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Hope for spinal injury
victims Effects of atomic radiation Concrete pumps can enforce quality
Colourful bacteria Trends Prof Yash
Pal THIS UNIVERSE |
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Hope for spinal injury
victims
A brain implant has allowed paralysed monkeys to move their limbs, by tapping into their thoughts and redirecting the signals to their muscles, scientists have announced. The feat is being seen as a major development in the hunt for treatments for people who have lost the use of their limbs due to spinal cord injuries or strokes. The work is the first to show that signals from single brain cells can be rerouted around damaged areas of the central nervous system, and restore function to paralysed limbs. Previously, scientists have shown that monkeys fitted with brain implants can move robotic arms or cursors on a screen. Scientists involved in the experiments sought to damp down hopes of the technique being ready to help disabled people in the near future, but others said they expected to see the first human trials within five years. More advanced versions of the implant could give people with paralysed legs the ability to walk again, and eventually give paraplegics control over all of their limbs, including very precise movements of the hands and arms. In the study, which appears in the journal Nature, scientists at the University of Washington in Seattle implanted ultra- thin electrodes into the brains of macaques which had been trained to play a game that involved rotating their wrists to the left and right. While the monkeys played, the electrodes picked up electrical signals in their brains that made them tense different muscles. The scientists then injected the monkeys with a chemical that temporarily paralysed their arms. This time, signals from nerves in their brains were fed into a computer, cleaned up and magnified, and sent down a wire to muscles in the monkeys' wrists. When the monkeys tried to play the game again, they were unable to at first, but soon learned to control their wrist movements using the brain implant. Astonishingly, even when the implant was connected to nerves that were not involved in wrist control, the monkeys could learn how to change their brain activity to control their actions. “The monkey was experimenting with different types of movement and different types of cognitive activity to drive those neurons and when he found something worked, he quickly repeated it and adopted the strategy,” said Eberhard Fetz, who led the study. Future work will focus on miniaturising the technology and developing wireless networks to send the brain's signals around damaged parts of the spine to limbs that have lost their connections to the brain. By arrangement with The Guardian |
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Effects of atomic radiation The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in its much awaited latest review published on August 5, 2008, concluded that radiation is not riskier than what was stated in earlier reports. Regulatory agencies can breathe easy as they need not alter the dose limits they prescribed to radiation workers and public The report (Volume I) consists of the main text and two of the five annexes: “Epidemiological studies of radiation and cancer” and “Epidemiological evaluation of cardiovascular disease and other non-cancer diseases following radiation exposure”. UNSCEAR may publish the remaining annexes before the end of 2008. UNSCEAR’s assessment of the risk of radiation depended heavily on the study of A-bomb survivors. The new analysis using the radiation doses recently re-estimated by the Radiation Effects Research Foundation, showed that the cancer risk factors may be lower. The committee considered cancer incidence and mortality due to cancers in 20 organs and tissues among A-bomb survivors; these were eight more than those in the earlier study. Nearly half of the survivors are still alive. Those exposed in childhood are now reaching the age at which larger numbers of cancers would be expected to arise spontaneously. There is compelling need to continue the study of A-bomb survivors for their entire life span. The UNSCEAR observed that the cancer risks obtained in new findings from the study of nuclear workers in 15 countries, studies of persons living near Techa river in the Russian Federation who were exposed due to radioactive discharges from Mayak plant and a study of persons exposed to fallout from the nuclear test site in Kazakhstan are generally more than those obtained from the study of A-bomb survivors. However, there are concerns about bias in these studies. The committee found significant associations between radiation exposure and cardiovascular diseases and other non-cancer diseases. Such associations can occur at doses below those hitherto considered as thresholds for other effects. Specialists consider that the harmful effects of irradiation originate in the irradiated cells. But there is evidence that non-irradiated cells may show effects such as “genomic instability” (cells surviving irradiation may produce daughter cells that over generations show changes though daughter cells themselves were not irradiated), “bystander effects” (the ability of exposed cells to convey damage to neighbouring cells not directly irradiated) and other effects. The committee concluded that the available data provide some disease associations but not for causation. It recommended future research designing studies that emphasize reproducibility, low dose responses and causal associations with health effects. High doses of radiation may suppress immunity mainly due to cell destruction. Low dose irradiation may suppress the immune system or stimulate it. The immune system may remove aberrant cells which have potential to form tumours. A-bomb survivors show perturbations to stable immune systems. In the final document, the Committee proposed methods to estimate risk from radon, a well established carcinogen, present in dwellings. To determine radiation risk at typical doses to workers, we need low dose studies. But most low dose studies have inadequate statistical power. The UNSCEAR completed the report in 2005. The Committee acknowledged that resource crunch was the cause for the delay