Hair/ Fiber Analysis History
The scientific study of hair is called trichology, and the field dates back into the middle of the nineteenth century. There are three techniques used to identify hair types. Chemical assays are used to identify the use of drugs in the body. The root of a hair has strands of DNA which can be used for DNA analysis. Also microscope comparisons can be made from two different hair samples.
Wednesday, September 9, 2009
Blood
Blood Types
There are four main types of blood. They are types A, B, AB, and O. The blood type system is a way of classifying blood based on whether or not there are inherited antigenic substances on the surface of red blood cells. These substances come in while the baby is in the womb based on what the mother eats or experiences. If someone has type A blood then they have anti – B antibodies. B is anti – A antibodies. AB is neither and O is both. This ABO system was founded by Austrian scientist Karl Landsteiner, who discovered three types in 1900.
Transfusions and Blood Mixing
Blood transfusions are when blood is transferred or blood based products are transferred from one person into the circulatory system of another person. This can be used to save people when they have lost so much blood they cannot carry oxygen throughout their body. Then when they get a transfusion or “fill up” as I like to call it they gain the necessary blood to stay alive. One can only receive blood from someone of the same blood type or else their immune system will attack the donor blood.
Positive and Negative Blood Types
The Terms “positive” or “negative” in reference to a blood type refers to the presence of certain antigens on the blood cells.
There are four main types of blood. They are types A, B, AB, and O. The blood type system is a way of classifying blood based on whether or not there are inherited antigenic substances on the surface of red blood cells. These substances come in while the baby is in the womb based on what the mother eats or experiences. If someone has type A blood then they have anti – B antibodies. B is anti – A antibodies. AB is neither and O is both. This ABO system was founded by Austrian scientist Karl Landsteiner, who discovered three types in 1900.
Transfusions and Blood Mixing
Blood transfusions are when blood is transferred or blood based products are transferred from one person into the circulatory system of another person. This can be used to save people when they have lost so much blood they cannot carry oxygen throughout their body. Then when they get a transfusion or “fill up” as I like to call it they gain the necessary blood to stay alive. One can only receive blood from someone of the same blood type or else their immune system will attack the donor blood.
Positive and Negative Blood Types
The Terms “positive” or “negative” in reference to a blood type refers to the presence of certain antigens on the blood cells.
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