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Oct. 14, 2002 -- Some of this week's stories: Researchers blend biology, semiconductors Wolfram to speak on "A New Kind of Science" Exercise helps prepare lab for emergencies APS hosts family day Nuñez honored for mentoring students First ACA raffle winners drawn

Tiny technology leads to big changes
in DNA research at Argonne

New gene therapy procedures, DNA-based sensors, and other medical applications may be possible using a new method developed by Argonne chemists to initiate and control chemical reactions on DNA strands.

The new technology uses specially designed nanometer-sized semiconductors - less than a billionth of an inch in size.

The technology is based on the group's discovery of "conductive linkers" - small organic molecules that connect the electronic properties of semiconductors to biological or organic molecules. The scientists have used conductive linkers to connect strands of DNA to titanium dioxide crystals measuring only 4.5 nanometers in diameter (a nanometer is about 10,000 times narrower than a human hair).

In the presence of light, a titanium dioxide nanocrystal acts as a semiconductor, generating strong oxidizing power that attacks organic molecules in the same uncontrollable way that laundry bleach attacks all colors in the wash. The researchers found that by using different conductive linkers they can selectively control oxidation.

These nanoparticles have a wide range of potential applications in DNA-based sensing devices.

The scientists use the speed of electron transfers to determine the sequence and structure of DNA strands. The four bases that make up DNA are known to have different electronic properties that vary with the sequence and structure of the DNA strand. Guanine is the most readily oxidized, and therefore has the fastest reaction. It is followed, in decreasing order of reactivity, by adenine, cytosine and thymine.

By activating the titanium dioxide with light, the team can study the reactions and determine the sequence by comparing the speed and efficiency of the reactions.

The team is part of the Argonne Chemistry Division and includes Chemistry Division Director Marion Thurnauer and chemists Tijana Rajh, David Tiede and Lin Chen (all CHM). The team collaborated with Gayle Woloshak of Northwestern University, formerly of Argonne, to exploit this chemistry for use in gene therapy.

In the body, proteins called restriction enzymes are normally used to recognize and cut defective gene sequences. The researchers have created a novel "artificial restriction enzyme" that can be focused and controlled by light.

For example, a synthetic DNA single strand containing the sequence of a genetic defect can be linked to titanium dioxide. The researchers have shown that the DNA strand will carry the attached titanium dioxide to the cell nucleus, and presumably to the site of the genetic defect on the chromosome. Light will initiate the oxidative chemistry, which clips the defective gene and permits repair with a healthy gene sequence.

Wolfram to speak on "A New Kind of Science"

The author of a new book that outlines a controversial new approach to science will present "A New Kind of Science" at a special lecture Wednesday, Oct. 16, at 1:30 p.m. in Argonne-East's Building 402 Conference Center.

Stephen Wolfram, president and CEO of Wolfram Research, Inc., has spent more than 20 years developing a new approach to science. Basic to his approach is the idea of studying not traditional mathematical equations but instead rules of the kind embodied in the simplest computer programs.

Wolfram will cover some of the key ideas and discoveries in his book, outline their implications and discuss their personal and historical context. An extended question-and-answer session period will be included.

Wolfram was a leader in the field of scientific computing and was the youngest recipient of a MacArthur Prize Fellowship. In 1981, he began to lay the groundwork for the emerging field that Wolfram called "complex systems research." Wolfram used his ideas to develop a new randomness generation system and a new approach to computational fluid dynamics, both of which are now in widespread use.

Wolfram is the author of "Mathematica," a widely used scientific computing program. In the mid-1990s, he began to develop a fundamentally new conceptual framework, which he applied to problems in physics, biology, computer science, mathematics and other fields. He describes this work in "A New Kind of Science," which became a best-seller.

Exercise helps prepare lab for emergencies

A recent lab-wide emergency exercise gave Argonne-East employees a chance to practice response procedures and provided participants with experience they would need in case of a real emergency on site.

Held Sept. 18, the exercise was a joint effort by Argonne and the U.S. Department of Energy's Argonne Area Office and Chicago Operations Office.

"We had a joint purpose to find out if changes in the last year improved the site's ability to respond to an operational emergency," said Gary Winner, laboratory emergency management officer.

The scenario involved a waste mechanic who became contaminated after touching a box. He spread the contamination as he moved to other buildings. When the box was investigated, it was determined it was a Radiological Dispersal Device - or a "dirty bomb." A tape containing a bomb threat was found at the Argonne Information Center. The area was cleared, and Argonne's protective force and fire department worked with the DuPage County Sheriff's Department Bomb Squad to deal with the bomb. The Chicago FBI participated by phone.

