00:00:30 The high-tech marriage of an electron microscope and a mini-computer is providing scientists

00:00:50 with a unique view of the chemistry of cells.

00:00:53 The unusual device, developed at the National Institutes of Health in Maryland, is an imaging

00:00:58 analytical electron microscope.

00:01:01 Not only can it provide a highly magnified picture of the shape of a cell, it produces

00:01:05 color images showing chemical elements inside.

00:01:09 Here for instance, how pancreas cells can be viewed.

00:01:12 The black and white image represents what the conventional electron microscope could

00:01:17 produce.

00:01:18 The analytical electron microscope, on the other hand, can produce not just that but

00:01:23 additionally the various chemical images.

00:01:25 For example, in red we have the distribution of nitrogen, where it is black would represent

00:01:30 very little nitrogen, and where it's very, very red would represent high nitrogen.

00:01:35 And you can see that this image correlates with this image.

00:01:38 Actually, NIH has developed two such microscopes.

00:01:42 One chemically images whole cells, the other cell parts as small as 200 atoms wide.

00:01:48 In both, an array of detectors picks up signals from the chemical elements in the specimen,

00:01:53 and the computer converts these into color images.

00:01:55 Again, here's the type of picture you'd see with a conventional device.

00:02:00 It's a scavenger cell or macrophage from a miner with black lung disease.

00:02:04 Without the AEM, you wouldn't know the long dark object inside is indeed a piece of coal.

00:02:10 Now this is the sort of image that the analytical electron microscope can provide.

00:02:14 In this particular example, blue is carbon.

00:02:18 And since we have a shard of coal here, the blue represents where the coal is.

00:02:25 The green is iron, and in the defense mechanism of the body of the macrophage, it surrounds

00:02:31 the foreign objects with a layer of iron.

00:02:35 The Imaging Analytical Electron Microscope, a new tool for all scientists to explore the

00:02:40 chemistry of the infinitely small.

00:02:43 On the science scene, I'm Alan Smith.

00:03:18 This steer is being injected with its own blood, following a process that has turned

00:03:37 some of its red blood cells into natural, slow-release medicine capsules.

00:03:41 This blood encapsulation process, developed by an agriculture department biochemist, is

00:03:46 designed to increase the effectiveness of drugs in the treatment of animals and humans.

00:03:51 We demonstrated that the drug that was administered and encapsulated was as effective as the normal

00:03:59 mode of administration for the drug, but it was effective at one-tenth the concentration.

00:04:07 Encapsulating drugs within the blood starts with whole blood drawn from the animal.

00:04:11 The red cells then are separated from the blood's other biochemical parts, and the cell's

00:04:15 salt concentration reduced.

00:04:18 With that reduction, the red cells, held in a dialysis bag, begin to swell until tiny

00:04:23 pores open in the cell's membranes.

00:04:26 The opening of the pores allows the cells to absorb a given drug.

00:04:30 Then the salt concentration is restored, causing the cells, now with the drug inside, to shrink

00:04:36 to normal size.

00:04:37 The blood is reconstituted and goes back into the animal.

00:04:41 As the blood circulates, the medication is slowly released through the red cell's membranes.

00:04:47 Biochemist Deloach, who has successfully tested the process with farm animals, is optimistic

00:04:51 his research will also benefit humans.

00:04:54 One possibility.

00:04:56 We think that in cancer chemotherapy that there are certain toxic drugs that we can

00:05:02 provide circulating drug levels for longer periods of time with a lower drug dosage than

00:05:10 with a normal method for drug administration.

00:05:14 Lower dosage, longer effectiveness, even targeting drugs to specific organs of the body.

00:05:20 These are all possibilities biochemist John Deloach foresees in using red blood cells

00:05:25 as natural, time-release medicine capsules.

00:05:28 On the Science Scene, I'm Alan Smith.

00:06:10 These empty plastic bottles aren't headed for the trash heap.

00:06:23 Here at the Plastics Recycling Institute at Rutgers University, scientists are developing

00:06:28 mechanical and chemical means for reclaiming plastic waste to convert it into useful new

00:06:34 products.

00:06:35 The institute, established by Rutgers and members of the plastics industry, is on the

00:06:39 leading edge in advancing the presently limited technology of plastics recycling.

00:06:44 Many plastic materials that are being used for consumer products in packaging and in

00:06:49 other applications still have a great deal of their value remaining after they've been

00:06:55 used once.

00:06:57 And it's a limited resource, and as a result we should recover those materials to use them

00:07:02 in terms of their engineering properties as many times as we can, rather than simply use

00:07:07 them once and throw them away.

00:07:09 To this end, in addition to laboratory research, the institute has built a pilot plan to advance

00:07:15 and demonstrate processes for recycling various plastics.

00:07:19 Present emphasis is on recycling a plastic called PET, the principal material used in

00:07:23 those soft drink bottles.

00:07:25 Here, shredded empties are processed by air, water, heat, and chemicals to remove syrup,

00:07:31 glue, and fragments of labels and caps.

