So here you go...
Highlights
The Natural World
1. 3D images of the cell published.
2. Who commands the white blood cells to attack invaders?
3. How anti is an antibacterial soap?
4. Tracking Evolution at the protein level.
5. Life like or life itself?
The Physical World
1. Power of a sheet of paper (You can take the printout of a battery).
2. What makes the earth to dance?
3. Cooling a chip with ions.
4. Is water essential to make life possible in a planet?
The Natural World
1. 3D images of the cell published
I guess it was two months ago that NASA published the first 3D images of the sun. The biologists are striving hard to catch up with them. The team at MIT has come up with the first ever 3D images of the cell. It can be used to provide the most detailed images of the cell and could help in knowing what is going on out there. Don't you ever think that this is an easy job. The cells do not absorb much of visible light. So how do you see a cell? Normally fluorescent markers are used to see the cell. But the MIT team used the refractive index property to achieve this. When light moves in a medium, its speed varies. It is faster in some media compared to others. The higher the refractive index, the slower the light travels. By measuring the refractive index at different portions of the cell, the team came up with a 2D image of the cell. 100 such 2D images taken from different angles are then overlapped to obtain the 3D image of the cell. But fortunately the time taken for the process is just about one tenth of a second. Now it is time for the fluorescent markers to give way to the new technique to observe the functional activities of the living cells in their native state.
2. Who commands the white blood cells to attack invaders?
White blood cells, or neutrophils, are the body's first line of defense against potentially harmful microbes, and are one of the swiftest cells in the body. What drives these soldiers to the invading disease causing germs? It is a burst of microscopic waves - says the research team lead by Orion Weiner of the University of California. Now let’s see the dramatic events in the process. When the invaders are found, a signaling protein called Hem-1 becomes active. The wave signaled by the Hem-1 protein control the pattern of assembly of building blocks of a second protein called actin, which physically contacts the cell membrane of the neutrophils pushing them towards the invading microbes. The actin also eliminates the Hem-1 protein which produced it – killing its creator. But before the Hem-1 protein is eliminated, it recruits an additional Hem-1 "next door". This helps in self sustaining the process. Imagine adding blocks to a tower from one end and removing the blocks from the other. Then you would get a moving tower moving in a direction of the end where the blocks are added. This is exactly what happens in the realm of neutrophils.
3. How anti is an antibacterial soap?
We live in a health cautious society. This attitude of the society has been exploited by the soap companies. They have come up with new variety of products to attract the masses. One such product which hit the stalls lately is the antibacterial soap. Are these effective as anti bacterial agents? "No", says Allison Aiello, a public health professor at the University of Michigan. Her team found that washing hands with an antibacterial soap was no more effective in preventing infectious illness than plain soap. Not only that it does not help us, but does harm as well. The main active ingredient in an antibacterial soap called triclosan may cause some bacteria to become resistant to commonly used drugs such as amoxicillin. Triclosan works by targeting a biochemical pathway in the bacteria that allows the bacteria to keep its cell wall intact. Because of the way triclosan kills the bacteria, mutations can happen at the targeted site, says the study.
4. Tracking Evolution at the protein level
Let us visit the world of genes. They are made of proteins. Let me take you back in time. We could encounter the ancestors of the genes who had entirely different functions than the present one. This would mean that the proteins which constituted the gene were different earlier. Scientists have determined for the first time the atomic structure of an ancient protein, revealing in unprecedented detail how genes evolved their functions. Going back in the world of proteins has long eluded evolutionary biologists, in large part because ancient proteins have not been available for direct study. The researchers focused on the glucocorticoid receptor (GR), a protein in humans and other vertebrates that allows cells to respond to the hormone cortisol, which regulates the body's stress response. They used computational techniques and a large database of modern receptor sequences to determine the ancient GR's gene sequence from a time just before and just after its specific relationship with cortisol evolved. The ancient genes – which existed more than 400 million years ago – were then synthesized, expressed, and their structures determined using X-ray crystallography, a state-of-the art technique that allows scientists to see the atomic architecture of a molecule. The structures allowed the scientists to identify exactly how the new function evolved. They found that just seven historical mutations, when introduced into the ancestral receptor gene in the lab, recapitulated the evolution of GR's present-day response to cortisol. They were even able to deduce the order in which these changes occurred, because some mutations caused the protein to lose its function entirely if other "permissive" changes, which otherwise had a negligible effect on the protein, were not in place first.
5. Life like or life itself?
Life is composed of organic molecules, which are simply the compounds of carbon, excluding carbonates and carbon dioxide. Now, an international team has discovered that under the right conditions, particles of inorganic dust can become organised into helical structures. Quite bizarrely, not only do these helical strands interact in a counterintuitive way in which like can attract like, but they also undergo changes that are normally associated with biological molecules, say the researchers. They can, for instance, divide, or bifurcate, to form two copies of the original structure. These new structures can also interact to induce changes in their neighbors and they can even evolve into yet more structures as less stable ones break down, leaving behind only the fittest structures in the plasma.