in publishing the report which is now called UNSCEAR 2006. According to a UN specialist, financial restrictions and-sometimes benign neglect- has slowed down the Committee’s work. UNSCEAR reports provide the scientific basis to arrive at dose limits (safe levels of radiation to radiation workers and members of the public). Set up in 1956, the UNSCEAR published 17 documents. The first two reports UNSCEAR 1958 and 1962 paved the way for prohibition of atmospheric weapon testing in 1963. India has been a member of the UNSCEAR from its very inception. Traditionally, the Chairman of UNSCEAR is from a non-nuclear weapons’ state. V.R. Khanolkar, a pioneer in pathology from India was Vice-Chairman in years 1958-1959; A.Gopal Ayengar a geneticist and the first research scientist Homi Bhabha recruited into the Department of Atomic Energy was Vice-Chairman in 1964-1965 and Chairman in 1966-1967. Let us hope that UNSCEAR will continue to function effectively in spite of various limitations. The writer is former Secretary, Atomic Energy Regulatory Board |
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Concrete pumps can enforce quality Correct placement of concrete is no less important than proper production and transportation of concrete. All the quality control measures taken during production of concrete tend to go waste if its fast and systematic placement is not done. There is no use of using Ready Mixed Concrete (RMC) unless concrete placement is fast, without segregation and without cold joints. The way switching over to RMC is a good step to produce concrete under fully controlled conditions and to transport it in truck mounted mixers, using Concrete pumps for placement of concrete in large and high rise structures is an equally good step. Tall RCC chimneys, large sized cooling towers, multi-storeyed buildings, long bridges, industrial parks and IT parks can enjoy best concrete placement by using concrete pumps instead of deploying manual labour or using conventional trolleys. Placing concrete in position in proper layers to allow their compaction without causing cold joints is essential for having a strong and durable structure. To achieve this, our placement arrangements must pour concrete at the required rate and nearest to the pouring point. In general, concrete is transported to the deck or pouring level by use of a tower crane or winch driven buckets or through manual labor. Many times, some vital factors get overlooked during this procedure. Ideal arrangement is to have an equipment that pours concrete directly at the pouring point. Concrete pumps convert this desire into reality. Concrete pumps receive the concrete in their hoppers equipped with agitators and then transfer it to amazingly long vertical and horizontal heights, direct at the concrete pouring point. The transfer takes place through the placer booms having hose pipe ends. How easier the construction work could be made by these pumps can be judged from the fact that pouring of concrete directly to the top level of Taipei 101, the world's highest building was made by concrete pumps. Deck slab of Taipei 101 is plus 442 metres i.e. 6 times the height of Qutab Minar. Concrete pumps can be either Trailer mounted or Truck mounted. These can be stationary or portable. These can be operated by use of electricity or oil. Some of the pump components can be listed as below: 1. Main frame. 2. Hydraulic pump. 3. Diesel/Electric motor. 4. Concrete pump kit. 5. Control block. 6. Hydraulic tank 7. Hopper and agitator. 8. Placer boom. 9. Remote control (optional) A good concrete pump must have a higher concrete pouring output, should be able to bear maximum concrete pressure, should automatically ensure lower power consumption, should have a flawless valve system and should be dirt resistant. Selection of right pump to suit site requirements should be doubly ensured. A wrong selection may erase all the advantages of concrete pumps. It is a long boom that carries concrete to the desired location. It is of 4 inch to 8 inch diameter. Most preferred diameter is 5 inch for aggregate size up to 40 mm. Z fold booms carry exceptional maneuverability and reach the most difficult areas. The pumps being produced today can reach up to 2 km in horizontal direction and ½ km in vertical direction. Concrete pumping rate required at site, the horizontal and vertical distances of the point of placement and concrete slump required at the point of placement are the deciding factors in choosing a pump. Depending upon these three factors, the diameter of the placer boom is worked out. Once the diameter is decided, the line pressure can be worked out. This pressure must be less than 85% of the maximum concrete pressure that the pump can take as per manufacturer's data. The pumps being produced today can place concrete quantity of even 150 cum per hour. The smallest pump can place concrete @ 15 cum per hour. The output however depends on the distance of pouring point from the pump, size or diameter of placer boom and the pump pressure. More is the number of bends in the pipeline, lesser is the output. Therefore, the number of bends in pipeline should be kept as minimum possible and pipe line should be supported well. It is preferable to use RMC or a batching plant when concrete pump is used. RMC has a controlled slump, delivery is fast and quality of concrete is uniform. Manual Production of concrete should be avoided. An indirect benefit of using concrete pumps becomes evident here that we automatically switch over to fully controlled concrete and best quality of work is ensured. If the concrete mix is not proper, the pump will refuse to accept it. Concrete pumps that can pump concrete at very high pressure are becoming available in India. Recently, a concrete pump laid 1750 cum of concrete in 2 days for a 11 storey building foundation in Chennai at a pumping rate of 50 cum per hour. India is fast switching over to RMC. Need of the hour is to ensure total quality management by adopting frequent use of concrete pumps as well. |
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Colourful bacteria
