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Bionic arm (Photo: CSIO) Artificial
kidney Prof Yash
Pal THIS UNIVERSE |
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Bionics comes of age Bionics is an amalgamated science of biology and electronics. We are all electrically charged in nature. Millions of cells in our body behave like tiny batteries carrying nearly a power of 20 per cent that of normal AA battery (30 mw appx). Body cells communicate with each other by electrical signals like microprocessor and proteins move in and out of cells under the influence of electrical connectivity. If we introduce electrical charge into our body in a targeted manner we can influence the way the body works at a molecular level. So, we can stimulate our nerves and muscles to make them work and thus we can achieve its infinite possibilities. The idea of bionics means something wonderful — doctors will be able to replace broken body parts with prosthesis that can work similar as real body parts. Today in electronics world under the umbrella of medical science, prosthesis has emerged as a new technology to make artificial replacement for missing body parts like a substitute hand, leg, eye or joint structure. The environment of our body is moist, salty and osmotic. Due to new invention in bio-materials and implants, we have a huge range of body parts that can sustain with our bodily system. Many early implants caused the body’s immune system to react producing inflammation and mismatch. With new discovery, we have bio-compatible materials to get established within a human or other organism without the material being damaged or causing damage. Table-1.1 and 1.2 enlist bio-medical devices and materials. From bionic eyes and ears to kidneys and spines, a surge of activities around the world has created huge advances in medical bionics during last decade. More recently, doctors have been able to reduce the tremor in Parkinson’s patients using deep brain stimulation technique. Under the detect of nanotechnology and nano carbon tubes (one by 40,000 times thinner than a human hair), an electrode is inserted deep in the brain to provide stimuli. Now the development of bionic has crossed the border of international boundaries and even in Indian Council of Scientific-Industrial Research Organisations, such a limb has been developed under a science and technology network programme of the Government of India. The developed prostheses also connect directly to thought and have feedback to have a sense of touch and feeling. The researchers at Vanderbilt University, USA, have developed a prototype bionic arm which combines a mechanical prosthesis with a miniature rocket motor used by space shuttle in orbit. It weighs same as real arm and very close in function with a wrist that twists and bends the finger and thumb that open and close independently. A power source pencil battery contains a catalyst that causes hydrogen peroxide to burn producing steam to open and close valves that work the arm’s joint. Other researchers in Virginia University, USA have regenerated torn ligaments in the knees of rabbits by building a synthetic scaffold seeded with ligament cells. Doctors at the Australian Bionic eye foundation (Prince of Wales Hospital, Sydney) have restored visual sensation in patients by surgically placing miniature electrodes over the outer surface of the eye or on the surface of the brain’s visual area. Here the patient wears a camera mounted on a pair of glasses and the images taken are processed by a microcontroller, which translates images into electrical stimuli. When such stimuli are transmitted to the electrode this causes the patient to see a matrix of small spots of light representing the shape and size. According to an Indian doctor Vivek Choudhary working in the said Prince of Wales Hospital, Sydney, this prosthesis will enable the challenged retarded people to locate doorways or large objects in their visual field area to navigate and increase their mobility. The other researchers in the US, Germany and Belgium are placing the optical electrodes in the retina itself. At the university of Southern California, retinal implants have enabled patients to see light, movement and shapes. The device comprises 16 electrodes. High resolution implants containing hundreds of electrodes can restore sight for people with age related blindness as stated by Professor Shephard of the institute. Amazing technology developed in United States can enable physically impaired people to control the lights, TV, mobiles etc through the power of thought itself. The brain gate system utilises cybernetics technology to analyse and apply the language of enurons or nerve cells. A sensor implanted in the brain analyses EEG waves, which are still generated even if these are not transmitted to the arms or legs in quadriplegics. Such signals are translated into cursor movements through a microprocessor. — The writer is from
CSIO, Chandigarh
