Search

The evaluation of health status by cardiopulmonary exercise test (CPET) has shown increasing interest in the paediatric population. Our group recently established reference Z-score values for paediatric cycle ergometer VO 2 max, applicable to normal and extreme weights, from a cohort of 1141 healthy children. There are currently no validated reference values for the other CPET parameters in the paediatric population. This study aimed to establish, from the same cohort, reference Z-score values for the main paediatric cycle ergometer CPET parameters, apart from VO 2 max. Cross-sectional study. In total, 909 healthy children aged 5 to 18 years old underwent a CPET. Linear, quadratic, and polynomial mathematical regression equations were applied to identify the best CPET parameters Z-scores, according to anthropometric parameters (sex, age, height, weight, and BMI). This study provided Z-scores for maximal CPET parameters (heart rate, respiratory exchange ratio, workload, and oxygen pulse), submaximal CPET parameters (ventilatory anaerobic threshold, VE/VCO 2 slope, and oxygen uptake efficiency slope), and maximum ventilatory CPET parameters (tidal volume, respiratory rate, breathing reserve, and ventilatory equivalent for CO 2 and O 2) (Fig. 1). This study defined paediatric reference Z-score values for the main cycle ergometer CPET parameters, in addition to the existing reference values for VO 2 max, applicable to children of normal and extreme weights. Providing Z-scores for CPET parameters in the paediatric population should be useful in the follow-up of children with various chronic diseases. Thus, new paediatric research fields are opening up, such as prognostic studies and clinical trials using cardiopulmonary fitness outcomes. [ABSTRACT FROM AUTHOR]

Pseudo-strain-hardening behavior of quasi-brittle materials reinforced by discontinuous, aligned fibers subjected to uniaxial tension is studied in this paper. An R-curve was used to describe transverse cracking of fiber-reinforced composites. The equivalent inclusion method and Mori-Tanaka theory were used to derive the strain energy release rate of the composites. The proposed model takes into account the influence of fiber distribution. When properties of fiber and matrix are known, the proposed model is capable of predicting whether or not a composite will fail with a single crack or multiple cracks. If a composite fails due to multiple cracks, the model can further predict its pseudo-strain-hardening behavior after the formation of the first transverse crack. The theoretical calculation reasonably matched the experimental results.

Mori-Tanaka method facilitates the analysis of constitutive equations of power-law composites and failure of materials having multiple cracks. Griffith fracture criterion calculates the critical volume fraction of multiple cracked materials, which leads to the failure of the material. Analyses of the reasons for failure of penny-shaped, flat, ellipsoidal and slit-like cracked materials show the linear relation between volume fraction of cracks and critical applied stress. Slit-like cracked body exhibits highest ductility while penny-shaped cracked body shows lowest ductility.

Using dislocation pileup theory, a model is given for the prediction of crack initiation life under contact fatigue. Near surface crack initiation is investigated by introducing the sliding contact boundary condition. Crack initiation originated at the surface and substrate are treated as extreme cases. The new model physically explains how a surface crack can be initiated and shows that the surface crack initiation life should be shorter than the subsurface crack initiation life under the same stress amplitude conditions. A discussion is given about the influence of residual stress, hardness, temperature, irreversibility of the plastic deformation, as well as other parameters that affect the crack initiation life. Preliminary comparisons show that the new model agrees well with the experimental observations of surface and near surface crack initiation.

The inclusion and inhomogeneity problems with frictional interfaces are investigated. Three cases involving a spherical inclusion, a nondegenerate ellipsoidal inclusion and a nondegenerate ellipsoidal inhomogeneity subjected to different eigenstrain and shear conditions are used in the study. These dynamic systems are solved using the equivalent inclusion method. Results show that the nature of the eigenstrains has significant effects on the behavior of the inclusion.

Summary: The aim of this study was to compare the effectiveness of the gene‐panel next‐generation sequencing (NGS) strategy versus the clinical‐based gene Sanger sequencing for the genetic diagnosis of autoinflammatory diseases (AIDs). Secondary goals were to describe the gene and mutation distribution in AID patients and to evaluate the impact of the genetic report on the patient's medical care and treatment. Patients with AID symptoms were enrolled prospectively and randomized to two arms, NGS (n = 99) (32–55 genes) and Sanger sequencing (n = 197) (one to four genes). Genotypes were classified as 'consistent/confirmatory', 'uncertain significance' or 'non‐contributory'. The proportion of patients with pathogenic genotypes concordant with the AID phenotype (consistent/confirmatory) was significantly higher with NGS than Sanger sequencing [10 of 99 (10·1%) versus eight of 197 (4·1%)]. MEFV, ADA2 and MVK were the most represented genes with a consistent/confirmed genotype, whereas MEFV, NLRP3, NOD2 and TNFRSF1A were found in the 'uncertain significance' genotypes. Six months after the genetic report was sent, 54 of 128 (42·2%) patients had received effective treatment for their symptoms; 13 of 128 (10·2%) had started treatment after the genetic study. For 59 of 128 (46%) patients, the results had an impact on their overall care, independent of sequencing group and diagnostic conclusion. Targeted NGS improved the diagnosis and global care of patients with AIDs. [ABSTRACT FROM AUTHOR]