Discovery of 5-hydroxymethylcytosine (5hmC) in mammalian genomes has excited the field of epigenetics, but information on the genome-wide distribution of 5hmC is limited. Globozoospermia is a rare but severe cause of male infertility. To date, the epigenetic mechanism, especially 5hmC profiles involved in globozoospermia progression, remains largely unknown. Here, utilizing the chemical labeling and biotin-enrichment approach followed by Illumina HiSeq sequencing, we showed that (i) 6664, 9029 and 6318 genes contain 5hmC in normal, abnormal, and globozoospermia sperm, respectively; (ii) some 5hmC-containing genes significantly involves in spermatogenesis, sperm motility and morphology, and gamete generation; (iii) 5hmC is exclusively localized in sperm intron; (iv) approximately 40% imprinted genes have 5hmC modification in sperm genomes, but globozoospermia sperm exhibiting a large portion of imprinted genes lose the 5hmC modification; (v) six imprinted genes showed different 5hmC patterns in abnormal sperm (GDAP1L1, GNAS, KCNK9, LIN28B, RB1, RTL1), and five imprinted genes showed different 5hmC patterns in globozoospermia sperm (KCNK9, LIN28B, RB1, SLC22A18, ZDBF2). These results suggested that differences in genome-wide 5hmC patterns may in part be responsible for the sperm phenotype. All of this may improve our understanding of the basic molecular mechanism underlying sperm biology and the etiology of male infertility.
It requires a damage tolerance assessment for all airframes and engines to set the inspection windows for safe operation. A certain rotorcraft main rotor yoke were analyzed with NASGRO model. The sensibility analysis of influence parameters in crack growth life has been done. In order to calculate the sensibility index of influence factors to crack growth life, the factors were divided into input parameters and crack growth model parameters. The results show that the input parameters have the following precedence ordering: fatigue crack growth threshold, fracture spectrum, initial crack, fracture toughness, the sensibility values are 11.25, 8.5417, 0.8333, 0.1125, respectively. The NASGRO model parameters have the following precedence ordering: n, p, C, q. the sensibility values are 6.0417, -3.9583, 1.25, 0.1812, respectively.
In ensemble learning, in order to improve the performance of individual classifiers and the diversity of classifiers, from the classifiers generation and combination, this paper proposes a kind of combination feature division and diversity measure of multi-classifier selective ensemble algorithm. The algorithm firstly applied bagging method to create some feature subsets, Secondly using principal component analysis of feature extraction method on each feature subsets, then select classifiers with high-classification accuracy; finally before classifier combination we use classifier diversity measure method select diversity classifiers. Experimental results prove that classification accuracy of the algorithm is obviously higher than popular bagging algorithm.
Plane strain fracture toughness is an important mechanical performance index for damage tolerance design, so how to obtain this value through test deserves consideration. In this paper, the ductile fracture toughness test was performed. It was difficult for the specimen with big dimensions in the case of plane strain to be carried out through ordinary testing machine with lower capacity because of the higher fracture toughness value of the material, that it was attained indirectly for plane strain fracture toughness value by the way of ductile fracture toughness test and pertinent formula calculation if proper specimen selected. The fracture property tests according to the corresponding standard were conducted. The compact tension specimens were obtained from the main rotor butt of a helicopter in service. Based on the single specimen measuring ductile fracture toughness method, the experiments of measuring the ductile fracture toughness were carried out. A method was given to determine the optimum fitting probabilistic distribution function of fracture toughness in the small sample size. The statistic results show that the optimum probabilistic distribution function of ductile fracture toughness is the Extreme Maximum. Value distribution. The following factors were taken into account, the linear relative coefficient, total fit effect probability relative coefficient, consistency with the relevant fatigue physics and tail most importantly, safety of design evaluation. The shape parameter, scale parameter, and location parameter are -1.1231, 860.53, 6036.4, respectively. The statistical variation coefficient is 11.22%. The result shows that there is a large risk probability for a definite value to fracture toughness only with one or two pieces of samples according to the test.
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