SCIENCE TRIBUNE Thursday, July 5, 2001, Chandigarh, India

Mobile phones and your health
Pravin Kumar
ESPITE scary and conflicting reports, the only harmful effects that can be positively pinned down, so far, on cellular or mobile phones are behavioural ones, rather than biological: for a car driver, the risk of a collision while using a cell phone is four times higher than while not using it. This makes it as dangerous as driving while drunk. Last February, the Westchester Country Legislature (New York) passed a law prohibiting motorists from talking on hand-held cell phones. Nine countries now have laws relating to hands-free mobile phones.

Energy needs and N-power
D.P. Singh
S major energy sources are becoming exhausted or are recognised as seriously polluting, a new energy source — nuclear power — has become available. The rising fuel costs, concerns about global warming and the growing demand for energy has made nuclear power a sine qua non factor of our life.


  • Cane trash for weed control
  • Biodegradable foams fight fire
  • New treatment for headaches
  • DNA to detect spurious chillies
  • The joy of sticks
  • Biofilm from baker’s yeast




Mobile phones and your health
Pravin Kumar

DESPITE scary and conflicting reports, the only harmful effects that can be positively pinned down, so far, on cellular or mobile phones are behavioural ones, rather than biological: for a car driver, the risk of a collision while using a cell phone is four times higher than while not using it. This makes it as dangerous as driving while drunk. Last February, the Westchester Country Legislature (New York) passed a law prohibiting motorists from talking on hand-held cell phones. Nine countries now have laws relating to hands-free mobile phones.

At least one mobile phone company advises users not to operate their mobile phones at petrol stations or near explosives because of the energy generated by the mobile phones. If you have a car-mounted antenna, you are advised to avoid touching the antenna while making or receiving a call, because the antenna carries a radio signal.

For now, the scientific jury is out on the question of the biological effects of mobile phones. No doubt, in theatres and auditoria, cell-phones can be a nuisance. In planes, they could create false alarms and interference with the aircraft’s radio signals, and cause the aircrew to make mistakes, such as not flying at designated heights — according to a statement made last May by Britain’s Civil Aviation Authority.

On the plus side, more lives have been saved by emergency calls made on cell-phones than have been lost through cell-phone related accidents. In fact, n 1994, the New York Police Department gave mobile phones, all programmed to dial 911, to crime-watch volunteers in 10 dangerous parks.

Numerous warnings have been issued regarding the potential health hazards of cell-phones. These range from headache, noise in the ears and stress to more scary reports of memory loss, DNA (genetic) damaged and malignant brain tumours. In 1993, a Florida (USA) resident filed a lawsuit against a local cell-phone company, alleging that his spouse died from a brain tumour caused by cell-phone use. But studies by various groups found no evidence of direct harm due to cell-phone use. However, The Times (London) reported on December 20, 2000, that Vodaphone, the world’s biggest mobile phone company, faced up to 10 compensation claims as a result of lawsuits launched by Pewter Angelos, one of America’s most successful lawyers. In each action, Angelos intends to claim compensation for the pain suffered by brain-tumour patients, plus loss of income due to the disease. Interestingly, a pioneering study in Denmark, published in the Journal of the National Cancer Institute (USA), while ruling out any increased cancer risk due to cell-phone use, failed to exclude other diseases like Alzheimer’s and various types of nervous complaints.

However, mobile phone use was unlikely to cause cancer or any other disease: this was the conclusion arrived at by a study by the Independent Expert Group on Mobile Phones, published in The Lancet of May 11, 2000. The report cautioned that children should be discouraged from using mobile phones for “non-essential calls”. Colin Blakemore, a co-author of the report, explained the cautionary approach as being warranted by the fact that, in children, the brain is smaller and still developing, the skull is thinner and there is a longer potential exposure time to electro-magnetic frequency waves (see “Box”). The report highlights the need for more epidemiological studies. Blakemore wanted a clear message to be sent to the industry that they should not continue to market mobile phones, especially to young children “until more research is done”.

Research carried out at the University of Essen (Germany), and published in the journal Epidemiology suggests that there is a three-fold increase in an eye cancer called uveal melanoma in people who regularly use cell-phones. In this disease, tumours form in the layer that makes up the iris and the base of the retina. Since the eye is not fully protected by the skull, its liquid components could absorb the cell-phone radiation. Dr Andreas Stang, who led the research team cautioned that the study needed confirmation.

