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| SCIENCE TRIBUNE | Thursday, January 17, 2002, Chandigarh, India |
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Gene therapy provides ray of hope World’s first wave energy generator Atmospheric electricity
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Gene therapy provides ray of hope Initially gene therapy was used to correct single genetic defects i.e. monogenic defects like ADA. But with the advent of new techniques like recombinant DNA technology and the availability of wide array of gene cloning techniques it is now being realised that gene therapy has more immediate applications to the acquired diseases such as cancer (transfer of cytokines & interferon genes) and other infectious diseases as well. Gene therapy can involve genetic modifications of cells in a living patient (in vivo gene therapy) or the genetic modifications of cultured cells which are then returned to the patient (ex vivo gene therapy). The genetic modifications can be both at somatic cells i.e. cells other than the reproductive cells (somatic gene therapy) and at germ cells level (germ line gene therapy). The gene therapy has different forms. The traditional approach to gene therapy is where DNA is added to the genome to replace a lost function and can be described as Gene Augmentation Therapy (GAT). Here the foreign gene replaces the product of the defective gene or missing gene but the defective gene itself is not replaced. Another form of gene therapy is called gene replacement therapy (GRT). In GRT the defective gene is replaced with the normal gene. This form of therapy is quite difficult because the gene instead of getting incorporated at a specific site with in the genome gets randomly incorporated causing inactivation of certain other celular genes. The focus nowadays therefore, is on Gene Augmentation Therapy (GAT). The transfer of genes to the cells is achieved by using various modes such as viral vectors e.g. adeno and adenoassociated viruses, herpes simplex viruses, receptor based and liposomal based delivery systems. Human gene therapy has wide clinical applications. The major clinical applications of the gene therapy are the correction of various monogenic diseases, management of neurological disorders, symptomatic control of vascular diseases, control of metabolic diseases and in cancers. Some of the genetic disorders curable by gene therapy are systic fibrosis, haemophilia, DMD, fammilial hypercholesterolemia & SCID. A light of hope is also seen in disorders like Alzheimer’s diseases, Cardiovascular Disorders, Parkinsons diseases, cancers and very recently AIDS as well. Other areas where gene therapy is applicable include the delivery of hormones, coagulation factors, anticoagulants and other therapeutic agents. It is believed that gene therapy will be applied to wide range of diseases over the next several years. How much impact gene therapy will have in medical practice in future can not be predicted as only very small segment of patients are treatable by the current existing techniques. The main problems are a) too much involvement of specialised technologies;b) development of efficient genetically engineered vectors and other gene delivery systems; c) the requirement of lot of scientific and medical expertise and above all one is yet to learn about the regulation of genes as well as gene sequences required for stabilisation of a gene when introduced into the genome of a cell. The recent translation of blueprint of life which had involved deciphering billion of strands of DNA will surely have tremendous impact on human gene therapy. One needs to address deeply the problems mentioned above to make gene therapy a successful therapeutic tool in the new millennium. Best of luck to all the medical scientists! |
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World’s first wave energy generator SCIENTISTS have successfully developed the world’s first commercial wave-power station that promises to fulfil a growing need of coastal communities all over the world, especially island, to replace diesel generation with clean indigenous power. Oceans cover about three quarters of earth’s surface and represent a vast natural energy resource in the form of waves. Waves are free and sustainable, created as air blows over the ocean surface. The greater the distances involved, the higher and longer the waves will be. All that is needed is the technology to harness their power, a report in British Commercial News said. Now, with the development of a wave energy generator, from the coast of a beautiful Scottish isle, Islay, waves are being harnessed to feed electricity into United Kingdom’s national grid. Known as Limpet (land-installed marinepowered energy transformer), the system has been developed by an Inverness-based renewable energy company, Wavegen, and Queen’s University, Belfast, Northern Ireland with funding from the European Union. The Limpet device is a half-megawatt commercial wave-energy converter, providing power to the national grid with enough electricity for about 400 homes. It harnesses the Atlantic Ocean waves that pound the Islay coastline with the aid of two basic devices — a collector chamber to capture the wave energy, and a turbo generator to transform its power into electricity. The wave-energy collector is in the form of a partially submerged shell into which seawater is free to enter and leave. External wave action causes the water level in the collector to oscillate. As the water enters or leaves, the level of water in the collector chamber also rises or falls in. The turbo generator then comes into play making use of Wells turbines. These have the “unique property of turning in the same direction regardless of which way the air is flowing across the turbine blades,” says Wavegen. Thus, the turbines continue turning on both the rise and fall of wave levels in the collector chamber, the report said. The turbine drives the generator which converts this power into electricity. The system has been developed after 20 years of collaborative academic research and 10 years after Queen’s University Belfast (QUB) installed a small research wave-energy station on Islay in 1990. The successfull operation of this plant led to the Limpet project. The air turbine is simple and highly reliable said Wavegen. Construction and installation are easy, there no marine operations, all electrical equipment is on land, and there is “maximum local content.” Furthermore,
maintenance is minimal. The system is designed to operate right on the shoreline. Alternatively, units may be incorporated in rubble mounds or breakwaters to provide self-financing coastal protection schemes, providing power or potable water to communities.