A new technique using bacteria that lights up so it is easy to spot could help better detect pollution from oil spills and other environmental leakage, researchers in Switzerland said on Thursday. The color-coded bacteria are cheap and can alert scientists to low level leaks from underground pipes, storage pipes and other substances that spill into the soil or sea, said Jan Van der Meer of the University of Lausanne in Switzerland. “The heart of our color sensor system is the bacteria themselves,” he said in a statement. “They reproduce themselves ... which makes the whole set up really cheap.” Van der Meer, who presented his research at a meeting of the Society of General Microbiology in Dublin, Ireland, said scientists have successfully tested the bacteria to measure a variety The main problem with detecting oil spills and other toxic substances is that many of the most dangerous chemicals do not dissolve in water, which makes them difficult to detect, he said. Instead, these pollutants tend to stick to rock, seabirds and shellfish where they can remain for many years. Unlike current methods, the new technique does not require chemicals to determine the source of leaks and is friendlier for the environment, he said. –
Reuters |
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Trends San Antonio city plans to turn the stench of its residents’ waste into sweet green cash and renewable energy. The San Antonio Water System will sell captured methane gas generated from the utility’s treatment of 140,000 tons of biosolids, or sewage, from customers each year. The city-owned utility’s board of trustees approved a contract Tuesday to provide at least 900,000 cubic feet of natural gas daily for the next 20 years to Ameresco Inc., a Framingham, Mass.-based energy services company. “Treating these biosolids generates an average of 1.5 million cubic feet of gas a day,” said Steve Clouse, the water system’s chief operating officer. “That’s enough gas to fill seven commercial blimps or 1,250 tanker trucks each day.” The utility already sells for reuse a portion of the water that’s cleaned at its wastewater treatment plants. It also converts some biosolids into compost that’s sold for use in yards and gardens. “As far as we know, SAWS is the only city in the United States that has completed the renewable recyclable
trifecta,” Clouse said. — AP Treasure found
Archaeologists have unearthed gold jewellery, weapons and pottery at an ancient burial site near Pella in northern Greece, the birthplace of Alexander the Great, the culture ministry said on Thursday. The excavations at the vast cemetery uncovered 43 graves dating from 650-279 BC which shed light on the early development of the Macedonian kingdom, which had an empire that stretched as far as India under Alexander’s conquests. Among the most interesting discoveries were the graves of 20 warriors dating to the late Archaic period, between 580 and 460 BC, the ministry said in a statement. Some were buried in bronze helmets alongside iron swords and knives. Their eyes, mouths and chests were covered in gold foil richly decorated with drawings of lions and other animals symbolizing royal power.
— Reuters New uses for molybdenum
Scientists from around the world have joined forces in what they call a “Molybdenum Offensive,” to work out strategies by the end of this year that will boost demand for the resilient metal. The Center for Advanced Interdisciplinary Research in Materials (CIMAT), based in Santiago, launched a challenge in March to global scientists to come up with proposals to boost the tonnage demanded by manufacturers in the shortest possible time. About 300 researchers in 32 countries responded with 96 preliminary proposals. From 10 to 20 percent of these will be short-listed in coming weeks, and winners of annual grants of $100,000 to develop ideas will be announced in December, CIMAT director Fernando Lund said.
— Reuters
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THIS UNIVERSE Energy can never be created nor can it be destroyed. Communication among human beings is through sound waves. Sound is also a type of energy. It means spoken words never really die. It means words can be retrieved, which implies we can listen to words, uttered few hours, few days before. Indeed we could hear the words spoken by great leaders, saints and revolutionaries of past. I think a suitable method/equipment has to be devised to recover such. What you have said is only partly true. Sound is a form of energy, as you say. As it propagates it loses amplitude. It may not be destroyed but it spreads out thin, so thin that we cannot hear it. You might be shouting from your house to get my attention, but it does not reach my ear sitting in Delhi. Furthermore, space attenuation is not the only diminution. You have to remember that sound is a mechanical vibration. When it meets an obstruction it tries to vibrate that obstruction and ultimately degrades into heat. This happening does not violate the law of conservation of energy — energy is just changed into another form. The change in the energy state of an object obstructing the sound is also impacted by other causes, other sounds and noise and random heating, say by sunlight or the beam of light from a car headlight, or even a bang produced by a child throwing stones. I think it would be very difficult to decode any detectable changes in obstructions into sound signals coming from different distances, physical and temporal. No it does not seem possible to recover the sounds of past great men, heroes or saints, floating around in the atmosphere. It would be much better to record such sounds on now available excellent recorders. Who knows some of those now around would also be remembered as saints and great men and women from the past! Hydrogen is highly inflammable and oxygen is supporter in combustion. Why does the combination of these two i.e. water not catch fire? The reason is simple. You will understand it immediately if you realise that water is nothing but the ashes that are produced when hydrogen catches fire. How can ashes burn again? Another way of looking at the problem is to realise that when hydrogen and oxygen are in a tight embrace we call it water. If you spend energy to separate the two gases, a fire would result if and when they get together again. Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com |
Using the implant, doctors hope severely disabled people will in future be able to use mind control to regain movement in their arms and legs.