Lead and health hazards
by Sudhir Dahiya
LEAD is one of those heavy metals which are recently in discussion for health hazards. Lead is present everywhere in environment. We inhale it with air, drinking water and ingest with food. It is a cumulative poison, once it crosses the tolerance limit in body, it causes irreparable damage to various body systems.

Science Quiz
by J. P. Garg

Moulding planets for life
by Sarabjeet Singh

PRESIDENT John F. Kennedy once asked his science advisor: “Can’t you fellows invent some other race, here on Earth, that will do some good?” We have heard the story of Icarus, son of King Daedalus who flew away from prison by the help of wax-feathers. But how about real humans growing feathers and flying up and away? Or men living under the sea just like fishes? Or imagine the planets of the solar system colonised by humans!

We are more or less reaching a stage where we will be able to alter the human architecture with rapidly advancing science of genetic engineering (the tool we will use to reshape every living thing).

If the Dolly scientists claim today that they can clone human beings, then someone else could work out miracles tomorrow. Yes, the concept of ‘Pantropy’, meaning “to change every thing”, introduced by James Blish could not be rejected at any cost.

In this infinite universe our earth is a cradle of life and man can’t live here forever. Further, we must take it for granted that our population explosion is going to prove more serious than any other explosion. And as the old saying goes necessity is the mother of invention. We will be forced to find a way to create more space to live..... of course on other worlds.

On earth adapting people for life in sea might not be so difficult if the adapted men had to stay Perpetually below the surface. Experiments with “water-breathing” mice have suggested that lungs might fairly be modified to extract Oxygen from water instead of from air.

But the real extravagance of human engineering lies in moulding men for life on other worlds. Like aquatic man, the flying man too could exist..... but more plausibly on a light-gravity planet.

There are only two general strategies for colonising other planets. We could alter ourselves to fit the planent (Pantropy) or we could alter the planet to fit ourselves (Terraforming).

According to Prof Philip Morrison, there are 100 million “cold planets” suitable for life within our own galaxy. But the chance of locating (and reaching) an earth-like planet perfectly comfortable for human life that we could simply step on to it is very low.

Venus is shrouded in thick clouds with the height of atmosphere upto 60 km, which causes surface pressure (atmospheric) 90 times than on earth. Further, it has a mean surface temperature of 371°C and any life that might exist there at all would have to lead an airborne existence in the cooler upper layers of venusian atmosphere. A man who landed on its surface would first be crushed, then eaten by acid and slowly burned to a crisp. And it is upto our capability and taste as to what extent we want to alter ourselves. If you want to become a monopoly king of the “evening star” and lead a peaceful (?) life there you must at least have a thick, hard and heat-insulating skin, which could not be damaged by rains of sulphuric acid. Plus a pair of artificial lungs.

Frederik Pohl seriously considers the notion of adapting a man by surgery and the use of artificial organs, to life in extremely hostile environment of mars which has a mean surface temperature of —37°C and escape velocity 5 km sec.

Pantropy will allow us to do anything to achieve the target. It may be hybridisation of man and machine, of man and animal or of man, machine and animals. Medical science is working hard to successfully transplant animal organs into human bodies and to get positive results. There are people with pacemakers and even whose bodies have been fitted, with permanent teflon sockets, called “scribner Shunts” so that they may literally plug themselves into their kidney machines. Don’t you smell “Pantropy” coming? No one has yet had a healthy arm removed so that a more capable prosthetic one can be fitted; but if there should come a day when artificial fingers are more dexterous than real ones, that might become a condition of employment for certain jobs.

The celebrated British biologist JBS Haldane, who first wrote about the possibilities of human engineering in 1924, suggested that political parties might one day fight an election over the proposal to equip the next generation of nation’s children with tails!

This all may seem horrible but the principle of altering the planet is a good one and ethically comfortable.

Besides Mars and Venus, our moon and several of Jupiter’s moon are on the hit list.

Astronomer Carl Sagan has suggested terraforming Venus by seeding its atmosphere with 1000 rocket-loads of blue green algae, which would release O2 from carbondioxide. Everything depends on how fast these algae would multiply before sinking to be destroyed by the heat below. An oxygen rich atmosphere on Venus might be created in years rather than in centuries if initial population of algae is very large. Then Venus would become cooler and whatever amount of water exists in its atmosphere would fall as rain forming shallow lakes.

