Competing ferromagnetic and nematic alignment in self-propelled polar particles

We study a Vicsek-style model of self-propelled particles where ferromagnetic and nematic alignment compete in both the usual "metric" version and in the "metric-free" case where a particle interacts with its Voronoi neighbors. We show that the phase diagram of this out-of-equilibrium XY model is similar to that of its equilibrium counterpart: the properties of the fully-nematic model, studied before in [F. Ginelli, F. Peruani, M. Baer, and H. Chat\'e, Phys. Rev. Lett. 104, 184502 (2010)], are thus robust to the introduction of a modest bias of interactions towards ferromagnetic alignment. The direct transitions between polar and nematic ordered phases are shown to be discontinuous in the metric case, and continuous, belonging to the Ising universality class, in the metric-free version

Large-scale chaos and fluctuations in active nematics

We show that "dry" active nematics, e.g. collections of shaken elongated granular particles, exhibit large-scale spatiotemporal chaos made of interacting dense, ordered, band-like structures in a parameter region including the linear onset of nematic order. These results are obtained from the study of the relatively simple and well-known (deterministic) hydrodynamic equations describing these systems in a dilute limit, and of a self-propelled particle Vicsek-like model for this class of active matter. In this last case, revisiting the status of the strong fluctuations and long-range correlations now considered as landmarks of orientationally-ordered active phases, we show that the giant number fluctuations observed in the chaotic phase are a trivial consequence of density segregation. However anomalous density fluctuations are present in the homogeneous quasi-ordered nematic phase and characterized by a non-trivial scaling exponent

Continuous theory of active matter systems with metric-free interactions

We derive a hydrodynamic description of metric-free active matter: starting from self-propelled particles aligning with neighbors defined by "topological" rules, not metric zones, -a situation advocated recently to be relevant for bird flocks, fish schools, and crowds- we use a kinetic approach to obtain well-controlled nonlinear field equations. We show that the density-independent collision rate per particle characteristic of topological interactions suppresses the linear instability of the homogeneous ordered phase and the nonlinear density segregation generically present near threshold in metric models, in agreement with microscopic simulations.Comment: Submitted to Physical Review Letter

Emergent smectic order in simple active particle models

Novel ‘smectic-P’ behavior, in which self-propelled particles form rows and move on average along them, occurs generically within the orientationally ordered phase of simple models that we simulate. Both apolar (head–tail symmetric) and polar (head–tail asymmetric) models with aligning and repulsive interactions exhibit slow algebraic decay of smectic order with system size up to some finite length scale, after which faster decay occurs. In the apolar case, this scale is that of an undulation instability of the rows. In the polar case, this instability is absent, but traveling fluctuations disrupt the rows in large systems and motion and smectic order may spontaneously globally rotate. These observations agree with a new hydrodynamic theory which we present here. Variants of our models also exhibit active smectic ‘A’ and ‘C’ order, with motion orthogonal and oblique to the layers respectively.Peer Reviewe

Attentes et expériences des patients à l’égard d’une intervention visant à améliorer l’expérience de navigation dans le système de santé

