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In this issue:
Deadly Carcinogen Unraveled
Cooling Tower CT-101 Remade: New Structure Nears Completion
'Walk the Farm' Participants Traverse Stanford and SLAC to Learn about Climate Change

SLAC Today

Tuesday - May 4, 2010

Deadly Carcinogen Unraveled

(Image - chemical structure of an aflatoxin)
3-D chemical structure of an aflatoxin molecule. (Image: user Giorgiop2 at the Wikimedia Commons; licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.)

Using the bright X-ray beam of the Stanford Synchrotron Radiation Lightsource, researchers have unveiled the mystery behind one of the deadliest toxins that causes liver cancer.

Aflatoxins are common contaminants of foods such as nuts and grains, which make up staple diets in many developing countries. These toxins are produced by mold and other fungi during food production, and are considered by the U.S. Food and Drug Administration to be an unavoidable food contaminant. Aflatoxin molecules are characterized by the presence of multiple aromatic rings. Chronic ingestion of one type of aflatoxin leads to liver tumors that are a major cause of death in Asia, Africa, and Central America.

This toxin wreaks havoc on an important gene that prevents cancer. Without the protective effect of this gene, aflatoxin further compromises immunity, interferes with body metabolism, and causes severe malnutrition. It is urgently important to find inexpensive strategies that help protect the world population from aflatoxin food contamination.  Read more...

A fan shroud goes into place. (Photo by Melinda Lee.)

Cooling Tower CT-101 Remade

New structure nears completion; testing comes next

Replacement of Cooling Tower 101 is nearly finished, with the crew on schedule for completion by the end of May. People passing by the intersection of Loop and Target roads have seen various stages of the project, from the demolition of the original tower to quick assembly of the skeletal structure, installation of the fill material and siding, and the addition of the enormous fans shrouds. (See the photo to the left.)

Building the new tower frame. (Photo by Julie Karceski.)

"The structure of the tower is almost 100 percent complete," said Javier Sevilla, deputy project manager. Right now, the construction team is working to complete electrical modifications and plan to begin testing equipment and commissioning the tower soon. Sevilla expects that buildings around SLAC can expect to receive water from this new tower by the end of May.

Putting final touches on the near-finished structure. (Photo by Julie Karceski.)

Cooling Tower 101 was the last original cooling tower at SLAC, built in the 1960s. Replacement of this tower, which re-circulates water to cool air compressors, low-conductivity water systems and chillers for air conditioning to many critical buildings, is the final part of an extensive, $15 million infrastructure project. The old tower was in need of a seismic upgrade, and cooling duties were transferred to a temporary cooling tower for the duration of the project. The project team is working closely with affected building managers as final utilities are connected to the new tower. Once commissioning of the new tower is complete, it will take on cooling duties for Buildings 23, 50, 84 and 44, among others.

'Walk the Farm' Participants Traverse Stanford and SLAC to Learn about Climate Change

Forty-two students, faculty and others took part in the fourth annual Walk the Farm on Saturday. (Photo: Stanford Report.)

Conditions seemed perfect Saturday on Jasper Ridge.

The mid-morning sun was finally warming a group of hikers who set out for the spot from Stanford's main campus at 6:15 a.m. The wind was calm. Purple, yellow and orange wildflowers dotted a field of wispy serpentine grass overlooking the San Francisco Bay.

But something was missing: the Bay checkerspot butterfly.

Undermining this pastoral perfection on an open swath of Stanford's biological preserve is the creeping onset of global warming. Erratic rainfalls beginning in the 1970s upset the butterflies' life cycles, killing many of them and forcing the survivors from one spot of the 1,189-acre preserve to another. Now, they're all gone.

"The butterflies were getting yanked around because there weren't enough average years of rainfall," said biology Professor Carol Boggs. "Too much or too little rain is no good. They need Goldilocks conditions, and they didn't have them here anymore."

Boggs was sharing the ecological lesson with 42 students, researchers and tagalongs on the fourth "Walk the Farm," an annual daylong hike across Stanford's property that follows a different route each year and explores various global themes by showing how the university fits into that bigger picture.  Read more from Stanford Report...


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