Correlations between clinical motor scores and CMAP in patients with type 2 spinal muscular amyotrophy treated with nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of the anterior horn cells of the spinal cord. Nusinersen for the treatment of SMA has been covered by public healthcare in France since May 2017.

OBJECTIVE

Our aim was to investigate whether there is a correlation between clinical and compound motor action potential (CMAP) measurements in SMA patients treated with nusinersen after 3  years' follow-up.

METHOD

Motor skills were evaluated regularly between M0 and M36 using the Motor Function Measure (MFM) score. CMAP measurements were collected regularly between M0 and M22.

RESULTS

Data for 10 patients with SMA type 2 were collected and divided into two age groups (< 5 years and > 5 years). Motor function improved, but not significantly, regarding distal motor skills (D3) in both groups, and in axial and proximal motor function (D2) in the younger group. CMAP measurements improved in all patients. CMAP increased significantly for the median nerve, and this improvement correlated significantly with global MFM and with axial and proximal tone (D2).

CONCLUSION

Our study shows gain in distal motor function with nusinersen, especially in younger patients with SMA type 2. These results encourage the screening of SMA patients and treatment as early as possible. CMAP measurements of the median nerve show clear improvement in patients treated with nusinersen and could be performed as routine follow-up.

Fluorine-18 and Radiometal Labeling of Biomolecules via Disulfide Rebridging

Biomolecules labeled with positron-emitting radionuclides like fluorine-18 or radiometals like copper-64 and zirconium-89 are increasingly employed in nuclear medicine for diagnosis purposes. Given the fragility and complexity of these compounds, their labeling requires mild conditions. Besides, it is essential to develop methods inducing minimal modification of the tertiary structure, as it is fundamental for the biological activity of such complex entities. Given these requirements, disulfide rebridging represents a promising possibility since it allows protein modification as well as conservation of the tertiary structure. In this context, we have developed an original radiofluorinated dibromopyridazine dione prosthetic group for labeling of disulfide-containing biomolecules via rebridging. We employed it to radiolabel octreotide, a somatostatin analogue, and to radiolabel fragment antigen binding (Fab) targeting programmed death-ligand 1 (PD-L1), whose properties were then evaluated in vitro and in vivo by positron emission tomography (PET) imaging. We next extended our strategy to the radiolabeling of cetuximab, a monoclonal antibody, with various radiometals commonly used in PET imaging (zirconium-89, copper-64) by developing various rebridging molecules bearing the appropriate chelators. The stabilities of the radiolabeled antibody conjugates were assessed in biological conditions.

NRP1 inhibition modulates radiosensitivity of medulloblastoma by targeting cancer stem cells

BACKGROUND

Medulloblastoma (MB) is the most common pediatric malignant brain tumor. Despite current therapies, the morbidity and recurrent risk remains significant. Neuropilin-1 receptor (NRP1) has been implicated in the tumor progression of MB. Our recent study showed that NRP1 inhibition stimulated MB stem cells differentiation. Consequently, we hypothesized that targeting NRP1 in medulloblastoma could improve current treatments.

METHODS

NRP1 inhibition with a novel peptidomimetic agent, MR438, was evaluated with radiotherapy (RT) in MB models (DAOY, D283-Med and D341-Med) in vitro on cancer stem-like cells as well as in vivo on heterotopic and orthotopic xenografts.

RESULTS

We show that NRP1 inhibition by MR438 radiosensitizes MB stem-like cells in vitro. In heterotopic DAOY models, MR438 improves RT efficacy as measured by tumor growth and mouse survival. In addition, clonogenic assays after tumor dissociation showed a significant reduction in cancer stem cells with the combination treatment. In the same way, a benefit of the combined therapy was observed in the orthotopic model only for a low cumulative irradiation dose of 10 Gy but not for 20 Gy.

CONCLUSIONS

Finally, our results demonstrated that targeting NRP1 with MR438 could be a potential new strategy and could limit MB progression by decreasing the stem cell number while reducing the radiation dose.