00:07:34 When they finally emerge, the plastic chips are ready for remanufacturing into a variety

00:07:38 of products, products like these.

00:07:42 Plastics recycling is a fledgling field.

00:07:44 Until the Plastics Recycling Institute, there had been little attempt at coordinated research,

00:07:49 process development, or widespread implementation.

00:07:52 Our primary focus in addressing the issue of plastics recycling is to bring this technology

00:07:59 to a much broader spectrum of the public, and for the use and benefit of the public.

00:08:05 As plastics recycling technology advances, much of the waste that now winds up in landfills

00:08:10 will be reclaimed, be used over and over again, until finally it's burned as a fuel.

00:08:18 On the science scene, I'm Alan Smith.

00:09:05 Titanium, a tough yet lightweight metal commonly used in jet aircraft engines, may one day

00:09:15 be commonplace in the dentist's office, replacing expensive gold or imported metals as tooth

00:09:21 crowns.

00:09:22 That's the object of research by the American Dental Association at the National Bureau

00:09:26 of Standards in Maryland.

00:09:28 We chose titanium primarily because it is very compatible with human tissues.

00:09:33 Dr. Waterstrat made the world's first titanium-based dental castings in 1977.

00:09:39 Now in perfecting the process, he's invented a small electric arc furnace.

00:09:44 Within minutes, a pellet of pure titanium becomes a precision-cast dental crown.

00:09:48 The furnace uses argon gas instead of air to prevent the titanium from turning brittle.

00:09:54 The electric arc quickly melts the pellet, and the molten titanium drops into a mold.

00:09:59 The mold itself is made of a special material to keep contaminants from getting into the

00:10:03 metal, a problem with other processes.

00:10:06 Magnesia-based mold materials have been used by other researchers, and they've encountered

00:10:12 problems with surface roughness and porosity.

00:10:16 We've chosen instead to adopt the use of the material zirconia, which is zirconium dioxide,

00:10:23 and we believe that we've eliminated the problems of surface roughness and porosity.

00:10:27 Indeed, it appears they have.

00:10:29 Dr. Waterstrat's colleague, Dr. Nelson Rupp, is conducting two years of testing with volunteers.

00:10:35 In fact, he was the first volunteer.

00:10:37 He's wearing a titanium crown next to a gold one, and reports no problems.

00:10:42 So far, we find that the material is extremely comfortable.

00:10:45 There's no aftertaste.

00:10:47 There's no shock.

00:10:48 And the gingival tissue around it is extremely healthy.

00:10:53 There's no untoward tissue response.

00:10:56 With a furnace so simple, a cast can be made right in the dentist's office.

00:11:00 Abundant titanium may eventually replace crowns now made of gold and imported metals.

00:11:06 On the Science Scene, I'm Alan Smith.

00:11:26 On

00:11:55 a TV monitor, an agriculture department scientist is seeing what his microscope has blown up

00:12:01 15,000 times, a petunia cell that he's injecting with gene-bearing chromosomes.

00:12:07 The process, called microinjection, is a recent biotech innovation by which researchers are

00:12:12 hoping to genetically engineer better strains of plants from blocks of genes.

00:12:17 What we're attempting to do is take chromosomes from a selected species of petunia and inject

00:12:22 those via a microscopic hollow glass tube into another species of petunia.

00:12:27 In doing this, what we're trying to do is identify the genes involved in traits like

00:12:32 resistance to sandy soils or drought.

00:12:35 Microinjection of itself seems simple enough.

00:12:37 It's the preparation of the plant cells that's complex.

00:12:40 First, getting inside the cell.

00:12:42 This requires using enzymes to chemically peel away the tough cell wall.

00:12:47 Next is the tricky problem of removing the cell's vacuole.

00:12:51 It's the large mass inside that holds wastes and, if punctured by the glass tube, would

00:12:55 contaminate the cell.

00:12:57 To resolve this, the cell, or cells, are spun in a centrifuge.

00:13:01 That forces the vacuoles out of the cells without breaking their membranes.

00:13:04 The vacuoles, by the way, will soon grow back in.

00:13:07 With all those preliminaries finally over, the cells are then injected with the chromosomes

00:13:12 carrying the desired gene blocks and left in tissue culture to grow.

00:13:16 Dr. Griesbach, who developed much of this technology, currently works with petunias

00:13:21 because they're one of the few plants that can be regenerated in tissue culture from

00:13:25 a single cell into a whole plant.

00:13:27 Ultimately, what may all this lead to?

00:13:29 One of the things we're attempting to do is develop a new genetic engineering system that

00:13:34 will transfer multiple genes.

00:13:36 The current genetic engineering techniques will only transfer one gene at a time.

00:13:40 This technique, hopefully, will be able to transfer these blocks of genes involved in

00:13:44 disease resistance or resistance to stresses like drought.

00:13:47 Microinjection.

00:13:48 Genetic engineering from a different approach.

00:13:51 On the Science Scene, I'm Alan Smith.