Nitrates like nitroglycerin widen the heart's fuel lines by relaxing blood vessels.
It had all started with a few trucks whose fuel lines had frozen.
As the night wore on, fuel lines froze and cellphone batteries died.
Inspect rubber fuel lines, gaskets and hoses regularly and replace them as needed.
They have no moving parts, fuel lines, valves, sealants or the messy hydraulics of conventional rockets.
This appears to allow damage, like cracks in components of the fuel lines, known as flowliners, to develop slowly.
Mr. Arnold examines the manifold, the valves that connect fuel lines to burners, pilot lights, thermostats, gauges and controls.
Gagarin felt the shudder of distant valves slamming shut, the rocket swaying as the fuel lines were pulled away.
It also touched off a major behind-the-scenes diplomatic effort by the Obama administration to rebuild the fuel lines.
But "if one or two fuel lines get narrowed," said Dr. Bertram Pitt of the University of Michigan, "that engine starts to sputter".
Brian France, the C.E.O. of Nascar, says he is looking into moving away from gasoline, despite the great cost of re-engineering the cars' fuel lines.
