The strong ${\mathrm{\Lambda }}_{b}NB$ and ${\mathrm{\Lambda }}_{c}ND$ vertices

We investigate the strong vertices among ${\mathrm{\Lambda }}_b$, nucleon and $B$ meson as well as ${\mathrm{\Lambda }}_c$, nucleon and $D$ meson in QCD. In particular, we calculate the strong coupling constants $g_{{\mathrm{\Lambda }}_{b}NB}$ and $g_{{\mathrm{\Lambda }}_{c}ND}$ for different Dirac structures entered the calculations. In the case of ${\mathrm{\Lambda }}_{c}ND$ vertex, the result is compared with the only existing prediction obtained at $Q^2=0$.