Friday 21 December 2007

Stop Bleeding in 15 Seconds

Researchers at Massachusetts Institute of Technology and University of Hong Kong have found a liquid that can stop bleeding in 15 seconds. If this liquid works on humans, as it worked on rodents, the discovery could be lifesaver.

Uncontrolled loss of blood often means loss of life. But now researchers have discovered a liquid(looking like a water) could stop bleeding anywhere in the body in less than 15 seconds without clotting the blood. This liquid can be poured or sprayed on and it will form a clear gel. The gel uses amino acids, the body's building blocks, to create nano-scale fibers that may be self assembling into a nano-patch. So, the analogy would be is if you have hair and it clogs the drain you actually stop the movement of fluid.

Researchers discovered the liquid by accident and they are still studying its exact mechanisms. One of the researchers says, "There doesn't seem to be any side effects. It doesn't create an immune response for the body because as the amino acids break down they become building blocks actually for the repair of the system, or they're excreted in the urine."

In medicine today people have to stop bleeding by using direct pressure or, in surgery, clamps, sponges, vasoconstrictors, cauterization and even super-glue. But if this liquid works for human, many lives, which might be lost because of access loss of the blood, can be saved. It will be very important in emergency medical situations because of the speed of its action and because it can create a barrier to the outside world. Such a barrier may be effective in reducing or stopping infections.

Thursday 20 December 2007

Fast Rechargable Batteries

Researchers at the Massachusetts Institute of Technology are developing a battery that could charge your cellphone or laptop in a few seconds rather than hours and also might never need to be replaced.

Joel Schindall and his team at Massachusetts Institute of Technology turned to the capacitor to make long charge times and expensive replacements a thing of the past. Capacitor was invented nearly 300 years ago, but Joel Schindall and his team made the connection between this old product and use of a new technology, nanotechnology, to make that old product in a new way.

Rechargable and disposable batteries use a chemical reaction to produce energy. "That's an effective way to store a large amount of energy," Joel says, "but the problem is that after many charges and discharges ... the battery loses capacity to the point where the user has to discard it."

But capacitors contain energy as an electric field of charged particles created by two metal electrodes. Capacitors charge faster and last longer than normal batteries. The problem is that storage capacity is proportional to the surface area of the battery's electrodes, so even today's most powerful capacitors hold 25 times less energy than similarly sized standard chemical batteries.

The researchers solved this by covering the electrodes with millions of tiny filaments called nanotubes. Each nanotube is 30,000 times thinner than a human hair. Similar to how a thick, fuzzy bath towel soaks up more water than a thin, flat bed sheet, the nanotube filaments increase the surface area of the electrodes and allow the capacitor to store more energy. Schindall says this combines the strength of today's batteries with the longevity and speed of capacitors.

This technology has broad practical possibilities, affecting any device that requires a battery. Schindall says, "Small devices such as hearing aids that could be more quickly recharged where the batteries wouldn't wear out; up to larger devices such as automobiles where you could regeneratively re-use the energy of motion and therefore improve the energy efficiency and fuel economy."

Schindall thinks hybrid cars would be a particularly popular application for these batteries, especially because current hybrid batteries are expensive to replace.

Schindall also sees the ecological benefit to these reinvented capacitors. According to the Environmental Protection Agency, more than 3 billion industrial and household batteries were sold in the United States in 1998. When these batteries are disposed, toxic chemicals like cadmium can seep into the ground.

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About Human Blood Group

Human blood is grouped based on the presense or absense of inherited antigenic (a molecule that sometimes stimulates an immune response) substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins or glycolipids, depending on the blood group system.

Most commonly known blood group system is ABO blood group system and Rhesus blood group system. ABO blood group system has A-antigen and B-antigen. The presense or absense of these two antigens will determine the blood group as A, B, AB or O (see figure below). Rhesus blood group system uses RhD antigen. The presense or absense of this antigen will determine Rh+ or Rh- blood group. Combining these two blood group systems, one can have 8 possible kind of blood groups named as A+, A-, B+, B-, AB+, AB-, O+ and O-.



Apart from antigen, blood also has antibodies, which will protect us from external bodies such as bacteria and viruses. It is a part of human immune system. As shown above, corrosponding antibodies are also present in perticular blood group. Blood group A will have antibody anti-B. Blood group B will have antibody anti-A. Blood group O will have antibodies anti-A and anti-B. Blood group AB will not have any of these antibodies (anti-A and anti-B). So, if during blood transfusion, if blood groups are not matching, these antibodies will bind to other blood's antigen and will damage the red blood cells. This can can lead to a more vigorous immune response with massive RBC destruction, low blood pressure, and even death. This explains why blood group AB is universal accepter and blood group O is universal donor. Since blood group AB is having no antibodies, it will not react to any kind of blood and thus can accept any kind of blood group. Similarly, blood group O is not having any antigen present, so any antibodies can not react with this type of blood and thus it can be transfused to any kind of blood group. But since, blood group O has both kind of antibodies, it can not accept A, B or AB blood group.
Blood group AB: Individuals have both A and B antigens on the surface of their RBCs, and their blood serum does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but can donate blood only to another group AB individual.

