WASHINGTON— AT one time or another, everyone has reached into a deep corner of the refrigerator, pulled out a long-forgotten plastic container and opened it to find a fuzzy, gray-green blanket of mold.

In fact, said Dianna Namisniak, Americans throw away 15 percent of their fresh food and leftovers because they forget what is in the refrigerator until it is too late. She and her husband, Lee, used to do that -- until they invented the Leftover Lifeguard.

"People create leftovers every day because we can't bring ourselves to throw away good food," Mrs. Namisniak said. "But then that's exactly what we do two weeks later."

So the Namisniaks patented an electronic inventory monitor that attaches to a refrigerator with magnets. On its face are 16 to 20 rows for tags showing the name and life span of foods. About 60 different magnetic tags come with the device -- one for ricotta cheese, for example, says it should last 7 days. After putting perishables in the refrigerator, a person chooses corresponding tags.

"You'd take the label and place it in any row," Mrs. Namisniak explained. "Then you'd press a 'select' button to the right of the row, enter the lifetime of the food -- for seven days you'd press it seven times -- and hit start."

Then forget about the ricotta. Until the countdown sets off a warning light.

"When you get to five days, a little warning light illuminates," Mrs. Namisniak added, "and at seven days the light starts flashing. If you still don't use the food, it will keep counting the days up to 99."

A deluxe model of the invention is all electronic -- food names and freshness days would be keyed in and appear on liquid-crystal displays.

The Namisniaks say they are negotiating licenses for their invention and hope it may someday be a built-in feature of refrigerators. Their patent is 5,335,509. Computer Scroll Bar To Highlight Words

Scroll bars are a common feature of many computer programs. They usually appear on the left and bottom of a screen and tell a user at a glance where he or she is in a document.

To several inventors at the Microelectronics and Computer Technology Corporation in Austin, Tex., the space could be put to better use. So they patented a scroll bar that tells users where certain words or characters appear in a document, and where additions were made or sections were recently edited.

"A user may ask where in a document the word 'taxonomy' appears," said David Sigmond, the company's patent lawyer. "Little marks in the shaft will show everywhere in the document that the word 'taxonomy' appears."

At the same time, each "taxonomy" is highlighted in the text on the screen.

"The occurrence of the marks is independent of where the elevator is in the shaft, and of what you're looking at on the screen," Mr. Sigmond explained.

The system can also mark and highlight recent revisions or additions to a document, or sections prepared by different authors.

"Say you wanted to know everything edited before today," Mr. Sigmond said. "If you hit the right function key, the attributes in the shaft would show those areas of the document."

Users can point a mouse at a mark in the shaft and click on that spot, and the indicated area will immediately appear on the screen.

The company hopes to license the enhanced scroll bar. Its inventors -- David A. Wroblewski, William C. Hill and Timothy P. McCandless -- received patent 5,339,391. nhalation-Therapy Computer Program

It hardly seems necessary to teach people how to inhale. But researchers have found that people who take medication through hand-held pumps often breathe so inefficiently that most of the medicine is wasted.

Now there is a computer program for teaching slow and deep inhalation to insure that medication reaches the small airways in the lungs. It was patented by Ted Lanpher, Gregory Lanpher, David Mishelevich and Steven Minar, who work for Circadian Inc. in San Jose, Calif.

The company says about 20 million Americans use inhalers to treat diseases like asthma and bronchitis.

"The right way to breathe to get small particles of medication into small airways of the lungs is not intuitive," said Ted Lanpher, Circadian's director of marketing. "The medication has to navigate as many as 23 generations of branches of airways in the lungs to get down into the small airways. If you inhale too fast, instead of making those turns, the medication just slams into the sides of the airways.

"And," he added, "people don't hold their breath long enough for all the particles of medication to settle."

Circadian attached a hand-held inhaler with a flow and pressure sensor to a computer with a program showing patients when they are breathing deeply and slowly enough.

The system is designed for use in a doctor's office or hospital. The company says it wants to produce a hand-held model eventually for home use. Circadian's patent is 5,333,106.