Is cardiac magnetic resonance of additional help in premature ventricular contraction work-up?

Background

Premature ventricular contractions (PVCs) are common in routine medical practice. PVCs are commonly asymptomatic but can also result in palpitations, dyspnea, presyncope or PVC-induced cardiomyopathy that may lead to sudden death. Cardiovascular magnetic resonance (CMR) provides morphological, functional, and tissue characterization in a single setting. CMR imaging proved to reliably identify fibrotic lesions and, hence, has developed into a valuable tool for etiological orientation in patients with PVCs.

Objectives

The aims of this study were: 1) to evaluate which ventricular arrythmia (VA) characteristics predicted CMR abnormalities and 2) the diagnostic yield and the impact in the management of CMR-based imaging versus non-CMR-based imaging in patients referred for PVCs.

Methods

This monocentric retrospective study was conducted in patients with PVCs referred for CMR imaging. Their baseline interview and characteristics, physical examination, surface electrocardiogram (ECG) analysis, ambulatory monitoring, echocardiography and treadmill exercise test data were collected when they were available. The CMR (1,5 T and 3.0 T) protocol included cine imaging and late gadolinium enhancement (LGE) using standard cardiac geometries.

Results

We analyzed 168 patients (65% males, mean age 54.2±16.8 years) referred to our center for PVCs over a two-year period. CMR reported abnormal findings in 73 patients (43.5%) with the diagnosis of structural heart disease (SHD) in 46 patients (27.4%). Left-ventricular late gadolinium-enhancement was documented in 43 patients with abnormal CMR. Using a multivariate analysis, age (p=0.026), sustained ventricular tachycardia (p=0.002) and presence of cardiomyopathy on echocardiography (p&lt;0.001) significantly predicted the presence of abnormal findings on CMR. Compared to non-CMR-based imaging, CMR had a diagnostic yield, by modifying the presumed diagnosis or by finding abnormalities requiring follow-up in 73 patients (43.5%).

Conclusions

Age, sustained ventricular tachycardia and presence of cardiomyopathy on echocardiography were the strongest predictors of positive CMR imaging results. Although echocardiography is generally used in first intention for the diagnosis of cardiomyopathy in patients with PVCs, this study showed that CMR-based imaging has a robust diagnostic yield in this indication.

Funding Acknowledgement

Type of funding sources: None.

Impact of Radiolabeling Strategies on the Pharmacokinetics and Distribution of an Anti-PD-L1 PET Ligand

Molecular imaging with PET offers an alternative method to quantify programmed-death-ligand 1 (PD-L1) to accurately select patients for immunotherapies. More and more clinical and preclinical trials involve radiolabeling of antibody fragments for their desirably fast clearance and high tumor penetration. As the radiolabeling strategy can significantly impact pharmacokinetics and biodistribution, we explored in this work a site-specific radiofluorination strategy on an anti-PD-L1 fragment antigen-binding (Fab) and compared the pharmacokinetic and biodistribution properties with the same Fab labeled using stochastic radiolabeling chemistry. We applied an enzymatic bioconjugation mediated by a variant of the lipoic acid ligase (LplA) that promotes the formation of an amide bond between a short peptide cloned onto the C terminus of the Fab. A synthetic analogue of the enzyme natural substrate, lipoic acid, was radiolabeled with fluorine-18 for site-specific conjugation by LplA. We compared the biodistribution of the site-specifically labeled Fab with a stochastically labeled Fab on lysine side chains in tumor-bearing mice. The two methods of fluorination demonstrate a comparable whole-body biodistribution. The ⁸⁹Zr-labeled Fab had different biodistribution compared to either ¹⁸F-labeled Fab. We attribute the difference to [⁸⁹Zr] metabolism. Fab-LAP-[¹⁸F]FPyOctA therefore reflects better the true pharmacokinetic profile of the Fab.