Introduction : Les patients défavorisés sont plus nombreux à ne pas avoir de médecin de famille et à vivre des expériences de soins négatives. En plus, ils ont souvent plus des problèmes de santé et ne savent pas où aller pour obtenir des soins de santé. Pour pallier à ce problème, une intervention de soutien à la navigation dénommée « Service Accueil Patient » a été mise en place dans le but d’améliorer l’affiliation des patients défavorisés à un médecin de famille. Cette intervention visait des patients défavorisés socialement et/ou matériellement et consistait à offrir de l’information sur la santé, une préparation à la première consultation avec leur médecin de famille et un soutien dans leur suivi. Objectif et méthodologie : Cette étude visait à décrire et à comprendre les attentes et les experiences des patients défavorisés à l’égard d’une intervention de soutien à la navigation tant auprès de ceux en ayant bénéficié qu’auprès de ceux n’ayant pas bénéficié d’une telle intervention. Une étude qualitative de type descriptive a été menée, car cette approche s’avère judicieuse lorsque l’on dispose de peu de données et que nous souhaitons explorer en profondeur la perspective de patients difficiles à rejoindre ou à impliquer par les devis traditionnels. Ces patients ont été recrutés dans des cliniques médicales situées en Montérégie. Seize entrevues semi-dirigées individuelles en personne et au téléphone ont été réalisées. L’analyse thématique semi-ouverte des données a été réalisée selon le modèle de Miles et collaborateurs (2014) et comprenait la réduction et l’organisation des données, la présentation et l’interprétation des résultats. Résultats et conclusions : Cette étude identifie trois attentes non documentées dans la littérature : le soutien communicationnel, la continuité informationnelle des soins et le soutien lors des déplacements pour les rendez-vous. Les autres attentes identifiées viennent corroborer celles énoncées par des études précédentes et donc documentées dans la littérature, soit l’information sur les ressources disponibles et le soutien émotionnel. Cette étude montre que le rôle de l’intervenant lors de la préparation à la consultation médicale a été apprécié par les participants, ce qui ressort peu dans les études antérieures. Les autres rôles de l’intervenant appréciés par les participants et participantes de cette étude soutiennent ceux d’études précédentes documentées dans la littérature, soit l’information sur les ressources disponibles et le soutien émotionnel. Cette étude contribue à mieux comprendre les attentes des patients défavorisés envers l’intervention de soutien à la navigation. L’implantation d’un tel service doit tenir compte de ces attentes afin de le rendre utile et efficace pour aider les patients défavorisés à naviguer dans le système de santé de première ligne

Etude histopathologique des adénopathies cervicales à Yaoundé, Cameroun

Introduction: les adénopathies cervicales ont été très peu étudiées au Cameroun. Méthodes: pour améliorer leur connaissance nous avons mené une étude rétrospective et descriptive dans les cinq principaux laboratoires de la capitale du pays en vue d’en déterminer les aspects histopathologiques. Résultats: nous avons colligé 292 cas. L’âge moyen était de 30,95 ±4,11ans et le ratio homme / femme était de 0,96/1. Les principaux diagnostics histologiques étaient les suivants: tuberculose ganglionnaire (39,38%),  les lymphadénites (18,49%), les lymphomes malins non hodgkiniens (12,33%), la maladie de Kaposi  ganglionnaire (5,82%), les métastases de carcinome (5,82%) et la maladie de Hodgkin (5,14%). Dans  95,65% des cas le diagnostic était posé au-delà du deuxième mois d’évolution des symptômes.Conclusion: nos résultats, quoique préliminaires, sont une contribution à l’amélioration de la stratégie  diagnostique et thérapeutique dans nos hôpitaux aux ressources limitées.Key words: Adénopathies cervicales, histopathologie, pathologie, ganglions, Yaoundé, tuberculose ganglionnaire, lymphadénite, Camerou

Hospital-based Surveillance Provides Insights Into the Etiology of Pediatric Bacterial Meningitis in Yaoundé, Cameroon, in the Post-Vaccine Era.

