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Column: The Wondrous World of Science

April 17, 2011

Plastic—from bananas, pineapples and coconuts

Most plastics are normally made through polymerisation reactions of certain chemicals that come from petroleum or natural gas. A group of researchers at Sao Paulo University in Brazil have now found that they can manufacture excellent plastic materials starting from pineapple leaves and stems, banana plants and coconut fibres. A special type of material, nano-cellulose, is prepared from these sources a pound of which can be used to prepare a hundred pounds of reinforced plastic. The resulting material is expected to be used in manufacture of plastics used in the automobile industry.

Driving a car while sitting on a car seat made of bananas and pineapples? Why not as after all this is the wondrous world of science.

Artificial arm—thought controlled

Thought controlled devices are becoming increasingly common. Today it is possible for paralysed persons to move wheel chairs or drive cars purely by thought control. Now two undergraduate biomedical engineering students, Thiago Caires and Michal Prywata, at Ryerson University in Toronto have developed an artificial arm that can be controlled by thought control. Powered by compressed air, the device is easy to construct and avoids the need of invasive surgery that is necessary to fit persons with amputated arms with artificial ones. The person using the arm sends signals to it through a skull cap. The cap has sensors which sense the changes in blood flow in the brain that occur when the thought command is issued. These signals are transmitted to a microprocessor in the arm which already has stored patterns for signals such as ‘up’, ‘down’, ‘left’, ‘right’, etc. The microprocessor compares the signals coming from the brain with those previously stored in it for various movements and acts accordingly.

The germs are winning

The micro organisms that are responsible for disease have built in mechanisms to survive by undergoing genetic changes (mutations) and by other means. This has allowed antibiotic resistant strains to survive and develop. There is, therefore, a constant race between scientists working to develop more powerful antibiotics to replace the ones which have lost their efficacy, and micro organisms which are evolving and developing resistance against existing antibiotics. Indeed infections by resistant strains of microorganisms represent a major threat in most hospital wards, and many deaths occur during hospital treatment.

The problem has been severely aggravated by the huge costs associated with new drug development. These can exceed a billion US dollars, and the investment is often a complete loss since Food and Drug Administration (FDA) often rejects those drugs which show side effects before they can be commercialised. Most pharmaceutical companies have, therefore, abandoned their research programmes directed to develop new antibiotics against resistant strains, as it is no longer economically feasible. As a result we are now losing the race against disease causing germs, and there is a growing risk of multiplication of disease resistant strains. This could lead to millions of deaths because of non-availability of effective antibiotics.

An exciting initiative to look at plant derived natural extracts for their antibiotic activity against resistant strains has been undertaken at the premier research institute of Pakistan—International Centre of Chemical and Biological Sciences (ICCBS) at Karachi University. Both H.E.J. Research Institute of Chemistry and Dr Panjwani Centre of Molecular Medicine and Drug Research, are two prestigious institutions that are integral parts of ICCBS. Over a dozen promising compounds have been discovered as a result of these efforts.

We may therefore go back to what nature has provided: the survival of mankind on this planet may lie in the biodiversity, and associated chemical diversity, that nature has blessed us with in the form of the plant kingdom.

A sonar device: for strokes

Sound propagation through water (sonar) is a standard technique used by submarines to detect and avoid other vessels. Passive sonar involves listening to the sounds made by other vessels. Active sonar involves emitting pulses of sounds and listening to the echoes that bounce back after colliding with objects.

Now sonar has been adapted to detect strokes in human brains. A device is worn on the head, and the pressure waves that are generated by the blood passing through blood vessels are detected by highly sensitive sensors on the device. Any abnormalities in such blood flow caused by clots in blood vessels or rupture of blood vessels can be readily detected by analysis of the resulting patterns. Strokes represent a major cause of death the world over, and early diagnosis of the problem is critical for recovery. The sonar device promises to add another tool in the hands of the physician to detect the nature of the stroke and the medication required to address the problem.