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Atmospheric electricity IT is the man’s elementary approach to explore the nature. From the ancient times, man studied nature and natural phenomena and reached certain conclusions, some of which were correct some were not. The lightning is one such phenomenon that occurs in spectacular fashion during the monsoon season. The flash of lightning is so brilliant and thunder that follows it so loud that no one can ignore it. Lightning causes the majority of the world’s forest fires, it causes building fires, burns out electrical appliances, disrupts telephone service, interferes with radio communications etc. Lightning burns are exceptionally life threatening, lightning can kill a living being. The study of such a spectacular phenomenon is quite fascinating partly because much of the time most of us are unaware of it. Lightning is the phenomenon, which accompanies the discharge of atmospheric charges from cloud to cloud, and cloud to the earth. The clouds get charged due to air friction, cosmic radiations and solar radiations. So the total positive charge collects at the bottom and negative charge collects at the top of the cloud. This charge on the cloud goes on increasing up to 20 C to 30 C and hence the potential difference between the cloud and the ground is of the order of 2x107 to 108 volts. This creates the electric field of strength 104 v/m to 3x104 v/m in the downward direction. This high electric field is sufficient for the dielectric breakdown of the moist air and hence the air between the cloud and the ground becomes conducting providing the path for the charges to neutralise each other. As lightning seeks the path of least resistance, it naturally tends to follow the shortest course between cloud and earth, such as buildings or towering projections. During each lightning stroke about 100 — 300 KA current flows between the cloud and ground. This very high current produces very much heating according to Joule’s Heating Effect of Current (I2Rt). A lightning stroke begins with a faint pre-discharge, called the leader, which goes from the cloud to the ground. The leader establishes a path for the highly luminous return stroke (what we really see) that propagates from the ground up to the cloud. The first stroke of a flash is usually preceded by a “stepped leader”, so called because it appears to progress in discrete steps (about 100 segments, each 50 m long) from cloud to ground. Thunder is formed from the shock wave formed by the rapid heating of the air along the path of the return stroke, which reaches some 30,000 degrees K. The sound of thunder varies depending on how far you are from the various parts of the stroke. The sound from a part of the stroke farther away will get to you later and be fainter. Positive electrical charges gather in the clouds and negative charges gather in the ground. When the attraction between these two charges is strong enough, they come together in the form of lightning. Statistical data shows that men are struck by lightning four times more often than women. It is suggested that either lightning is attracted to testosterone, or men spend an inordinate amount of time outdoors. Most doctors are more familiar with electrical shocks, such as those received by industrial workers when they have an accidental run-in with high-voltage equipment. But lightning injuries are not the same as electrical shocks. For one thing, the contact voltage of a typical industrial electrical shock is 20 to 63 kilovolts, while a lightning strike delivers about 300 kilovolts. Industrial shocks rarely last longer than half a second (500 milliseconds) because a circuit breaker opens or the person is thrown far from the live conductor. Lightning strikes have an even shorter duration, only lasting up to a few milliseconds. Most of the current from a lightning strike passes over the surface of the body in a process called “external flashover.” Both industrial shocks and lightning strikes result in deep burns at point of contact — for industry the points of contact are usually on the upper limbs, hands and wrists, while for lightning they are mostly on the head, neck and shoulders. Industrial shock victims sometimes exhibit deep tissue destruction along the entire current path, while lightning victims’ burns seem to center at the entry and exit points. Both industrial shock and lightning victims may be injured from falling down or being thrown, and the leading cause of immediate death for both is cardiac or cardiopulmonary arrest. To avoid being struck by lightning, one should seek shelter when he hears even the faintest thunder. Some of the best places to take refuge are enclosed buildings, or cars and buses (but don’t touch the metal!). In case there are no safe spaces nearby, bend into a crouching position until there is a break in the storm. Isolated trees, telephone booths, and open structures like porches make poor lightning shelters. If there is a tall object nearby, move as far away as possible — at least 2 meters (7 ft). Standing next to tall isolated objects like poles or towers makes you vulnerable to secondary discharges coming off those objects. The lightning conductor, which is pointed edge conductor fixed at the top of buildings and towers connected to a thick copper wire. The wire runs downside the building and ends on the metal plate buried in the ground. When the charged cloud passes over the building the opposite charge induced on the pointed edges of the lightning conductor. This opposite charge neutralise the charge on the cloud, if lightning stroke occurs then it prefers to pass through the lightning conductor to the earth without damaging the building. |
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NEW PRODUCTS & DISCOVERIES
Self-cleaning windows Wouldn’t it be great if you never had to clean the windows in your house again? That’s the promise of SunClean glass, which is lined with a transparent coating that breaks down dirt (and bird droppings) in the sun. When it rains or you spray the windows with a hose, the remaining residue is supposed to wash away without streaking. Available on a variety of window types for the home, the SunClean technology also works on insulated glass that blocks ultraviolet light. To learn more: www.ppgsunclean.com Five: Optimum number
for digits British researchers have discovered, by studying mice, that five is the optimum number of digits in an animal as digits more than five dramatically affect their ability to catch prey and flee form predators. “It seems that five is the maximum,” says Chris Hayes, who studies abnormal mice at the Medical Research Council’s Mouse Genome Centre in Harwell,Oxfordshire. “The growth of other limb bones is compromised to accommodate any extra digits,” he says adding if animals grow more than five digits, their other limb bones get distorted to such an extent that they can not walk or run properly, thereby affecting their ability to catch prey and flee from predators. Hayes has found that extra digits stress the limbs of mice so much that they are forced to grow in an arc instead of a straight line, a report in New Scientist said.
