Energy conditions and a bounce in FLRW cosmologies
  Exploiting the existence of two "cosmological" constants, one associated with the classical Lovelock theorem and one with the vacuum energy density, we argue, in a model independent way, that in spatially closed FLRW cosmologies with a positive definite effective cosmological constant there exists a range in this constant that serves as a sufficient condition for the satisfaction of the null, weak, strong and dominant energy conditions at a bounce. The application of energy conditions is not unambiguous and we show how the bounce can be considered classically and how, we believe more reasonably, it can be considered a matter of quantum cosmology. 
Benjamin K. Tippett and Kayll Lake