Finite element and automatic remeshing methods for the simulation of complex blow molded polymer components

International audienceThis paper presents a three dimensional finite element model of the extrusion blow molding process. The code Tform3 has the following characteristics: membrane formulation, linear triangle elements, updated Lagrangian implicit formulation, viscoelastic differential constitutive equations. The paper presents a brief recall of the formulation and then addresses three key issues of the simulation: automatic identification of constitutive equation parameters, automatic remeshing, coupling between gas pressure and inflation. An example of application to the extrusion blow molding of a bottle is presented

Spinopelvic sagittal alignment of patients with transfemoral amputation

This study aims to describe the spinopelvic sagittal alignment in transfemoral amputees (TFAs) from a radiologic study of the spine with a postural approach to better understand the high prevalence of low back pain (LBP) in this population. METHODS: TFAs underwent X-rays with 3-D reconstructions of the full spine and pelvis. Sagittal parameters were analyzed and compared to the literature. Differences between TFAs with and without LBP were also observed. RESULTS: Twelve subjects have been prospectively included (TFA-LBP group (n = 5) and TFA-NoP group (n = 7)). Four of the five subjects of the TFA-LBP group and two of the seven in TFAs-NoP group had an imbalanced sagittal posture, especially regarding the T9-tilt, significantly higher in the TFA-LBP group than in the TFA-NoP (p = 0.046). Eight subjects (6 TFA-NoP and 2 TFA-LBP) had abnormal low value of thoracic kyphosis (TK). Moreover, the mean angle of TK in the TFA-NoP group was lower than in the TFA-LBP group (p = 0.0511). CONCLUSION: In the considered sample, TFAs often present a sagittal imbalance. A low TK angle seems to be associated with the absence of LBP. It can be hypothesized that this compensatory mechanism of the sagittal imbalance is the most accessible in this population. This study emphasizes the importance of considering the sagittal balance of the pelvis and the spine in patients with a TFA to better understand the high prevalence of LBP in this population. It should be completed by the analysis of the spinopelvic balance and the lower limbs in 3D. These slides can be retrieved under Electronic Supplementary Material

Evolution of vaulting strategy during locomotion of individuals with transfemoral amputation on slopes and cross-slopes compared to level walking

Background: Vaulting is a walking strategy qualitatively characterized in clinics by the sound ankle plantiflexion in midstance to assist prosthetic foot clearance. Even though potentially harmful, this strategy is often observed among people with transfemoral amputation to secure clearance of the prosthetic limb during swing phase. The aim of the study is to provide a quantitative analysis of the evolution of the vaulting strategy in challenging situations of daily living. Methods: 17 persons with transfemoral amputation and 17 able-bodied people participated in the study. Kinematic and kinetic gait analyses were performed for level walking, 10% inclined cross-slope walking, 5% and 12% inclined slope ascending. To study vaulting strategy, peak of generated power at the sound ankle at midstance was identified and quantified in the different walking situations. In particular, values were compared to a vaulting threshold corresponding to a peak of generated power superior to 0.15 W/kg. Findings: The vaulting threshold was exceeded for a larger proportion of people with amputation during crossslope locomotion and slope ascent than during level walking. In addition, magnitude of the peak of generated power increased significantly compared to level walking in these situations. Interpretation: Vaulting seems to be widely used by patients with transfemoral amputation in daily living situations. The number of patients using vaulting increased with the difficulty of the walking situation. Results also suggested that patients could dose the amount of vaulting according to gait environment to secure prosthetic toe clearance. During rehabilitation, vaulting should also be corrected or prevented in daily living tasks

Reliability quantification and gait loading asymmetry assessment with wearable insoles in transfemoral amputee people at different speeds

Introduction Amputee people have gait defaults, as for example loading asymmetry, which increase with daily living situations. Replication of realistic daily living environment in a motion analysis laboratory (MAL) is difficult. Wearable pressure insoles, by providing normal ground reaction force (NGrF), can be used to quantify loading gait asymmetry in real life conditions. This asymmetry, considered as an indicator of the quality of the gait, is useful for physicians to monitor the rehabilitation progress or the prosthetic fitting suitability. The study aimed at quantifying the reliability of NGrF measurement and assessing the gait asymmetry of transfemoral amputee people with Pedoped® insoles against force plates. Walking speed effect was also evaluated on gait asymmetry for transfemoral amputee people (TFP). Material and methods In a MAL, five active TFP walked at three self-selected speeds on level ground wearing Pedoped® insoles. Reliability was assessed by comparing NGrF obtained from both systems with Bland-Altman plots, normalized RMSE (NRMSE) and correlation coefficient. Gait loading asymmetry was computed by Absolute Symmetry Index in loading at the three self-selected speeds with insoles. Results The mean NRMSE of NGrF was 7.2% (± 2.8%) and 9.8% (± 3.5%); and coefficient correlation was 0.91 and 0.95 for the prosthetic side and the intact side respectively. Loading asymmetry increased significantly with walking speed for each specific variable of NGrF. Discussion–conclusion After overcoming the calibration problem in amputee population, Pedoped® insoles could be easily used for gait asymmetry follow-up during rehabilitation

Interpersonal Synchronization, Motor Coordination, and Control Are Impaired During a Dynamic Imitation Task in Children With Autism Spectrum Disorder

