|SCIENCE & TECHNOLOGY|
cells may work miracles
ears? Busy brain
April 22 is Earth Day
cells may work miracles
Dr Steven Cutts discusses today’s hottest topic; one which has caused heated international debate about the ethical and moral ramifications of what is potentially the greatest advance yet made by medical science
When I was a kid in the early 80s I was blown away by the early home computer with its Random Access Memory of what seemed then a massive 3.5 kilobytes. Yet at around the same stage of my life I managed to grasp just how very much more genetic information can be stored in the human genome, which puts even the most advanced modern computer to shame. An entire genetic blueprint has been engraved by Nature into not just each human body but into every nucleated cell of the body. What’s more, the DNA replica is so exact that, in principle, it could be used to assemble a complete replica of your person; an identical twin - a clone in fact.
Stem-cell science is going to determine our ability to treat many of the chief diseases of the 21st century. Huge sums of money are being ploughed into this field of research and desperate sufferers everywhere are praying for a breakthrough. So what are stem cells and how can we use them to such advantage?
Everyone of us begins life as a single cell. That cell is a fertilised egg and it soon develops into an embryo containing many distinct tissues. Cells in each part of the embryo have the potential to develop into a further sub-group of tissues but they have already lost the power to form any tissue. Later on, individual cells acquire a unique identity. These cells have become specialised and they soon lose the capacity to divide and reproduce. They may be neurons in the spinal cord or the myocardial muscle cells that keep the heart beating. In short they usually represent organs crucial to life and if those tissues are damaged by disease or injury they are incapable of self-repair — which is part of the reason why people suffering wasting diseases in such cellular tissues as the brain are so difficult to treat.
Each of these specialised cells has shut down nearly all of its DNA and can access only that small part of the human blueprint required to do its job. Just as most of us never use most of the software packages in our computers, most adult cells of the body have no need of the fantastically complex instructions that tell an ovum how to make an entire human being. That vital part of the blueprint has been lost and in most adult cells we can never recover it.
To treat patients whose specialised cells are damaged we want the immature stem-cells of childhood to make a comeback in the adult body. We need those unspecialised cells to multiply and become specialised, replacing damaged tissue with brand-new healthy cells.
The practical implications of stem-cell treatment are nothing less than staggering. Take diabetes as an example. At present we merely palliate each diabetic with daily injections of insulin. If we could rebuild the missing insulin-producing cells in the pancreas, the disease might be banished. Since diabetics are prone to all kinds of other medical problems ranging from cataracts to vascular disease, they crowd our hospital clinics. If they were cured, the crippling costs of their care could be diverted to other vital medical fields of research and treatment.
So where can we find stem cells? There are two possible answers. One is based on the theory that some of the cells in the adult body might have retained stem-cel1 properties. Another idea is that we cultivate in the laboratory human embryos from which barely developed tissue is subtracted. That tissue injected into patients would form newly developed stem cells that migrate to diseased tissue and reconstruct damaged organs.
Granny was right
Ancient Indian wisdom that drinking water should be stored in brass vessels for good health has now been proved scientifically by researchers.
Microbiologists say that water stored in brass containers could help combat many water-borne diseases and should be used in developing countries rather than their cheaper alternatives, plastic containers, researchers said.
Water-borne diseases remain a serious threat in many poor regions of the world, with around two million children dying each year from diarrhoea. Efforts to provide safe drinking water have had difficulty reaching remote areas.
Even in places with basic water-purification systems, people often opt for riskier wells under trees because the water is cooler, Rob Reed, who led the brass study, was quoted by ‘Nature’ magazine as saying.
He has now found that bacteria are indeed less likely to thrive in brass water pots then in earthenware or plastic ones. "It’s one of the traditional ideas of water treatment and we were able to find a microbiological basis for it," he was quoted as saying.
Reed, with his colleagues Puja Tandon and Sanjay Chhiber, carried out two series of experiments, ‘Nature’ reported.
In Britain, the researchers filled brass and earthenware vessels with a diluted culture of Escherichia coli bacteria, which can cause illnesses such as dysentery. They then counted the surviving bacteria after six, 24 and 48 hours. A similar test was carried out in India using naturally contained water.
The amount of live E. coli in the brass vessels dropped dramatically over time, and after 48 hours they fell to undetectable levels, Reed told the Society for General Microbiology’s meeting last week in Edinburgh, UK.
The key to the result is copper, which can disrupt biological systems, Reed explains. The element acts by interfering with the membranes and enzymes of cells; for bacteria, this can mean death.
Pots made of brass, an alloy of copper and zinc, shed copper particles into the water they contain. The amounts that circulate into the brass water vessels could not harm humans, Reed added.
Even a person drinking 10 litres of such water in a single day would take in less than the daily recommended dose of copper or zinc, ‘Nature’ quoted researchers as saying.
Brass water pots also easily outperformed plastic ones, the researchers discovered. Plastic, Reed was quoted as saying, did not inactivate the bacteria. But many people in developing nations use plastic drinking vessels, because they view them as more modern. — PTI
Burning ears? Busy brain
If your ears are burning it’s said someone is talking about you, but Australian scientists say its more likely you’re having a brainwave.