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Scientists and technologists are working actively to enable people to control prostheses-wheel chairs with their brain signals. Paralytic challenged people will also be stimulated to control breathing, bowel movements and bladder. Another team is also engaged over an innovative treatment for depression that uses techniques developed in deep brain stimulation and artificial hippo campus — the area of the brain responsible for new memories, mood, feelings and awareness. A semiconductor based silicon integrated circuit chip can replicate the activities of damaged brain stimuli. Human cells are under trial and it holds definite hopes for such patients who are suffering from Parkinson’s disease, Alzhemier’s or stroke. Group of medical scientists in Indian IIT’s are collaborating with All India Institute of Medical Science, New Delhi, Post graduate institute and medical research centre, Chandigarh and U.S. universities to develop bionic kidney that will do away with the need for the lifetime dialysis or a transplant for the welfare of millions of people worldwide with end stage renal failure and hephrological diseases. The artificial kidney or human nephron filter sits inside two membranes. These emulate the function of kidney, filtering toxic substances from the blood while maintaining the water and salt balance by reabsorbing required salts and other nutrients. Nanotechnology based atom size membrane pores control what passes through it with high accuracy and resolution. Wastes filtered out from the membranes are discarded along with urine into an external bag retaining the nutrients, salt and calcium inside the body itself. Initially the device size will be bigger but bearable. After the use of new biomaterials and nano carbon tubes, the size of kidney will be reduced enough to be implanted keeping cohesion with our biological system and body. Nanotechnology allows doctors to create tiny nanotubes to build a scaffold along which nerves can grow. Using the intelligent polymers, one can deliver the right combination of growth and inhibition factors to get the nerves to join up with the ones below. It means not only the feelings can be restored but brain messages will also travel down. The new nerves and newly damaged spinal cord can be repaired if the body found in receptive condition. —
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THIS UNIVERSE 1. I understand why boiling point increases with increase in atmospheric pressure but I’m not able to visualise and link out why melting point decreases with increase in pressure (for water)? 2. A vertical glass jar is filled with water at 10 degrees C. It has one thermometer at the top and other at the bottom. The central region of the jar is gradually cooled. It is found that the bottom thermometer reads 4 degrees C earlier than the top thermometer and the top thermometer reads 0 degrees C earlier than the bottom thermometer. Why? Let me take your first question first. Your main curiosity is “why the melting point of ice should decrease when you apply pressure.” That this happens is experienced by all those who play with ice or snow. You must have seen the demonstration that a steel wire loop draped over an ice block and loaded with a weight hanging below can cut through the block sealing it up as it descends. The ice melts below the wire and the water oozing up freezes back on top. Skaters can glide over ice because the weight of the skater on thin blades of the skates melts a layer of ice that freezes after the skater has passed. You can join two ice cube together just by pushing them together. But your question is “Why is it so”? This happens for water and ice system because ice is lighter than water. There is a general principle that when you apply a force or do something else to a system, the system acts to make your effort superfluous. When you apply force on ice you are trying to make it denser. The denser form of the water - ice system is water. Therefore melting results - or the melting point is lowered .Now let me take your second question. When you start cooling a vertically held cylinder of water in the middle, the cooled water, being denser will begin to descend and warmer water from below will take its place. This convection cooling would go on and after sometime when the bottom layer has cooled to 4 degrees C it will stop moving up because then it is as dense as it can get. Further cooling would produce water that is lighter. If you follow this operation it would be obvious that the bottom will get to 4 degrees first. Further cooling will move it up because it gets lighter. So the top begins to get colder. Ultimately everything might freeze. Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com |
This bionic hand has been developed in Central Scientific Instruments Organisation, Chandigarh by the Bio-medical Group of scientists. Mechanical Electrodes on the arm skin pick up electrical signals from arm muscles and its control system enables the person (whose hand has been amputated during accident/injury) to move each finger individually so he can pick up objects gently and also with precision.
A bionic ear is being used to restore hearing power to the deaf. Even babies deaf by birth below one year age fitted with such a bionic ear can develop normal sense. A microcontroller based miniaturised receiver is implanted inside the skin behind human ear. The audio or radio frequency signal from an antenna and external coil are received through a microphone. This is sent to speech processor which converts sound to an electrical code transmitted through skin to the internal implant. Here the signal is decoded and its requisite amplitude is sent to electrode sitting in the cochlear/internal ear. Nerve endings in the cochlear are stimulated and message is directed to the brain for a meaningful interpretation. Scientists and technologists in India and abroad age now working for improving its performance in noisy environment of more than 60 decibel to extend music appreciation and restore hearing using proteins medically known as nerve factors.