Background: Impairments in imitation abilities have been commonly described in children with autism spectrum disorder (ASD). How motricity in interpersonal coordination impacts imitation, during long lasting semi-ecological conditions, has not been carefully investigated.Methods: Eighty-five children and adolescents (39 controls with typical development, TD; 29 patients with ASD; 17 patients with developmental coordination disorder, DCD), aged 6 to 20 years, participated to a behavioral paradigm in which participants, standing and moving, interacted with a virtual tightrope walker standing and moving as well. During the protocol, we measured automatically and continuously bodily postures and movements from RGB sensor recording to assess participants' behavioral imitation.Results: We show that (1) interpersonal synchronization (as evidenced by the synchrony between the participant's and the tightrope walker's bars) and (2) motor coordination (as evidenced by the synchrony between the participant's bar and its own head axis) increased with age and were more impaired in patients with ASD. Also, motor control as evidenced by the movement angle standard deviations of participants' bar and head were significantly impaired in ASD compared to TD or DCD.Conclusion: Interpersonal synchronization and motor coordination during ecological interaction show both subtle impairment in children with ASD as compared to children with TD or DCD. These results questioned how motricity mature in terms of motor control and proprioception in children with ASD

APSIC: Training and fitting amputees during situations of daily living

Today, the prevalence of major amputation in France can be estimated between 90,000 and 100,000 and the incidence is about 8300 new amputations per year (according to French National Authority for Health estimation). This prevalence is expected to increase in the next decade due to the ageing of the population. Even if prosthetic fitting allows amputee people recovering the walking ability, their autonomy remains limited when crossing obstacles such as slopes, stairs or cross-slopes frequently encountered during outdoors displacements. The aim of the project APSIC was to complete scientific knowledge about adaptation strategies to situations of daily living compared to level walking through an extensive motion analysis study of transtibial and transfemoral amputee compared to non-amputee people. APSIC succeeded in identifying physiologic joint functions and current prosthetic joint limitations in the studied situations, which notably resulted in the design of a prototype of ankle-knee prosthesis adapted to multimodal locomotion of transfemoral amputee. Perspectives of the clinical use of motion analysis within the rehabilitation process were explored and proved to be relevant for personalized approach of motor learning

Emery-Dreifuss Muscular Dystrophy 1 is associated with high risk of malignant ventricular arrhythmias and end-stage heart failure.

BACKGROUND AND AIMS Emery-Dreifuss muscular dystrophy (EDMD) is caused by variants in EMD (EDMD1) and LMNA (EDMD2). Cardiac conduction defects and atrial arrhythmia are common to both, but LMNA variants also cause end-stage heart failure (ESHF) and malignant ventricular arrhythmia (MVA). This study aimed to better characterise the cardiac complications of EMD variants. METHODS Consecutively referred EMD variant-carriers were retrospectively recruited from 12 international cardiomyopathy units. MVA and ESHF incidence in male and female variant-carriers was determined. Male EMD variant-carriers with a cardiac phenotype at baseline (EMDCARDIAC) were compared to consecutively recruited male LMNA variant-carriers with a cardiac phenotype at baseline (LMNACARDIAC). RESULTS Longitudinal follow-up data were available for 38 male and 21 female EMD variant-carriers (mean [SD] ages 33.4 [13.3] and 43.3 [16.8] years, respectively). Nine (23.6%) males developed MVA and five (13.2%) developed ESHF during a median [IQR] follow-up of 65.0 [24.3, 109.5] months. No female EMD variant-carrier had MVA or ESHF, but nine (42.8%) developed a cardiac phenotype at a median [IQR] age of 58.6 [53.2, 60.4] years. Incidence rates for MVA were similar for EMDCARDIAC and LMNACARDIAC (4.8 and 6.6 per 100 person-years, respectively; log-rank p = 0.49). Incidence rates for ESHF were 2.4 and 5.9 per 100 person-years for EMDCARDIAC and LMNACARDIAC, respectively (log-rank p = 0.09). CONCLUSIONS Male EMD variant-carriers have a risk of progressive heart failure and ventricular arrhythmias similar to that of male LMNA variant-carriers. Early implantable cardioverter defibrillator implantation and heart failure drug therapy should be considered in male EMD variant-carriers with cardiac disease.The work reported in this publication was funded by: a British Heart Foundation Clinical Research Training Fellowship to D.E.C. (FS/CRTF/ 20/24022); a British Heart Foundation Clinical Research Training fellowship to A.P. (FS/18/82/34024); The Ministry of Health, Italy, project RC-2022-2773270 to E.B.; the National Institutes of Health (NIH) (R01HL69071, R01HL116906, R01HL147064, NIH/NCATS UL1 TR002535, and UL1 TR001082) to L.M.; and support from the Rose Foundation for K.M.S

Bloodborne Viral Hepatitis Infections among Drug Users: The Role of Vaccination

Drug use is a prevalent world-wide phenomenon and hepatitis virus infections are traditionally a major health problem among drug users (DUs). HBV and HCV, and to a lesser extent HAV, are easily transmitted through exposure to infected blood and body fluids. Viral hepatitis is not inevitable for DUs. Licensed vaccines are available for hepatitis A and hepatitis B. The purpose of this overview is to show some epidemiological data about HBV and the other blood-borne viral hepatitis among DUs and to summarize and discuss use of hepatitis vaccinations in this population. Successful vaccination campaigns among DUs are feasible and well described. We try to focus on the most significant results achieved in successful vaccination programs as reported in scientific literature. Vaccination campaigns among DUs represent a highly effective form of health education and they are cost-saving