AUSTIN, Texas -- A new family of monitors from 3M provides complete surveillance of grounding in electronics assembly, particularly for soldering irons and process tools. The 3M Down to Earth brand Monitor Series instantly alerts workers of a problem as it occurs, allowing corrective action to restore grounding and prevent further damage to sensitive electronics.
Stem cells come from three main sources. Embryos are one--they're the reason some of the work on stem cells is controversial. Many cells in an early embryo are stem cells, and they can form any kind of tissue. A second source is blood from the umbilical cords of newborn babies. And it turns out that adults also have a few stem cells, lurking in places such as bone marrow and skin. Stem cells from those sources are not quite as versatile as embryonic stem cells, but their use is uncontroversial. And it is a batch of human adult bone marrow stem cells that I've just seen injected. The surgeon stuffs the womb back into the sheep (somehow it all fits) and sews up the incision. The ewe is carried off to the recovery room. The operation has taken just fifteen minutes.The surgeon cuts down the middle of the belly, in the gap where the stomach muscles meet. (If the sheep had a six-pack, the cut would be down the center.) A few more cuts, and we have a window into the sheep's insides. The surgeon slides a hand into the opening and starts to haul out the womb. It's red, and glistens. I feel I'm watching downs getting out of a clown car: the womb keeps coming and coming. I watch in astonishment. I had no idea you could partly pull out an animal's insides like this."Now we inject human stem cells into the fetus. We don't need to cut into the womb, we just inject the human cells by pushing the needle through the wall of the womb and into the body of the fetus. This is very safe: we haven't lost a fetus since we started doing the operations this way" (they haven't lost any ewes either)."Does that affect the sheep?"As a place to start, the liver is of particular interest, because it can regenerate its own tissue. So if you needed a liver transplant, you wouldn't have to grow an entire human liver inside a sheep; it would be enough to have a human chunk.At least, that's the idea. But my bet is that the human-organs-from-sheep scenario will never make it to the clinic. For one thing, there are questions of safety. New infectious diseases regularly jump into people from animals. HIV came from chimpanzees; SARS, from bats or civets. A transplant is an intimate contact, and animal cells may harbor viruses that, though harmless to their animal hosts, could be dangerous to people. Before transplants from animal tissues could go ahead, that risk would have to be assessed.The series consists of four monitors:As for the fetus, "In another ninety days or so, it will be born," says the surgeon."A sheep's womb is a different shape from a human womb," says the surgeon. "A human womb looks like a sack. A sheep's womb has two horns that join at the base." She arranges the womb so that I can see both horns and starts running her hands over them, squeezing slightly. "The fetuses can be in either horn," she says. "Sometimes you have one in each, sometimes you have three in one and none in the other. This sheep has only one fetus. Here it is. The hips are here." The outlines of the fetal sheep, now almost nine weeks old and about six inches long, show through the lining of the womb; it's like looking at a child covered by a blanket.If left undetected, grounding problems can damage electronics products and result in warranty returns and loss of user confidence. The Down to Earth monitors, which are smaller than a cell phone, can help protect electronics wherever sensitive components are handled, including repair and service, the medical environment, military and aerospace."That contains the stem cells?" I ask.The single-story building was constructed of concrete block walls with a supporting steel roof and a metal roof deck. It did not have a fire detection or suppression system, but did have a motion detector connected to a burglar alarm. The motion detector alerted the police department, who later called the fire department reporting the fire inside the building. At the time of the incident the building was closed for the night.The Iron Man monitor detects overvoltage incidents that can be caused by a poorly grounded soldering iron, power screwdriver, or other hand tool used in assembly. Audio and visual alarms signal the operator to isolate the exposed circuit board and trace the cause of the overvoltage. The problem with a soldering iron, for example, may be in the electrical outlet to which it is grounded, its internal operation or oxidation in the tip.
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