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North Carolina State University engineers have created a non-toxic “wrinkled” coating for use on ship hulls that resisted buildup of troublesome barnacles during 18 months of seawater tests, a finding that could ultimately save boat owners millions of dollars in cleaning and fuel costs.

The research conducted by Dr. Kirill Efimenko, research assistant professor in the Department of Chemical and Biomolecular Engineering, and Dr. Jan Genzer, professor in the same department, shows for the first time that surface coatings containing nests of different-sized “wrinkles” are effective in preventing barnacles from firmly latching on to the coatings.

“The results are very promising,” Efimenko said. “We are dealing with a very complex phenomenon.  Living organisms are very adaptable to the environment, so we need to find their weakness. And this hierarchical wrinkled topography seems to do the trick.”

Researchers created the coatings by stretching a rubber sheet, applying an ultra-violet ozone treatment to it, and then relieving the tension, causing five generations of “wrinkles” to form concurrently. The coatings were further covered with an ultra-thin layer of semifluorinated material.  During ocean tests performed in Wilmington, N.C., the wrinkled materials remained free of barnacles after 18 months of seawater exposure, while flat coatings with the same chemical composition showed barnacle buildup after just one month in seawater.

Engineers and scientists have strived for decades to uncover ways to keep barnacles off ship hulls.  Barnacle colonization on a ship bottom increases the ship’s “drag” in the water, forcing the engine to burn more fuel to maintain the same speed.  After six months in the water, a ship’s fuel consumption increases substantially, Efimenko said.  That costs ship owners – including the military – plenty of extra cash.

“It’s like running your air conditioner with the windows open,” Genzer said.

Barnacle buildup also forces owners to remove ships from the water and place them on dry docks for cleaning.  This expensive procedure costs ships valuable time at sea when they could be making money.

For many years, ship owners fought barnacles by coating their hulls with toxic substances that resisted barnacle buildup.  But those substances killed fish and other marine life in harbors, causing governments around the world to ban ships from using them.

That led to increased interest in endowing the ship coatings with wrinkled topographies.  The coatings share traits with surfaces found in nature, where rough surfaces such as shark skin generally stay free of debris buildup.  In contrast, other marine species, such as whales, have smooth skin but often carry barnacles as unwanted hitchhikers.

The NC State team collaborated on the research with Drs. John Finlay, Maureen E. Callow and James A. Callow from the University of Birmingham in the U.K.  The work was funded by the U.S. Office of Naval Research.

The group’s findings are published in the May 27 issue of the journal ACS Applied Materials and Interfaces. The work is also highlighted in the May 8 edition of Science.

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Note to editors: The study abstract follows.

“Development and Testing of Hierarchically Wrinkled Coatings for Marine Antifouling”

Authors: Kirill Efimenko, John Finlay, Maureen E. Callow, James A. Callow, and Jan Genzer, North Carolina State University and University of Birmingham, U.K.

Published: May 27, 2009, in ACS Applied Materials and Interfaces

Abstract: We report on the formation and testing of novel marine coatings comprising hierarchically wrinkled surface topographies (HWST) having wrinkles of different length scales (generations) ranging from tens of nanometers to a fraction of a millimeter. The individual wrinkle generations are arranged in nested patterns, where each larger wrinkle resides underneath and represents a scaled-up version of the smaller wrinkle. We present and discuss results from ?eld tests in seawater and laboratory experiments. The results of our ?eld tests reveal that while coatings with ?at topographies foul after relatively short time periods (4-15 weeks), the HWST coatings with the same chemistries as ?at coatings remain relatively free of biofouling even after prolonged exposure to seawater (18 months). In contrast to ?at coatings, the HWST substrates are not colonized by barnacles. These observations suggest that surface topography plays a dominant role in governing the coating defense against barnacle fouling even without ?ne-tuning the chemical composition of the overcoat. Laboratory experiments indicate that settlement of zoospores of the green alga Ulva and the strength of attachment of sporelings (young plants) depend on the chemical composition of the coating as well as surface topography.

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Research by a North Carolina State University biologist and colleagues shows that using landscape corridors, the “superhighways” that connect isolated patches of habitat, to protect certain plants has a large “spillover” effect that increases the number of plant species outside the conservation area.

