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May 2001

The Laboratory in the News

Advanced Technology for Stockpile Stewardship
Commentary by Jeff Wadsworth

Uncovering Hidden Defects with Neutrons
High-energy neutrons can effectively image heavily shielded objects that are essentially opaque to x rays.

The Human in the Mouse Mirror
Comparative genomics may help us to better understand our genetic heritage and evolution, or why humans are human and mice are mice.

The NIF Target Chamber—Ready for the Challenge
Good progress is being made on the construction of the world's largest laser.

Indoor Testing Begins Soon at Site 300
The world's largest explosives chamber nears completion.

Patents and Awards

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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View the Entire May 2001 Issue in PDF (11.3MB)

  • Uncovering Hidden Defects with Neutrons
  • (pdf file, 2.5MB)
    Experiments conducted over the past four years at Ohio University by a Lawrence Livermore team have demonstrated that high-energy (10- to 15-megaelectronvolt) neutron imaging holds considerable promise to probe the internal structure of thick objects. High-energy neutron imaging offers advantages over conventional x-ray and thermal neutron imaging, particularly for inspecting light (low-atomic-number) elements that are shielded by heavy (high-atomic-number) elements. The design of Lawrence Livermore's neutron imaging system consists of a powerful, high-energy neutron source, a multiaxis staging platform to hold and manipulate an object, and an efficient imaging detector. The work on this project is funded by the Department of Energy's Enhanced Surveillance Campaign, which is responsible for developing advanced nondestructive diagnostics for the surveillance of stockpiled nuclear weapons systems.

  • The Human in the Mouse Mirror
  • (pdf file, 2MB)
    The draft sequence of the human genome is complete, but work is just beginning on understanding what parts of the sequence are genes, what individual genes do, and how they do it. Lawrence Livermore bioresearcher Lisa Stubbs leads a group that is shedding light on the mystery of the human genome by comparing human and mouse genomes, piece by piece, focusing on chromosome 19. Using comparative genomic tools such as percent identity plots and dot plots developed at Livermore, they uncover the differences and similarities between the sequence of the two species, with intriguing results. They have found that only about 7 percent of the sequences are similar enough to be recognized as related. Many regions of the human genome are significantly larger than the corresponding regions in the mouse, with the human genome containing more "filler" sequences. Each species has a significant number of species-specific genes, many of which appear to be involved in regulating other genes. The sequences that control or regulate how genes act—when they produce proteins, where, and how much—is one of the next genomic frontiers that Stubbs and her team are researching.

  • The NIF Target Chamber—Ready for the Challenge
  • (pdf file, 1MB)

  • Indoor Testing Begins Soon at Site 300
  • (pdf file, 1.5M)



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    UCRL-52000-01-5 | May 25, 2001