One of the ways in which scientific journals are compared is by their "impact factor". How are these factors calculated? It is actually pretty simple. Let's say I publish an article based on microbe X in a peer reviewed journal. Other labs working on microbe X may cite my work when they publish their findings, if my work has directly impacted their research. My article on microbe X now has one citation. The average number of citations for articles in a particular journal denote it's impact factor. So, if a journal has an impact factor of 10, each article gets cited, on average, 10 times. Presumably that means that the work published here is of higher quaility or more interest than articles published in a journal with an impact factor of 5. Of course, the pitfalls here are obvious. Not all research will be of interest to all labs, and a disproportionate amount of weight is given to journals that publish reviews along with research articles, as reviews are cited more often. A study release this week in Science (impact factor 31.36) (link to article HERE) focuses on another huge problem with this system. Some journals basically force authors to cite other previously published work from the same journal to boost the impact factor. These citations are added without actually having contributed any useful information to the current study. While the article focuses on economics, business, sociology and psychology, the problem is likely endemic to all journals. As an added bonus, in the supplemental tables they list the most coercive journals!
Please cite this article often and randomly. My impact factor is at risk of fading into oblivion.
Today's story was passed along to me by one of your classmates. In the article (abstract found here), a group of scientists was studying the feasibility of using non-thermal plasma to kill bacteria in a wound. Currently, almost all wound-associated antimicrobials are chemical agents. These may have limited ability to kill bacteria that is naturally resistant, or that lives in a biofilm (as most bacteria do). In their research, they discovered that treatment with non-thermal plasma reduced the number of colony forming units in both a rat model and biofilm. While the study is very preliminary, it may eventually lead to a novel form of treatment for infected wounds.
As we struggle through the remains of today's blizzard, it's a good time to ask, "do microbes make snow"? Apparently it is possible that they do. In this news item from 2008 by David Biello from Scientific American, he discusses how ski resorts use microbes when they are making artificial snow. The article also outlines other evidence supporting a role for microbes in manufacturing that which is falling all around us today.
Victoria's very own Times Colonist had two articles today about DNA sequencing (article 1, article 2). Both of them relate to "personalized medicine". The concept of personalized medicine is that a patient would have all or part of their genome sequenced. Using this information, it would then be possible to tailor treatments so they are more specific and effective for the patient. This not only leads to greater chances of successfully managing illness, but it also avoids the expense of undergoing treatments that will not be effective. The two sequencing techniques described in the second article, concerning the $1000 genome, are Illumina and Ion Torrent (Life Technologies).
Here is an interesting article that demonstrates a link between the diversity of the bacteria found on somebody's skin with their likelihood to attract the mosquitos that serve as vectors for malaria. The diversity was determined by comparing 16SrRNA sequences, determined by pyrosequencing (which, of course, was not a technique we covered in the last lecture). It turns out that a high abundance, and low diversity of bacteria is more attractive to the mosquitos. In a similar, but more disgusting, study, it was revealed that the mosquitos are also attracted to "smelly feet".
Click here for a quick explanation of pyrosequencing.