Mars is much more difficult to work upon due to little atmosphere. It would first be warmed up by sprinkling it with dark dust (perhaps mined from its moon) which will absorb much more heat. Giant orbiting mirrors could reflect more sunlight in the frozen CO2 ice caps to cause greenhouse effect.

With unlimited thermonuclear power Mars could be moved in orbit closer to Sun thus making it warmer. Oxygen could be released from the rocks and ice brought from the asteroid belt. In a similar way, asteroids and moons of the outer planets could be shifted to positions around the swing of Earth’s Orbit and converted into small self-contained planets.

Terraformed planets and moons will not only need people; they will need animals, trees, fishes, grains and bacteria.

It would not be appropriate to reject terraforming as a wild dream. We need to know how successfully we have unconsciously terraformed our own planet. We have increased the amount of atmospheric carbon dioxide, reduced the water table producing heavy ground subsisdence, deforested much of Earth, our deserts are advancing (the Sahara) by 40 km a year.

Lead and health hazards
by Sudhir Dahiya

LEAD is one of those heavy metals which are recently in discussion for health hazards. Lead is present everywhere in environment. We inhale it with air, drinking water and ingest with food. It is a cumulative poison, once it crosses the tolerance limit in body, it causes irreparable damage to various body systems.

Chemically it is represented by Pb. It has bluish white colour and gives bright lustre. In earth crust, it exists as lead sulphide, lead carbonate and lead chloride forms. Galena is its major ore and about 90 per cent of the total lead is extracted from it alone. Organic forms of lead are more hazardous than inorganic forms. Earth crust contains about 0.00002 per cent of lead. According to WHO its safe limit in drinking water is 0.01 ppm, but the ICMR has permitted upto 0.1 ppm. Volcanic eruptions are major natural contributors of lead pollution. Man-made sources include metal smelters, beverages, coal burning, packed food, mining, paints, ointments and gasoline. The major culprit among all is leaded petrol which is responsible for more than 65 per cent of total lead pollution. The leaded gasoline used in Indian subcontinent contains 0.572 to 0.64 gm lead per litre. Because of regular use of leaded petrol in India the lead concentration is much higher in India than in a developed country. In India blood lead level of a common man is 4 to 5 times higher than resident of any developed country. Other lead pollution causing sources are drinking water and meat products. According to a recent research report all the locally made toffees and chocolates also contain a high percentage of lead.

Everything, whether plants or soil, near a highway has higher concentration of lead. Various vegetables such as lettuce, spinach, potato, beans, carrots and turnips, when grown near national highways have three to four times more lead than the permitted limit. Other major source of lead pollution in a developing nation like India is the metal processing waste imported from developed nations. Several developed countries are using India as a dumping site and annually exporting million of tonnes of this waste containing lead. Countries and quantity of lead-containing metal processing wastes exported to Indian are given below.

Lead exposure causes weight loss, constipation, abdominal pain, teeth loss, decline in bone marrow, blood pressure, damage to liver and kidney. Chronic exposure to lead affects nervous system which may result in coma and death. Lead is more harmful for children and pregnant women. Lead exposure to children is mainly from ingestion of wall paints, chewing of toys and toffees etc. Children’s exposure to these may cause mental retardation, physical abnormalities, decrease in attention spans and IQs and hearing. Blood level from 0.8 to 1.8 ug per litre may cause death in children of age below seven. Lead toxicity may result in pregnancy wastage in women. Lead replaces calcium of bones and in old age it creates acute problems for survival of man.

Prevention of lead exposure is strongly advocated by environmentalists, toxicologist and medicos as there is no specific treatment for lead poisoning. Lead exposure can be controlled by adopting the following precautions.

*Use unleaded petrol. If it is not available till its availability the lead concentration in gasoline should be decreased.

* Use of leaded petrol driven vehicles in densely populated areas should be discouraged.

* Check ingestion of wall paints, soil, toys and locally made toffees by children.

* Avoid use of municipal sewage sludge as manure without proper treatment.