PTI Faster data transfer Scientists are developing optical switches, devices which would overcome the need to convert optical signals into electrical signals and vice-versa, thereby greatly enhancing the speed of data transfer. Although the long-distance operator has long since disappeared from the telephone service — superceded first by electrical relays and then by electronic circuits — and new technologies such as fibre-optics cables enable swelling volumes of data to be transmitted around the globe at ever increasing speed, the networks still use the old, slow switching elements. At these switching elements, optical signals are converted into electrical signals before being switched and are then converted back into optical signals for their onward journey over the next section of optical cable. Since data transfer could be much faster if the optical signals were switched directly, without conversion, the Fraunhofer Institute for Silicon Technology ISIT is targeting this market with its microsystem solution, a report in Fraunhofer Gesellschaft said. “The operational reliability of optical switches depends primarily on the precision of the manufacturing process,” points out Ulrich Hoffman of the ISIT. “You have to realise that each single optical switching matrix consists of several hundred or even thousand mirrors, each measuring no more than one millimetre in diametre. And each of these mirrors must be able to variably reflect incoming laser light very precisely into a specific glass fibre,” Ulrich says.
PTI New Generation
Computer mouse Scientists have developed a new generation of computer mouse which no longer needs to have physical contact with a pad or other flat surface and which is completely sealed thereby extending its use even in dusty or damp rooms. Roller bearing and wheels and axles of traditional cursors had to be regularly cleaned. But these regular cleaning exercises would not be necessary in case of the “accelerator mouse” — the new generation of plastic rodents has been given this name because their mechanical “feet” have been replaced by acceleration sensors.
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Science & Technology crossword — 2 Clues: Across
1. An equipment for faster construction. 6. Agency for International aviation. (abbr). 8. He did commendable work on plasticity of clay. 9. A lightweight material. 12. Term for notice inviting tenders. 13. A water-tight structure sunk for laying foundation under water. 14. Plasticity index (abbr). 16........ buckle, a device for tightly connecting parts. 18. Provide this if steel bars are short in length. 19. International system for units of measurement. 20. Prevalent design method.
Down
1. A hard white substance found as flint or quartz. 2. A term used in telecommunication technology. 3. Indicates presence of voids. 4. An important beam of an RCC roof. 5. Dealing with waste and refuse disposal. 7. Add retarders to concrete to delay this. 9. A fellow of Institution of Engineers. 10. Dark hard substance used in roads. 11. Having moisture. 15. Unique organisation working for an accident free society (abbr). 16. Conduct this before using a material. 17. A method of construction planning. Solution to last week’s crossword:
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THE recombinant DNA revolution has equipped the medical fraternity with many new approaches in the fight against human diseases. One such approach is gene therapy which has progressed from speculations to reality within a decade. Gene therapy is now emerging as a powerful concept in the treatment of diseases though it is still in an experimental phase. Gene therapy involves the therapeutic use of DNA to alleviate diseases. The first attempt of gene therapy in human being was made in 1980 in the USA when the cloned ß globin gene was used to treat two patients of thalassaemia. This attempt however proved quite unsuccessful and thereafter many serious conceptual, technical and ethical problems emerged. Later, the first federally approved gene therapy was performed on September 14, 1990 which involved transfer of the gene for the enzyme adenosine deaminase (ADA) into the lymphocytes of patients having this enzyme deficiency which ultimately leads to immune deficiency in such patients. 
