background: sperm vitrification is a technique of ice and cryoprotectant free cryopreservation by direct plunging of sperm suspension into liquid nitrogen (ln2). the aim of this study was to investigate the influence of cryoprotectant free-vitrification on human sperm fine structure by msome technology and the fertility potential by zona binding assay (zba). methods: 20 normo-ejaculates were pr...

We study the 3-Coloring problem in graphs with small diameter. In 2013, Mertzios and Spirakis showed that for $n$-vertex diameter-2 this can be solved subexponential time $2^{\mathcal{O}(\sqrt{n \log n})}$. Whether polynomial remains a well-known open question area of algorithmic graph theory. paper we present an algorithm solves $2^{\mathcal{O}(n^{1/3} \log^{2} n)}$. This is first improvement ...