich GO brings the fluorophores of MB and GO into close proximity. And then, the fluorescence of fluorophores is quenched by GO. But in the presence of targets DNA, PHBV and PHW hybridize with their targets DNA resulting in the formation of double-stranded DNA （dsDNA）, causing the separation of PHBV and PHW from the surface of GO and the recovery of the fluorescence of fluorophores （FAM and ROX） simultaneously. The simultane- ous detection of T1 and T2 can be realized by measuring fluorescence signals of FAM and ROX, respectively. Under the op- timum conditions, the fluorescence intensities of two dyes all exhibit good linear dependence on their target DNA concentra- tion in the range of 5×10-11-5×10 9 M. The detection limit of T1 is 3×10-11 M （3σ）, and that of T2 is 2×10-11 M. Compared with other methods for DNA detection based on GO, the proposed method has some advantages including higher selectivity and shorter analytical time.
基金supported by the Fundamental Research Funds for the Cental Universities under Grant No.JB140706the National Funds of China for Young Scientists under Grant Nos.11302157 and 11301409
文摘Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this study, the authors use the Mean Shift Outlier Model(MSOM) to detect outliers in HIV model based on the two-step estimation of ODE. Approximate formula for shift parameter is derived. Furthermore, a score test statistic is constructed and its approximating distribution is established. The simulation results show that: 1) The boundary points have more impact on the parameter estimation relative to interior points. 2) The proposed procedure can detect the outliers effectively. The authors illustrate the proposed approach using an application example from an HIV clinical trial and find similar pattern to the simulation studies.
