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A.
The Threat of Certain Herbal Products on the Internet
Narrator:
This is Science Today. A Chinese herbal product
known to cause kidney failure and cancer has been
banned for importation by the FDA but is readily
available on the Internet. Lois Swirsky Gold, the
director of the Carcinogenic Potency Project at
the University of California, Berkeley, has been
tracking the herb, which contains a toxin called
aristolochic acid.
Gold:
It turned out to be a very potent carcinogen,
meaning it caused tumors in rats at very low doses
and it caused the tumors very quickly and in multiple
target organs.
Narrator:
Gold says the sale of dangerous herbal products
over the Web is an imminent threat to human health.
Gold:
We looked on the Web and found 19 products that
they said contained Aristolochia and another 95
products that said they contained a plant that Aristolochia
can be substituted for! None of these are supposed
to be available to American consumers, but they're
all over the Web.
Narrator:
For Science Today, I'm Larissa Branin.
B.
How MRI Technology May Be Used in Agriculture
Narrator:
This is Science Today. Using technology borrowed from
the medical field, University of California agriculture
engineers have developed a new device for detecting
freeze damaged citrus fruits without having to cut
them open. Agricultural engineer Jim Thompson says
the device was built to measure water quality content
and uses the same principle as magnetic resonance
imaging.
Thompson:
When the fruit has been frozen, the cell structure
is disrupted compared with normal fruit and the magnetic
resonance signal will detect the fact that the water
is held different in the fruit cells in those areas
where the fruit cells have been damaged by freezing.
Narrator:
But
as in the medical field, an MRI-type fruit scanner
would be expensive.
Thompson:
At this point the magnetic resonance imaging cost
in the range of about forty thousand dollars, which
is fairly expensive. Although, some of the detection
systems we use now in packing lines are about that
same cost. So while it is expensive, if it's accurate,
it would be worthwhile.
Narrator:
For
Science Today, I'm Larissa Branin.
C.
New Insight into What Triggers Deep Earthquakes
Narrator:
This is Science Today. In August of 2002 two massive
deep earthquakes, centered in the same underwater
trench below the Fiji Islands in the Pacific, occurred
seven minutes apart. Geologist Harry Green of the
University of California, Riverside, says the observation
that one earthquake, measuring 7.6 on the Richter
Scale, caused another 7.7 quake nearby, may have major
implications for understanding how earthquakes are
initiated.
Green:
The effects of the first earthquake 300 km away and
65 km deeper is really very, very small and that's
what causes the great interest-because how could this
very small effect, within seven minutes, produce an
earthquake even larger than the one that triggered
it?
Narrator:
Green says this event may help us understand the physical
mechanism that causes earthquakes, so that we can
better predict damaging quakes in the future - even
ones at more shallow depths.
Green:
It
gives us a new time element to combine with seismology
that can give us insight as to how the earthquakes
get started.
Narrator:
For Science Today, I'm Larissa Branin.
D.
Yo-Yo Dieting a Major Cause of Extreme Obesity
Narrator:
This is Science Today. There's a general perception
that extremely obese women have become that way because
of extreme self-indulgence and a lack of weight control
willpower. But University of California, Berkeley
nutrition education specialist, Joanne Ikeda, says
their recent year long survey examining the diets
of women well over 200 pounds, painted a different
picture.
Ikeda:
The largest women had started dieting before they
were fourteen years of age. This appears to be a risk
factor for becoming really large. The other thing
we found was the women who were extremely large had
dieted more often.
Narrator:
The problem is, these women will lose a significant
amount of weight and then gradually regain that weight
… and then some.
Ikeda:
What has happened to these women who, let's say, weigh
four hundred, five hundred, six hundred pounds - they
have basically weight cycled up to really large weights.
Narrator:
For Science Today, I'm Larissa Branin.
E.
The 'Mr. Mom' Concept is Not So New
Narrator:
This is Science Today. Even in today's changing workforce,
the concept of a husband taking a larger role in household
chores or childcare is considered a rarity. But according
to sociologist Scott Coltrane of the University of
California, Riverside, the concept of husbands and
fathers cooperating more in the household economy
goes back a century ago.
Coltrane:
When most people lived on farms, we did not have women
who worked out of the labor force, they were actually
very much in the labor force. The labor force was
actually the household economy. So women were doing
the sorts of things that produced valuable goods and
services and resources and they did this cooperatively.
Men were not uninvolved in the raising of kids.
Narrator:
Coltrane
says many people forget this because so many social
scientists used the 1950s as a benchmark for the behavior
of men and women.
Coltrane:
Now unfortunately, the 1950s were anomaly. That's
when we had a big move to the suburbs, stay at home
wives, women not staying in the labor force or even
entering the labor force for the first time, early
age at marriage. All those trends were actually being
reversed - we're actually getting back to patterns
of a century ago.
Narrator:
For Science Today, I'm Larissa Branin.
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