BACKGROUND:Meningitis is endemic to regions of Cameroon outside the meningitis belt including the capital city, Yaoundé. Through surveillance, we studied the etiology and molecular epidemiology of pediatric bacterial meningitis in Yaoundé from 2010 to 2016. METHODS:Lumbar puncture was performed on 5958 suspected meningitis cases; 765 specimens were further tested by culture, latex agglutination, and/or polymerase chain reaction (PCR). Serotyping/grouping, antimicrobial susceptibility testing, and/or whole genome sequencing were performed where applicable. RESULTS:The leading pathogens detected among the 126 confirmed cases were Streptococcus pneumoniae (93 [73.8%]), Haemophilus influenzae (18 [14.3%]), and Neisseria meningitidis (15 [11.9%]). We identified more vaccine serotypes (19 [61%]) than nonvaccine serotypes (12 [39%]); however, in the latter years non-pneumococcal conjugate vaccine serotypes were more common. Whole genome data on 29 S. pneumoniae isolates identified related strains (<30 single-nucleotide polymorphism difference). All but 1 of the genomes harbored a resistance genotype to at least 1 antibiotic, and vaccine serotypes harbored more resistance genes than nonvaccine serotypes (P < .05). Of 9 cases of H. influenzae, 8 were type b (Hib) and 1 was type f. However, the cases of Hib were either in unvaccinated individuals or children who had not yet received all 3 doses. We were unable to serogroup the N. meningitidis cases by PCR. CONCLUSIONS:Streptococcus pneumoniae remains a leading cause of pediatric bacterial meningitis, and nonvaccine serotypes may play a bigger role in disease etiology in the postvaccine era. There is evidence of Hib disease among children in Cameroon, which warrants further investigation

Presentation of Dogmatis, An Inter and Multidisciplinary Programme for the Assessment of the Impacts of Genetically Modified Fish, and Results About Risk of fortuitous Import on French Market

DOGMATIS is a research project funded by the French Research Agency (ANR, programme ANR-OGM 2007-2010). The transgenic technologies have been applied to fish since more than 20 years now and some strains are at the premarket or market stage in countries outside Europe. In Europe the main risk is a fortuitous import. Any rumour of uncontrolled arrival of GM fish on the European market may have strong impacts on the market chain, the research and innovation system and the trust in public regulation. The aim of DOGMATIS is to anticipate the answers. It associates specialists of fish transgenesis, GMO detection and regulation, fish market chain economy, consumer sociology and contemporary science philosophy and epistemology. To tackle this multifactorial subject, we developed original methodologies including assumptions based on the quantitative and qualitative knowledge from the different experts of DOGMATIS. We propose to present the programme and the results of our investigation concerning an assessments of the risk of fortuitous presence of GM Fish on the French market, which has been done by crossing the data from scientific literature gathered in a data bank and an expert analysis of filtered statistics of international trade, for the two farmed species concerned by transgenesis techniques and imported on the French market, salmon and tilapia.Keywords: Posters, Markets and Trade, Fisheries Economic

Nucleoside Reverse Transcriptase Inhibitor Resistance Mutations Associated with First-Line Stavudine-Containing Antiretroviral Therapy: Programmatic Implications for Countries Phasing Out Stavudine

Background The World Health Organization Antiretroviral Treatment Guidelines recommend phasing-out stavudine because of its risk of long-term toxicity. There are two mutational pathways of stavudine resistance with different implications for zidovudine and tenofovir cross-resistance, the primary candidates for replacing stavudine. However, because resistance testing is rarely available in resource-limited settings, it is critical to identify the cross-resistance patterns associated with first-line stavudine failure. Methods We analyzed HIV-1 resistance mutations following first-line stavudine failure from 35 publications comprising 1,825 individuals. We also assessed the influence of concomitant nevirapine vs. efavirenz, therapy duration, and HIV-1 subtype on the proportions of mutations associated with zidovudine vs. tenofovir cross-resistance. Results Mutations with preferential zidovudine activity, K65R or K70E, occurred in 5.3% of individuals. Mutations with preferential tenofovir activity, ≥two thymidine analog mutations (TAMs) or Q151M, occurred in 22% of individuals. Nevirapine increased the risk of TAMs, K65R, and Q151M. Longer therapy increased the risk of TAMs and Q151M but not K65R. Subtype C and CRF01_AE increased the risk of K65R, but only CRF01_AE increased the risk of K65R without Q151M. Conclusions Regardless of concomitant nevirapine vs. efavirenz, therapy duration, or subtype, tenofovir was more likely than zidovudine to retain antiviral activity following first-line d4T therap

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival