UNC-TV Science Week In Review: July 25, 2013
A Gentle Hand
Experiments, especially in the physical sciences, tend to involve a good deal of punishment. Ammonia was first created industrially by heating hydrogen and nitrogen to 1000-degrees Farenheit while squeezing them together at 20 times atmospheric pressure. Since ammonia is just nitrogen and hydrogen put together, why not put them in a steel chamber and beat them up until they make ammonia?
Science, however, has a softer side. Whether researchers are dealing with ways to treat our environment more gently or delicately manipulating experiments in the lab, sometimes the pursuit of new knowledge requires a gentle hand.
Going Easy on the Environment
Thanks to a $45,000 grant from the NC Agricultural Foundation, professors David Domermuth and Ok-Youn Yu from Appalachian State University will be able to further their research on biofuels. This grant, and another from the EPA will go toward completing a greenhouse and biomass conversion facility at the Watauga County Landfill.
Ironically, their method of fuel creation involves some harsh processes. Gasification (or bio-volatilization) involves heating wood, animal waste or plant matter in an environment with limited oxygen until it breaks down into a mixture of carbon monoxide and hydrogen gases, called synthesis gas. Synthesis gas (or syngas) is a building block for diesels and combustible fuels.
Domermuth and Yu also planned uses for the byproducts of gasification to make the system more sustainable. Excess heat given off by the process will heat the facility and biochar, a solid carbon-rich byproduct can be used as a fertilizer and soaks up pollutants in soil. The end goal of the project is to design a sustainable energy source for use on farms.
Doing a Little Reconnaissance
Antibiotic resistant bacteria get a great deal of attention because of their ability to adapt. We make stronger antibiotics and if even one cell in a million can withstand them, a new resistant strain can be born. So instead of throwing another antibiotic punch at these bacteria, scientists from UNC–Charlotte tried to determine how some of those resistant properties evolve.
Specifically, the group, led by professor Dennis Livesay, examined an enzyme common in bacteria called Beta-Lactamase (BL). Enzymes can evolve in similar ways to organisms. A rogue mutation in the DNA that describes how to put the enzyme together can change how well the enzyme works. If an altered enzyme works well, bacteria that have it will live on and reproduce. In this way different forms of enzymes are created. If you were to chart this progression over time, it would look like a tree continually branching out. Where the enzyme falls on the branch is called its phylogeny.
BL is a particularly important enzyme because certain forms have the ability to recognize and chew up a specific chemical structure in penicillin-type antibiotics. The researchers tested 12 forms of BL, comparing their phylogenies with antibiotic resistant properties.
They found that phylogeny was a good predictor of many properties, including shape, hydrogen bonding and the internal electronic attractions. Resistant properties, however, showed up all across the phylogeny, seemingly independent of the huge evolutionary changes in how the enzymes were put together.
What does this tell us? This work tells us that BL is readily adaptable to antibiotics in all its forms. It also narrows down where scientists have to look to find how these enzymes adapt to antibiotics.
Just a Dash of Laser
A group of engineers from NC State University recently discovered that the key to brighter lasers is gentler blasts. Lasers are focused beams of light. Materials called gain media make the laser brighter or amplify it. Gain media absorb energy from light or heat. Then when a beam of light is passed through them, they release that energy by emitting light of the same wavelength and direction as the beam that passes through. The process is called stimulated emission.
A gain medium’s ability to amplify light is called its optical gain and the researchers were trying to measure and maximize the optical gain of a polymer called MEH-PPV. MEH-PPV is an attractive material because it is cheap and easily integratable with silicon computer chips.
Previous attempts to measure the optical gain of MEH-PPV involved blasting it with laser pulses for eight nanoseconds (eight billionths of a second) at a time. The researchers found that by dropping that pulse time to 25 picoseconds (25 trillionths of a second), the optical gain was five times better.
According to Zach Lampert, the lead author of the paper, which appeared in Applied Physics Letters, the 8 nanosecond blasts were long enough to heat up and warp the MEH-PPV. By cutting that pulse time down, the MEH-PPV stayed intact better and acted as a better amplifier.
To deviate just a little from the “Week in Review” model I’d like to highlight this story from UNC Health Care. Thanks to a joint effort from UNC Medical Center, a Mooresville non-profit called Solace for the Children and the generosity of hospital volunteer Rita Bigham, her husband Eric and North Carolina residents, Maryam, an 8-year-old girl with a congenital heart defect was able to travel to Chapel Hill from Afghanistan to receive treatment earlier this month.
Solace for the Children brought Maryam and five other Afghan children to the United States for medical care while the Rita and Eric Bigham Cardiology Special Project Fund will pay for Maryam’s two surgeries.
Maryam is doing well after surgery on July 9. Click here for videos of Maryam’s story. To give to the Rita and Eric Bigham Cardiology Special Project Fund, go to www.medicalfoundationofnc.org/gift, select “Other” for “Designation” and enter “Rita and Eric Bigham Cardiology Special Project Fund.”
- Daniel Lane
Daniel Lane covers science, medicine and the environment as a reporter/writer. He is currently pursuing a master's degree in medical and science journalism at UNC - Chapel Hill.