Tensile post-impact behaviour of thin carbon/epoxy and glass/epoxy hybrid woven laminates – Part II: Numerical study

International audienceThis article concerns the modelling of post-impact damage propagation in thin woven composite laminates. Simulations of low velocity impacts and post-impact quasi-static tension are performed on single-material and hybrid laminates. The modelling is based on the semi-continuous approach implemented into the explicit finite element code RADIOSS. The bundles are modelled with rod elements and a specific damageable shell element is used to stabilize this truss structure. Improvements are brought with the introduction of a compressive failure criterion for the rod elements and the development of a pseudo-plastic law with damaging for in in-plane shear. The results provided by the modelling well correlates the experimental observations in terms of damage propagation and load-displacement curves for all the configurations studied

Clinical implementation of deep learning-based automated left breast simultaneous integrated boost radiotherapy treatment planning.

Automation in radiotherapy treatment planning aims to improve both the quality and the efficiency of the process. The aim of this study was to report on a clinical implementation of a Deep Learning (DL) auto-planning model for left-sided breast cancer. The DL model was developed for left-sided breast simultaneous integrated boost treatments under deep-inspiration breath-hold. Eighty manual dose distributions were revised and used for training. Ten patients were used for model validation. The model was then used to design 17 clinical auto-plans. Manual and auto-plans were scored on a list of clinical goals for both targets and organs-at-risk (OARs). For validation, predicted and mimicked dose (PD and MD, respectively) percent error (PE) was calculated with respect to manual dose. Clinical and validation cohorts were compared in terms of MD only. Median values of both PD and MD validation plans fulfilled the evaluation criteria. PE was < 1% for targets for both PD and MD. PD was well aligned to manual dose while MD left lung mean dose was significantly less (median:5.1 Gy vs 6.1 Gy). The left-anterior-descending artery maximum dose was found out of requirements (median values:+5.9 Gy and + 2.9 Gy, for PD and MD respectively) in three validation cases, while it was reduced for clinical cases (median:-1.9 Gy). No other clinically significant differences were observed between clinical and validation cohorts. Small OAR differences observed during the model validation were not found clinically relevant. The clinical implementation outcomes confirmed the robustness of the model

Bronchoalveolar lavage in infants with recurrent lower respiratory symptoms

Background: Few data are available about the inflammatory cytokine profile of bronchoalveolar lavage (BAL) from young children with frequent wheeze. The first aim was to investigate the BAL cellular and cytokine profiles in infants with recurrent lower respiratory symptoms in whom bronchoscopy was indicated for clinical symptom evaluation. The second aim was to relate the BAL results with the histological findings of the endobronchial carina biopsies. Methods: Thirty-nine infants (median age 0.9 years) underwent lung function testing by whole-body plethysmography prior to the bronchoscopy. The BAL differential cell counts and cytokine levels were quantified. These findings were compared with the histological findings of the endobronchial carina biopsies. Results: The differential cytology reflected mainly that described for healthy infants with lymphocyte counts at the upper range level. A positive association between BAL CD8+ lymphocytes and neutrophils and endobronchial reticular basement membrane was found. Detectable levels of pro-inflammatory cytokine proteins IL-1 beta, IL-17A, IL-18, IL-23, and IL-33 were found, whereas levels of Th2-type cytokine proteins were low. Frequent wheeze was the only clinical characteristic significantly related to detectable combined pro-inflammatory cytokine profile. Lung function did not correlate with any cytokine. Conclusions: A positive association between BAL CD8+ lymphocytes and neutrophils and endobronchial reticular basement thickness was found. Detectable production of pro-inflammatory cytokines associated positively with frequent wheeze.Peer reviewe

Caracterización de actinomicetos de sedimento marino y su actividad antagonista frente a Vibrio sp aislados de «langostino blanco» Litopenaeus vannamei (Boone, 1931)

The aim of the present study was to evaluate the antagonistic activity of a collection of 24 actinomycetes of marine sediment against wild species of Vibrio. Actinomycetes were characterized by their growth in Marine Agar and their extracellular enzymatic activity on different substrates. The antagonist activity was determined by in vitro tests against six strains of Vibrio isolated from Litopenaeus vannamei. Actinomycetes with greater antagonism were evaluated by their growth in standard ISP media and observations of microphotographs by scanning electron microscopy (SEM) techniques were done. The Vibrio strains were evaluated and identified by conventional biochemical techniques and confirmed by PCR. The results indicated that all actinomycetes showed at least some extracellular multi-enzymatic activity, predominating those that hydrolyze starch (79%). Antagonism tests indicated that 54% (13/24) of actinomycetes had anti-Vibrio activity, being the strains M10-77 and M11-116 (B) those that produced the largest inhibition halos. On the other hand, the sequence-based identification of the 16S rRNA gene corroborated the relationship of the isolated strains of L. vannamei with the genus Vibrio; likewise, some of these actinobacteria were identified as Streptomyces.El objetivo principal del presente estudio fue evaluar la actividad antagonista de una colección de 24 actinomicetos de sedimento marino frente a especies silvestres de Vibrio. Los actinomicetos fueron caracterizados por su crecimiento en Agar Marino y su actividad enzimática extracelular sobre diferentes sustratos. La actividad antagonista se evaluó mediante pruebas in vitro frente a seis cepas de Vibrio aisladas de Litopenaeus vannamei. Los actinomicetos de mayor antagonismo fueron evaluados por su crecimiento en medios estándares ISP y se hicieron observaciones de microfotografías por técnicas de microscopía electrónica de barrido (MEB). Las cepas de Vibrio fueron evaluadas e identificadas mediante técnicas bioquímicas convencionales y confirmadas por PCR. Los resultados indicaron que la totalidad de actinomicetos mostraron al menos alguna actividad multi-enzimática extracelular, predominando las que hidrolizan almidón (79%). Las pruebas de antagonismo señalaron que el 54% (13/24) de actinomicetos tuvieron actividad anti-Vibrio, siendo las cepas M10-77 y M11-116 (B) las que produjeron los halos de inhibición de mayor tamaño. Por otro lado, la identificación basada en secuencia del gen 16S ARNr corroboró la relación de las cepas aisladas de L. vannamei con el género Vibrio; asimismo, algunas de estas actinobacterias fueron identificadas como Streptomyces

