Sentence examples for proved difficult to improve from inspiring English sources

Although several inhibitors were discovered, most of these were either toxic, thiol-alkylating compounds [18] (Fig. S1A) or were compounds acting through other mechanisms that proved difficult to improve despite extensive medicinal chemistry optimization efforts (Fig. S1B).

But safety advocates say it has proven difficult to improve the situation.

3) The final section on mouse male germline DNA methylation is the least developed, but this should not prove difficult to improve.

Ongoing efforts to develop more potent auxin agonists might also provide other small molecule tools, although the high water solubility, small size, low toxicity, and nominal cost of auxin might prove difficult to improve upon.

This suggests that pursuing tight glucose control targets in those in whom it proves difficult to improve A1C is associated with higher death risk, even if insulin and oral agents are used appropriately.

Ostensibly these mergers were aimed at increasing efficiency and improving integration, although such centralisation of purpose has sometimes proved difficult to achieve in practice [ 25].

All the models improved during SAFA's five year history and removing erroneous forecasts proved difficult to do in operations.

Neutrality proved difficult to maintain, though.

Alas, it proved difficult to find.

Genocide has proved difficult to prosecute.

The effect proved difficult to measure.