Two researchers in Canberra have developed a high-tech hat that monitors brain activity via changes in ear temperature — offering a cheap way to assess risks for patients ahead of brain surgery.
By plugging the converted hard hat into a patient’s ears researchers can measure tiny changes in eardrum temperature caused by an increased flow of blood to the side of the brain used to concentrate on a task.
‘’If an area of the brain is more active it needs more blood, which flows up the carotid artery on either side of the neck,’’ said Nicolas Cherbuin, one of the psychology researchers involved in the project at the Australian National University.
‘’This blood is shared between the brain and the inner ear, so by measuring the ear temperature we can work out which side of the brain is more active,’’ Cherbuin said in a statement.
The researchers said the hat could be used to cheaply monitor brain activity to gauge risks before a patient underwent surgery.
The bright red prototype cost A $ 5000. It can be used many times in place of magnetic resonance imaging scans commonly used for brain testing, which cost A$1,000 a time.
The researchers said the hat, yet to be approved for general use, would also allow them to study the theory that some people are right-brained and others are left-brained.
The left side is often associated with linguistic skills, while the right side is said to control visual and spatial functions.
‘’Everything points to people often having one side that is more active than the other, but it may not be as clear-cut as simply saying someone is left-brained or right-brained,’’ said Cherbuin.
The researchers said the hat may also help pinpoint damaged brain functions in stroke victims to aid rehabilitation.
‘’This technique is non-invasive and therefore may be a useful adjunct to other ways of measuring the functioning of the brain in very broad terms,’’ said Skye McDonald, president of the Australian society for the study of brain impairment. — Reuters
April 22 is
4600 million years: (henceforth called my.) Earth, Moon and planets formed; Earth’s magnetic field formed in this period
3500 my ago: First permanent crust crustified
3500 my ago: Atmosphere ( with some carbon dioxide) & seawater formed
3300 my to 2500 my. ago: Oldest sedimentary rocks (layered rocks !) formed; photosynthesizing blue green algae flourished & around 2500 my. ago abundant free oxygen in atmosphere
2300 my: First large scale glaciation on earth
2000-1000 my ago: Rapid growth of continents by accretion of microcontinents & possible formation of a super – continent; southern continents combine into Gondwanaland
700-600 my ago: Major glaciation affecting every continent & around 600 my. ago first appearance of soft bodied, multicellular organisms
550 my: Worldwide emergence of marine animals with shells & skeletons; algal colonies declined. If factors on earth or outside led to biomineralization in life forms is a topic endlessly debated across the world; also volcanic episodes
480 my: First freshwater fish and plants
440 my: Giant sea scorpions ( upto 3 metres in size)
420 my: First land plants ( without this could not ever think of all the coal which came from dense forests which came later around 340 my. & dominated Gondwanaland!);
400 my ago: Age of fishes
250 my ago: Mass extinction of marine life
270 my: Supercontinent Pangea stretches from 60° N to the S pole & 250 my. ago this moved north to straddle Equator; many continents in warm arid climates; Asian microcontinents begin to move away from Australia & Gondwanaland
220 my ago: Dinosaurs developed from Thecodont reptiles; also earliest bird came
210-145 my: Dinosaurs dominant; birds spread & 180 my. ago Africa & South America begin to split from North America opening up the Central Atlantic; 150 my. ago Rocky Mountains began forming
145-65 my: Massive flood basalts erupted through gaping fissures in W,C India Dinosaurs dominated land; flowering plants emerged
120 my: India split from Africa & Antarctica & began moving north; Australia split from Gondwanaland which started breaking up
100 my: S America & Africa began to split
65 my: Mass extinction of marine & land life; dinosaurs (land) & ammonites (sea) disappeared
40 my: Rockies uplifted; 50 my grasses emerge on land & grazing animals & monkeys emerge; whales & dolphins return to sea & 35 my first Apes emerge; lush green grasses cover land
30 my: Japanese islands split from Asia opening up Japanese Sea
25 my: Northern North Atlantic opens between Greenland & northern Europe; Africa moves north to close the Tethys Sea & collide with Europe.
20 to 15 my: Alps formed
20 my: India begins to collide with Asia initiating beginning of the mightiest & youngest mountain chains Himalayas; 11-10 my great Apes & Hominid (human like!) separated
15 my: Basalt lavas outpoured in southern Siberia, Central Europe, E Africa & Antarctica
3 my: Antarctica isolated South America moves away; the last pieces of Gondwanaland break apart; climate cooled dramatically; first Hominids ( Australopithecus appeared)
2 my: Major glaciation
1 my: Homo erectus disperses from Africa as far as China & Java & 5 lakh years back man appears in Africa & migrates to Europe & 250,000 years ago modern humans emerged in southern Africa
After the peak of last glaciation 18,000 years ago, man reached every continent.
— Arun D. Ahluwalia
New Products and Discoveries
For the first time, scientists have found eggs with shells inside a dinosaur fossil, strengthening previous conjectures about the ancient reptiles’ reproductive physiology.
