Dystrophinopathy is a group of inherited diseases caused by mutations in the DMD gene. Within the dystrophinopathy spectrum, Duchenne and Becker muscular dystrophies are common X-linked recessive disorders that mainly feature striated muscle necrosis. We combined multiplex ligation-dependent probe amplification with Sanger sequencing to detect large deletions/duplications and point mutations in the DMD gene in 613 Chinese patients. A total of 571 (93.1%) patients were diagnosed, including 428 (69.8%) with large deletions/duplications and 143 (23.3%) with point mutations. Deletion/duplication breakpoints gathered mostly in introns 44-55. Reading frame rules could explain 88.6% of deletion mutations. We identified seventy novel point mutations that had not been previously reported. Spectrum expansion and genotype-phenotype analysis of DMD mutations on such a large sample size in Han Chinese population would provide new insights into the pathogenic mechanism underlying dystrophinopathies.

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Copy number variation (CNV) is of great significance in human evolution and disorders. Through tracing the parent-of-origin of de novo pathogenic CNVs, we are expected to investigate the relative contributions of germline genomic stability on reproductive health. In our study, short tandem repeat (STR) and single nucleotide polymorphism (SNP) were used to determine the parent-of-origin of 87 de novo pathogenic CNVs found in unrelated patients with intellectual disability (ID), developmental delay (DD) and multiple congenital anomalies (MCA). The results shown that there was a significant difference on the distribution of the parent-of-origin for different CNVs types (Chi-square test, p = 4.914 × 10−3). An apparently paternal bias existed in deletion CNVs and a maternal bias in duplication CNVs, indicating that the relative contribution of paternal germline variations is greater than that of maternal to the origin of deletions, and vice versa to the origin of duplications. By analyzing the sequences flanking the breakpoints, we also confirmed that non-allelic homologous recombination (NAHR) served as the major mechanism for the formation of recurrent CNVs whereas non-SDs-based mechanisms played a part in generating rare non-recurrent CNVs and might relate to the paternal germline bias in deletion CNVs.

316L stainless steel samples are fabricated by metal injection molding using water-atomized and gas-atomized powder with different oxygen contents. The influences of oxygen on the microstructural evolution and fatigue properties of the samples are investigated. The oxygen tends to react with Mn and Si to form oxide particles during sintering. The oxides hamper the densification process and result in decreased sintered density. Moreover, their existence reduces the Mn and Si dissolving into the base metal and compromises the solution strengthening effect. The oxides lead to stress concentration in the tensile and fatigue tests and become the initiation sites of fatigue cracks. After sintering, the samples made from the gas-atomized powder have a much lower oxygen content compared to those made from the water-atomized powder, therefore, exhibiting much better mechanical properties. The tensile strength, yield strength and the elongation of the samples made from the gas-atomized powder are 560 MPa, 205 MPa, and 58%, respectively. Their fatigue lives are about one order of magnitude longer than the samples made from water-atomized powder, and also longer than those fabricated by powder metallurgy and selective laser sintering which were reported in other studies.

The traditional bearing applied in the turbo-pump for the hydraulic servo system is rolling element bearing. To satisfy the demand of the high rotating speed for turbo-pump, the oil lubricated foil bearing can be employed in the rotor system. For the working liquid of the servo system is oil and the rotor for the turbo pump is submerged in the hydraulic oil, the bearing has to operate in an oil-rich environment, where the air bearing cannot be employed. The theoretical analysis and numerical simulation are carried out in this study to investigate the static and dynamic characteristics of multi-leaf oil lubricated foil bearing. For the structure form of the multi-leaf foil bearing with five symmetrical arrangements, the foil deformation equation and the Reynolds equation are solved coupled by successive over relaxation method, where the Reynolds boundary condition is employed. Then the load capacity, lift-off speed and static equilibrium position are acquired. By deriving the dynamic deformation equation of the foil, the dynamic stiffness coefficients and damping coefficients are obtained based on the perturbation method. The effect of the rotating speed and perturbation frequency on dynamic characteristics is analyzed. It indicates that the load capacity of the multi-leaf foil bearing is smaller than that of the fixed geometry oil bearing without foil deformation, whereas the stability of the bearing is increased.