Sentence examples for proved difficult to detect from inspiring English sources

These were the samples spiked with S. Typhimurium DT40, which also proved difficult to detect with several other salmonella detection methods used in the study.

Cheating, though, has proved difficult to detect and almost impossible to punish.

The element fluorine, however, had proved difficult to detect because Earth's atmosphere blocks the wavelength absorbed by hydrogen fluoride, the fluorine compound thought to be most common in space.

"When we're able to trace it all the way back to the source and stop the printing, that's a big coup". The bills, allegedly produced with computers and ink jet printers, were of particular concern to agents because they had proved difficult to detect and were passed in locations across the United States.

Proinflammatory cytokines such as IL-1 and TNF-α are abundant in rheumatoid synovium, whereas the T cell-derived cytokines, especially IL-4 and interferon-γ, have often proved difficult to detect in RA synovium [ 24].

In spite of the strong environmental variation in the Baltic region, and the spawning site fidelity, it has until recently proved difficult to detect consistent or strong population structure in herring in the Baltic Sea, possibly due to the young age of the Baltic (<9000 kyr) and because herring populations are large, and hence genetic drift is expected to be weak (cf. Cano et al. 2008).

Our clinical studies in Ethiopia have relied on RT-PCR as an adjunct to in vitro ELISA and ELISpot, because IL-4 has proven difficult to detect as a protein, being both labile and present in very low quantities [34].

Possibly due to the diffusion/export of the cofactor to the growth media, in an experimental scale this change could be transitory and hence prove difficult to detect.

The ultrafast photochemical processes, essential for capturing the excitation energy to drive the subsequent hydride- and proton-transfer chemistry, have so far proven difficult to detect.

Alas, it proved difficult to find.

It was proving difficult to find.