Novel [18F]-labeled thiol for the labeling of Dha- or maleimide-containing biomolecules

Background

Prosthetic approach for the radiolabeling of biologics with fluorine-18 is a robust strategy and has been employed for many years. It requires fast, biocompatible and selective reactions suited to these fragile molecules. Michael addition of a nucleophilic thiol moiety on α,β-unsaturated carbonyl entities is an interesting compromise between simplicity of preparation of the prosthetic reagent and control of the selectivity of the addition. The α,β-unsaturated carbonyl entity of the biologic can easily be generated by addition of a maleimide function using adequate heterobifunctional linkers or generated by selective modification of a cysteine residue leading to a dehydroalanine moiety. We report here the design, synthesis and radiosynthesis of a new fluoropyridine-based thiol [¹⁸F]FPySH and its conjugation via Michael addition on model dehydroalanine- or maleimide-containing biologics.

Results

The preparation of cold reference and labeling precursor of [¹⁸F]FPySH was achieved and its radiosynthesis was fully automated, enabling production of the thiol prosthetic group with a 7 ± 2.1% radiochemical yield after two steps. The conjugation of [¹⁸F]FPySH to two model Dha-containing molecules was then carried out in reducing conditions, yielding the corresponding adducts in 30–45 min reaction time. Furthermore, [¹⁸F]FPySH was employed to radiolabel the maleimide-modified c(RGDfK) peptide, affording the radiofluorinated analogue in 15 min.

Conclusion

We have developed an original [¹⁸F]-labeled thiol for site-selective conjugation and radiolabeling of Dha or maleimide-containing biomolecules of interest. Labeling of three model compounds was successfully carried out and gave the expected radiofluorinated adducts in less than 45 min, thus compatible with fluorine-18 half-life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41181-022-00160-5.

Unusual cause of obstructive shock following esophagectomy: a case report

Obstructive shock usually has an intrathoracic origin, such as pneumothorax, pericardial tamponade or pulmonary embolism. We report a case of hemo- dynamic shock in a 74-year-old patient four days after esophagectomy, just after the start of mechanical ventilation for bilateral pneumonia. The sudden onset of severe abdominal distension and the presence of air in the intra-abdominal drain suggested tension pneumoperitoneum, confirmed by radiography. No pneumothorax was associated. Urgent decompression was required to improve hemodynamics. Perforation of the gastrointestinal tract was ruled out. The cause was a bronchopleural fistula opened by mechanical ventilation. Rarely, cardiorespiratory failure may occur after tension pneumoperitoneum by reducing lung volume and cardiac preload, similar to obstructive shock from the usual intrathoracic causes or acting as an abdominal compartment syndrome (ACS). Its recognition and abdominal decompression are key steps in the patient’s recovery. Tension pneumoperitoneum related to mechanical ventilation and airway injury without associated pneumothorax is exceptional and, to our knowledge, has never been reported as a postoperative complication of esophagectomy.

Identification of TB space-time clusters and hotspots in Ouest département, Haiti, 2011-2016

BACKGROUND

Haiti has the highest incidence rate of TB in the Western Hemisphere, with an estimated 170 cases per 100,000 in 2019. Since 2010, control efforts have focused on targeted case-finding activities in urban areas, implementation of rapid molecular diagnostics at high-volume TB centers, and improved reporting. TB analyses are rarely focused on lower geographic units; thus, the major goal was to determine if there were focal areas of TB transmission from 2011 to 2016 at operational geographic levels useful for the National TB Control Program (PNLT).

METHODS

We created a geocoder to locate TB cases at the smallest geographic level. Kulldorff's space-time permutation scan, Anselin Moran's I, and Getis-Ord Gi* statistics were used to determine the spatial distribution and clusters of TB.