* Make the masses aware about lead pollution and its health hazards.

Science Quiz
by J. P. Garg

1.What is the general term used for objects such as bullets, bombs, missiles etc. which are fired from a gun, an aircraft or a launcher and move under the combined effect of a uniform horizontal motion and a non-uniform vertical motion under gravity?

2. What is the study of the motion of such objects called? Which are the three branches of this study?

3. Missiles that aim to destroy installations like air bases, bridges, ammunition depots etc located in enemy’s territory are called strategic missiles. What are the missiles used in the battlefield to destroy enemy tanks, aircraft, submarines etc. called?

4. What general name given to bombs, rockets missiles etc. which hit a selected target with pin-point accuracy?

5. Name the gun that can fire very rapidly and whose speed and elevation can be adjusted quickly.By which war item are these guns being replaced now?

6. Apart from the use of mechanical instruments of war like guns, mortar, tanks, aircraft, submarines etc., modern warfare involves the use of radio and radar waves, microwaves, laser beams etc. What is this invisible “battle of beams” called?

7. What purpose do the remotely controlled or automatically controlled pilotless aircraft, which follow a prescribed path, serve in war?

8. Unexploded bombs or ordnance have to be quickly and efficiently neutralised after the defeated enemy has left the battlefield. This is done by the use of HDCs. What is the full form of HDC?

9. What general name is given to the defensive equipment used for protection of soldiers and war vehicles in warfare?

10. A chemical weapon that has been used in wars in the past is mustard gas. It is filled in the shells in liquid form and the shells are fired on the enemy. The gas causes irritation and swelling of eyes, produces blisters on the skin and affects the lungs, besides producing other long-term harmful effects. What is this gas chemically?

ANSWERS

1. Projectiles 2. Ballistics; interior ballistics, exterior ballistics and terminal ballistics 3. Tactical missiles 4. Precision guided ammunition 5. Anti-aircraft gun; surface-to-air missiles 6. Electronic or electromagnetic warfare 7. To assess enemy’s strength, fortifications etc. , called reconnaissance mission 8. Heavy Destruction Charges 9. Armour 10. Dichloroethyl sulphide (it has nothing to do with mustard, except smelling like mustard oil when in high concentration).

Watch that runs on body heat
Looking for a hot time? The Seiko Thermic is the first watch powered by body heat, which it converts into electrical energy. Extra power is diverted to a storage cell that keeps the watch ticking for as long as 10 months, even while it’s off your wrist. When you doff the watch, the second hand moves in a direction that indicates how much power is left. Price: approximately $ 2,600. (Popular Science)

Faster gene tailoring
Corn that resists pesticides and herbicides. Soybeans that are heart-healthy like olive oil. Coffee beans that do not need to have caffeine removed because they are genetically programmed to grow with less caffeine.

All are possibilities from a new gene-altering technique known as chimeraplasty, billed as a potential treatment for up to 80 per cent of human genetic diseases, but also showing promise in plants, reports AP.

The technique could lead to more accurate modifications to crops and faster delivery of new seeds to farmers while also alleviating some of the problems associated with genetically altered crops, researchers say.

“It’s going to be much faster, first for the farms to see a benefit and then the consumers to see a benefit,” said Charles J Arntzen, president of the Boyce Thompson Institute for Plant Research at Cornell University in New York.

Arntzen conducted the research on corn with Kimeragen Inc. of Philadelphia and Pioneer Hi-Bred International of lowa. Two articles on the research were published in the Proceedings of the National Academy of Sciences.

Combating drug addiction
Krench scientists have discovered a substance that could combat addiction to cocaine, AFP reports.

A molecule dubbed BP 897 by the researchers binds to a receptor in the brain and limits the transmission of dopamine, a substance which promotes the sensation of pleasure and whose effect is enhanced by cocaine.

The result is to diminish the expectation of pleasure from taking more cocaine, triggered by a stimulus such as the sigh of white power.

The scientists, led by Pierre Sokoloff, who discovered the receptor ten years ago, conditioned addicted rats to associate a light with the availability of cocaine.

If given BP 897 before the light was turned on, the rats showed a decreased interest in the cocaine fix.