It is a well known fact that the human heart uses electrical currents in order to keep the cardiac muscles pumping in time. The current it taken to the muscle cells by conducting cells which pass the current through the heart to the correct places. The sinoatrial node is the originator of the signal which then moves to activate the atria and then the ventricles.
Now I actually have been diagnosed with having first degree heart block, which is so minor it doesn’t even cause noticeable bradycardia (slowing of heart beat). This means that the due to a lack of conductivity in my heart there is a slight delay between the contraction of the atria and the ventricles although not enough to have any noticeable adverse effects. For others though, it can be a lot more serious. Cardiovascular diseased cause the highest number of deaths in the world according to the World Health Organisation (WHO?), with many of these being caused by arrhythmias.
In 1994 and 1996 two papers were released both on the topic of polymers transporting through nanopores. Since then the quite niche filed has been very active with over forty different theoretical and experimental papers being written on the subject. This is because the concept of a large chemical chain fitting through an enclosed space has acute relevance in biology as well as medicine. Almost all of these studies have been based on using an electric field to drive the movement of the polymers. A break through was made with the development of the tension propagation theory. This is where the driving force acting towards the trans side of the membrane causes mechanical tension to develop in the polymer. This produces mobile and immobile parts of the polymer as some parts are acting under the force and some have yet to experience it, see the diagram below:
When people have myocardial infarctions (heart attacks) the cardiomyocytes (heart muscle cells) can suffer hypoxia (lack of oxygen) and so apoptosis (the death of cells) can occur. The (very complicatedly named) effects can be mitigated through a process called angiogenesis. This is where new blood vessels are created rapidly in order to perforate some living tissue and in this case combat the hypoxia. Now when it comes to treating and intervening in patients with growing areas of dead cells (the infarct) in the heart, fitting a catheter is the most reliable cure. Cell based therapies or those that angiogenic assistance could be used to treat the growing risk of a heart attack but no clinical trials have proven them to be a success. It can be seen as worrying that in the last fifty years (the nobel prize for cardiac catheters was awarded in 1956) there have been no more advancements or great innovations.
It can be seen as a miracle the approximately 35 trillion cells that make up a human’s body have managed to fit themselves into the right place. All the way when we were a foetus and our form was taking shape the cells had to make sure they getting into the right positions then. It is rare for a brain cell to end up dispersed in the muscle cells or vice versa as the cells are very adept at forming their tissue boundaries. The mechanism that causes such precise delimitation is still quite unclear and so this is considered a prime focus of study in biophysics.
Cancer seems to be almost ever present in today’s society. Everyday more things are announced that might cause cancer and various chemicals that are potential cures are discovered. But to this day, the most common thing that can cancer, that run into every single day, is ultraviolet light. Ultraviolet light has a direct photochemical effect on the DNA of humans; catalysing the bonding of two thymine bases (pyrimidines) into either a cyclobutane pyrimidine dimer or a 6-4 photoproduct:
These conversions result in the DNA becoming bent out of shape and hampers the correct reproduction and duplication. Now although the smaller wavelengths of ultraviolet light have greater energy, they are actually completely removed by the Earth’s atmosphere. It is the range of 280 to 400 nanometres that offers the most tangible risk.
Carotenoids are organic pigments that you will have likely seen and will remember due to their distinctive red and orange colour. They are almost exclusively produced in plants, the only exceptions being aphids and some forms of mite, and are responsible for the red of tomatoes and the orange of autumn leaves. In animals, when gained by consumption, they act as antioxidants and are believed to have some connection to the functioning of the retina.
The Greek historian Herodotus (whose historical accounts most people should be sceptical about) once wrote about the Egyptian Pharaoh, Psammeticus, who performed an experiment to determine where language came from. He gave two newborn children to a shepherd and demanded that while they were looked after no one may speak to them. Eventually one of the children, having grown a bit, was heard saying “bekos,” a word in Phrygian, but most contemporary thought is that the baby was actually imitating a sheep’s bleat. Although it isn’t an exact analogy it is similar to the topic of today’s paper. How do the neurons of the brain develop without visual input for early years of life?