Biologists doing stem cell research are working to learn how a single cell develops into a complete organism and how cells can renew themselves and replace damaged cells.  This second part of the research is particularly important to the treatment of diseases (regenerative medicine).

Stem cells are unspecialized cells that when divided through the process of cell division, can form specialized cell types such as the cells of the heart that cause the heart’s muscle to beat and pump blood.

The two main types of stem cells that are used for research are embryonic stem cells (embryos are organisms on their earliest stage of development, in humans they are considered from the moment of implantation, which is done in a laboratory for stem cell research purposes, until the end of the 8^th week.) and adult stem cells.

This research started several years ago using mice embryos to obtain stem cells.  From these studies scientists learned how to isolate stem cells from human embryos; these cells were initially used to treat infertility.

Stem cells in the developing tissues of a 3 to 5 day-old embryo provide the generation of specialized cells that make the organs in a fetus.  In adults, stem cells regenerate into replacement cells for cells that die because of age, injury or disease.

Because of this stem cells are believed to contain the information necessary to be able to treat diseases and birth defects.

Two properties of stem cells are the main focus of research:

• How they remain unspecialized, and how they can self renew.
• The fundamental internal and external factors that cause these cells to become specialized (part of an organ’s function).

Parkinson’s disease is currently being heavily researched and might be the first disease to be able to be treated using stem cell transplantation.  This disease is caused by progressive degeneration and loss of the neurons that produce dopamine (needed by the brain to communicate messages between neurons).  Stem cell research has produced methods to generate cells with many of the functions of the neurons that produce dopamine; these cells could be used to treat the disease by replacing the lost neurons.

All about Insulation

Proper insulation of our homes is very important, both for our comfort and our wallets; heating and cooling costs count for the most part of the utility expenses in a house.

When there are differences in temperature between two physical objects that are in contact, a transfer of energy takes place between them eventually having both objects at an equal temperature (if you drop ice cubes inside a glass with warm water, the ice cubes will melt and the result will be water at a cooler temperature than the original water).  This happens in a house; when it is hot outside and the air conditioner is working trying to cool the air inside, the difference in temperature between inside and outside causes a transfer of energy trying to equalize the temperatures; the cold from inside escapes outside and the hot from outside comes inside. Because the temperature outside the house is being caused by a much larger energy source (the sun) than the air conditioner inside the house, the house will not cool down unless insulation material is placed between the two areas.  The walls in the house serve to block the energy transfer, but a wall alone is not very efficient, that is why insulation material is placed inside the walls to help.

The process of insulation consists of adding the corresponding insulation material to different locations within a house with the purpose of blocking the flow of energy between the interior and exterior.  There are different materials used for this purpose:

Cellulose – Is made of 80% post-consumer recycled newsprint.  Cellulose is rapidly becoming the first choice for insulation, replacing fiberglass.  Cellulose can be blown using a machine in attics and inside walls.  It provides resistance to fire and mold growth.

Fiberglass – It is formed out of sand and recycled glass.  Direct contact with fiberglass materials or exposure to airborne fiberglass dust may irritate the skin, eyes, nose and throat.  When working in a place where there is fiberglass insulation, such as the attic, proper attire is highly recommended; coveralls, gloves, safety glasses and a disposable dust respirator.  It provides resistance to fire and mold growth.

Vermiculite – This is a naturally occurring mineral that expands when it is heated.  This minerals provides fire resistance and good absorption, it is also very light and odorless.  Prior to 1990 most of this mineral was extracted from a mine that had a natural deposit of asbestos which resulted in contaminated Vermiculite.  The mineral today is extracted from different mines whose levels of contamination are much lower than the initial product.  If you have this insulation material in your home it is wise not to disturb it.  If the insulation is in your attic, for example, covering the floor of the attic (where the material is settled) with plywood will prevent from stepping on it and releasing any asbestos particles.

Wood Shavings – This type of insulation is popular in very old homes.  Because of the wood’s high flammability this type of insulation is not much considered these days.

Mineral Wool (Rock and Slag Wool) – High resistance to fire.  Slag wool is made out of industrial waste products and Rock wool is made out of natural rocks.

Polyurethane – This compound is used to fabricate foam boards used for insulation.  It offers high resistance to fire.  These boards can absorb moisture which decreases their insulation properties.  Some insects such as termites and carpenter ants use these boards for protection and tunneling.

Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-value, the greater the insulating effectiveness is.  Knowing the R-values of the different materials out there can help you make a good decision about which one to use for your home.  An insulation professional can help you to make a good decision and make the installation easy.

The Oak Ridge Laboratory from the Department of Energy offers plenty of information about insulation.  Visit them at http://www.ornl.gov/sci/roofs+walls/insulation/ for more information.