In the Lab

Is Remote Sensing the Answer to Today's Agriculture Problems?

Today's wheat growers face many economic and environmental challenges, but arguably their greatest challenge is the efficient use of fertilizer.

Growers need to apply nitrogen-based fertilizer in sufficient quantities to achieve the highest possible crop yields without over-applying -- a situation that could lead to serious environmental effects. In wheat, a critical factor comes down to timing in order to determine how efficiently plants will use nitrogen fertilizer. Current methods for determining the optimum timing of nitrogen fertilizer application can be costly, time consuming, and difficult.

To assist wheat growers, scientists at North Carolina State University recently developed a technique to properly time nitrogen fertilizer applications. The technique? Remote sensing - a relatively new technology to today's modern agriculture that uses aerial photography and satellite imagery.

In this 2000-2001 study, scientists used remote sensing in the form of infrared aerial photographs to determine when early nitrogen fertilizer applications were required. By relating the infrared reflectance of the crop canopy to wheat tiller density, the scientists were able to differentiate wheat fields that would benefit from early nitrogen fertilizer applications compared to wheat fields that would benefit from standard nitrogen fertilizer applications. They tested 978 field locations, representing a wide range of environmental and climatic conditions. The remote sensing technique was found to accurately time nitrogen fertilizer applications 86 percent of the time across all field locations. The results of this study are published in the January/February 2003 issue of Agronomy Journal.

Michael Flowers, project scientist, said, "This is one of the first applications of remote sensing technology for nitrogen management available to growers. With the ability to cover large areas in a quick and efficient manner, this remote sensing technique will assist growers in making difficult nitrogen management decisions that affect profitability and environmental stewardship."

These scientists at North Carolina State University and other institutions around the world are continuing to research remote sensing techniques to improve the efficiency of nitrogen fertilizer applications in crops. These techniques will allow growers to more efficiently apply nitrogen fertilizer, increase profitability, and avoid detrimental environmental effects.

For more information, please visit www.asa-cssa-sssa.org.

Ceramic Membrane Extracts Hydrogen

If hydrogen fuel cells are ever to replace gasoline engines in cars, they will need a cheap source of highly pure hydrogen -- and Argonne technology could provide one.

A team of ceramics experts in Argonne's Energy Technology Division has developed a ceramic membrane that can extract hydrogen from methane, the chief component of natural gas.

Using hydrogen to power cars and factories would minimize the nation's reliance on foreign oil because the United States has abundant natural gas resources. And, since hydrogen produces only water vapor when it burns, the environment would benefit as well.

Until now the process of obtaining hydrogen from natural gas has been difficult.

But by passing methane through a ceramic membrane, the ceramics team lead by Balu Balachandran can extract highly pure hydrogen from methane. Such high purity is necessary if hydrogen fuel cells -- one of the most promising technologies that harness hydrogen -- are ever to become economical.

"Ceramic membranes make possible the widespread use of hydrogen," Balachandran said. "Just as conventional cars need gas stations, fuel cells will need an infrastructure to support them. Ceramic membranes could eliminate the need for costly refineries -- they are small enough and efficient enough to have one at every gas station."

The membrane material is so dense that only electrons and individual ions can pass through it, which is why it produces such pure hydrogen.

According to Balachandran, the same technology could produce other chemicals necessary for synthetic fuels and fertilizer.

Ceramic membranes could be a key development for the U.S. Department of Energy's (DOE) "Vision 21" program, which seeks to develop highly efficient power technologies that discharge no pollutants.

DOE funds the research through its National Engineering Technology Lab.

Industry has also partnered with Balachandran's team. The group currently has cooperative research and development agreements with two Colorado companies, ITN Energy Systems of Littleton and Eltron Research of Boulder.

Balachandran is pleased with the ceramic membranes' prospects, though he emphasizes that the technology is still in its infancy.

"We have proven that this can work in principle," he said. "But we need to meet several engineering challenges, such as scaling up the system and integrating it into existing systems in power plants, to develop ceramic membranes for the marketplace. If we can meet those challenges, we could see the technology on the market within five to six years."

For more information, please visit www.anl.gov.

New Cell Process Helps Cells Respond to DNA Damage

Scientists at St. Jude Children's Research Hospital in Memphis, Tenn., have discovered a novel biochemical process that plays a critical role in helping cells in the body respond to DNA damage, such as that caused by exposure to radiation, environmental toxins or free radicals.

The findings could lead to new approaches to prevent cancer, better ways to treat cancer and to the development of sensitive methods determining whether people have been exposed to radiation or environmental toxins, according to the researchers.

A report on this discovery, published in the January 30, 2003, issue of the journal Nature, describes this critical early step in a cell's response to DNA damage. This step, a chemical modification of an enzyme called ATM, allows the enzyme to initiate a series of events that ultimately halt the growth of a damaged cell and help the cell survive.

The finding is important because DNA damage caused by radiation and environmental toxins can lead to mutations or cell death, and can also contribute to the development of cancers.