Clinical and microbiological efficacy of micafungin on Geosmithia argillacea infection in a cystic fibrosis patient

Cystic fibrosis are at risk of colonization by a number of fungi, including Geosmithiaargillacea which appears to be an emerging pathogen in these patients. This pathogen has been recently reported as a cause of invasive/systemic mycosis in immunocompromized patients such as colonized patients who are immunosuppressed for lung transplantation. In this context, we report here a case of clinical and microbiological efficacy of micafungin in a French cystic fibrosis patient chronically colonized with G. argillacea. O.D., a female F508Del-CFTR homozygous patient was diagnosed at birth with cystic fibrosis in January 1996. She was found chronically colonised with multi-resistant Staphylococcus aureus (MRSA) from 1997 to 2011, and with Aspergillus fumigatus from 2001 to 2006. She was treated alternatively with oral voriconazole and itraconazole from 2004 to 2008, and with posaconazole since february 2008. Geosmithia argillacea was first diagnosed in May 2007, and chronic colonisation was persistent from this date to August 2010 with 23/28 fungus positive sputum samples, in spite of posaconazole therapy. For an isolate obtained in October 2008, minimal inhibitory/effective concentrations (MIC/MEC, mg/ml) determined using the Eucast method were 2.0, 2.0, 16.0, 2,0, 0.25 and 0.015 for amphotericin B, itraconazole, voriconazole, posaconazole, caspofungin and micafungin, respectively. The FEV1 predicted value was 73% at the time of first fungus isolation and was decreased to 47% in October 2009. She then was given caspofungin for 21 days ((70 mg/day, later reduced to 50 mg) which resulted in clinical improvement (FEV1 = 64% in January 2010) without eradication of G. argillacea. In June 2010, treatment with micafungin (75 mg, 21days) was realized owing to deterioration of the respiratory function (FEV1 = 56%),without clinical improvement ( FEV1 = 47% in August 2010). O.D. was then treated from September, 23 to November 3, 2010 with micafungin (100mg bid for 21 days and 100mg/day for the following 21 days) which resulted in clinical and microbiological improvement. FEV1 predicted ranged 67-68% in October and December 2010, and February and May 2011, and from the end of treatment to December 2010, 5/6 sputum samples were found negative for G. argillacea. The positive sample contained fungus of the same genotype as previous isolates. The present case is to our knowledge the first description of G. argillacea eradication in a chronically colonized cystic fibrosis patient. Similar to previous studies, G. argillacea colonization was detected in the presence of chronic MRSA after A. fumigatus eradication. Since no change in bacterial colonization was observed before, during, and after G. argillacea colonization, the present case is consistent with a pathogenic role of the fungus in cystic fibrosis patients. In vitro antifungal susceptibility assays suggested that echinocandins are most effective agents against this fungus with a lowest MEC for micafungin (7 isolates studied, MEC range: 0.015-0.03), although eradication could only be obtained with high dose micafungin for a long time (6 weeks)

Helical Chirality: a Link between Local Interactions and Global Topology in DNA

DNA supercoiling plays a major role in many cellular functions. The global DNA conformation is however intimately linked to local DNA-DNA interactions influencing both the physical properties and the biological functions of the supercoiled molecule. Juxtaposition of DNA double helices in ubiquitous crossover arrangements participates in multiple functions such as recombination, gene regulation and DNA packaging. However, little is currently known about how the structure and stability of direct DNA-DNA interactions influence the topological state of DNA. Here, a crystallographic analysis shows that due to the intrinsic helical chirality of DNA, crossovers of opposite handedness exhibit markedly different geometries. While right-handed crossovers are self-fitted by sequence-specific groove-backbone interaction and bridging Mg2+ sites, left-handed crossovers are juxtaposed by groove-groove interaction. Our previous calculations have shown that the different geometries result in differential stabilisation in solution, in the presence of divalent cations. The present study reveals that the various topological states of the cell are associated with different inter-segmental interactions. While the unstable left-handed crossovers are exclusively formed in negatively supercoiled DNA, stable right-handed crossovers constitute the local signature of an unusual topological state in the cell, such as the positively supercoiled or relaxed DNA. These findings not only provide a simple mechanism for locally sensing the DNA topology but also lead to the prediction that, due to their different tertiary intra-molecular interactions, supercoiled molecules of opposite signs must display markedly different physical properties. Sticky inter-segmental interactions in positively supercoiled or relaxed DNA are expected to greatly slow down the slithering dynamics of DNA. We therefore suggest that the intrinsic helical chirality of DNA may have oriented the early evolutionary choices for DNA topology

PLoS One

[This corrects the article DOI: 10.1371/journal.pone.0196711.]