The new designs point to a persistent challenge for medical device regulators.

Nevertheless, widespread poverty, socioeconomic inequality, and poor governance remain persistent challenges.

Garnett's criticism reflected a persistent challenge for the Commission.

The most surprising aspect of the Senate impeachment trial is the persistent challenges to the senators' constitutional right to run it.

Minimizing human-wildlife conflict is a persistent challenge in wildlife management and conservation.

Interoperability between airborne networking waveforms has been a persistent challenge.

And environmental and financing questions pose persistent challenges to the rapid growth of the hemisphere's oil production.

There is another persistent challenge for chief marketing officers: justifying their expenditures.

Our powerful economy gives America a unique chance to confront persistent challenges.

The grants will target millions in public and private funds to grow effective solutions to persistent social challenges across more than 20 states.