Used properly, these formulas can be an acid test to help a worker judge whether his or her retirement savings plan is on track.

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"The next few weeks will be an acid test for the host cities, " added Valcke, who has clashed with Brazilian authorities in the past when questioning the delay in preparations for FIFA's forthcoming events.

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Clive Bates from Action on Smoking and Health said the government's backing of the Bill meant it had passed an "acid test of credibility".

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The teams went into the game level on 27 points, with only points difference keeping the Exiles in top spot in the table, and London Irish coach Toby Booth described the game as an "acid test" for his team.

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To investigate whether acid reflux is involved at all, doctors can do a 24-hour pH test, inserting an acid-sensitive probe through the patient's nose into the esophagus, where it records any episodes of reflux.

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After experimenting with more than a dozen different formulations, drying them with custom-made machinery and heating them in ovens to test shelf life, Nektar hit upon a successful recipe that mixes insulin with glycine (an amino acid), citrate (the salt of an organic acid found in humans) and mannitol (a sugar used in intravenous products).

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