Science Square

  • Issue 89 / September - October 2012



    Frosty freezers no more

    The Fountain

    1- Frosty freezers no more
    Original article: Kim P. et al, ACS Nano (2012, online ahead of print)
    Frost formation on aircrafts at high altitudes poses major safety threats and high-maintenance costs. Now, Joanna Aizenberg with her research team present a solution in their recent publication reporting on outstanding capabilities of a surface coating to prevent frost formation on metal surfaces. The technology called SLIPS (Slippery, Liquid-Infused Porous Surfaces) was inspired by the slippery surface of the carnivorous pitcher plant, which enables the plant to capture insects. "Some of the most extreme examples in biology can provide the most amazing and unexpected ideas..." says Aizenberg, who is a professor at the Wyss Institute for Biologically Inspired Engineering at Harvard University. Rendering surfaces slippery is not new to scientists, and the earlier inspirations also came from biology. Mimicking the surface of the leaf of another plant (Nelumbo nucifera, or commonly known as the Lotus plant), scientists have been successful in fabricating surface coatings that would repel water-based dirt, but Lotus-inspired coatings failed for oily substances. On the other hand, Aizenberg's SLIPS technology offers a single solution for repelling any type of accumulated unwanted material. The pitcher plant thus offers a solution that virtually proves to be the "silver bullet" in generating non-sticky coatings as described again in Aizenberg's own words: "In following its example, we should be able to develop a platform that works for almost any sticky problem, no matter how seemingly unrelated, whether it's ice accumulation, bacterial attachment, environmental contamination, clogging of pipes, marine biofouling, or graffiti, rather than having to come up with a host of individual solutions." Thanks to the wondrous design in the pitcher plant, it looks like doctors will be delivered from replacing bacteria-contaminated arterial stents, and we can all give a kiss goodbye to frosty freezers.

    2- Airborne bird flu virus possesses a great risk
    Original articles: Herfst S. et al, Science 336, 1534 & Russell C.A. et al, Science 336, 1541.
    Science magazine recently published a special issue (June 22, 2012 issue) on the H5N1 infection (a.k.a. bird flu) with two reports revealing the pandemic (a disease prevalent throughout an entire country, continent, or the whole world, such as AIDS) potential of bird flu. Bird flu virus has so far killed millions of birds and many more millions of birds were culled to stop the propagation of the virus. Thankfully, this virus has not yet caused a pandemic in humans mainly because of its inability to spread easily among humans. One mechanism that makes viruses highly contagious is their ability to spread through air, such as through the nose and mouths of people when they cough and sneeze. Viruses that spread through air are called airborne viruses. One big difference between bird flu virus and the more recent swine flu virus (H1N1) was that swine flu is an airborne virus and bird flu is not, and therefore swine flu caused a mild pandemic in 2009. As reported in these studies, researchers identified several genetic mutations that will cause bird flu virus to become airborne. Viruses undergo mutations all the time and unfortunately some of these identified mutations have already started taking place in circulating virus strains. This poses a great risk. One important aspect of these reports is that they were written about a year ago but withheld since now, because of concerns about misuse of this information to pose a threat to humanity. Now that the information is public, our hope is that it will be used to monitor the virus closely and be prepared if bird flu virus transforms into an airborne virus.

    3- Not all bacteria are the same after all
    Original article: Chung H. et al, Cell 149, 1578 (2012)

    The impact of our own bacteria on human life has been intensely researched in recent years. One of the common ground is that humans acquire many useful bacteria over their existence. However, this microbial flora constantly changes as the conditions do. Therefore, the real number of 500 to 1000 microbial species inhabiting mammals is anybody's guess. Nonetheless, some scientists did not shy away predicting a connection between having a specific microbial flora to avoid certain diseases. A recent article by Chung et al presented an interesting clue why constant change in microbial flora, especially if that leads to a loss of important bacteria, may be linked to the increase in human autoimmune disorders. "For every cell in your body that is you, that contains your specific genetic information, there are approximately nine foreign bacterial cells, primarily in your digestive tract and even on your skin," said Dennis Kasper, professor at Harvard Medical School and senior author on the paper. To address the question if microbial affects immune system development, authors compared two groups of mice, both of which had never had bacteria in their intestine before the experiment. One group of mice received mice microbial flora and the other received human microbial flora. Both groups had similar number of bacteria in their digestive tracks. However, authors observed a stark contrast between the two groups in terms of the level of immune cells in intestinal tissues. Mice that received human flora had surprisingly low number of immune cells compared to the mice that received mouse flora, which is native to mice. When this experiment was repeated with rat microbial flora, astonishingly, similar immune deficiency was observed. "I was very surprised to see that. I would have expected more of a half-way response," Chung said, considering how closely rats and mice are related. The study points out that we really need to preserve our own microbial flora that has been tailored for us. Disrupting this balance by means of current antibiotics overuse may have detrimental effects in the future.

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