36 research outputs found
Finite element stress analysis of polymers at high strains
A numerical analysis is presented for the problem of a flat rectangular rubber membrane with a circular rigid inclusion undergoing high strains due to the action of an axial load. The neo-hookean constitutive equations are introduced into the general purpose TITUS program by means of equivalent hookean constants and initial strains. The convergence is achieved after a few iterations. The method is not limited to any specific program. The results are in good agreement with those of a company sponsored photoelastic stress analysis. The theoretical and experimental deformed shapes also agree very closely with one another. For high strains it is demonstrated that using the conventional HOOKE law the stress concentration factor obtained is unreliable in the case of rubberlike material
Are all cases of paediatric essential thrombocythaemia really myeloproliferative neoplasms? Analysis of a large cohort
Sporadic essential thrombocythaemia (ET) is rare in paediatrics, and the
diagnostic and clinical approach to paediatric cases cannot be simply copied
from experience with adults. Here, we assessed 89 children with a clinical
diagnosis of ET and found that 23 patients (258%) had a clonal
disease. The JAK2 V617F mutation was identified in 14 children, 1 child
had the MPL W515L mutation, and 6 had CALR mutations. The monoclonal
X-chromosome inactivation pattern was seen in six patients (two with
JAK2 V617F and two with CALR mutations). The other 66 patients
(742%) had persistent thrombocytosis with no clonality. There were no
clinical or haematological differences between the clonal and non-clonal
patients. The relative proportion of ET-specific mutations in the clonal
children was much the same as in adults. The higher prevalence of nonclonal
cases suggests that some patients may not have myeloproliferative
neoplasms, with significant implications for their treatment