The study found that corridors caused such a wide range of “spillover” beyond the patches – to more than the area of the patches themselves – that the results were a surprise, says Dr. Nick Haddad, associate professor of biology at NC State and a co-author of a paper published online this week in Proceedings of the National Academy of Sciences. He adds that the finding has broad implications for conservation efforts – most importantly that the benefits of landscape corridors, the strips of habitat that connect isolated patches of habitat, extend well beyond those borders.

“Most conserved areas are small – two-thirds are less than one square kilometer – so the spillover effect with corridors gives a larger conservation bang for the buck,” Haddad says. He adds that exotic or invasive species of plants showed no signs of spillover effect.

Haddad says that he and his colleagues used an idea from marine protection strategies in their study. In oceans, certain areas are off limits to fisherman in order to protect fish. In time, excess fish within the protected areas spill over into waters where fishing is permitted. Dwindling fish stocks rise while fishermen catch the excess fish – a mutually beneficial scenario.

To perform the research, the scientists collaborated with the U.S. Forest Service at the Savannah River Site National Environmental Research Park, a federally protected area on the South Carolina-Georgia border, to create the world’s largest experimental site devoted to the study of landscape corridors. Much of the Savannah River Site is covered with pine plantations. The U.S. Forest Service created eight identical sites, each with five openings, or patches, by clearing the pine forest. A central patch was connected to one other patch by a 150-meter-long, 25-meter-wide corridor, while three other patches were isolated from the central patch – and each other – by the surrounding forest. The patches are home to many species of plants and animals that prefer open habitats, many which are native to the historical longleaf pine savannas of this region.

The study shows that areas surrounding the connected patches had 10 to 18 percent more spillover than patches not connected by corridors.

Haddad adds that plant species dispersed by birds and mammals – wild hollies, blueberries and cherries, for example – were most affected by the spillover effect. That makes sense, he says, because previous research suggested that foraging birds frequently use landscape corridors. These birds would then spread seeds some distance outside the patches.

The research was funded by the National Science Foundation and by the Department of Energy-Savannah River Operations Office through the U.S. Forest Service Savannah River Site. The U.S. Forest Service-Savannah River Site provided critical assistance with the creation and maintenance of the experimental landscapes. Scientists at Washington University, the University of Washington, and the University of Florida co-authored the study.

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Note: The paper’s abstract follows.

“Landscape connectivity promotes plant biodiversity spillover into non-target habitats”

Authors: Lars A. Brudvig and Ellen I. Damschen, Washington University; Joshua J. Tewksbury, University of Washington; Nick M. Haddad, North Carolina State University; and Douglas J. Levey, University of Florida

Published: Online the week of May 18, 2009, in Proceedings of the National Academy of Sciences

Abstract: Conservation efforts typically focus on maximizing biodiversity in protected areas. The space available for reserves is limited, however, and conservation efforts must increasingly consider how management of protected areas can promote biodiversity beyond reserve borders. Habitat corridors are considered an important feature of reserves because they facilitate movement of organisms between patches, thereby increasing species richness in those patches. Here we demonstrate that by increasing species richness inside target patches, corridors additionally benefit biodiversity in surrounding non-target habitat, a biodiversity ”spillover” effect. Working in the world’s largest corridor experiment, we show that increased richness extends for approximately 30 percent of the width of the 1-ha connected patches, resulting in 10-18 percent more vascular plant species around patches of target habitat connected by corridors than around unconnected but otherwise equivalent patches of habitat. Furthermore, corridor-enhanced spillover into non-target habitat can be predicted by a simple plant life-history trait: seed dispersal mode. Species richness of animal-dispersed plants in non-target habitat increased in response to connectivity provided by corridors, whereas species richness of wind-dispersed plants was unaffected by connectivity and increased in response to changes in patch shape – higher edge-to-interior ratio – created by corridors. Corridors promoted biodiversity spillover for native species of the threatened longleaf pine ecosystem being restored in our experiment, but not for exotic species. By extending economically driven spillover concepts from marine fisheries and crop pollination systems, we show how reconnecting landscapes amplifies biodiversity conservation both within and beyond reserve borders.

North Carolina State University officials have broken ground on the next building to be developed on its Centennial Campus.