The Physical World
1. Power of a sheet of paper (You can take the printout of a battery)
What would be a battery like in the future? It would be like a sheet of paper, say researchers at the Rensselaer Polytechnic Institute. The prototype for this has been developed by them. It is a nanoengineered product, ultra thin, lightweight, flexible and above all derives the power from human sweat, blood or urine. This remarkable invention can be folded, rolled twisted or even cut into many pieces. More than 90 percent of the device is made up of cellulose, the same plant cells used in paper. The paper infused with aligned carbon nanotubes, which gives the device its black color, uses ionic liquid, which is essentially a liquid salt, as an electrolyte. This electrolyte does not have water in it, which enables the device to operate at very high temperatures. Let us now wait for the release of this product from the lab to the public.
2. What makes the earth to dance?
The Earth is a unique planet with tectonic plates jiggling around, rearranging themselves into new configurations, colliding and rising mountains, creating volcanoes etc. What makes the earth perform this plate tectonic dance that shapes the earth itself? Let’s go down to the depth of the earth. Beneath the continents about 150km deep and beneath the oceans about 60km deep, lies the asthenosphere. If we go deeper at about 220km depth the asthenosphere comes to an end and the mantle goes back to a less flexible state. The restlessness of the plates is because of its slippery asthenosphere. What made this slippery? This question has given sleepless nights to geologists for decades. Now the answers are starting to emerge. Previous theories have suggested that this ‘wet’ and slippery layer exists because minerals leave their water behind them when they melt and turn into magma. This explains why the asthenosphere appears beneath oceans, but it doesn’t explain why we have an asthenosphere beneath the continents. It also fails to explain why there is a lower boundary to the asthenosphere. Hans Keppler, a geologist at the University of Bayreuth in Germany has come up with a new model to explain the existence of the asthenosphere called the water solubility model. The studies done by Bjorn Winker and Keith Refson had contributed largely to Keppler's theory. According to the new model, the water present in the form of hydroxyl (OH) groups in the asthenosphere minerals are the reason for the lubricating behavior. The minerals in the mantle cannot contain all the water and the excess water forms a hydrous silicate melt which is responsible for the lubrication.
3. Cooling a chip with ions
Cooling of a computer chip when the chip operates is a major design hurdle in their design. Researchers have demonstrated a new technology using tiny "ionic wind engines" that might dramatically improve computer chip cooling, possibly addressing a looming threat to future advances in computers and electronics. The Purdue University researchers, in work funded by Intel Corp., have shown that the technology increased the "heat-transfer coefficient" which describes the cooling rate, by as much as 250 percent. The experimental cooling device, which was fabricated on top of a mock computer chip, works by generating ions - or electrically charged atoms - using electrodes placed near one another. The device contained a positively charged wire, or anode, and negatively charged electrodes, called cathodes. The anode was positioned about 10 millimeters above the cathodes. When voltage was applied to the device, the negatively charged electrodes discharged electrons toward the positively charged anode. Along the way, the electrons collided with air molecules, producing positively charged ions, which were then attracted back toward the negatively charged electrodes, creating an "ionic wind." This breeze increased the airflow on the surface of the experimental chip.
4. Is water essential to make life possible in a planet?
Is water necessary for a planet to be an abode of life? To search whether a planet hosts life or not, is it enough to find whether the planet has water or not? Scientists at the University of Illinois say "No". Enceladus is the icy moon of Saturn. Cassini spacecraft, which has been orbiting Saturn from June 30, 2004 has revealed a south polar region with an elaborate arrangement of fractures and ridges, intense heat radiation and geyser like plumes consisting of ice crystals and gases such as methane, nitrogen and carbon dioxide. Researchers at the University of Illinois have come up with a model explaining these salient features without requiring the presence of liquid water. The fractures and ridges in the pole were considered as the proof for the presnece of water. But the new model explains that the fractures and ridges can be formed without the presence of water. The new model says that as the heat source is warmed at depth, it expands and stretches the clathrate-rich shell above, giving rise to tensile stresses in the south polar cap. As a result of this pulling force the shell cracks, forming the fractures. The researchers estimate that the heat source could have been only 40 degrees warmer than the surrounding shell. The researchers also show that, northwards of the south polar cap (in which the stresses were tensile), the stresses turned first from tensile to compressive – forming the circling ring of ridges and then back to tensile – forming the set of “starfish” fractures that radiates northward from the ring of ridges. After the stripes are formed, the clathrates exposed on the cracked surfaces of the stripes would be decompressed. Upon decompression, the exposed clathrates absorb heat from the source at depth and dissociates explosively, exposing more clathrates to decompression. The gaseous products of clathrate dissociation rush up the stripes, transporting heat to the surface where they may occasionally leak in the form of plumes. The transport of heat by fast-moving gases is called “heat advection.” In contrast to “heat conduction”, where the transport of heat (in a bar of steel, for example) can only occur from points at higher temperature towards points at lower temperature, heat advection takes place at a nearly uniform temperature. The model is indeed a new eye for us to view at extraterrestrial life.
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