Two other important studies are also in progress — one in the UK and the other in Sweden. However, given the rapid spread of cell-phone use, such studies would be hamstrung in finding enough non-users (what researchers call “controls”) for comparison purposes. The number of mobile-phone users world wide is expected to exceed 450 million this year. In India, the number reached 3.7 million by April-end — a growth of 88.7 per cent over the previous year, according to the Cellular Operators Association of India.

Hands-free kits

For motorists, even hands-free kits may not be the solution. They were believed to protect drivers who risk warming their brains by holding mobile phones close to their heads. One hands-free set (Jabran Ear-set) is claimed to keep phone radiation at a safe distance from the user’s head: a fixed sensitive microphone points directly at his mouth and soft ear-phones provide a near-custom fit in the outside ear. The user can still hear outside sounds — ideal for safe driving. But, last year, “which?,” the British consumer research group, reported that hands-free mobile kits could more than triple the brain’s exposure, compared to conventional mobile phones. At least nine countries — Australia, Brazil, England, Italy, Israel, Malaysia, Singapore, South Africa and Switzerland — have laws relating to hands-free kits. The Cellular Telecommunication Industry Association (CTIA) — the $ 200-billion-a-year industry association — is against legislation because there are not enough data to pinpoint hands-free kits as the right solution. The CTIA also maintains that “there is no convincing evidence that electromagnetic frequency waves induced or promote cancer”.

The regulations governing human exposure to microwaves emitted by mobile phones are solely concerned with the radiation heating effects. However, a study by David de Pomerai of the University of Nottingham (UK), published in the scientific journal Nature (Vol 405:417-18) suggests that there may be non-thermal effects as well. The nematode (worn) Caenorhabditis elegans, when exposed to microwave radiation, produced certain proteins which are attributed to non-heating effects. One expert (Alan Preece of the Bristol Oncology Centre, UK) said he would like to see this effect investigated further.

The fracas over cell-phone hazards has driven an emerging market for devices that manufacturers say will shield users from electromagnetic waves. Three popular ones are:

  • Safeshield, a coin-seized, mesh earpiece that is claimed to absorb more than 95 per cent of the radiation emitted.
  • Less EMF is a line of radiation-shielding products, including phone jackets and earpiece shields. The company claims its devices will ward off headaches, heat sensation near the ear, disorientation and irritability.
  • Zeropa (or Ladybird) is a ceramic device that is attached close to the base of the antenna and protects the user from potentially harmful electromagnetic radiation from cell-phones, pagers and cordless phones.

Critics say that shields actually disturb the transmission of the base antenna, which may thus cause the phone to boost its power in order to keep the phone call connected to the network.

All in all, the whole question of the health effects of cell-phones is still an open one. Says Dr Stanley Kornhauser, president of the National Institute for Electro-medical Information Inc. (USA): “should we take comfort in reports that evidence regarding cell-phone danger is not conclusive, or should we take steps to mitigate or reduce exposure to EMF waves — even if the scientific jury is still out?

Effects of cell-phone radiation

Cell-phones and their base-stations are radios, producing non-ionising radiation, the effects of which are quite different from those caused by ionising radiation generated by X-ray machines and radioactive material. X-rays and gamma rays have enough energy to break chemical bonds, stripping electrons from atoms. This damages the cell’s genetic material and could lead to cancer and other diseases. The effect of non-ionising radiation is mainly heating.

The mobile phone handset converts voice into impulses which are transmitted over radio waves at various frequencies. (Frequency is the rate at which electromagnetic fields change direction, and is measured in hertz (Hz). Mobile phones use frequencies from 800 mega-hertz (800 million cycles per second) to over 1,900 MHz. Radio-frequency energy interacts with molecules, causing them to speed up their movements. This increases friction, raising the temperature. The effect is not cumulative. As in a microwave oven, there is cooling when the electricity is switched off.

The effect of radio-frequency radiation on the body depend on its frequency and power. Microwave ovens use a frequency of 2,450 Hz, while X-rays have a frequency of above one million MHz. The radiation emitted by cell-phones is 1,000 times less than a medical X-ray, with the skin and the skull absorbing half the energy and the rest reaching the brain tissue, where it is converted into heat. Since a mobile phone has a power output of only one watt, any heating effect should be minimal.

Typically, cellular antennas are mounted atop a car’s roof or trunk; an antenna’s operating power is less than three watts. Studies have found that externally mounted antennas are shielded by the car’s metal body, which lowers exposure to passengers. The exposure potential is still more reduced by the intermittent nature of cellular transmission and the improbability that a person would get that close to the antenna. To best control potential exposure, antennas should be mounted in the centre of the car’s roof, or on the trunk, rather than on the back window.