Michael Kastan, MD, PhD, chair of the Department of Hematology-Oncology at St. Jude, and Christopher Bakkenist, PhD, also of St. Jude, co-authored the research.

The St. Jude researchers found that ATM is activated by a signal from damaged DNA only seconds after the damage occurs. The activated ATM, in turn, activates other proteins by attaching a molecule called "phosphate" to them in a process called phosphorylation. This sets off a cascade of biochemical reactions that amplifies the initial ATM response.

Among the proteins phosphorylated by ATM are Brca1 and p53. It was already known that these proteins play important roles in preventing cancer, and that mutated forms of Brca1 and p53 are responsible for inherited cancers, such as familial breast cancer. The new St. Jude findings thus provide new insights into the way cells signal to both Brca1 and p53 following DNA damage.

The scientists are hopeful that they can use this information to improve therapy for many types of tumors.

"Because ATM is central to a cell's response to irradiation, blocking its activation or activity might make virtually any type of tumor much more sensitive to radiation therapy," Kastan said. "The new molecular mechanisms identified here should allow us to achieve this aim by blocking ATM activity, which would make tumors more sensitive to radiation."

The St. Jude researchers also developed an antibody that specifically recognizes activated ATM, and thus identifies only those ATM molecules that are responding to DNA damage. "Our technique for identifying activated ATM is so sensitive that we've been able to show that it takes only a couple of breaks in the entire DNA of the cell to activate and initiate all of the cell's response mechanisms," Kastan said.

The identification of these molecular mechanisms and the development of specific antibodies against activated ATM might also provide a very sensitive way to determine if cells in a person have been exposed to an agent or toxin that damages DNA, according to Kastan.

"Such an assay has many obvious potential uses," Kastan said, "including the assessment of exposure to dangerous agents in the environment." Another potential clinical benefit of these discoveries applies to cancer prevention. Since damage to the DNA appears to contribute to the vast majority of human cancers, enhancing the response of cells to DNA damage could reduce cancer development, Kastan noted.

Therefore, the discovery of how ATM is activated could help guide the development of ways to improve cellular responses to DNA damage, including responses to oxidative stress that are either induced or natural.

"Based on the insights we've gained from our findings, we may be able to develop ways to activate ATM and thereby prevent or reduce the problems associated with DNA damage," Kastan said.

For more information, please visit www.stjude.org.

Researchers Plan to Connect Petrol Stations to Natural Gas Supply to Fuel Hydrogen Powered Cars

Researchers at the University of Warwick's Warwick Process Technology Group in England are leading a program called "Hydrofueler" to connect petrol stations to the normal natural gas supply to fuel hydrogen powered vehicles. The 2.8 million euro EC funded, three-year research program has already drawn interest from Exxon Mobil and BMW.

One of the problems with using hydrogen powered cars is how to keep their fuel cells supplied with a ready source of hydrogen. The Warwick researchers believe that much of the necessary infrastructure already exists -- the new technology can be fitted to pre-existing filling stations who will then use it to produce hydrogen from the normal pre-existing natural gas pipeline supply system. To do this, however, a number of problems need to be resolved. In particular, how to produce the hydrogen from that natural gas in a confined space, using a simple automated remotely controlled process. Obviously, very large scale industrial processes already exist to produce hydrogen from natural gas, but these technologies cannot be scaled down to the compact size needed to be practical in a filling station context, and the costs of using these processes would be prohibitive.

The new University of Warwick research solves these problems by a combination of innovative heat exchange technology, novel ways of managing and using heat and pressure within a reactor, novel compact plated reactor technology and the use of new coated nanocrystaline catalysts to greatly increase the efficiency of the reactions. These techniques will allow the researchers to develop a reactor around the size of three average office desks, which can be used in the confined space available on pre-existing petrol station forecourts and will produce hydrogen at a cost effective rate and without any emissions problems.

The research will draw on technology developed by University of Warwick Process Technology Group researcher Dr. Ashok Bhattacharya and the following research partners: Chart Heat Exchangers Ltd. in Wolverhampton, England; France's Commissariat a l'Energie Atomique; Norway's Foundation for Technical and Industrial Research in Strindveien (SINTEF); The National Research Council of Italy; and catalyst specialists Dytech in Sheffield, England.

Another advantage of the technology proposed by the Warwick team is that the process employs a number of stages at which hydrogen reaches different rates of purity. This is ideal, as different sorts of fuel cell will require different mixes of hydrogen. Thus the technology proposed can in one reactor simultaneously produce what one might describe as two, three and four star hydrogen.

The researchers are also considering using the technology to carry out hydrogen production within car engines and also as a possible replacement for large industrial hydrogen production processes.

For further details contact Dr. Ashok Bhattacharya, director Warwick Process Technology Group, University of Warwick, via e-mail at Ashok.Bhattacharya@warwick.ac.uk




This article originally appeared in the March 2003 issue of Environmental Protection, Vol. 14, No. 2, p. 18.

This article originally appeared in the 03/01/2003 issue of Environmental Protection.

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