The Centennial Science Center, a privately developed two-story facility, will house corporate partners and university laboratories, including the National Science Foundation (NSF) Engineering Research Center for Future Renewable Electric Energy Delivery and Management (FREEDM) Systems. Continue Reading »

A new tool will help researchers identify the minute changes in DNA patterns that lead to cancer, Huntington’s disease and a host of other genetic disorders. The tool was developed at North Carolina State University and translates DNA sequences into graphic images, which allows researchers to distinguish genetic patterns more quickly and efficiently than was historically possible using computers.

David Cox, a Ph.D. student in computer science at NC State, devised the “symbolic scatter plot” tool to provide a visual representation of a DNA sequence. Cox explains, “The human visual system is more adept at identifying patterns, and differentiating between patterns, than existing computer programs such as those that try to identify repetitions of DNA sequences.” In other words, the naked eye sees patterns better than computers can.

Identifying patterns in a sequence of DNA is important because it can help researchers identify the minute genetic variations between subjects that suffer from a disease, such as cancer, and subjects that do not. “Improved identification of relevant DNA sequences will hopefully expedite the development of successful treatment for a range of diseases,” Cox says, “by allowing researchers to focus on the components of DNA that are related to the disease and improving our understanding of the genetic mechanisms of these diseases. For example, what turns specific genes on and off?”

So, how does the symbolic scatter plot create a visual representation of DNA? DNA is composed of a series of nucleotides. There are only four types of nucleotides, represented by the letters A, T, G and C. Each three-letter string of these nucleotides, such as AAA or ATG, is called a 3-mer. Cox explains, “There are only 64 possible 3-mers, thus each 3-mer maps to a number from zero to 63. The symbolic scatter plots take a very long string of letters representing a DNA sequence and split it into a bunch of 3-mers. It then plots a point for each 3-mer, zero through 63, with that number serving as the y-coordinate.” The x-axis is the order that the 3-mer appears in the genetic sequence.

“If this seems really simple,” Cox says, “that’s because it really is simple. Even so, the resulting scatter plots reveal interesting patterns in the original DNA.  I can also string these scatter plots together to produce animations for the purpose of comparing DNA sequences.”

Cox chose to focus on 3-mers because they correlate to codons, which are the genetic codes the body uses to specify the insertion of a specific amino acid during the creation of proteins. In other words, they oversee the creation of proteins – which are themselves the basic building blocks of the human body. “There are 64 3-mers, but only 20 amino acids,” Cox says, “so each amino acid corresponds to multiple 3-mers.” Cox designed the symbolic scatter plot so that those 3-mers that correspond to the same amino acid are adjacent to one another.

“This way,” Cox says, “it is easier to determine when a difference in 3-mers is significant – from one amino acid to another – rather than a difference in 3-mers that still results in the production of the same amino acid. A change in a single amino acid can be the difference between a relatively harmless disease and a fatal one,” Cox says.

Cox will present the research this July at BIOCOMP ’09 – The 2009 International Conference on Bioinformatics and Computational Biology in Las Vegas. The research was co-authored by Dr. Lina Dagnino of the University of Western Ontario.

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Note to editors: The presentation abstract follows.

“An Analysis of DNA Sequences Using Symbolic Scatter Plots”

Authors: David Cox, North Carolina State University; Lina Dagnino, The University of Western Ontario

Presented: July 13-16, 2009, at BIOCOMP ’09 – The 2009 International Conference on Bioinformatics and Computational Biology in Las Vegas, Nev.

Abstract: Deciphering DNA is an important and open research question. The key to answering this question is determining which nucleotides in a sequence constitute a single coherent region. A symbolic scatter plot is a novel graphical representation of DNA. Similar to search techniques such as BLAST, the initial step hashes small overlapping k-mers. The novelty of the technique is that all subsequent processing relies on the human visual system. To assess its usefulness, the technique is compared to Tandem Repeats Finder. The result is that the human visual system is superior to Tandem Repeats Finder in recognizing the majority of repeats and other patterns in DNA sequences.

