The wondrous world of science

PROF ATTA-UR-RAHMAN

‘Immortal’ human cells

Is it possible for the cells that make up your body to continue to live and proliferate long after you have died? Indeed it is! One striking example is that of ‘HeLa’ cells, so named because they were taken from the cervix of a 31-year-old African-American lady, Henrietta Lacks in 1951 without her permission when she died of cervical cancer. These cells are still ‘alive and kicking’ today.

Some 50 million metric tons of the living cells have been produced in laboratories all over the world, and over 60,000 studies using them published on a wide range of such topics as ageing, cancer, cellular effects of working in sewers and mosquito mating.

What is so special about these cells is that they multiply abnormally rapidly, as compared to other cancer cells, which makes them very useful in research. The children of Henrietta Lacks first received the shocking news that their mother was ‘alive’ in the form of these cells in 1973. By then the HeLa cells had been taken to outer space and spread worldwide, even contaminating many experiments as far as Russia, because of their extraordinary proliferation abilities. Henrietta Lacks lives on in the form of her living body cells. Her ‘HeLa’ cells continue to benefit virology, biotechnology and medical research.

Energy from the sun

The sun bathes our plant with a huge amount of energy, about 85,000 terawatts, each year. Our annual consumption of energy, by comparison, is only about 16 terawatts. This means that the sun provides about 5,000 times more energy than the world needs today. It seems silly, therefore, that we are polluting our planet by burning fossil fuels whereas so much abundant energy from the sun is largely going waste. This situation is now beginning to change rapidly and new technologies are emerging that Pakistan needs to make use of.

Solar cells are normally made of silicon wafers. These crystalline materials have achieved a commercial efficiency of 22 percent but the solar panels made from them are expensive, and largely suitable for remote areas where the grid system cannot provide cheaper electricity. Thin-film solar cells, produced from amorphous, nanocrystalline and some other forms of silicon by chemical vapour deposition, have efficiencies of about nine percent, but they can be produced at one-fifth the costs and their efficiencies are improving rapidly.

However, the most attractive form of solar energy involves the simple use of thousands of mirrors that can focus the energy of the sun on boilers located on

towers. The steam generated by this energy from this ‘Concentrating solar power’ (CST) technology is heated to a temperature of up to 850ºF, and used to drive turbines that generate electricity. Google has funded a five-megawatt facility near Los Angeles that involves 24,000 mirrors arranged in arrays on 20 acres of land. They are controlled by computers that focus the sun light on to the boilers. It is expected that the use of CST technology will double every 16 months worldwide, increasing from 457 megawatts in 2007 to 6,400 megawatts by 2012. Pakistan has abundant sunshine and an acute shortage of electricity. All we require is a vision and a determination to act.

Wind energy — from the oceans

You would have noticed when you visited the sea side that usually there is a strong wind blowing. The sea can, therefore, be an excellent choice for installing floating wind mills for several reasons. The wind speeds are generally greater than on land, floating wind mills do not consume valuable land that can be used for agriculture or construction, and they do not bother residents unhappy with wind farms blocking their views.

The new technology has been applied on the sea about six miles off the coast of Norway.

This has resulted in the installation of a 2.3 megawatt turbine, weighing 152 tons, on a floating platform which is tied to the ocean floor by cables to avoid excessive turbulence. The project, ‘Hywind’, has been implemented by the Norwegian energy giant Statoil, and the first floating wind turbine was installed in September last year.

It will be tested over a two-year period and then commercial floating wind farms will be installed on oceans.

The world energy consumption is mainly from oil (37 per cent), coal (25 per cent), gas (23 per cent), nuclear (six per cent), biomass (four per cent) and hydro (three per cent). Wind accounts for only 0.3 per cent and solar heat only 0.5 per cent of the total energy consumption.

With the development of new technologies, renewable energies based on sun and wind are likely to contribute increasingly to the world energy profiles. Pakistan must invest in such technologies instead of buying hugely expensive electricity from obsolete power plants that benefit a few vested interests.

Dawn.com