As circuits become more and more integrated the components of the circuits are going to become more and more exposed to different conditions. Now dielectric breakdown is a well known effect where as you begin upping the charge on a capacitor, eventually dielectric you’re using between will simply not be able to handle the strength of the electric field and it breaks down into becoming a conductor. A spark will then leap between the capacitor plates and that’s the stored charge gone. The main theory behind this is called the percolation theory. According to this theory a dielectric within an electric field develops tiny point defects which can connect to other defects in proximity. As the defect concentration increases with growing electric field sooner or later both sides of the dielectric will be connected by a network of defects, dielectric breakdown will occur, and the dielectric’s electrical properties will be significantly changed to become conducting.
In 2010 two dimensional molybdenum disulphide (MoS2), just a few layers thick, was being isolated and examined. It was discovered that in this state the electron movement fell under the theory of ballistic conduction, this is where the electrons have a mean free path great enough that the majority of their interactions are rebounding off a materials edges rather than the defects that normally cause restive scattering. Since then, 2D transition metal dichalcogenides have been the focus of intense research for various other esoteric electronic transport properties with ranging successes.
Human Immunodeficiency Virus Type 1 (HIV-1) is one of the most notorious viruses worldwide. According to Avert.org 36.7 million people are infected with HIV making 0.8% of the adult population of the planet. Since the epidemic started in the 1980s, 35 million people have died from the diseases which Acquired Immune Deficiency Syndrome leaves them vulnerable to with an estimated one million people still dying every year. The development of combination AntiRetroviral Therapy (cART) has managed to enhance the lifetimes of the infected but no treatment can ever purge the central nervous system and lymph system of the virus.
Isotopic labelling is the process of replacing an atom in a molecule with an isotope of that atom. Isotopes of the same element are chemically (almost) exactly the same as each other so any reaction that the labelled molecule will take part in will progress as normal, except now we can track what happened to that particular atom during the process. In the pharmaceutical industry, knowing where your atoms are going is very important for chemical synthesis and as hydrogen (H) is common in many organic chemicals, deuterium (D) or tritium (T) is often used as a labeller.
When we emerge from a dim place and the light glares upon our eyes our pupil contracts to protect the retina in an incredibly short space of time. It would be very unfortunate in general if the light sensitive chemicals in our eye took a long time to respond any light falling upon them. This kind of quick chemistry where photochemicals change their shape and electronic properties very rapidly is hard to study. Many attempts have been made to try and observe the dynamics of molecular species on very short time scales and there has been some success with using X-ray diffraction and photoelectron diffraction for this task. However these processes require complex data analysis for their results to be understood on a physical level as well as the fact that they also lack the resolution to observe the subtlest changes in electronic structure which despite being small are still very relevant.
Bismuth (Bi) is a metal with very low toxicity and an ability to be therapeutic to gastrointestinal illness such as ulcers or diarrhoea. Selenium (Se) is a nonmetal which is incorporated into selenoproteins when it enters our body and assists in the removal of reactive oxygen species. Of course what else was to be tried but putting both of these things together and seen what was produced. Bismuth selenide (Bi2Se3), often in the form of nanoparticles, have recently shown a great deal of potential when it comes to diagnosis and treatment of a range of diseases.
If a solution contains metal ions, lets say copper (Cu2+), it is possible to regain the copper metal by returning the electrons to the ions. A simple way to do this would be adding a metal which is more reactive then copper (which would be most of them). Iron would do. The iron would react with whatever negative ion was present to produce Fe2+ or Fe3+ while electrons given off in the process will reduce the copper ions back to copper. Another method would be to feed electrons into the solution by using an electrode. A negative electrode placed in the solution will attract the copper ions and when they make contact with the electrode, electrons will move onto them. This will change the ions back into copper metal resulting in a layer of copper over the negative electrode, this is electroplating. Electrodeposition is a similar process to this except that rather than a solution of ions the charged particles that will be deposited are larger and are just suspended in a liquid as a colloidal mix.