|SCIENCE & TECHNOLOGY|
new world of nanomedicine
new world of nanomedicine
Nanomedicine, an emerging new field, is an outcome of fusion of nanotechnology and medicine. It can be broadly defined as the science and technology of diagnosis, treatment, preventing disease and traumatic injury, of relieving pain, and of preserving and improving human health using materials and devices designed at the level of molecular or nano scale.
The nanodevices used in medicine generally have sizes ranging from 1 to 100 nanometres (nm) or so. A nanometer compared to the size of a meter is roughly of the same proportion as a golf ball compared to the dimension of the world. Scientifically, a nanometer is one millionth of a millimeter.
Nanomedicine is not a physician’s job exclusively. It is rather a unique mixture of multidisciplinary experts from medicine, engineering, physics, chemistry, biology, computer science and the material sciences.
Most of the man-made nanostructures or nanodevices used in medicine are carbon based such as fullereness (third allotropic from the carbon after diamond and coal) and their relatives, carbon nanotubes, carbon nanoparticles and porus carbon. The polymeric dendrimers and quantum dots (QDs) represent other nanostructured materials that are also finding their way into medical therapeutics. These nanomaterials are thousand times thinner than the human hair and are too small to be seen even with best light microscope. There smallness coupled with their physical and chemical properties enable them to be used widely in the human system. Most of the nanomaterials used in medicine when injected move through the body without being recognised as "foreign" by the immune surveillance system.
Attempts have already been made to send various nanoparticles, particularly quantum dots, into the body to detect and treat cancer when only few cancerous cells exist. The nanoparticals are loaded with different biological markers (acting at tags specific for particular type of cancer) and drugs so that these could reach straight to the cancerous cells and kill them exclusively without affecting the surrounding healthy tissue.
The nanoparticles used in medicine are thousand times smaller then the dot above ‘i’, yet they have the carrying capacity of 100,000 molecules of the drug and the biological marker. By using nonaparticles, it is now possible to develop new advanced nano-sized therapeutic drugs called "smart drugs" for safe targeting the right place in the patient’s body and release therein in a controlled way.
Nanoscientists have also designed fluorescent nanoparticles that "light up" while doing MRI/CT scan. It would help in revealing the accurate and precise locations of the cancerous growth in the body. Nanoporous materials, in future, would be used as oxygen haemoglobin carrier mimicking the hemoglobin. This would, in turn, prevent the damage to those tissues, which are devoid of adequate oxygen. The nanomaterials such as dendrimers are used commercially in gene therapy for carrying genes to the cells. Numerous nanodevices and nanosystems for even sequencing single molecule of DNA are also feasible nowadays.
Recently two nanotech proprietary drug delivering technologies namely "Nanodry" and "Nanocoat" have been developed. These technologies would produce improved pharmaceuticals with high yield, having more versatility and cost effectiveness than the conventional technologies. Their focus is on providing relief to migraine headache instantly rather than in hours, improved breathing for asthmatics throughout the day with a single miniscule dose, and taking only a hundredth part of the normal dose of an antibiotic for the infection with little side effects.
Molecular nanotechnologists are also developing medical nanorobots, which would circulate freely throughout the body when injected into the blood stream. It is interesting to note that a nanorobot of the size of 100 nm would roughly be 80 times smaller than our red blood cell. The nanorobots used in medicine would have a small computer, several chemical binding sites on it to identify the abnormal cells in the body and would also carry the supply of the drug which would be selectively released on coming in contact with the diseased or abnormal cell. The computer would be pre-programmed with the profile of the abnormal cell to distinguish the abnormal cell from everything else.
By recording faint blue-green twinklings in a huge subterranean detector, physicists have observed signatures of radioactivity deep within earth. The new data enable the scientists to directly measure planet-wide quantities of the elements thorium and uranium, whose radioactive disintegrations generate about half of the planet’s heat, according to previous estimates.
The power from those nuclear decays-which exceeds that of 10,000 nuclear power plants-propels many dynamic features of the planet, including crustal motions that give rise to earthquakes and volcanoes and the convection of softened rock within the planet’s mantle.
California fiddler crabs may be among the world’s pickiest animals when it comes to selecting a mate.
A study conducted by a biologist at the University of California, San Diego that appears in the August issue of the journal Animal Behaviour found that females of the species Uca crenulata may check out 100 or more male fiddler crabs and their burrows before finally deciding on a mate.
"As far as I know, no other species has been observed sampling nearly as many candidates as the California fiddler crab," said Catherine deRivera, who conducted the study while a doctoral student and a lecturer at UCSD.
