Sentence examples for proved difficult to test from inspiring English sources

However, it proved difficult to test this concept because rigid-rod and flexible-coil polymers are usually demixed.

This expected change of 16 in the power has previously proved difficult to test precisely, but it is shown here that available data on the deposition of small aerosol particles (Sc ∼ 106) confirm that the deposition is indeed 10 times faster on very rough surfaces.

The hypotheses investigated experimentally in microcosms are of broad relevance to our understanding of host parasite interactions in general, yet have proved difficult to test in natural populations.

Consequently, it has proven difficult to test these agents in traditional rat and mouse models of anxiety and depression.

The notion of electron viscosity had been suggested before in theory, but it had proven difficult to test because nobody had come up with a way to directly observe such phenomena.

Although the relative contributions of structural and psychosocial variables are intensely debated, the validity of differing hypotheses has proven difficult to test because the incidence of serious disabling LBP illness is low in healthy subjects.

This approach could help solve a conundrum that has vexed investigators for decades: how to sort through and to understand the human impact of nearly 80,000 human-produced chemicals listed by the Environmental Protection Agency many of which show up inside of people in trace amounts that have proven difficult to test for harmful effects.

Fetal surgery has been around for nearly 30 years, but it's proven difficult to test how well it really works.

It is appealing to predict that DPN acted on AVPV Kiss-ir neurons directly, but this hypothesis may prove difficult to test.

Although this idea has drawn attention from a variety of disciplines, it has proven difficult to test empirically (Richerson and Boyd, 2008; Fuentes et al., 2010).

Although this theory has proven difficult to test, the argument is provocative and, given the prominent place occupied by familistic societies among the pioneers of very low fertility, worth putting to the test.