Canavan disease (CD) is a rare fatal childhood neurological autosomal recessive genetic disease caused by mutations in the ASPA gene, which lead to catalytic deficiency of the ASPA enzyme, which catalyzes the hydrolysis of N-acetyl-L-aspartate (NAA) into aspartate and acetate. CD occurs frequently among Ashkenazi Jewish population, however it has been reported in many other ethnic groups with significantly lower frequency. Here, we report on two Egyptian patients diagnosed with CD, the first patient harbors five missense mutations (c.427 A > G; p. I143V, c.502C > T; p. R168C, c.530 T > C; p. I177T, c.557 T > C; p. V186D c.548C > T; p. P183L) and a silent mutation (c.693 C > T; p. Y231Y). The second patient was found to be homozygous for two missense mutations (c.427 A > G; p. I143V and c.557 T > A; p. V186D). Furthermore, molecular modeling of the novel mutation p. P183L provides an instructive explanation of the mutational impact on the protein structure that can affect the function of the ASPA. Here, the clinical, radiological, and biochemical profile of the two patients are reviewed in details.
Mechanical properties of Carbon Nanotube (CNT) reinforced composites are obtained utilizing finite element (FE) method-based indentation simulations considering large strain elasto-plastic behavior of elements. This study includes nanoindentation simulations for chemically non-bonded CNT/matrix interface, including the length scale effect of nanocomposites. In order to investigate the mechanical properties of CNT reinforced nanocomposites, a number of FE models for nanoindentation tests have been simulated. Sample nanocomposites are examined to determine the suitable types of CNTs and their effectiveness as a reinforcement of different potential matrices. The Parametric study is conducted to obtain the influence of wall thickness, relative positioning, and volume fraction of CNT and strain hardening parameter of matrix on the mechanical properties of nanocomposites. The obtained results indicate that, properties such as modulus of elasticity and hardness of the nanocomposites are largely dependent on wall thickness of CNT and strain hardening parameter of the matrix. This study also suggests, the minimum wall thickness of CNT to avoid local buckling in nanocomposite which is required to be at least 0.2 nm for a diameter to thickness ratio of 5.0. Moreover, a matrix having a value of strain hardening parameter near 0.1 is expected to be significantly effective for nanocomposite.
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