Bio-nanotubes that are smart
The nanotubes are "smart" because in the future they could be designed to encapsulate and then open up to deliver a drug or gene in a particular location in the body. The scientists found that by manipulating the electrical charges of lipid bilayer membranes and microtubules from cells, they could create open or closed bio-nanotubes, or nanoscale capsules. The news is reported in an article in the August 9 issue of the Proceedings of the National Academy of Sciences.
The scientists used microtubules purified from the brain tissue of a cow for their experiments. Microtubules are nanometer-scale hollow cylinders derived from the cell cytoskeleton. In an organism, microtubules and their assembled structures are critical components in a broad range of cell functions.
From where and how oxygen could get so much hydrogen to form water on this earth when hydrogen is hardly available in gaseous or combined form except in water?
Hydrogen is by far the most abundant element in the universe. This is also true of the sun and the nebula from which the solar system was formed. It is true that in the highly untypical environment of the earth free hydrogen is not found in great abundance because it is not easily retained by earth gravity. But there is a lot in various molecular forms.
The early atmosphere of the earth had to be reducing, and methane and ammonia might have been quite high in abundance. We could not have had much oxygen, because it would not have allowed the conglomerations of molecules necessary for initiating life.
Oxygen in our atmosphere was created when early life became active and photosynthesis started. Some questions do remain about how we came to have so much water, not because we are worried about paucity of hydrogen in the original mix from which the solar system coalesced.
There must have been a great deal of water vapour in the atmosphere, lot of it coming from intense volcanic activity; however it could not have condensed on to the surface in early hot stage of the planet.
On the other hand it is also believed that much of the water on earth could have been brought through the intense bombardment of planet by comets in early history of the solar system — it is known that comets are primarily "dirty" snowballs.
It is possible that much of the water vapour produced in early history of the earth and other planets was pushed out by solar wind and radiation pressure towards the edges of the solar system where, combining with interplanetary dust, it slowly coagulated into comets! It is interesting that payback of this water might have been done through catastrophic collisions of comets with the earth at a time in its geologic history when it had cooled down sufficiently to retain that water in a liquid state.
I frequently get questions wherein there is a passionate desire to find some connection between stories of mythology, some beliefs of astrology, or some untenable and amusing statements. Sometimes I can give useful answers but on many occasions I am completely floored. Here are a few examples:
"According to the Rigveda, the word Krishna stands for one which attracts every other object into itself, like The Black Hole."I do not think this analogy does any justice to the personality of Krishna or properties of a Black Hole. The problem lies in not distinguishing between different contextual meanings of the word "attracts".
I am also asked to explain why Krishna and Rama were both slightly dark skinned while all their relatives were fair. I cannot give any answer beyond saying that the authors of these creations felt that way and they may not have been violating any laws of genetics.
I have been asked whether the fact that theoretical physicists talk of 10-dimensional space while constructing theories of the universe has not been forestalled by something said briefly in Atharva Veda. I cannot agree. You do not give theories just by making a statement somewhere.
What the space physicists are talking about is part of a mathematical construct wherein they also have to state that six of those dimensions got wound up tightly and do not manifest themselves in our universe. Also they show that various force fields can be described by different modes of vibrations of strings including their harmonics.
The questioner also enquires whether this has anything to do with astrology! Astrology of the present epoch cannot even comprehend these things because they do not function within laws of nature.
Any one who thinks that planets can affect the future of different individuals in trivial matters do not understand gravity leave aside any other laws.
Another query is whether Brahma, Vishnu and Mahesh could be symbols of electrons, protons and neutrons. I believe it would amount to trivialising great philosophical ideas and concepts through forced and superfluous "scientism" of a trivial kind.
Can we watch the movement of the earth and its rotation from any point in space sitting in a spacecraft? How wonderful is, or will be, this scene?
All observed motion is relative. We forget that the earth itself is a space ship. Sitting on it we daily watch the rise and disappearance of star systems, the planets and the moon. If we were living on the moon we would observe the phases of earth very much like phases of the moon from earth. We would also see earth rise and earth set. Such pictures taken from the moon are available.
You must have seen them. We have launched several remote-sensing satellites. They orbit in the north-south direction and take images of the earth.
The direction of the axis of this orbital ring can be considered as fixed in space. Over a period of time we are able to see all parts of the earth because the earth keeps rotating in this ring.
If you continuously watch the train of images
taken by one of these satellites you find that they are not aligned north-south
but in a tilted direction because while satellite is moving north-south the
earth is rotating west to east.