Want to be sure that Spot’s social behavior is spotless? Dr. Barbara Sherman, a specialist in animal behavior at North Carolina State University, says the best way to prevent dog bites is to start training puppies in proper social behavior early on. She shares some suggestions as part of National Dog Bite Prevention Week (May 17-23).
Some 4.5 million Americans are bitten by dogs each year, and one in five dog bites results in injuries that require medical attention. According to Sherman, here are the best ways to raise your puppies into well-mannered adult dogs:

• If selecting a puppy from a breeder, ask to see the parents and pass up puppies whose parents are aggressive. Don’t be swayed by phrases like “the mother is just guarding her puppies” or “the father is just being territorial” since the best predictor of a young puppy’s future behavior is the behavior of its parents. If you want your puppy to grow up to be a friendly family dog, select a puppy whose parents are friendly and a breeder who values good temperament.
• Puppies handled gently and exposed to many positive experiences during the critical “socialization period” (3-14 weeks) are less likely than unhandled puppies to show fear and aggression when they become adults.
• Puppies that are not well socialized are likely, as adult dogs, to be fearful of strangers and to display “keep away” aggression toward them.
• Children and puppies should be well supervised; it is important that puppies have positive and not fearful experiences with children.
• Puppies should be taught “bite inhibition.” When your puppy uses its sharp teeth on your hand during play, yelp or say “ow,” look away and withdraw from the interaction – no more play for a short time. The pup needs to learn that the fun stops when he uses his teeth on you. Then, give the puppy an appropriate toy and resume the interaction. Do not punish or frighten the puppy, since this can lead to defensive behavior. When the puppy behaves appropriately, praise him and resume play.
• See your veterinarian for suggestions about how to socialize and train your puppy.

Sherman can discuss these, and other suggestions related to preventing dog bites, as part of National Dog Bite Prevention Week. She can be reached at 919/513-6141 or 919/460-8512, or via e-mail at barbara_sherman@ncsu.edu.

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What do a college of veterinary medicine and a cancer treatment and research center have in common? The answer may be as plain as the nose on your dog’s face. Researchers from North Carolina State University’s College of Veterinary Medicine and the University of North Carolina’s Lineberger Comprehensive Cancer Center are combining their expertise to pinpoint the cause of – and improve treatments for – non-Hodgkin lymphoma in human and canine patients.

The dog is an excellent model to study human cancer, particularly lymphoma. The disease is biologically similar in human and canine patients, but is much easier to narrow down problematic areas in a dog’s genome because the genetic variation among dogs of the same breed is so much lower than genetic variation in humans. These factors, coupled with the publication of the human and canine genomes, make the dog the perfect candidate for this collaborative research.

Drs. Steven Suter, professor of clinical sciences, and Matthew Breen, professor of genomics, along with statistics professor Dr. Alison Motsinger-Reif and Dr. Dahlia Nielsen, research assistant professor of genetics, lead the NC State component. Researchers at the UNC Lineberger Comprehensive Cancer Center are led by Dr. Kristy Richards, geneticist and clinical oncologist. The team is recruiting dogs diagnosed with lymphoma to collect tissue samples for study. A simple and speedy procedure at the NC State Veterinary Teaching Hospital, the collection causes no discomfort to the dog and owners receive $1,000 for their pet’s participation.

Labs from both institutions will study tissue samples from human and canine patients, with the hope of creating a genomic “profile” of non-Hodgkin lymphoma that would give oncologists and veterinarians greater insight into the disease’s biology, and improve their ability to diagnose the illness early.

“Non-Hodgkin lymphoma ranks fifth in cancer deaths among human patients, and the mortality rate for dogs is even higher,” Suter says. “By combining the strengths of our programs, we expect to enhance our understanding of the disease and speed improved treatments for people and pets. This is another example of ‘One Health,’ the concept of comparative medicine that acknowledges human and animal health relies on a common pool of medical and scientific knowledge and is supported by overlapping technologies and discoveries.”

Richards adds, “Traditionally, lymphoma researchers have used laboratory mouse models of lymphoma, but it would be advantageous to study lymphoma in a large animal model with spontaneously occurring lymphomas that more closely mimic the situation in humans. There are very few places in the country where a top-rate veterinary program is in such proximity to a top-rate medical school with a comprehensive cancer center. We aim to take full advantage of this partnership to discover, develop and test new treatments much faster than could be done in either organism alone.”

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North Carolina State University will break ground on the next office and lab building to be constructed on Centennial Campus. It will house, among other offices and labs, the NSF-funded FREEDM Systems Center that will develop new technologies to transform the century-old power grid. Continue Reading »

Dr. Larry Nielsen announced that he will step down from his position as provost at North Carolina State University effective May 22. Nielsen will be joining the faculty in NC State’s College of Natural Resources. Continue Reading »