RESULTS

With 91% of cases linked using the geocoder, TB clusters were identified each year. Getis-Ord Gi* analysis revealed 14 distinct spatial clusters of high incidences in the Port-au-Prince metropolitan area. One hundred retrospective space-time clusters were detected.

CONCLUSION

Our study confirms the presence of TB hotspots in the Ouest département, with most clusters in the Port-au-Prince metropolitan area. Results will help the PNLT and its partners better design case-finding strategies for these areas.

Introducing new and repurposed TB drugs: the endTB experience

In 2015, the initiative Expand New Drug Markets for TB (endTB) began, with the objective of reducing barriers to access to the new and repurposed TB drugs. Here we describe the major implementation challenges encountered in 17 endTB countries. We provide insights on how national TB programmes and other stakeholders can scale-up the programmatic use of new and repurposed TB drugs, while building scientific evidence about their safety and efficacy. For any new drug or diagnostic, multiple market barriers can slow the pace of scale-up. During 2015-2019, endTB was successful in increasing the number of patients receiving new and repurposed TB drugs in 17 countries. The endTB experience has many lessons, which are relevant to country level introduction of new TB drugs, as well as non-TB drugs and diagnostics. For example: the importation of TB drugs is possible even in the absence of registration; emphasis on good clinical monitoring is more important than pharmacovigilance reporting; national guidelines and expert committees can both facilitate and hinder innovative practice; clinicians use new and repurposed TB drugs when they are available; data collection to generate scientific evidence requires financial and human resources; pilot projects can drive national scale-up.

Producing three-dimensional printed models of the hepatobiliary system from computed tomography imaging data

INTRODUCTION

Macroscopic anatomy has traditionally been taught using cadaveric material, lectures and a variety of additional resources including online modules and anatomical models. Traditional plastic models are effective educational tools yet they have significant drawbacks such as a lack of anatomical detail, a lack of texturisation and cost. Three-dimensional printed models stand to solve these problems and widen access to high-quality anatomical teaching. This paper outlines the use of three-dimensional multiplanar imaging (computed tomography) in the development of an accurate model of the hepatobiliary system.

MATERIALS AND METHODS

Computed tomography scans were used to construct a virtual three-dimensional model of the hepatobiliary system. This was printed locally as a full-size colour model. We give a complete account of the process and software used.

DISCUSSION

This study is among the first of a series in which we will document the newly formed Oxford Library of Anatomy. This series will provide the methodology for the production of three-dimensional models from computed tomography and magnetic resonance imaging scans, and the library will provide a complete collection of the most complex anatomical areas. We hope that these models will form an important adjunct in teaching anatomy to medical students and surgical trainees.

Feasibility of the single-incision subxiphoid approach for video-assisted thoracoscopic surgery in dogs

OBJECTIVES

To report early results of uniportal video-assisted thoracoscopic surgery in dogs using a single-incision subxiphoid approach.

MATERIALS AND METHODS

Retrospective study of 10 client-owned dogs with: pyothorax (n=5), pericardial effusion (n=2), bilateral pneumothorax (n=1), retained surgical swab (n=1), cranial mediastinal mass (n=1). With the dog in dorsal recumbency a 3-4 cm incision was made over the xiphoid process. After resection of the xiphoid process, a tunnel was created towards the pleura and open access maintained with an Alexis™ wound retractor. The pleural cavity was explored with a 10 mm 30° or 5 mm 0° telescope and straight laparoscopic instruments.

RESULTS

Median surgical time was 75 minutes. The SISA technique was performed successfully in five of 10 cases and allowed easy and adequate inspection of the intra-thoracic structures. One case was converted to lateral thoracotomy after laceration of the vena cava and one converted to median sternotomy because of adhesions. An additional port was placed in three cases to facilitate triangulation and surgical manipulation. No other intra-operative complications were encountered.

CLINICAL SIGNIFICANCE

In this initial report of uniportal thoracic approach in dogs, this technique allowed excellent access and treatment of mediastinal structures. Further cases are required to assess its suitability for pulmonary surgery.