Energy needs and N-power
D.P. Singh

AS major energy sources are becoming exhausted or are recognised as seriously polluting, a new energy source — nuclear power — has become available. The rising fuel costs, concerns about global warming and the growing demand for energy has made nuclear power a sine qua non factor of our life.

Our civilisation and our standard of living depend on an adequate supply of energy. We need energy to cook our foods or to heat/light our homes. It makes long-distance travel and communication possible. Our factories use it to produce the goods that we need.

Until the end of 19th century the world’s energy needs were fulfilled almost wholly from coal and traditional sources, such as wood, animal dung and crop residues. These are still major sources of energy, particularly, in developing countries. Wood and dung are estimated to provide an amount of energy equivalent to one billion tons of oil each year, to about two billion population of developing countries.

During 20th century, the world’s population and commercial output have increased rapidly. This has led to about tenfold increase in energy consumption. The use of new sources of energy such as oil and gas fuels, hydroelectricity and nuclear power has also come into vogue. Today, the per capita consumption of commercial fuels in industrial nations is about 10 times than that in developing world. Energy markets in the industrial countries are maturing, which may even peak and decline with continued improvements in energy efficiency.

On the other hand the energy needs of people in the developing countries are doubling every 15 years. Moreover, their population will soon be 7-10 times greater than that of the industrial world. If we assume that the developing world eventually uses only half of the energy per capita consumed by industrial nations today, even then they will need about 5x106 MW of new electricity generating capacity in the coming decades. It amounts to about five times their present generating capacity. So, the world is in need of more energy, despite the immense amount of energy being consumed at present.

Finding ways of satisfying our energy needs is an urgent problem. We must consider all possible sources and evaluate them objectively. In developing countries wood is still and extensively used energy source. But it is impractical as a major energy source as it occupies much land and adds to atmospheric pollution on burning. Oil is needed by the petrochemical industry and is fast running out. It also adds to pollution on burning. Hydropower though pollution free and renewable yet it uses up valuable land. Bigger dams affect the flora and fauna of their surroundings adversely. The number of rivers with suitable gradient is also limited. It is estimated that hydropower could provide no more than 8 per cent of world’s energy needs.

Power generation using tidal waves is limited by geographical considerations. It is also intermittent in nature. The other sources such as wind, solar and geothermal account for only a few per cent of the global energy consumption. Wind and solar power energy sources had contributed only 0.15 per cent of the world’s energy production in 2000. Wind and solar power generation is unreliable and relatively costly. These energy sources disfigure large areas of land as well. Despite continued efforts, wind and solar energy sources contribute less than 0.5 per cent of our energy production. Thus there is no hope that they can supply for our energy needs.

Coal, however, can act as a major source of energy for at least a few centuries. But, to produce 1 giga-watt year of electricity, a typical coal-fired power station requires about 3.5 million tons of coal. In the process, it emits about 11 million tons of carbon dioxide, 1 million tons of ash, 500 thousand tons of gypsum, 29 thousand tons of nitrous oxide, 21 thousand tons of sludge, 16 thousand tons of sulphur dioxide and one thousand tons of dust and other chemicals such as calcium, potassium, titanium and arsenic etc. Coal-fired power stations produce radioactive pollution also.

All these wastes are poured into the air we breathe and are major sources for causing damage to our health and environment. The continual dependence on coal could lead to widespread environmental damage and unpredictable climate change.

Thus, the only practical substitute for fossil fuels we are left with is nuclear power. It is already in use to generate about 20 per cent of the world’s electricity. Nuclear power stations had generated about 1.9x1012 kwh of electricity in 1988. Nuclear power provides for 50 per cent and 80 per cent of electricity production in Western Europe and France, respectively. UK, Japan and USA are getting about 39 per cent, 32 per cent and 20 per cent of their total energy production from nuclear power, respectively. The total installed capacity of nuclear power generation in India, at present, is around 2250 MW.

Nuclear power has little harmful effect on the environment. As per the report of a commission constituted by the Belgian government, nuclear power is more reliable, safer and less detrimental than the alternatives. It is substantially cheaper as well. Though the use of nuclear power produces nuclear radiations yet the ways and means for their satisfactory containment are well developed.

With the replacement of current “thermal reactors” with “fast reactors” in future, this problem will be further sorted out. Recently, researchers have found that by using spallation neutrons from a proton accelerator, radioactive wastes produced in a nuclear reactor can be completely burnt inside the reactor. “People-bed” reactors are another promising development in this direction.

