Three-dimensional Numerical Analysis of a Joint Bonded Reinforced with Silica Nanoparticles (SiO2)

Nanostructured adhesives may be defined as those materials whose elements imbedded in an epoxy matrix have dimensions in the 1 to 100 nm range. One of the most interesting aspects of ceramic nanoparticles is that their mechanical properties depend strongly upon the particle size and shape. Silica nanoparticles (SiO2) have different physical and mechanical properties from bulk ceramics. The aim of the present study is to investigate the effect of the nanoparticles rate on the equivalent stress, peeling stress and shear stress as well as the strains developed in the adhesive joint. Three-dimensional finite element models of adhesive joint were developed to determine the stress intensity as well as strain with different nanoparticles rate in the epoxy resin. Dispersion of nanoparticles with different percent in the epoxy resin allows for reinforcing the adhesive. Polymer embedded silica nanoparticles (SiO2) proved to be highly effective

Detection of Multiple Pathways in the Spinal Cord White Matter Using Q-Ball Imaging

International audienceHigh angular resolution MRI such as q-ball imaging (QBI) allows to recover complex white matter architecture. We applied this technique to an ex vivo spinal cord of one cat using a 3T scanner, 100 directions and b-values varying from 1000 to 3000 s/mm2. As a result, QBI can retrieve crossing fibre information, where the diffusion tensor imaging approach is constrained to a single diffusion direction. To our knowledge, this is the first study demonstrating the benefits of QBI in observing longitudinal, commissural and dorso-ventral fibres in the spinal cord. It is a first step towards in vivo characterization of the healthy and injured spinal cord using high angular resolution diffusion imaging (HARDI) and QBI

Evaluation of q-ball metrics for assessing the integrity of the injured spinal cord

International audienceAssessment of spinal cord integrity following injury is crucial for evaluating the potential for functional rehabilitation [1]. Previous studies showed the benefits of diffusion tensor imaging (DTI) for the non-invasive characterization of the healthy and injured spinal cord [2]. However, biases related to the incapability of DTI to represent complex diffusion profiles suggested the use of less constraining techniques. Recently, we demonstrated that q-ball imaging (QBI) is capable of partly solving fiber crossing information in the intact spinal cord [3]. In this study, we extended the application of QBI in a model of cat partial spinal cord injury and we compared various QBI quantitative metrics to the ones used in DTI. We also proposed an original QBI-based metric to quantify the homogeneity of diffusion directions

Association of respiratory symptoms and lung function with occupation in the multinational Burden of Obstructive Lung Disease (BOLD) study

Background Chronic obstructive pulmonary disease has been associated with exposures in the workplace. We aimed to assess the association of respiratory symptoms and lung function with occupation in the Burden of Obstructive Lung Disease study. Methods We analysed cross-sectional data from 28 823 adults (≥40 years) in 34 countries. We considered 11 occupations and grouped them by likelihood of exposure to organic dusts, inorganic dusts and fumes. The association of chronic cough, chronic phlegm, wheeze, dyspnoea, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)/FVC with occupation was assessed, per study site, using multivariable regression. These estimates were then meta-analysed. Sensitivity analyses explored differences between sexes and gross national income. Results Overall, working in settings with potentially high exposure to dusts or fumes was associated with respiratory symptoms but not lung function differences. The most common occupation was farming. Compared to people not working in any of the 11 considered occupations, those who were farmers for ≥20 years were more likely to have chronic cough (OR 1.52, 95% CI 1.19–1.94), wheeze (OR 1.37, 95% CI 1.16–1.63) and dyspnoea (OR 1.83, 95% CI 1.53–2.20), but not lower FVC (β=0.02 L, 95% CI −0.02–0.06 L) or lower FEV1/FVC (β=0.04%, 95% CI −0.49–0.58%). Some findings differed by sex and gross national income. Conclusion At a population level, the occupational exposures considered in this study do not appear to be major determinants of differences in lung function, although they are associated with more respiratory symptoms. Because not all work settings were included in this study, respiratory surveillance should still be encouraged among high-risk dusty and fume job workers, especially in low- and middle-income countries.publishedVersio

Cohort Profile: Burden of Obstructive Lung Disease (BOLD) study

The Burden of Obstructive Lung Disease (BOLD) study was established to assess the prevalence of chronic airflow obstruction, a key characteristic of chronic obstructive pulmonary disease, and its risk factors in adults (≥40 years) from general populations across the world. The baseline study was conducted between 2003 and 2016, in 41 sites across Africa, Asia, Europe, North America, the Caribbean and Oceania, and collected high-quality pre- and post-bronchodilator spirometry from 28 828 participants. The follow-up study was conducted between 2019 and 2021, in 18 sites across Africa, Asia, Europe and the Caribbean. At baseline, there were in these sites 12 502 participants with high-quality spirometry. A total of 6452 were followed up, with 5936 completing the study core questionnaire. Of these, 4044 also provided high-quality pre- and post-bronchodilator spirometry. On both occasions, the core questionnaire covered information on respiratory symptoms, doctor diagnoses, health care use, medication use and ealth status, as well as potential risk factors. Information on occupation, environmental exposures and diet was also collected

Fully Automated Straightening of the Spinal Cord using Fiber Tractography

International audienc

STRAIGHTENING THE SPINAL CORD USING FIBER TRACTOGRAPHY

International audienc

Detection of multiple pathways in the spinal cord using q-ball imaging

International audienceMagnetic resonance diffusion tensor imaging (DTI) has been extensively applied to the spinal cord for depicting its architecture and for assessing its integrity following spinal lesions. However, DTI is limited in representing complex white matter architecture, notably in the presence of crossing fibres. Recently, q-ball imaging (QBI) has been proposed as a new method for recovering complex white matter architecture. We applied this technique to both ex vivo and in vivo spinal cords of cats using a 3T scanner. For the purpose of comparison, gradients have been applied in 55 and 100 encoding directions and b-values varied from 800 to 3000 s/mm2. As a result, QBI was able to retrieve crossing fibre information, where the DTI approach was constrained in a unique diffusion direction. To our knowledge, this is the first study demonstrating the benefits of QBI for detecting the presence of longitudinal, commissural and dorso-ventral fibres in the spinal cord. It is a first step towards in vivo characterization of the healthy and injured human spinal cord using high angular resolution diffusion imaging and QBI