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Turning Oil Into Gas

When you see all those cars at the gas station filling up with unleaded, you may not stop to think about how that gasoline got there. It wasn't pumped out of the ground in that form. The same goes for jet airplane fuel. It didn't start out that way--it took a long refining process to become fuel. You could never fly an airplane with gasoline, but ...

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TurningOilIntoGas
Biology

The Limbic System

The limbic (meaning 'ring') system is virtually identical in all mammals. It sits above the brain stem, resembling a bagel with a finger (the brain stem) passing through it. This limbic 'system' ... Continue reading

LimbicSystem
Chemistry

Liquid Glass Is All Wet

As a liquid changes to a solid, its molecules go from a state of turmoil and chaos to a state of order. As these molecules slow down to form a solid, they arrange themselves into a crystalline ... Continue reading

LiquidGlass
Astronomy

Sputnik and The Dawn of the Space Age

History changed on October 4, 1957, when the Soviet Union successfully launched Sputnik I. The world's first artificial satellite was about the size of a basketball, weighed only 183 pounds, and took ... Continue reading

Sputnik
Engineering

Red Dot Replacing Cross Hairs

A bullet fired from a gun becomes subject to the pull of gravity and begins to fall the instant it leaves the gun barrel. The farther away from the gun the bullet travels, the lower to the ground it ... Continue reading

RedDotReplacingCrossHairs

Facts About Angina

FactsAboutAnginaAngina is a recurring pain or discomfort in the chest that happens when some part of the heart does not receive enough blood. It is a common symptom of coronary heart disease (CHD), which occurs when vessels that carry blood to the heart become narrowed and blocked due to atherosclerosis Angina feels like a pressing or squeezing pain, usually in the chest under the breast bone, but sometimes in the shoulders, arms, neck, jaws, or back. Angina is usually precipitated by exertion. It is usually relieved within a few minutes by resting or by taking prescribed angina medicine. Episodes of angina occur when the heart's need for oxygen increases beyond the oxygen available from the blood nourishing the heart. Physical exertion is the most common trigger for angina. Other triggers can be emotional stress, extreme cold or heat, heavy meals, alcohol, and cigarette smoking.

An episode of angina is not a heart attack. Angina pain means that some of the heart muscle in not getting enough blood temporarily--for example, during exercise, when the heart has to work harder. The pain does NOT mean that the heart muscle is suffering irreversible, permanent damage. Episodes of angina seldom cause permanent damage to heart muscle. In contrast, a heart attack occurs when the blood flow to a part of the heart is suddenly and permanently cut off. This causes permanent damage to the heart muscle. Typically, the chest pain is more severe, lasts longer, and does not go away with rest or with medicine that was previously effective. It may be accompanied by indigestion, nausea, weakness, and sweating. However, the symptoms of a heart attack are varied and may be considerably milder.

When someone has a repeating but stable pattern of angina, an episode of angina does not mean that a heart attack is about to happen. Angina means that there is underlying coronary heart disease. Patients with angina are at an increased risk of heart attack compared with those who have no symptoms of cardiovascular disease, but the episode of angina is not a signal that a heart attack is about to happen. In contrast, when the pattern of angina changes--if episodes become more frequent, last longer, or occur without exercise--the risk of heart attack in subsequent days or weeks is much higher.