Most readers will probably be aware of how important stem cells are when it comes to medical research. As they have yet to differentiate they have the possibility of becoming any cell in the body if required, but this great variability comes with an inherent instability. The hematopoietic stem cells in the bone marrow, the cells from which the blood cells can be formed, have the potential to produce leukaemia and other blood cancers. There is also the risk of local tumours spreading their cells into the bone marrow which can result in cancer stem cells and rapid bone metastasis as the skeleton is invaded by the cancer. It is important to understand how the standard and malevolent stem cells interact with each other in the bone marrow so that these conditions can be counteracted and prevented.
A few months ago I wrote this post about using two photon fluorescence to study the capillary system. The basic idea being to use infrared light, which passes through flesh easily, to excite the fluorescent dye but to use the process of two photon absorption so that the remitted photon can be of greater frequency than infrared. Now although this can be done with a chemical dye, there is another option.
Occasionally I struggle when it comes to finding papers to write about over the course of a week. Sometimes there is a shortage of papers published, sometimes the papers are there but I can’t understand them well enough to be confident in writing about them. Luckily most of the time it’s the opposite problem and I end the week with at least a few papers that I didn’t have room include because there were just six others papers slightly more interesting. Today I’ll be writing a quick blurb on each of these papers over the last week and perhaps I’ll continue this into the future.
There was a paper that described the recent evolution in the longwave radiation output of the Earth. The Earth’s main method of radiating the heat it absorbs is through longwave radiation which can then affect global precipitation. A Hadley cell is a specific air circulation where warm air rises at the equator, moves poleward and then descends in the subtropics. This paper examined the results of the shrinking accession current of this cell and the reduced numbers of high clouds (cirrus and its brethren) on outgoing radiation. Paper link: Tightening of tropical ascent and high clouds key to precipitation change in a warmer climate
Another paper described the application and adaptation of neuroimaging techniques, that have hereto only been used on rodents, onto non human primates such as marmosets. Using a double excitation technique on calcium ions (Ca2+) which work to form dendric (tree like) formations for neurones in the brain. It may be possible to study the entire primates brain under both sick and healthy conditions using this technique. Paper links: Targeted Patching and Dendritic Ca2+Imaging in Nonhuman Primate Brain in vivo
The final paper that didn’t quite make the cut was describing the development of new magnetic nanostructures. Traditionally such structures, which have applications in memory storage, imaging methods, magnetic fluids, magneto-optics and so on, are flat and two dimensional. New synthesis techniques presented aim to grow these structures into three dimensions which is a completely unexplored area of science. Paper links: Three-dimensional nanomagnetism
There you go, three papers (technically the last one is a review article but its still very interesting) which could easily have been made into posts and there are three more beyond these that I could also try writing a paragraph on. But sometimes you need to smile and be happy with the work you’ve done and move on to something else. Until tomorrow, goodnight.
When people talk about organs the instant thoughts probably go to the heart, liver, stomach and kidneys. The liver is the largest of these internal organs but when it comes to largest organ overall it us outstripped by the skin which is often not thought of as an organ but does contribute to about 15% of a human’s body weight. The skin is, like almost everything else in the human body, made of a lot of water. 64% of the skin is in fact made of water.
Positron emission tomography (PET) is the process of injecting a radioactive dye into a human’s so that when it decays positrons (positive electrons) are emitted which can be used to learn about what might have gone wrong in the body. Often the dye is in fact glucose with the radioactive component attached so it will easily be absorbed into the blood and transferred around the body to the locations of interest. One of the other options is to use a metal ion as many of these are also required by the body and so accepted willingly. This study is looking primarily at copper (Cu) and the possibility of using it as the radioactive dye.
The blood brain barrier is an extremely selective semipermeable mmembrane which separates the blood that circulates in the body from the fluids that exist in the brain. Despite being excellent at preventing various neurotoxins and blood based diseases from infiltrating the brain, it manages to become a hindrance when it comes to administering drugs which want to directly effect the brain. This is one of the reasons that central nervous system diseases are so difficult to cure. One of the methods that has been employed for over fifteen years is to administer focused ultrasound which can work with induced microbubbles circulating in the body to increase the permeability of the blood brain barrier.
When an ion is produced by ionising radiation this is normally considered the end of the story at least from the perspective of the ion. The radiation goes flying off and the ion goes to destroy some DNA or something similar. In reality the situation is a bit more complicated than that. The ion, almost always positive, interacts with the electrons in whatever medium it’s found itself in leading to it losing energy. These interactions result in many electrons, called secondary electrons, gaining the energy to ionise the surroundings. This means that following the path of the primary radiation there is a cloud of secondary ionisations called the track structure as represented on the diagram: