Scanning Electron Microscope (SEM) is a powerful research tool, but since it requires high vacuum conditions, the wet materials and biological samples must undergo a complex preparation that limits the application of SEM on this kind of specimen and often causes the introduction of artifacts. The introduction of Environmental Scanning Electron Microscope (ESEM), working in gaseous atmosphere, represented a new perspective in biological research. Despite the fact that many biological applications have demonstrated the convenience of ESEM, the full potentialities of this technology are still under investigation. In this review, the exploration of the recent literature data confronted with the first results obtained in our experimental work suggest that ESEM represents an important extension of conventional scanning microscopy.

Abstract. A method to extract turbulent statistics from three-dimensional (3D) PIV measurements via ensemble averaging is presented. The proposed technique is a 3D extension of the ensemble particle tracking velocimetry methods, which consist in summing distributions of velocity vectors calculated on low image density samples and then extract the statistical moments from the velocity vectors within sub-volumes, with the size of the sub-volume depending on the desired number of particles and on the available number of snapshots.The extension to 3D measurements poses the additional difficulty of sparse velocity vectors distributions, thus requiring a large number of snapshots to achieve high resolution measurements with a sufficient degree of accuracy. At the current state, this hinders the achievement of single-voxel measurements, unless millions of samples are available. Consequently, one has to give up spatial resolution and live with still relatively large (if compared to the voxel) sub-volumes. This leads to the further problem of the possible occurrence of a residual mean velocity gradient within the subvolumes, which significantly contaminates the computation of second order moments.In this work, we propose a method to reduce the residual gradient effect, allowing to reach high resolution even with relatively large interrogation spots, therefore still retrieving a large number of particles on which it is possible to calculate turbulent statistics. The method consists in applying a polynomial fit to the velocity distributions within each sub-volume trying to mimic the residual mean velocity gradient.

We study the self-similarity and dissipation scalings of a turbulent planar jet and the theoretically implied mean flow scalings. Unlike turbulent wakes where such studies have already been carried out (Dairay et al. 2015 J. Fluid Mech . 781 , 166–198. ( doi:10.1017/jfm.2015.493 ); Obligado et al. 2016 Phys. Rev. Fluids 1 , 044409. ( doi:10.1103/PhysRevFluids.1. 044409)), this is a boundary-free turbulent shear flow where the local Reynolds number increases with distance from inlet. The Townsend–George theory revised by (Dairay et al. 2015 J. Fluid Mech . 781 , 166–198. ( doi:10.1017/jfm.2015.493 )) is applied to turbulent planar jets. Only a few profiles need to be self-similar in this theory. The self-similarity of mean flow, turbulence dissipation, turbulent kinetic energy and Reynolds stress profiles is supported by our experimental results from 18 to at least 54 nozzle sizes, the furthermost location investigated in this work. Furthermore, the non-equilibrium dissipation scaling found in turbulent wakes, decaying grid-generated turbulence, various instances of periodic turbulence and turbulent boundary layers (Dairay et al. 2015 J. Fluid Mech . 781 , 166–198. ( doi:10.1017/jfm.2015.493 ); Vassilicos 2015 Annu. Rev. Fluid Mech . 95 , 114. ( doi:10.1146/annurev-fluid-010814-014637 ); Goto & Vassilicos 2015 Phys. Lett. A 3790 , 1144–1148. ( doi:10.1016/j.physleta.2015.02.025 ); Nedic et al. 2017 Phys. Rev. Fluids 2 , 032601. ( doi:10.1103/PhysRevFluids.2.032601 )) is also observed in the present turbulent planar jet and in the turbulent planar jet of (Antonia et al. 1980 Phys. Fluids 23 , 863055. ( doi:10.1063/1.863055 )). Given these observations, the theory implies new mean flow and jet width scalings which are found to be consistent with our data and the data of (Antonia et al. 1980 Phys. Fluids 23 , 863055. ( doi:10.1063/1.863055 )). In particular, it implies a hitherto unknown entrainment behaviour: the ratio of characteristic cross-stream to centreline streamwise mean flow velocities decays as the −1/3 power of streamwise distance in the region, where the non-equilibrium dissipation scaling holds.

Human adipose tissues surgically resected from the subcutaneous abdominal region were enzymatically processed to obtain Human Adipose Stem cells (fibroblast-like adipose tissue-derived stromal cells-ADSC-FL) that were immunophenotypically characterized using a panel of mesenchymal markers by flow cytometry. The formation of new hydroxyapatite crystals in culture dishes, by differentiating cells, further demonstrate the osteogenic potential of purified cells. The aim of this study was to evaluate the osteogenic differentiation potential of ADSC-FL seeded onto a porous beta-tricalcium phosphate (beta-TCP) matrix. ADSC-FL was cultured on the beta-TCP matrix in medium with or without osteogenic differentiation additives. Time-dependent cell differentiation was monitored using osteogenic markers such as alkaline phosphatase (activity assay), osteocalcin and ostopontin (ELISA method) expression. Our results reveal that beta-TCP triggers the differentiation of ADSC-FL toward an osteoblastic phenotype irrespective of whether the cells are grown in a proliferative or a differentiative medium. Hence, a beta-TCP matrix is sufficient to promote osteoblastic differentiation of ADSC-FL. However, in proliferative medium, alkaline phosphatase activity was detected at lower level respect to differentiative medium and osteocalcin and osteopontin showed an expression delay in cells cultured in proliferative medium respect to differentiative one. Moreover, we observed an increase in FAK phosphorylation at level of tyrosine residue in position 397 (Western-blot) that indicates a good cell adhesion to beta-TCP scaffold. In conclusion, our paper demonstrates that a three-dimensional beta-TCP scaffold in vitro triggers on its own the differentiation of ADSC-FL toward an osteoblastic phenotype without the need to use differentiative media.