Sentence examples for difficult to maintain over from inspiring English sources

Expansion of primary human myoblasts and formation of myotubes in two-dimensional (2D) systems is well known, however, these cultures are difficult to maintain over long times, lack the architecture of native muscle, and require complex media components to initiate spontaneous contractions (Blau and Webster, 1981; Eberli et al., 2009; Guo et al., 2014).

Building infra-structure to make that possible will be expensive, and difficult to maintain over the long term, as tsunamis are rare in that region.

But such improvements were found only in conjunction with other changes in the subjects' overall lifestyle, like regular exercise and stress reduction, and such changes are difficult to maintain over a long period.

We know that it is very difficult to maintain over time.

It's possible to buy services that are not custom-made and, as a result, difficult to maintain over time.

Communication campaigns inciting primary physicians to limit unnecessary prescriptions for LRTI have a moderate impact, which is difficult to maintain over time [12, 13].

However, exploiting user cooperation in higher dimensional IMVS is difficult, since users watching different views makes it difficult to establish partnership, and users switching views frequently and independently makes it difficult to maintain partnership over time.

Arbitrary changes to the exams systems and the multiple purposes that qualifications are now often expected to take on - accountability, driving up standards in schools, individual selection, and allowing greater access to education - have made it difficult to maintain standards over time.

I was just 5 feet 8 and 175 pounds, and it was difficult to maintain that intensity over 100 games.

Because it is difficult to maintain full attention over very long periods, it must be modulated; that is, stimulated, relaxed, and stimulated again.

But in the seven years since we launched, what we've seen is people have taken those projects, they've turned it into services that are running and then they piled a bunch of other stuff on top of it — and that becomes really difficult to maintain and manage over the long term".