Nathan Stevens's research while affiliated with City University of New York - York College and other places

... Currently, organic-based materials and nanocomposites with nonlinear optical (NLO) behaviour are of considerable importance for the modification or development of electronic devices [1], optical devices self-actions (i.e., self-trapping and cross-phase modulation), optical limiting, organic super-resolution imaging, and optical switching in future photonics technologies [2][3][4][5][6][7][8]. Previous studies have reported the NLO behaviour of various dye-composites such as dye-doped silica [9][10][11][12], dye-polymer [13][14][15], and dye-doped nematic liquid crystal [16][17][18]. Owing to the good physical and optical properties of sol-gel based dye-doped silica nanocomposites are gaining interest during the last decade [9]. ...

... MeOH vapor was also chosen as an analyte for the chemosensing since it is also widely encountered in daily life and harmful for human health. As a probe for the MeOH detection, coumarin, a natural organic chemical compound found in many plants and sensitive to the MeOH vapor 46 , was applied to the SNAF. Figure 5e shows the fluorescent response of the coumarin-doped silk nanofibers exposed to MeOH fume. As the SNAFs were exposed to the MeOH fume, the fluorescence intensity of the dye gradually increased. ...

... The DFT method was chosen because it is computationally less demanding than other approaches as regards inclusion of electron correlation. Moreover, in addition to its excellent accuracy and favorable computation expense ratio, the B3LYP calculation of Raman frequencies has shown its efficacy in our earlier studies, often proving itself the most reliable and preferable method for many molecular species of intermediate size, including carbon nanotubes (CNTs) and transition metals [41][42][43][44][45][46][47]. We would like to point out that the Raman, IR and electronic spectra of the molecules studied here were plotted using the GaussSum software [48]. ...

... Finally, we conclude with our personal perspectives about potential outlook in this field. While our aim is to emphasize the state-of-art of FRET-based nucleic acid probes that are now available for bioimaging, there are several other relevant reviews that may be of interest to our readers, who may refer to the references for more elaborated introduction about design principles of other probes, typically small molecular fluorogenic probes [19] for bioimaging [2,3], or more detailed insight into the specific types of nucleic acid probes (i.e., molecular beacon [20], DNAzyme [21], binary probes [22] and others [17,18]) and their application for analytical detection [23,24], cancer diagnostics and therapy [25,26]. Throughout this review, we'd like to provides comprehensive overview of the FRETbased nucleic acid probes that are used for bioimaging from live cells to small animals and anticipate more nucleic acid probes as well as nanomaterials be enrolled in constructing workable sensing devices in biomedical application. ...

... Especially, optimizing the delivery method and component expression could facilitate immediate expression and editing, thereby mitigating off-target effects. For instance, genome editing could be induced through Doxycycline-induced expression [48], mRNA delivery [49], and protein/RNA complexes [50]. ...

... They internalize in nucleoli, 19 as do phosphorescent heavy-metal (non-lanthanide) 23 and fluorescent ruthenium complexes. 24 Our results demonstrate that some structures outside the nuclei are also labelled by Eu-DPA, even though much less prominently. ...

... The novel fluorescent biosensor was constructed successfully on account of DNA-specific recognition between target DNA and hairpin probe. It was credited to the hairpin DNA, which was an optimal candidate for making the opportunity to bring donor-acceptor pair together (Farjami et al. 2011;Jockusch et al. 2006). In this developed strategy, an obvious FRET occurred to induce the fluorescent signal "turn off." ...

... A strategy along different lines to improving the S:N ratio of the MB has been the enhancement of F open by increasing the maximal fluorescence intensity of a given fluorophore using techniques such as multiple fluorophore based systems [16][17][18][19], wavelength-shifting MBs [20], conjugated polymers [21], and quantum dot MB systems [22]. In particular, quantum dots and conjugated polymers have been shown to produce a much higher fluorescence intensity than that of a single small molecule organic fluorophore. ...

... One solution to minimize direct excitation of the acceptor is to use a system of three partners, where an intermediate dye serves as a relay to transfer the energy of a donor to an acceptor. This provides a large apparent Stokes shift, but a less efficient FRET (9). Another effective strategy is to use fluorescence quenchers in place of the acceptor, such as in the popular molecular beacons (MB) introduced by Tyagi and Kramer ( Figure 1B). ...

... Work to date has included a [Ru(bpy) 3 ] 2+ -based enzyme-cleavable sensor 25 and DNA sequences covalently labeled with RPCs to examine DNA− DNA assembly. 26,27 Studies employing a DNA-binding RPC as a FRET donor are even rarer, yet the potential for this was explored by Lakowicz et al., who demonstrated successful RET between [Ru(bpy) 2 (dppz)] 2+ and BO-PRO 3 when both molecules were intercalated to DNA. 28,29 A disadvantage of this was that two reversibly binding DNA molecules were employed, thereby introducing an additional variable that makes assay development problematic. ...