Comparison between classical potentials and ab initio for silicon under large shear

The homogeneous shear of the {111} planes along the <110> direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials to complement this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localization of shear in the shuffle set

Dislocation formation from a surface step in semiconductors: an ab initio study

The role of a simple surface defect, such as a step, for relaxing the stress applied to a semiconductor, has been investigated by means of large scale first principles calculations. Our results indicate that the step is the privileged site for initiating plasticity, with the formation and glide of 60$^\circ$ dislocations for both tensile and compressive deformations. We have also examined the effect of surface and step termination on the plastic mechanisms

Evaluation et calibration d'un LIDAR DIAL Expérience avec SO2 et O3

National audienceLes appareils de mesures de la pollution atmospherique en reseau font l'objet d'une evaluation selon un mode operatoire precise dans la norme NF X20-300 en vue de determiner leurs principales caracteristiques metrologiques

Learning fluid trajectory models for time-resolved PIV

International audienceWe present a new multiframe cross-correlation (Lucas-Kanade based) algorithm for time-resolved PIV. This algorithm leverages time coherence in image sequences by decomposing the temporal dependency of motion on an arbitrarily chosen trajectory basis. We propose to learn this basis from the data by performing a Principal Component Analysis on trajectories sampled from the studied sequence. We show on simulated data that such an approach can outperform the polynomial models classically used in multiframe PIV

Epigenetic status of H19/IGF2 and SNRPN imprinted genes in aborted and successfully derived embryonic stem cell lines in non-human primates

AbstractThe imprinted genes of primate embryonic stem cells (ESCs) often show altered DNA methylation. It is unknown whether these alterations emerge while deriving the ESCs. Here we studied the methylation patterns of two differentially methylated regions (DMRs), SNRPN and H19/IGF2 DMRs, during the derivation of monkey ESCs. We show that the SNRPN DMR is characteristically methylated at maternal alleles, whereas the H19/IGF2 DMR is globally highly methylated, with unusual methylation on the maternal alleles. These methylation patterns remain stable from the early stages of ESC derivation to late passages of monkey ESCs and following differentiation. Importantly, the methylation status of H19/IGF2 DMR and the expression levels of IGF2, H19, and DNMT3B mRNAs in early embryo-derived cells were correlated with their capacity to generate genuine ESC lines. Thus, we propose that these markers could be useful to predict the outcomes of establishing an ESC line in primates

A short G1 phase is an intrinsic determinant of naïve embryonic stem cell pluripotency

AbstractA short G1 phase is a characteristic feature of mouse embryonic stem cells (ESCs). To determine if there is a causal relationship between G1 phase restriction and pluripotency, we made use of the Fluorescence Ubiquitination Cell Cycle Indicator (FUCCI) reporter system to FACS-sort ESCs in the different cell cycle phases. Hence, the G1 phase cells appeared to be more susceptible to differentiation, particularly when ESCs self-renewed in the naïve state of pluripotency. Transitions from ground to naïve, then from naïve to primed states of pluripotency were associated with increased durations of the G1 phase, and cyclin E-mediated alteration of the G1/S transition altered the balance between self-renewal and differentiation. LIF withdrawal resulted in a lengthening of the G1 phase in naïve ESCs, which occurred prior to the appearance of early lineage-specific markers, and could be reversed upon LIF supplementation. We concluded that the short G1 phase observed in murine ESCs was a determinant of naïve pluripotency and was partially under the control of LIF signaling

Assessment of risk factors of treatment discontinuation among patients on paliperidone palmitate and risperidone microspheres in France, Germany and Belgium

BACKGROUND: Long-acting antipsychotics (e.g. 1-monthly (PP1M) / 3-monthly (PP3M) injection forms of paliperidone palmitate) have been developed to improve treatment continuation in schizophrenia patients. We aim to assess risk factors of treatment discontinuation of patients on paliperidone palmitate and risperidone microsphere. Additionally, treatment discontinuation between patients with PP1M and PP3M was compared. METHODS: The IQVIA Longitudinal Prescription databases were used. Risk factors of treatment discontinuation were identified by a multilevel survival regression using Cox proportional hazards model. Kaplan Meier analyses were performed by identified significant risk factors. RESULTS: Twenty-five thousand three hundred sixty-one patients (France: 9,720; Germany: 14,461; Belgium: 1,180) were included. Over a one-year follow-up period, a significant lower treatment discontinuation was observed for patients newly initiated on paliperidone palmitate (53.8%) than those on risperidone microspheres (85.4%). Additionally, a significantly lower treatment discontinuation was found for ‘stable’ PP3M patients (19.2%) than ‘stable’ PP1M patients (37.1%). Patients were more likely to discontinue when drugs were prescribed by GP only (HR = 1.68, p  50 years: HR = 0.91, p < 0.001 vs. 18–30 years). CONCLUSIONS: This study demonstrates that patients stay significantly longer on treatment when initiated on paliperidone palmitate as compared to risperidone microspheres. It also indicated a higher treatment continuation of PP3M over PP1M. Treatment continuation is likely to be improved by empowering GPs with mental health knowledge and managing patients by a collaborative primary care-mental health model. Further research is needed to understand why females and younger patients have more treatment discontinuation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-022-03914-2