Electrolysis is the chemical processin which the dcomposition of ionic compounds is dne by passing electricity through molten compounds or aqueous solutions of compounds. It can be used to cover a metal surface with another metal by electroplating, the purification of copper, the extraction of reactive metals such as aluminium, an dthe manufacturing of chemicals such as sodium chlorine and bleach. The apparatus used for electrolysis is called an electrolytic cell. It consists of two electrodes in aliquid electrolyte. A direct current power source is connectd to the electrolytes, decomposing it to simpler substance.
The seperation of substances using electrolysis is also possible. One example would be extracting sodium sodium chloride. Sodium choride is an ionic compound consisting of sodium ions and chloride ions, In the solid state, the oppositely charged ions attract each other and thus are not free to move, but in teh molten state, the ions are free to move. When a current is passed through the molten sodium chloride, a silvery liquid forms at the cathode(negetive electrode), this is molten sodium. Bubbles of a yellow-green gass appear aroung the anode(positive electrode, the gas chlorine. This happens as the ions are attracted to the oppositely charged electrode instead of each other, and hence a sample of sodium is extracted.
ScienceDaily (Aug. 23, 2010) — Human pluripotent stem cells, which can become any other kind of body cell, hold great potential to treat a wide range of ailments, including Parkinson's disease, multiple sclerosis and spinal cord injuries. However, scientists who work with such cells have had trouble growing large enough quantities to perform experiments -- in particular, to be used in human studies. Furthermore, most materials now used to grow human stem cells include cells or proteins that come from mice embryos, which help stimulate stem-cell growth but would likely cause an immune reaction if injected into a human patient.
The research team, led by Professors Robert Langer, Rudolf Jaenisch and Daniel G. Anderson, describes the new material in the Aug. 22 issue of Nature Materials. First authors of the paper are postdoctoral associates Ying Mei and Krishanu Saha.
Human stem cells can come from two sources -- embryonic cells or body cells that have been reprogrammed to an immature state. That state, known as pluripotency, allows the cells to develop into any kind of specialized body cells.
It also allows the possibility of treating nearly any kind of disease that involves injuries to cells. Scientists could grow new neurons for patients with spinal cord injuries, for example, or new insulin-producing cells for people with type 1 diabetes.
To engineer such treatments, scientists would need to be able to grow stem cells in the lab for an extended period of time, manipulate their genes, and grow colonies of identical cells after they have been genetically modified. Current growth surfaces, consisting of a plastic dish coated with a layer of gelatin and then a layer of mouse cells or proteins, are notoriously inefficient, says Saha, who works in Jaenisch's lab at the Whitehead Institute for Biomedical Research.
"For therapeutics, you need millions and millions of cells," says Saha. "If we can make it easier for the cells to divide and grow, that will really help to get the number of cells you need to do all of the disease studies that people are excited about."
Previous studies had suggested that several chemical and physical properties of surfaces -- including roughness, stiffness and affinity for water -- might play a role in stem-cell growth. The researchers created about 500 polymers (long chains of repeating molecules) that varied in those traits, grew stem cells on them and analyzed each polymer's performance. After correlating surface characteristics with performance, they found that there was an optimal range of surface hydrophobicity (water-repelling behavior), but varying roughness and stiffness did not have much effect on cell growth.
They also adjusted the composition of the materials, including proteins embedded in the polymer. They found that the best polymers contained a high percentage of acrylates, a common ingredient in plastics, and were coated with a protein called vitronectin, which encourages cells to attach to surfaces.
Using their best-performing material, the researchers got stem cells (both embryonic and induced pluripotent) to continue growing and dividing for up to three months. They were also able to generate large quantities of cells -- in the millions.
The MIT researchers hope to refine their knowledge to help them build materials suited to other types of cells, says Anderson, from the MIT Department of Chemical Engineering, the Harvard-MIT Division of Health Sciences and Technology, and the David H. Koch Institute for Integrative Cancer Research. "We want to better understand the interactions between the cell, the surface and the proteins, and define more clearly what it takes to get the cells to grow," he says.
Other MIT authors of the paper are Said Bogatyrev, Z. Ilke Kalcioglu, Maisam Mitalipova, Neena Pyzocha, Fredrick Rojas and Krystyn Van Vliet. Jing Yang, Andrew Hook, Martyn Davies and Morgan Alexander of the University of Nottingham (United Kingdom) and Seung-Woo Cho of Yonsei University (Korea) are also authors of the paper.
Source: http://www.sciencedaily.com/releases/2010/08/100822150643.htm (thanks to Mr Tan Kai Yuan for posting this on facebook)