It is also hoped that fusion energy will ultimately become available. Intensive work is in progress to design fusion reactor. A fusion rector needs deuterium for production of energy. As deuterium is present in water in the proportion of about one part in 5000, so the energy available from these future fusion reactors is likely to be practically limitless.

Thus with rising fuel costs, concerns about the global warming and growing demand of energy from the developing countries, nuclear power is panacea for world’s energy needs.



Cane trash for weed control

SUGARCANE, trash, if left on the field after harvest, impedes the growth of certain noxious plants thereby reducing the need for chemical herbicides, researchers have discovered.

Chemical herbicides often have a control efficiency lower than 90 per cent due to factors such as errors in product specification and preparation, errors in application and equipment adjustment, wind occurrence during application and inadequate air temperature and humidity. Cane residue thus poses as a strong contender to replace chemical herbicides.

A team of scientists led by Celio Manechini of the Copersucar Technology Centre, Brazil, found the distribution and quantities of residue left on field significantly influenced the final weed population in the cane field.

In field trials, researchers used four treatments varying from all residue left on the field to no residues left in the field, a report in Cooperative Sugar said.

The team concluded that residue quantities above 66 per cent of the total controlled annual weeds have efficiencies above 90 per cent and are therefore compatible with most successfully employed herbicide treatments in sugar cane productions.

However, some species of perennial noxious plants that propagate in a vegetative manner are not adequately suppressed by cane residue, the report said.

Scientists said decision to adopt any residue-based weed-control system should be preceded by technical and economical viability analyses of the alternatives. PTI

Biodegradable foams fight fire

With fire fighting foams being held to more stringent environmental standards, scientists have developed two new foams and an additive that are biodegradable.

The three products — Bio Filmpol 3 and Bio Newpol 3S foams and the Bio For C additive — are resistant to thermal shock from fire and cold weather.

The foams are formulated to combat hydrocarbon and solvent fires, and the additive helps fight forest or house fires, a report in Mechanical Engineering said.

When either of the multipurpose foams — developed by Bio-Ex based in Le Havre, France — is applied, it forms a film on hydrocarbons, and creates a thin gel on solvents and acids to prevent the risk of re-ignition or release of gases and toxic fumes. PTI

New treatment for headaches

Researchers have demonstrated a new and successful treatment for headaches linked to C2-3 joint injury — one of the joint near the base of the skull.

Many of the headaches are linked to whiplash in car accidents, sudden falls or head trauma. The sudden jolt from behind whips heads back and forth and puts excess pressure on the neck’s 14 joints, including the C2-3 joint, that connect the skull to the spine.

A team of doctors, at the University of Pennsylvania’s Department of Rehabilitation Medicine, led by Curtis W Slipman in a retrospective study focused on 18 patients who had daily pain.

Under the study, a steroid was injected through a small needle directly into the neck joint’s synovial cavity lining to reduce inflammation, a report in Philadelphia International Medicine News Bureau said.

The result was “almost miraculous for 11 per cent of patients who were completely free of pain afterward,” said Slipman. Another 61 per cent had fewer than three headaches a week that were relieved by common oral pain medicine. PTI

DNA to detect spurious chillies

Scientists have used the DNA fingerprinting technology for the first time to detect spurious chilli seeds that were being sold as seeds of an elite branded variety.

This is the first report of its kind in India where DNA technology has been used to test the identity of the commercially authorised breed, J. Nagaraju of the Centre for DNA fingerprinting and Diagnostics (CDFD) said.

The CDFD scientists have reported their work in a recent issue of Forensic Science International.

Although Nagaraju’s team developed this method specifically to resolve a dispute between two plant breeders, their technology is now available for distinguishing different varieties of chillies on the basis of their genetic fingerprints.

As there were no earlier reports on using DNA analysis in chillies, the CDFD researchers started from scratch. They designed the primers that could hunt certain short DNA segments called Microsatellite Repeats distributed in the chilli genome.

The fingerprinting technology exploits the difference in the number of Microsatellite Repeats between different varieties of chilli. PTI

The joy of sticks

Engineers have taken the notion of replacing car steering wheel and pedals with a joystic a step further and demonstrated its feasibility by building dual ‘force-feedback’ sidesticks into a simulator.

In the new system, developed by Daimler Chrysler, the simulator is equipped with two side sticks coupled by computer logic. The sidesticks are active in transverse axis and isometric in the longitudinal axis. This means that they can only deflect left and right for steering, while acceleration and braking is proportional to the force extended in either pressing forward or pulling back on the stick, a report in Design Engineering said.

