Publish in OALib Journal
APC: Only $99
This work proposes authentication based on
identity as a way to increase the efficiency and security of communications in
vehicular ad-hoc networks. When using identity-based cryptography to achieve
certificateless authentication, membership revocation is not a trivial problem.
Thus, in order to improve the performance of revocation in such networks, the
use of a dynamic authenticated data structure based on perfect k-ary hash trees
combined with a duplex version of the new standard SHA-3 is here presented.
Efficient algorithms in the used revocation trees allow reaching a refresh rate
of at most simple updates per inserted node. Consequently, the proposal is especially
useful for situations with frequent revocations, which are foreseeable when
vehicular ad- hoc networks are widely deployed.
Sperm of poor quality may affect syngamy after fertilization, embryo development up to the blastocyst stage and reproductive outcome. Subsequently, sperm selection based on morphological characteristics and sperm DNA quality may help to partially avoid these problems. Today, highly efficient sperm selection based on morphological characteristics can be attained using the motile sperm organelle morphology (MSOME) examination, and the spermatozoa selected can be used for ICSI through a fertilization strategy known as intra-cytoplasmic morphologically selected sperm injection (IMSI). The aim of this investigation was to develop a simple methodology to assess sperm DNA fragmentation in single spermatozoa following MSOME/ IMSI, to test the hypothesis that morphologically normal spermatozoa, with an absence of vacuolization, is free of DNA damage. The results indicated that MSOME/IMSI-selected sperm, combined with the Sperm Chromatin Dispersion test (SCD; Oligo-Halosperm), can be reliably used to assess sperm DNA damage in selected single spermatozoa (75% average efficiency), thereby establishing a direct relationship between a good morphological pattern on the sperm and a good DNA quality. Furthermore, results showed spermatozoa presenting a normal morphology and no traces of vacuolization to be fully free of DNA damage. However, traces of vacuolization and more severe morphological alterations were accompanied by significant increases in the proportion of sperm containing a damaged DNA molecule. Interestingly, subtle morphological differences observed between normal and non-vacuolated and normal but vacuolated sperm exhibited significant differrences in the ability of the SCD-Oligo-Halosperm treated sperm to expand DNA fibers following protein depletion.