Contact us

Popular Posts

DNA Fingerprinting: Definition, Method and Application

Image
What is DNA fingerprinting? DNA fingerprinting is a laboratory technique that is used to determine the identity of a person using a unique pattern in the minisatellites of the genome of an individual. It was first invented in 1984 by Sir Akec Jeffreys after he realized that we can detect variations in human DNA based on these minisatellites. On average, about 99.9% of DNA between two individuals is the same, the remaining 0.1 % makes the person unique. DNA profiling, DNA testing, DNA examination, Genetic profiling, and Genetic fingerprinting are branches of DNA fingerprinting. Following is the complete process of DNA fingerprinting: RFLP (Restriction Fragment Length Polymorphism) The first step of DNA fingerprinting is to extract DNA from the biological fluid of human-like blood, buccal swabs, etc. Then molecular scissors, also called restriction enzymes are used to cut the DNA into thousand pieces of different lengths. These pieces of DNA are now separated using gel electrophoresis...
Read more

History of Fingerprint Science

Image
Prof. Jan Evangelista Purkinje The history of fingerprint science dates back three 3000 years as it was first used in Chinato to sign legal documents. Then, In 1823 Prof. Jan Evangelista Purkinje published a thesis describing the friction ridge patterns and classifying fingerprints into Nine categories. Sir William Herschel In 1858, An English civil servant Sir William Herschel posted in Bengal, India, started the practice of recording handprints of native Indians to sign the contract. This, greatly prevented the cheating and impersonation among native Indians to sign the contract. But, William Herschel did not publish any of his findings. Dr. Henry Fauld In 1874, Dr. Henry Fauld , a Scottish physician working in a hospital in Tokyo, Japan, published his theory on the potential use of fingerprints for personal identification. In 1880, Dr. Fauld suggested that skin ridge patterns can be proved important for the identification of criminals. He also published his findings in Boo...
Read more

Conducting Polymers: Definition, Examples, Properties and Applications

Image
What are Conducting Polymers? As the name suggests organic polymers that conduct electricity are known as conducting polymers. They are also known as intrinsically conducting polymers (ICPs) and they have alternating single and double bonds along the polymer backbone (conjugated bonds) or that are composed of aromatic rings such as Phenylene, naphthalene, anthracene, pyrrole, and thiophene which are connected through carbon-carbon single bonds. Examples: Polyacetylene, Polypyrrole, Polyaniline, etc What is the reason behind conducting nature of these polymers? Conducting polymers comes in two forms that are doped conducting polymers and non-doped conducting polymers. The conductivity of non-doped conjugated polymers is due to the existence of a conductivity band similar to a metal. In a conjugated polymer, three of the four valence electrons form strong sigma bonds through sp² hybridization where electrons are strongly localized. The remaining unpaired electron of each carbon atom re...
Read more