The absence of forward-backward motion of the stick allows the clear separation of the steering, acceleration and breaking, resulting in increased steering accuracy.

If the driver does not push or pull on the sidestick, the car maintains a constant speed. Cruise control is automatic, and when the vehicle is at rest the brakes are automatically applied until the next acceleration.

Features like the indicator and horn are activated by push buttons and triggers mounted on the sidestick.

The sidestick differs from steering wheel mainly in terms of rotation. When a steering wheel is turned, the rotation is reduced by a ratio of 1:20, allowing precise movement.

However, sidesticks can only deflect around 20 degree to the left and right, and transmitting this motion directly to the wheels would make the vehicle undrivable at speed.

This, it is the force exerted on the stick, and not the deflection of the stick, that is measured.

The lack of steering wheel also improves access to the vehicle and allows more space for controls and displays.

Studies also show that drivers take around 0.2 seconds to move their foot from the accelerator to the brake. At 30 mph, this adds 3m to the braking distance, and it’s thought that by speeding braking reaction the number of rear-end collisions could be reduced.

Engineers are confident that the concept would take off. Though, they say, the main obstacles would be cost and acceptance. Although, the notion of driving with sidesticks has proven exceptionally popular amongst youngsters. PTI

Biofilm from baker’s yeast

Scientists hope to conquer many fungal and bacterial pathogens with their success in coaxing a harmless fungs, baker’s yeast, to form a biofilm — a way of clinging together for germs which make them resist traditional clinical attack.

Fungal and bacterial pathogens are relatively easy prey for anti-microbial drugs. But many of these germs cling together in resilient sheets and globs called biofilms that resist traditional chemical attack.

But lack of good model system has made fungal biofilms — which frequently contaminate medical devices, cause chronic vaginal infections, and lead to life-threatening systemic infections in people with hobbled immune systems — harder to study.

However, it is predicted that success in biofilm formation would help micobiologists expose vulnerabilities that can be targeted in other pathogenic fungi biofilms, as baker’s yeast (Saccharomyces cerevsiae) has been studied very well and its entire genome has been sequenced, a report in Science said. PTI



1. This Canadian physician shared the 1923 Nobel Prize for making a major breakthrough by extracting the hormone insulin from the pancreas in human body and thus help prolong the lives of patients of diabetes. Name this humanist who, on finding that his assistant who actually worked with him was not selected for the award, passed on half the prize money to him.

2. A recent study has shown that the chemical “allethrin” used in various mosquito repellents in the market such as mat coils and vapourisers can produce a variety of health problems. Can you tell mainly which ones?

3. This common fruit is rich in natural sugar carbohydrates, fibre, proteins, carotene, potassium, calcium, vitamin B and many other trace minerals and enzymes. It has more calories than any other fruit for the same weight. Which is this fruit that is usually taken by players during matches and is recommended as an excellent baby food?

4. QCL is a wonderful outcome of the rapidly emerging nanotechnology which is especially useful for detecting gases in very low concentration. Thus it has applications in detecting toxic gases emitted from industries and waste sites and chemical gases used in warfare, in non-invasive medical diagnosis, in space exploration, etc. What does QCL stand for?

5. Certain crystals such as tourmaline acquire opposite electrical charges on their opposite faces on heating. What is this phenomenon called?

6. The eggs laid by the female of this fish species are carried by the male in its mouth till the young ones are hatched. Thus the male has to do without food for about a month. Which is this fish species?

7. Using a telescope fitted with sensitive light detectors, measuring the intensity of sunlight reflected from the earth to the dark side of the moon has been found to be a good method of studying gradual climate changes taking place on earth. What is the sunlight reflected by the earth called?

8. What is the method of food preservation called in which the bacteria and enzymes responsible for spoiling food are rendered inactive by creating conditions which inhibit their growth and action?

9. “Lycopodium” is a typical plant that grows in south-east India. This medicinal plant is used to heal wounds and to cure urine infection. What is the common name of this plant which is also used for decorative purposes but may become extinct if not protected?

10. We are familiar with moving-coil galvanometer, an instrument used to detect small currents. Do you know who invented it and in which year?


1. Sir Fredrick Grant Banting
2. Breathing, cough, asthma, headache, eye irritation etc.
3. Banana
4. Quantum Cascade Laser
5. Pyroelectricity
6. Catfish
7. Earthshine
8. Bacteriostatic method
9. Fox-tail fern
10. British physicist William Sturgeon.