Original synthesis of radiolabeling precursors for batch and on resin one-step/late-stage radiofluorination of peptides

Radiolabeling of peptides with fluorine-18 is hurdled by their chemical sensitivity and complicated processes. Original triflyl-pyridine intermediates afforded ammonium precursors that were radiolabeled at low temperature. From that study, a generic tag has been designed to allow a simple one-step/late-stage radiolabelling of peptides. The strategy has been transposed to an automated "on-resin" radiolabelling.

[18 F]FPyZIDE: A versatile prosthetic reagent for the fluorine-18 radiolabeling of biologics via copper-catalyzed or strain-promoted alkyne-azide cycloadditions

Methods for the radiolabeling of biologics with fluorine-18 have been of interest for several decades. A common approach consists in the preparation of a prosthetic reagent, a small molecule bearing a fluorine-18 that is conjugated with the macromolecule to an appropriate function. Click chemistry, and more particularly cycloadditions, is an interesting approach to radiolabel molecules thanks to mild reaction conditions, high yields, low by-products formation, and strong orthogonality. Moreover, the chemical functions involved in the cycloaddition reaction are stable in the drastic radiofluorination conditions, thus allowing a simple radiosynthetic route to prepare the prosthetic reagent. We report herein the radiosynthesis of ¹⁸ F-FPyZIDE, a pyridine-based azide-bearing prosthetic reagent. We exemplified its conjugation via copper-catalyzed cycloaddition (CuAAC) and strain-promoted cycloaddition (SPAAC) with several terminal alkyne or strained alkyne model compounds.

New fluorine-18 pretargeting PET imaging by bioorthogonal chlorosydnone–cycloalkyne click reaction

A PET pretargeting approach using strain-promoted sydnone–alkyne cycloaddition.

Loss to follow-up among patients receiving anti-tuberculosis treatment, Haiti, 2011-2015

Setting: Tuberculosis (TB) treatment facilities in Haiti. Objective: To assess factors associated with loss to follow-up (LTFU) among patients receiving treatment for tuberculosis (TB) in Haiti. Design: We analyzed Haiti's national surveillance data for patients started on anti-tuberculosis treatment from 2011 to 2015 to determine factors associated with LTFU using multivariable logistic regression and describe LTFU in terms of subnational units to target future intervention strategies. We also conducted a survival analysis to estimate hazard ratios of factors associated with time to LTFU. Results: Of 81 490 TB cases reported, 7423 (9.1%) were LTFU during anti-tuberculosis treatment, increasing from 7.1% in 2011 to 10.3% in 2015. Six high-volume facilities had significantly higher rates of LTFU (14.3-31.9%) than the rest of the country, accounting for 18.8% of all TB cases reported, but 41.7% of all LTFU patients. Male sex, previous treatment history, and human immunodeficiency virus infection were associated with higher rates of LTFU. The median time to LTFU was 94 days. Conclusion: A small number of facilities accounted for disproportionately high rates of LTFU. These results identify characteristics of facilities and individuals leading to concentrated interventions to reduce LTFU and improve treatment success.

Stimulation of medulloblastoma stem cells differentiation by a peptidomimetic targeting neuropilin-1

Medulloblastoma (MB) is the most common malignant pediatric brain tumor. Despite the progress of new treatments, the risk of recurrence, morbidity, and death remains important. The neuropilin-1 (NRP-1) receptor has recently been implicated in tumor progression of MB, which seems to play an important role in the phenotype of cancer stem cells. Targeting this receptor appears as an interesting strategy to promote MB stem cells differentiation. Cancer stem-like cells of 3 MB cell lines (DAOY, D283-Med and D341-Med), classified in the more pejorative molecular subgroups, were obtained by in vitro enrichment. These models were characterized by an increase of NRP-1 and cancer stem cell markers (CD15, CD133 and Sox2), meanwhile a decrease of the differentiated cell marker Neurofilament-M (NF-M) was observed. Our previous work investigated potential innovative peptidomimetics that specifically target NRP-1 and showed that MR438 had a good affinity for NRP-1. This small molecule decreased the self-renewal capacity of MB stem cells for the 3 cell lines and reduced the invasive ability of DAOY and D283 stem cells while NRP-1 expression and cancer stem cell markers decreased at the same time. Possible molecular mechanisms were explored and showed that the activation of PI3K/AKT and MAPK pathways significantly decreased for DAOY cells after treatment. Finally, our results highlighted that targeting NRP-1 with MR438 could be a potential new strategy to differentiate MB stem cells and could limit medulloblastoma progression.