The Emergency Response Center, Emergency Press Center, DOE Chicago Operations Emergency Operations Center and the Radiological Assistance Program (RAP) were activated in response to the contamination.

"I am very pleased with the professional and proactive response shown by all emergency personnel in this exercise," said Winner. "The exercise scenario had to be the most complex and eye-opening the site has dealt with in a long time."

Each response to the exercise was evaluated by personnel from DOE, Argonne or Excalibur Associates, a company specializing in emergency management.

"It was a good test of the integration of our emergency centers and an emergency scenario that stressed our capabilities," said Christine Van Horn (DOE-CH), the exercise director. "Overall, the response was well done."

APS hosts family day

For many of the Advanced Photon Source (APS) employees and users whose families ask them, "But, what do you do at work?" APS family day provided an answer.

Nearly 500 people came to the APS Sept. 28 for tours, science exhibits and demonstrations, and to watch members of management being grilled as they flipped burgers.

Volunteers from the APS user and employee communities were on hand to offer a kid-friendly demonstration of the principles of magnetism, an overview of high-pressure X-ray science and an interactive introduction to synchrotron research. They also provided a chance to operate a virtual APS linac control system, a close-up look at the proper method for searching and clearing a research station, a 3-D X-ray tomographic reconstruction of a bug's head (complete with 3-D glasses), and a hands-on encounter with the APS laser-tracker alignment system.

Tours of the experiment hall afforded a look at a multitude of scientific apparatus, as well as a rare peek inside the storage ring enclosure. The day's events were capped off by a presentation by Lester Erwin (AOD) on "The Magic of Electricity" in the APS Auditorium.

Nuñez honored for mentoring students

Luis Nuñez (CMT) has received an Outstanding Mentor Award from the U.S. Department of Energy.

Nuñez, a researcher in Argonne's Chemical Technology Division, has been mentoring undergraduate students for 13 years. His commitment to the mentoring program stems from his own experience as an intern at Argonne when he was both an undergraduate and graduate student.

"The mentors I had were very patient and provided guidance and inspiration to continue as a researcher," said Nuñez. "Now I try to get students involved in every research area that I'm involved with, ranging from nuclear waste separation to magnetic particle development for industrial applications."

"I enjoy interacting with students, and I am honored for the recognition," said Nuñez. "I believe that students from different background can contribute to technically complex projects if sufficiently motivated - sometimes they come in with the motivation, other times you may have to jump-start them."

Nuñez said both the mentors and the students can benefit from the program. "I get to see the research I do from the eyes of someone that is unfamiliar with the topic, which gives me a fresh perspective on it," he said. "At the same time, I can provide them with the tools necessary to approach and solve research problems in the future."

Nuñez said he will mentor students for as long as he is in science.

First ACA raffle winners drawn

The winners of the first week's Argonne Combined Appeal raffle were Horst Friedsam (ASD), Roberta Gianpetro (IPD-TIS), Marianne Mintz (ES) and Judith Yaeger (XFD).

Each winner received $25, and their division coordinators were given $10.

Every week in October there will be a new raffle. To participate, employees should sign and return their ACA forms and envelopes to their coordinator, even if they don't plan to contribute. The envelopes and forms should have come in a package through interoffice mail at the beginning of October. Every Friday, the coordinator will turn in the envelopes collected for the week to be entered into a drawing.

The next three weeks will follow the same guidelines as the first - winners receive $25 and coordinators receive $10. The second week, however, there will only be three winners, the third week two winners, and the fourth week one winner will be drawn.

Details can be found on the ACA Web site.

4th quarter retirement interest rates announced

Staff and non-staff retirement plan interest rates for the 4th quarter of 2002 are:

(* Only Available to non-staff participants)
(** No longer excepting contributions)

MetLife to offer insurance information, quotes

A representative from MetLife will visit Argonne-East Tuesday, Oct. 22, to meet with individual employees for insurance comparisons and quotes for the "METPAY" group automobile and homeowners insurance program.

MetLife insurance is a voluntary benefit available to regular Argonne employees and Argonne retirees. Participants enrolled in the program can insure their cars, homes and other personal property at group rates.

To schedule an appointment, call Craig Riddick at (630) 810-0346, ext. 143.