Sentence examples for proved difficult to characterize from inspiring English sources

The phenyl moieties of these compounds are referred to as p-hydroxyphenyl (H) and guaiacyl (G) units, and they are linked together to form a complex three-dimensional structure that has proved difficult to characterize [ 3].

As a result, the gp120 V1V2 region has been of intense interest owing to its immunogenic promise; however, V1V2 has proven difficult to characterize structurally.

In many systems, however, it has proven difficult to characterize where robustness breaks down and to reconcile such results with mathematical models, which often predict exact robustness [ 31].

Although different studies have been proposed to characterize SBF rheology, yield stress and time dependency proved difficult to determine.

Yet reform proved difficult to implement.

The furlough plan proved difficult to enforce.

The advice proved difficult to follow.

Genocide has proved difficult to prosecute.

The effect proved difficult to measure.

The latter aim proved difficult to enforce.

Neutrality proved difficult to maintain, though.