The dinosaur remains were unearthed in southern China from petrified sediments laid down between 100 million and 65 million years ago. The fragmentary fossil includes six back vertebrae, two adjacent tail vertebrae, and other bones from the dinosaur’s pelvic area, says Tamaki Sato of the Canadian Museum of Nature in Ottawa.
The remains were too scant to assign to a particular species but enough for Sato and her colleagues to identify the creature generally as an oviraptorosaur, a member of a group of dinosaurs that includes the feathered Caudipteryx and the vegetarian Incisivosaurus. The newfound specimen probably would have measured about three metres from head to tail.
Ultra-realistic surround sound is a step closer for everyone thanks to a new method that will cheaply and efficiently compute the way individuals hear things.
Currently, creating accurate "virtual sound fields" through headphones is almost exclusively the domain of high-budget military technologies and involves lengthy and awkward acoustic measurements. The new approach eliminates the acoustic measurement step altogether and promises to produce the required results in mere minutes.
The breakthrough has been made by researchers at the University of York’s Department of Electronics, funded by the EPSRC. The researchers are working in collaboration with colleagues at the University of Sydney, Australia.
The team are now working to commercialise the idea. Tony Tew, lead researcher at York explains: "We envisage booths in the high street, like those used for passport photos, where customers can have the shape of their head and ears measured easily. The shape information will be used to quickly compute an individual’s spatial filters".
Antarctica and women
Fancy something different? The British Antarctic Survey may have just the job.
The scientific research organisation has launched a recruitment drive to attract tradeswomen.
The organisation is looking for female electricians, plumbers, carpenters, steel erectors, chefs and boat handlers to work for 6-18 months at its five research stations on and around the Antarctic.
"Where else can you work in an environment surrounded by penguins, seals and icebergs and climb down a crevasse during your lunch hour?" said Jill Thomson, head of building services at the BAS.
The starting salary is $18,338 pounds ($34,640) plus an Antarctic allowance. All food, accommodation and travel are paid for.
More women are going into the trades and the BAS said it wants to tap into that market. — Reuters
Rice with a human touch
A human gene that Japanese researchers have inserted into rice enables the plant to break down a portfolio of chemicals now used on farms to kill weeds. The unusual breadth of that herbicide resistance could circumvent a major shortcoming of existing genetically engineered crops and also open new avenues for cleaning up contaminated soils.
Some scientists, however, are concerned that weeds growing with the rice could eventually acquire the human gene and become herbicide-resistant superweeds.
The herbicide resistance of many crops, including much of U.S. soy and cotton, results from genetic elements that scientists have transferred from other species. These engineered plants can tolerate powerful weed-control chemicals. To date, most plants tweaked this way are resistant to only one type of chemical, so farmers must use both the herbicide-resistant crop and the matching herbicide to keep weeds at bay without killing the plants they want to harvest.
Q If sharing of needles used for injections can transmit AIDS virus, why not mosquito bites?
A This is an intriguing question. I have searched the web for answers that would be truly convincing. I must confess that I am not fully satisfied that mosquito bites will never, never be able to transmit AIDS. The probability might be very small but may not be zero. The arguments against the possibility of infection through insect bite are strong, but they go something like this:
AIDS virus needs blood, or other body fluids to grow. It cannot survive for long without growing. Mosquitoes do not provide such an environment. The saliva of mosquitoes that is injected into a person during preceding a bite is meant to stop the blood for coagulating. No blood is injected. The saliva in the mosquito "needle" does allow the malaria virus to live but not the AIDS virus. It is also argued that mosquitoes rest a while after sucking the blood of a victim. During this time interval any AIDS virus particles sucked in from the victim die off - at least reduced in number. Because of all these reasons the chance of infecting their next victim is very small.
This argument seems convincing, but not completely. We find that squashing a mosquito while it is engaged in its business often produces a red smear made by blood. I do not know whether we can say with absolutely certainty that this is some of our blood or some that was acquired by the mosquito in an earlier blood-sucking mission.
A doubt remains, therefore, that our vulnerability may not be zero. It would be good to know of some other arguments
Q Gravitational pull of the moon is 1/6th that of the earth. Then how is the moon able to cause tides, i.e. how can it pull up the water of oceans towards itself?
A First let me clarify the meaning behind the information in the first sentence of your query. I think this statement should be properly understood as saying that the weight of an object on the surface of the moon would be 1/6th of its weight on the surface of the earth.
We have to remember that the gravitational force between two objects varies inversely as the square of the distance between them.
As a result the force on the moonward side of the earth (including its oceans) is greater than that on the opposite side. It is this difference that causes tides. Sometimes we call the difference between the force on near and far sides as the Tidal Force.
For the earth moon system the magnitude of this force is enough to cause observable tides. The moon and the earth are tied together because of their mutual gravitational attraction.
The diameter of the earth is about 1/30th the distance between the earth and the moon.
It implies that the force on the moonward side of the earth would be greater than that on the opposite side by an amount that is about 1/1000th of the force that keeps the earth and the moon together.
It might appear insignificant but it is enough to produce the lunar tidal phenomenon. Long time ago the moon was much closer to the earth and tidal force much greater.