Raman spectroscopy is commonly used to determine the number of layers of few-layer graphene (FLG)samples. In this work, we focus on the criteria based on the G-band integrated intensity and on the laseroptical contrast. Limitations due to stacking order are discussed and lead to the conclusion that it isnecessary to combine Raman and optical contrast to avoid misinterpretation. Both methods enable todistinguish unambiguously between single layer graphene and multilayer graphene. However, neithereach method separately nor the combination of the two enable a determination of the number of layers forall possible stacking orientations. Importantly, since the two methods always significantly disagree whenthey fail, the comparison of the values deduced by each method allows to discriminate if the determinednumber of layers can be specified or not. Other important parameters (substrate, laser wavelength,objective numerical aperture) are discussed to define a reliable method to determine the number ofgraphene layers in FLG and its domain of validity. The proposed method which combines Raman andoptical contrast measurements, carried out with a 532 nm laser and using a 100x objective with anumerical aperture of 0.9, allows the determination of the number of layers for (up to 5) FLG on thefollowing substrates: (i) glass (soda lime glass or similar with refractive index between 1.50 and 1.55) and(ii) oxidized silicon (SiO2 on silicon, with a SiO2 thickness of 90 ± 5 nm). The method is however limited tohigh quality graphene and FLG with small defect density and low residue.

Spinal cord injuries (SCI) lead to major disabilities affecting > 2.5 million people worldwide. Major shortcomings in clinical translation result from multiple factors, including species differences, development of moderately predictive animal models, and differences in methodologies between preclinical and clinical studies. To overcome these obstacles, we first conducted a comparative neuroanatomical analysis of the spinal cord between mice, Microcebus murinus (a nonhuman primate), and humans. Next, we developed and characterized a new model of lateral spinal cord hemisection in M. murinus. Over a 3-month period after SCI, we carried out a detailed, longitudinal, behavioral follow-up associated with in vivo magnetic resonance imaging (1H-MRI) monitoring. Then, we compared lesion extension and tissue alteration using 3 methods: in vivo 1H-MRI, ex vivo 1H-MRI, and classical histology. The general organization and glial cell distribution/morphology in the spinal cord of M. murinus closely resembles that of humans. Animals assessed at different stages following lateral hemisection of the spinal cord presented specific motor deficits and spinal cord tissue alterations. We also found a close correlation between 1H-MRI signal and microglia reactivity and/or associated post-trauma phenomena. Spinal cord hemisection in M. murinus provides a reliable new nonhuman primate model that can be used to promote translational research on SCI and represents a novel and more affordable alternative to larger primates.