107 research outputs found
Note sur des <i>Aporrhais pespelicani</i> L. (Mollusque gastéropode marin) provenant de l'Adriatique et recueillis vivants à Ostende
Dynamics of Rumor Spreading in Complex Networks
We derive the mean-field equations characterizing the dynamics of a rumor
process that takes place on top of complex heterogeneous networks. These
equations are solved numerically by means of a stochastic approach. First, we
present analytical and Monte Carlo calculations for homogeneous networks and
compare the results with those obtained by the numerical method. Then, we study
the spreading process in detail for random scale-free networks. The time
profiles for several quantities are numerically computed, which allow us to
distinguish among different variants of rumor spreading algorithms. Our
conclusions are directed to possible applications in replicated database
maintenance, peer to peer communication networks and social spreading
phenomena.Comment: Final version to appear in PR
Lensfree diffractive tomography for the imaging of 3D cell cultures
International audienceNew microscopes are needed to help realize the full potential of 3D organoid culture studies. In order to image large volume of 3D organoid cultures while preserving the ability to catch every single cell, we propose a new imaging platform based on lensfree microscopy. We have built a lensfree diffractive tomography setup performing multi-angle acquisitions of 3D organoid culture embedded in Matrigel ® and developed a dedicated 3D holographic reconstruction algorithm based on the Fourier diffraction theorem. With this new imaging platform, we have been able to reconstruct a 3D volume as large as 21.5 mm 3 of a 3D organoid culture of prostatic RWPE1 cells showing the ability of these cells to assemble in 3D intricate cellular network at the mesoscopic scale. Importantly, comparisons with 2D images show that it is possible to resolve single cells isolated from the main cellular structure with our lensfree diffractive tomography setup
Direct transfection of clonal organoids in matrigel microbeads : a promising approach toward organoid-based genetic screens
Organoid cultures in 3D matrices are relevant models to mimic the complex in vivo environment that supports cell physiological and pathological behaviors. For instance, 3D epithelial organoids recapitulate numerous features of glandular tissues including the development of fully differentiated acini that maintain apico-basal polarity with hollow lumen. Effective genetic engineering in organoids would bring new insights in organogenesis and carcinogenesis. However, direct 3D transfection on already formed organoids remains challenging. One limitation is that organoids are embedded in extracellular matrix and grow into compact structures that hinder transfection using traditional techniques. To address this issue, we developed an innovative approach for transgene expression in 3D organoids by combining single-cell encapsulation in Matrigel microbeads using a microfluidic device and electroporation. We demonstrate that direct electroporation of encapsulated organoids reaches up to 80% of transfection efficiency. Using this technique and a morphological read-out that recapitulate the different stages of tumor development, we further validate the role of p63 and PTEN as key genes in acinar development in breast and prostate tissues. We believe that the combination of controlled organoid generation and efficient 3D transfection developed here opens new perspectives for flow-based high-throughput genetic screening and functional genomic applications
Reply to "Comment on: 'Case for a U(1) Quantum Spin Liquid Ground State in the Dipole-Octupole Pyrochlore ' "
In his comment [arXiv:2209.03235], S. W. Lovesey argues that our analysis of
neutron scattering experiments performed on CeZrO is invalid.
Lovesey argues that we have not properly accounted for the higher-order
multipolar contributions to the magnetic scattering and that our use of
pseudospin- operators to describe the scattering is inappropriate. In this
reply, we show that the multipolar corrections discussed by Lovesey only become
significant at scattering wavevectors exceeding those accessed in our
experiments. This in no way contradicts or undermines our work, which never
claimed a direct observation of scattering from higher-order multipoles. We
further show that Lovesey's objections to our use of pseudospins are unfounded,
and that the pseudospin operators are able to describe all magnetic scattering
processes at the energy scale of our experiments, far below the crystal field
gap. Finally, we comment on certain assumptions in Lovesey's calculations of
the scattering amplitude which are inconsistent with experiment.Comment: 6 pages, 1 figur
Normalized STEAM-based diffusion tensor imaging provides a robust assessment of muscle tears in football players: preliminary results of a new approach to evaluate muscle injuries
- …