Drug Addiction, Polluted Cyclones and Roaring Lions
Nicotine as a gateway to Cocaine Addiction
Being a smoker may increase your chances of also becoming addicted to cocaine.
Working with experimental animals and also data from human subjects, University of Columbia scientist Amir Levine and his colleagues found that nicotine alters the activity of a gene called FosB, which has previously been linked to addiction. These changes increase the likelihood of developing a subsequent cocaine dependency.
Amir - We saw an increase in the different behavioural paradigms that are related to addiction. Finally, we looked at a certain gene that's called the FosB gene, that has been shown to be very important for addiction and we saw that when we give nicotine first and then cocaine, there is an enhancement in the expression of the FosB gene. And the final step is that we discovered that nicotine basically opens up chromatin and that is how it primes the brain to the effects of cocaine.
Cyclone Risk increased by pollution
High levels of pollution are
increasing the intensity of cyclones over Asia. Carbon-rich brown clouds over the Arabian sea, which have grown six-fold since the 1930s, are cooling the water surface, resulting in a drop in vertical wind shear - the difference in wind speed and direction - between the upper and lower parts of the atmosphere. This increases the efficiency with which storm systems can form, making super-cyclones, with wind speeds exceeding 185 kilometres per hour, much more likely to form. Amato Evan, from the University of Virginia, led the study published this week in Nature.
Amato - What we're really showing is that human activity can actually change this massive atmospheric phenomenon, but what it also says is that because these aerosols reside in the lower part of the atmosphere, if emission stops, this effect would essentially reverse in a timescale of a couple of months. The relevance of these findings is that although we have in this way, changed the climate in such a way that creates very powerful storms, it's not irreversible.
Seeing the Light
Skin can 'see the light' to protect us from UV radiation. Elena Oancea and colleagues from Brown University has found that a light-sensitive chemical called rhodopsin, normally found in the retina, is also present in melanocytes, skin cells that produce the suntan pigment melanin. The cells use the rhodopsin to detect UV rays and then switch on melanin production in under an hour. Previously melanin production was thought to occur only after a few days in response to shorter wavelength UVB radiation, which can damage DNA.
Elena - So, if a small amount of initial UVA exposure increases the skin's defence to UVB, it's really important not to have for example UVB only sunscreens. The other thing is that if this is a protective response and we have identified the molecules that mediate this response that leads to melanin production then we can activate the pathway artificially and increase the skin protection.
New Chemical Elements
Three new chemical elements have been officially named by the general assembly of the International Union of Pure and Applied Physics - IUPAP. Elements 110, 111 and 112 in the periodic table have beennamed darmstatdium, roentgenium and copernecium respectively. They were named by physicists from around the world and are now officially part of the periodic table.
The Key to a Roaring Success
The secret of a lion's roar lies in the
shape of its vocal cord, new research has shown. A lion can generate sounds as loud as 114 decibels, equalling that of a jet engine taking off. Scientists had believed that the loud, low-pitched roar was down to the weight and presence of fat within the animals' vocal cords. But now, by analysing samples of lion and tiger vocal tissues, Sarak Klemuk's team at the University of Utah identified the key features to be stretchiness, pliability and square shape of the vocal folds themselves.
Sarak - Little lung pressure is really needed to set these vocal folds into vibration. The Panthera vocal fold is a very square shape. The mechanical properties, along with that square shape allows a lion to generate a very loud roar at a very low pitch.
The researchers equated the sound to that of a baby's cry. Both sounds demands attention; but lions use it as a scare tactic to keep intruders away, rather than a call for help...
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