Downregulation of heat shock protein B8 decreases osteogenic differentiation potential of dental pulp stem cells during in vitro proliferation

OBJECTIVES

Tissue-derived stem cells, such as dental pulp stem cells (DPSCs), reduce differentiation capability during in vitro culture. We found that cultured DPSCs reduce expression of heat shock protein B8 (HspB8) and GIPC PDZ domain containing family member 2 (Gipc2). Our objectives were to evaluate the changes in DPSC composition during in vitro proliferation and to determine whether HspB8 and Gipc2 have function in differentiation potential of DPSCs.

MATERIALS AND METHODS

Different passages of rat DPSCs were evaluated for changes in CD90+ and/or CD271+ stem cells and changes in osteogenic potential. Real-time RT-PCR and immunostaining were conducted to determine expression of HspB8 and Gipc2. Expression of the genes in DPSCs was knocked down by siRNA, followed by osteogenic induction to evaluate the function of the genes.

RESULTS

About 90% of cells in the DPSC cultures were CD90+ and/or CD271+ cells without dramatic change during in vitro proliferation. The DPSCs at passages 3 to 5 (P3 to P5) possess strong osteogenic potential, but such potential was greatly reduced at later passages. Expression of HspB8 and Gipc2 was significantly reduced at P11 versus P3. Knock-down of HspB8 expression abolished osteogenic potential of the DPSCs, but knock-down of Gipc2 had no effect.

CONCLUSIONS

CD90+ and CD271+ cells are the major components of DPSCs in in vitro culture. High-level expression of HspB8 was critical for maintaining differentiation potential of DPSCs.

Strain-Gradient Position Mapping of Semiconductor Quantum Dots

We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35  nm down to ±1  nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.

Limit theorems for supercritical age-dependent branching processes with neutral immigration

We consider a branching process with Poissonian immigration where individuals have inheritable types. At rate θ, new individuals singly enter the total population and start a new population which evolves like a supercritical, homogeneous, binary Crump-Mode-Jagers process: individuals have independent and identically distributed lifetime durations (nonnecessarily exponential) during which they give birth independently at a constant rateb. First, using spine decomposition, we relax previously known assumptions required for almost-sure convergence of the total population size. Then, we consider three models of structured populations: either all immigrants have a different type, or types are drawn in a discrete spectrum or in a continuous spectrum. In each model, the vector (P1,P2,…) of relative abundances of surviving families converges almost surely. In the first model, the limit is the GEM distribution with parameter θ /b.

Toward evidence-based medical statistics: Re-evaluate the efficacy of antidepressants by using Bayes factors

Introduction

Studies have been reported the similar efficacy of antidepressants (effect size around 0.3), and it is difficult for clinicians to select an antidepressant. This may partly due to the use of a p<.05 null-hypothesis significance testing (NHST) framework to evaluate “substantial evidence”. This framework only allows dichotomous conclusions and does not quantify the strength of evidence supporting efficacy. In addition, meta-analyses based on publications may offer positively biased results due to selective publications.

Objectives

Demonstrate that the Bayesian framework can provide valuable information on the strength of the evidence for drug efficacy.

Aims

Re-evaluate the efficacy of FDA-approved antidepressants applied to anxiety disorders and depression by means of Bayes factors.

