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Gd3+- free carbon dots (CDs) were synthesized by one-step solvothermal method using urea, citric acid and 3-(trifluoromethyl)aniline as precursors. Additionally, Gd3+-doped CDs were prepared by incorporating gadolinium chloride (Gd3+ ions) into the synthesis. Size selection of the purified CDs was achieved through filter membranes ranging from 3 kDa to 100 kDa. The chemical composition and optical properties of the obtained samples were characterized by Energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), Dynamic Light Scattering (DLS), proton relaxation time measurements, Ultraviolet–visible (UV-vis) and fluorescence spectroscopies. A comparative analysis revealed a strong size-dependent behavior in the optical properties of both Gd3+-doped and Gd3+-free CDs. Furthermore, in vitro tests confirmed the non-cytotoxicity of Gd3+-doped CDs, indicating their potential applicability in biomedicine for magnetic resonance imaging (MRI) and red fluorescence-based cell and tissue imaging. [ABSTRACT FROM AUTHOR]

The domain-structure of samples containing a series of starch/poly(sodium acrylate)-grafted superabsorbents, pure starch, pure poly(sodium acrylate), and blend of starch/poly(sodium acrylate) has been studied by high-resolution solid-state 13C NMR spectroscopy at room temperature. The result shows that the crystallinity of starch decreases greatly in the grafted and blended samples. The values of 1H spin-lattice relaxation time in rotating frame T 1 ρ and 1H spin-lattice relaxation time T 1 shows that starch and poly(sodium acrylate) components in both grafted and blended samples have good compatibility in nanometer scale. In the 13C cross-polarization/magic-angle-spinning (CP/MAS) spectra, the chemical shift of the carbonyl group of poly(sodium acrylate) depends on the composition of the grafting samples, which indicates that the starch and the poly(sodium acrylate) components of the grafting samples exhibit better compatibility with each other than that of blended samples at molecular level. [ABSTRACT FROM AUTHOR]

It is generally accepted that the water content in the brain tissue of immature animals is so great as to be responsible for the prolongation of proton relaxation time, namely, the spin-lattice relaxation time (T) and the spin-spin relaxation time (T). In assessing edema in the immature rat brain with the passage of time, we measured the water content, T, and T, and then compared these parameters with those in rats aged 5 weeks. Traumatic cerebral edema was experimentally produced in immature rats aged 7 days (group A) and mature rats aged 5 weeks (group B). In group A, the water content of the gray matter and the white matter increased significantly on the 1st day after the development of experimental brain edema, continued at a high level in white matter, but normalized in gray matter on the 7th day. On the other hand, for group B, the water content of gray and white matter also increased significantly 1 day after the production of the brain edema, but was reduced to within the normal range on the 7th day for both regions. [ABSTRACT FROM AUTHOR]