Abstract: Disclosed are a 1,8-naphthalimide derivative, a preparation method therefor and a use thereof. The 1,8-naphthalimide derivative is easy to prepare, and is an enhanced Cu2+ fluorescent probe, which can detect Cu2+ by two wavelengths and be applied to almost-all-water systems. According to atitration experiments and blank experiments at 392 nm and 754 nm, the detection limit of the 1,8-naphthalimide derivative of the present invention for Cu2+ is 2.6368×10?7 mol/L and 2.0156×10?7 mol/L, respectively, indicating that same can perform quantitative detection for Cu2+ with a high selectivity and a high sensitivity by using two wavelengths. In addition, a pH colorimetric switch based on 1,8-naphthalimide can rapidly and reversibly respond to a pH by means of three ways: a maximum absorption wavelength, absorbance and color change. Same has a narrow switching pH range, a good selectivity and a high sensitivity, can be used in almost-all-water systems.

Abstract: Disclosed are a 1,8-naphthalimide derivative, a preparation method therefor and a use thereof. The 1,8-naphthalimide derivative is easy to prepare, and is an enhanced Cu2+ fluorescent probe, which can detect Cu2+ by two wavelengths and be applied to almost-all-water systems. According to atitration experiments and blank experiments at 392 nm and 754 nm, the detection limit of the 1,8-naphthalimide derivative of the present invention for Cu2+ is 2.6368×10?7 mol/L and 2.0156×10?7 mol/L, respectively, indicating that same can perform quantitative detection for Cu2+ with a high selectivity and a high sensitivity by using two wavelengths. In addition, a pH colorimetric switch based on 1,8-naphthalimide can rapidly and reversibly respond to a pH by means of three ways: a maximum absorption wavelength, absorbance and color change. Same has a narrow switching pH range, a good selectivity and a high sensitivity, can be used in almost-all-water systems.

Abstract: We present a method for informed optimization of sampling vectors in multi-directional diffusion-weighted magnetic resonance imaging. The advantage of this optimization is that it is informed rather than being a naïve optimization of sampling vectors. Typically, sampling vectors are set relatively uniformly along a spherical surface. In this case, a scan at high imaging resolutions utilizes sampling vectors that are chosen based on the knowledge of the overall orientation distribution for the entire sample or region of interest. This overall orientation distribution is obtained by performing multi-directional diffusion-weighted scans at high angular resolution, but low or minimal voxel resolution. A subset of the vectors used in this high-angular-resolution scan is chosen to minimize the error in the final results. This optimal subset is not necessarily uniform in space.