Blood group A: Individuals have the A antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the B antigen. Therefore, a group A individual can receive blood only from individuals of groups A or O (with A being preferable), and can donate blood to individuals of groups A or AB.

Blood group B: Individuals have the B antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can receive blood only from individuals of groups B or O (with B being preferable), and can donate blood to individuals of groups B or AB.

Blood group O: Individuals do not have either A or B antigens on the surface of their RBCs, but their blood serum contains IgM anti-A antibodies and anti-B antibodies against the A and B blood group antigens. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (ie A, B, O or AB). If anyone needs a blood transfusion in a dire emergency, and if the time taken to process the recipient's blood would cause a detrimental delay, O Negative blood can be issued.

RecepientDonner
O-O+A-A+B-B+-AB-AB+
O-YesNoNoNoNoNoNoNo
O+YesYesNoNoNoNoNoNo
A-YesNoYesNoNoNoNoNo
A+YesYesYesYesNoNoNoNo
B-YesNoNoNoYesNoNoNo
B+YesYesNoNoYesYesNoNo
AB-YesNoYesNoYesNoYesNo
AB+YesYesYesYesYesYesYesYes

Tuesday 18 December 2007

Radio Antenna Made of Plasma

A radio antenna made of plasma (electrified gas) could be next generation jamming-resistant transmitter. Sealed glass, ceramic or flexible plastic tubes of electrified gas can behave just like conventional antenna. These antennas only works when energized and vanished when turned off.

Metal antennas can scatter incoming radar signal and thus give away their presence. But, plasma antennas can be powered off after a brief use, thus making them stealthy.
In addition, to counteract jamming attempts, plasma antennas can rapidly adjust which frequencies they broadcast and pick up by changing how much energy the plasma is given. This way, they avoid interference from enemy signals. Metal antennas, on the other hand, are each forced to receive and transmit only a given range of frequencies, making them vulnerable to jamming.

The fact that plasma antennas can get reconfigured to broadcast and receive a wide range of frequencies also means you can create a kind of 'all-in-one' antenna, with one plasma antenna performing the jobs of several metal antennas.

The scientists are also developing a "smart" plasma antenna that can steer a beam of radio waves 360 degrees to scan a region and then find and lock onto transmitting antennas. A comparable radio array using metal antennas would be much larger and heavier

Friday 14 December 2007

What is a Mirage?

Ever wondered, why you see distant cars' distorted mirror images on the tar road on the hot sunny day? Well, these images are called Mirage. It is naturally occurring optical phenomena in which light rays are bent and produce displaced image of distant objects. The English word "Mirage" is having root in Latin word "Mirare", which means "to seem". Mirage is not an optical illusion. One can take photographs of it.

Unlike mirror, the principal physical cause for a mirage is refraction rather than reflection. Refraction is the change in direction of a wave due to a change in its speed. It is measured by Refractive Index. Refractive Index is the measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. For example, typical glass has a refractive index of 1.5, which means that light travels at 1 / 1.5 = 0.67 times the speed in air or vacuum.

Cold air is denser than warm air, and has therefore a greater refractive index. That means, light waves become slower in cold air compared to hot air. As light passes from colder air to warmer air it bends away from the direction of the temperature gradient when it passes from hotter to colder, it bends towards the direction of the gradient.



The diagram above shows a light ray coming from the sky toward the hot ground. If the air near the ground is warmer than that higher up, the light ray bends in a concave upwards trajectory. Once the ray reaches the viewer’s eye, the eye traces it as the line of sight, which is the line tangent to the path the ray takes at the point it reaches the eye. The result is that an inferior image for the above sky appears on the ground.

'Altair' is the Name Given to Next Generation Moon Lander: NASA

NASA has introduced a new name and logo for its next generation moon lander, which was previously referred to as the Lunar Surface Access Module.

The new name is revealed by Jeff Hanley, NASA's Constellation Program manager at a meeting with industry representatives held at Johnson Space Center.



Altair is the brightest star in the constellation Aquila and is the twelfth brightest star in the night sky. The word 'Altair' finds its origins in Arabic and is derived from a phrase that means 'the flying one'. In Latin, 'Aquila' means Eagle, tying the new lander to the historic Apollo 11 Eagle.

Altair project logo emphasizes that connection. It depicts a bald eagle clasping an olive branch in its talons, an image chosen by Michael Collins, Apollo 11's command module pilot, based on a photo in a 1965 book published by National Geographic.