Methods

To avoid selective publication, data of double-blind placebo-controlled trials for FDA-approved antidepressants for the treatment of anxiety disorders and depression were extracted from the FDA. Bayes factors (BFs) were calculated and compared with the results obtained under NHST framework.

Results

A large variance of evidence for the efficacy of antidepressants was found for both depression and anxiety disorders. Among trials providing “substantial evidence” according to the FDA for anxiety disorders, only 27 out of 59 dose groups obtained strong support for efficacy according to the typically used cut-off of BF≥20. For depression, all FDA-approved antidepressants had BF≥20, except for bupriopion. Moreover, it was shown that the tested antidepressants can be differentiated based on the strength of evidence and effect size.

Conclusions

The BFs quantified the comparative evidence base for the efficacy of antidepressants.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Enrichir les classifications en psychiatrie par les données textuelles : création d’une ontologie de la psychiatrie

Le projet Covalmo s’est développé en partenariat entre le centre hospitalier Sainte-Anne et le Laboratoire d’Ingénierie des Connaissances en e-Santé. L’objectif premier de Covalmo, situé à mi-chemin entre l’Informatique et la Médecine, est d’expliciter l’ensemble des déterminants possibles de maladies psychiatriques dans le but de contribuer au développement d’un consensus sur les catégories descriptives des troubles psychiatriques, au travers d’outils et méthodes de l’Ingénierie des Connaissances. Covalmo vise ainsi au développement d’outils répondants à deux problématiques : (1) mieux décrire les diagnostics posés et les actes pratiqués, et ainsi (2) mieux indexer les dossiers patient. L’Ingénierie des Connaissances traite de la modélisation des connaissances et des problématiques qui y sont liées. Pour cela, elle développe des ontologies informatiques, qui sont des modèles permettant de recenser, organiser et lier des concepts entre eux grâce aux relations qui les unissent. Les concepts sont des entités ayant un sens dans le domaine représenté, et les relations sont les liens sémantiques entretenus entre ces concepts. Le développement de l’ontologie du domaine de la psychiatrie, OntoPsychia, est réalisé à partir des informations contenues dans un corpus textuel composé de 8000 CRH préalablement anonymisés selon un protocole strict. L’hypothèse de base de ce travail étant que les mots et les différentes verbalisations présentes dans les textes sont des traces de la conceptualisation du domaine et peuvent être utilisés pour construire l’ontologie. Les différentes nomenclatures utilisées depuis dix ans pour annoter les dossiers patients (CIM-10, DSM, ATC) sont aussi utilisées pour enrichir l’ontologie.

La validation de l’ontologie sera effectuée par les experts du domaine, ainsi que par sa mise en opérationnalisation au sein d’applications dédiées, par exemple : indexation de comptes rendus et de dossiers patients ou découverte de profils de patients résistants aux traitements médicamenteux. Ci-dessous, un extrait du module d’OntoPsychia modélisant la vie sociale (Fig. 1).

Strain-mediated coupling in a quantum dot-mechanical oscillator hybrid system

Recent progress in nanotechnology has allowed the fabrication of new hybrid systems in which a single two-level system is coupled to a mechanical nanoresonator. In such systems the quantum nature of a macroscopic degree of freedom can be revealed and manipulated. This opens up appealing perspectives for quantum information technologies, and for the exploration of the quantum-classical boundary. Here we present the experimental realization of a monolithic solid-state hybrid system governed by material strain: a quantum dot is embedded within a nanowire that features discrete mechanical resonances corresponding to flexural vibration modes. Mechanical vibrations result in a time-varying strain field that modulates the quantum dot transition energy. This approach simultaneously offers a large light-extraction efficiency and a large exciton-phonon coupling strength g0. By means of optical and mechanical spectroscopy, we find that g0/2 π is nearly as large as the mechanical frequency, a criterion that defines the ultrastrong coupling regime.